kdrolt

Or maybe fun enough with just the engine and A727 swap.

In the spirit of this threads title "WTF we like these heads now" and with your comment in mind, I'd be remiss if I didn't mention that Mopar made some of the 318 heads with heart-shaped combustion chambers and swirl port intake ramps (gasp!) as early as 1985. HRM ported them for a 318 "junkyard jewel" builup that made over 400 fwhp:

http://www.hotrod.com/howto/113_0304_junk/index1.html

FWIW a 318 that made over 400 fwhp and 408 fw ftlbs using a Comp 268 cam (.480" lift; 224/230 deg duration i/e) stamped factory rockers and the usual exh mods. The heads flowed 215 cfm @ 0.500" lift (intake), up from 135 cfm stock (nearly the same flow #s by HRM on the LB4 4.3 v6 build). That intake flow is on-par with an aluminum LT1 head but not quite as good as the iron LT1/L31. The exh numbers were not posted... but they couldn't have been that bad given the dyno results.

Scaling the Mopar 318's 400 hp result back to sameMods + unportedHeads, using 400*(135/215), and scaling from 318 to 305 cid (305/318), you get 241 fwhp.... which is on-par with Dewey316's 305 when he used a milder cam (208 rwhp).

Scaling the fwhp from the junkyard jewel 318 up to a 350:

400*(350/318) = 440 fwhp

which probably overestimates power but is pretty good given that the Comp 268 isn't far from the GM LT4 HOT cam, and 440 fwhp isn't far from the 420+ fwhp that can be obtained from a GM 350 with L31 heads and the HOT cam.

The stock Mopar SP heads are also not very good bone stock, but they're quite good for DIY porting as proven by the flow and dyno tests. And HRM's results for the Mopar 318 are on-par with the GM ones discussed here on TGO.

Dewey316

I was planning to. I don't know how my engine turned into this big discusion. But, I have talked with many people much smarter than myself, who all thought that same thing I did. We all know how much trial and error is involved in some of this, I'll dyno her with the new heads, if I go backwards, then I go backwards, and I work on a new plan, relook at all the old data, etc. If I pick up some HP, great.

This is the fun part for me, I have learned SO much from working with the combo, and learning to read the data, the datalogs, and finding out where the parts and tune are lacking. This engine for me, is an experment, and a learning experiance. I have a SJ 327 in the garage, that will one day go in, and it will be the fun, high HP engine. Right now, I'm doing what I can to this engine (as cheap as I can). And using the whole thing to learn, and hone my tuning skills. So far it is doing just that.

83 Crossfire TA

iTrader: (2)

heh, yea, I’m betting that you’re talking about the early 90’s (and some late 80’s) 5.2 heads. They have vortec like chambers and swirlport like ports. It’s a pretty slick head… open them up some and then put them on something that has a decent quench distance (what is with mopar having quench distances of like ¼”???) and you have a pretty trick setup. Add to the fact that you have 15* valve angles and built right now you have a combination that has some serious detonation control you can run some fairly high compression and maximize efficiency for whatever flow you get out of the head (or run moderate compression and some big boost )

Tim, those L05 swirl ports are larger and flow better then the L03 ones. I want to snag a set of L03 ones to experiment with on my truck (an L05). I’m hoping to mess with the chambers and see if I can get decent detonation control out of them at a high enough compression that I could get some reasonable gas mileage out of them. I’m also thinking about swapping the crossfire setup off of my TA onto it at the same time. I could care less what that engine does at higher RPM’s, the truck has no gear, 3.42’s, 33” tall tires, a tight converter and is usually over 6000lbs (there’s always something in it). It never sees over 2500rpm unless I’m really doing something dumb and is all done by 4000rpm, maybe a little higher, but it does some fun burnouts and it’s all about low end.

83 Crossfire TA

iTrader: (2)

People don’t like being told that they’re wrong, or when you imply it by saying something like “I understand what you’re saying but I’m going to do just the opposite because I believe that I have evidence that is my problem, not what your saying" (ie “you’re wrong…”)

You’ll make more power if you can get the tune right. The issue here is that all of this is dancing around is in the interest of detonation control. The fact is that is the big deal in this range, with things optimized for low and midrange where cylinder pressures rise quickly and are hard to control. This is all a lot easier if you don’t fight that uphill battle and stick the bigger cam in there where the overlap will relieve some of that cylinder pressure and everything will be happy with much less tuning. Of course, that gives you more power but at the expense of streetability.

If I was going to modify your experiment some I’d love to see results with ported L03 heads instead because I believe that the swirl ports will control detonation better and allow for a more aggressive tune in the end.

On the other hand, there is something magical with the 416’s on a 305 TBI car. I have a set in my garage off of my crossfire TA which ran 13.8’s, got insane gas mileage with a factory compression ratio of 9.8:1 and did this all on 87 octane if I wanted it to (it did get better mileage on premium, I suspect because it allowed more timing at light throttle cruise).

I’ve always explained it as an efficient setup + a small bore, but if you did your experiment with ported swirl ports that would give me more data about what is really happening.

If I don’t find some 305 swirl ports for my L05 experiment I will try the 416’s and approach it from a different angle.

See, to me that’s part of it, and then the second part of it is being able to predict what happens with some math, that’s why I was so excited that someone posted flow numbers that fit right in with what I was guessing they were based on your numbers.

Fast355

iTrader: (2)

The ports on the LB4, LO3, L05 are all right at the same 185 CC. The valves are 1.84 & 1.50 on the L03 and 1.94 & 1.50 on the LB4 and L05. The chambers on the L03 are 58 cc and 64 on the LB4 & L05. The TBI heads are pretty detonation resistant and offer a Fast Burn requiring less than 30* timing advance for Max power/efficiency at WOT and no more than 42* at part throttle. My G20 ran in the high 20's going down the highway per the datalog (swapped Output SA into the IAC output) If your block supports a roller cam, the F-Body LT1 roller cam makes a geat, torquey truck cam with decent HP. Leaving the heads stock, I would expect a 20-30 HP increase with a torque increase in the 30-40 ft/lbs region. I would get rid of the pellet style catalytic converter immediately and upgrade to the high flow monolith style along with a good low-restriction muffler of your choice (sound?). I have a feeling due to the port size the crossfire intake would be a mistake even on a truck. I would go with a Holley Projection intake(they make one for the newer intake bolt angles) and a 454 TBI assembly with ATLEAST 68 lb/hr injectors in it. Some computer tuning and you would not believe how that truck would wake up.

Dewey316

Depending on what happens with this combo, you may just see that.

Yeah, I wanted to go with a bit more caom, and I still may, later next year. Truth is, I'm sticking with this cam, because I really can't justify another $300 for a HR cam of some sort, right around the holiday's.

Tuning will be interesting. I can likely give you a ball park predication on HP increases, based on the VE changes I make while tuning it. I was almost shocked by how much fuel i had to add when I put in the cam and intake. I guess the numbers showed that it really did need that much more fuel, as it did pick up a fairly significant about of HP.

Fast355

iTrader: (2)

When you go to the 416s your BSFC will more than likely increase, meaning you will need more fuel to make the same HP. Make sure that upgrading your injectors is on the list. 68 lb/hr 9c1 injectors would be awesome if you can get ahold of them. They can deliver enough fuel for around 260 FWHP at 15 psi fuel pressure.

Your old 305 injectors, even if run at 20 PSI only have enough fuel delivery to make 240 FWHP. I am going to guess you are somewhere under 20 PSI.

va454ss

iTrader: (1)

I'd be interested to see that, along with the engine specs.

JPrevost

From the first page of that link on HRM;
"First, we need to establish clarity here; 318s can run. Though the bore is a little under the "magic" 4.00-inch spec, the bore-to-stroke ratio is actually slightly better than a 350 Chevy's, and there's no refuting that this is the true measure of breathing potential per unit of displacement. With the stock 6.123-inch rods, the 'teen offers a rod ratio the competition would die for (1.85:1). Like all Mopar small-blocks, the valves are inclined at an advantageous 18-degree angle, the realm of older Chevy NASCAR race heads."
Seems like comparing a Mopar to a standard sbc with very simple math seems... ahhh... dumb. Now to lead into why your math of scaling is asinine.
Look at the differences above between the engines. Notice that the exhaust numbers were not posted by that they are on an 18 degree angle as apposed to the sbc 23. Right there you could assume that they have a better potential (word of the day). Then they speak of how much they opened up the exhaust ports... hmm I wonder if that was a major player in making the 400hp mark?
Now for the real kicker, and I can't believe you did this.
Your logic is saying that you believe displacement to be free hp. It isn't, so why generalize it as such? While all along you're comparing some very different heads and engines to each other. BTW, not grasping at anything, not even straws.

So if I'm making 330hp with my vortecs at 5400rpm then from your logic I should make 377hp by increasing my displacement to 400. I can't agree less. See above where I put in bold the real difference between displacement engines. There is more potential but with the same heads they won't make a multiple of the horsepower. They will shift the horsepower down in RPM. If you unshroud the valves with the lager bore, that changes EVERYTHING. All of a sudden the rotating assembly is heavier (not always), more pumping losses at all RPM (always) AND, get this, the heads would flow DIFFERENT NUMBERS (usually more). You're looking at very limited info and trying to come to some conclusions when you should just accept the fact that you can't.
If you wanted to do basic math then do more of it to get a better idea. Example; a scalor for the head flow, scalor for the displacement, scalor for the in/ex ratio, scalor for the cam, scalor for the rod length ratio, scalor for the size of the headers/intake vs RPM vs displacement... even after all of that it's a pathetic guess. You're just coming up with numbers that are close to make your simple math look effective. User your logic from this thread and "the other" one about v6 vs v8, I've come up with this; 4.3v6 LB4 vs 5.0v8 L03 = 1.163 scalor. So with swirl port heads, the similar dinky peanut cam, similar intakes, and only dropping the displacement/cyl and adding 2 whole cylinders I get 186hp when GM rated them at 170hp. So I guess they're similar . The actual difference is only 10hp but with your logic it's 26hp. That's a rather large difference when comparing relatively low hp engines... now let's add a ton more variables and see how accurate your math is.
I truely believe that in this day and age people shouldn't be wasting their time and money into lo-po heads. With the same money spent that you would spend on porting and machining these crap heads you could get some newer heads and be that much faster. Right now, as it has been for over 5 years now, the vortecs ARE the best bang for the buck build up to 450hp EVEN if you already have swirl port heads. Why? Because swirl port heads can be had for free making them worthless in all sense of the word. With that being said, I'm NOT trying to take away from the people that have kept these heads. If you are getting that feeling then it's in your mind, not mine. It's commendable that some people have gotten great results from the heads. Through much of my skepticism it's been proven to everybody that with diligent work and a good deal of thought you can extract some respectable power out of these heads. My personal belief is that being "different" only goes so far. It's like TBI. I've got it and it'll be proven to be fast when my car is back together. It won't hold me back like those that have been "different" with small bore 305's, or "different" with keeping the stock long tube TPI's, or "different" with keeping swirl port heads . Take a look at the differences between TBI and you'll understand that there is no conclusive evidence stating that the design of introducing fuel above the throttle blades has any effect on total horsepower output... yet there is plenty of evidence showing the other "different" people have been fighting an uphill battle.
I've yet to see a swirl port headed engine make 450hp n/a nore do I think I ever will. If I do, I bet the true cost would show it as being the least favorable path to that number.

Kdrolt- I'm glad you stated your logic was overestimating the power. It removes some of the harshness to my reply.

kdrolt

I don't consider it dumb to compare a 318 with swirl port heads that made 400 fwhp to a sbc engine, like Fast355s or Dyno Don's or even to Dewey's. I also don't consider it dumb to compare it to a 330 hp Vortec 350 like yours. I find it interesting, and I want to know how/why such poor heads could make so much power.

As for the asinine math, I'll let the readers decide that for themselves.

Both 90-deg OHV 4-stroke internal combustion gasoline-fired v8s with hydraulic (or HR) lifters and pushrod-driven stamped rockers. Similar displacements (5.0, 5.2 for the 318, 5.7), different manufacturers, both street-engines for production cars of the 1980-90s.



Yes, but the "LA" engine (the Mopar 318) breathes more poorly than the stock swirl port 305 head, so the valve inclination angle is irrelevant -- and besides, they're SWIRL PORT heads.... so the valve angle doesn't matter in this discussion. It's not significant.



With swirl port heads on a 318? The exhaust is only useful if the intake allows the flow. So concentrating on exh differences is a distraction. That's why I didn't complain a lot about the lack of flow data on the exhaust, because the overall engine output shows that there is enough total airflow. That 318 makes more power than your Vortec 350 even with swirl port heads. That makes it a very interesting comparison despite the different manufacturers and the different displacements.



Both have swirl port heads Jon (TBI v8 vs Mopar LA 318).
Both are v8s.
Both are undervalved (2 per cylinder).
The rod ratio suggests magic gains but that's only helpful in very high output engines, as proven by a careful back-to-back dyno test in HRM recently.
If one engine were magically better than the other, then one would have been Darwined-out, like flatheads were when OHV was introduced.

They are similar in layout, configuration, cost and displacement. That's why they can be compared. You already should have known that instead of going into another rant.



With the same cam, yes it would be very close to 377 hp because your heads (L31) would allow the 400 to breathe enough to get the cylinder filling needed. The VE wouldn't drop so much, so yes Jon you would get very close to 377. If you swapped in a larger cam, and then jumped from 350 to 400, the gain would be less linear because at some point the small-runner-volume L31 heads will limit the airflow.



I know.



Your statement is only true if you were at the cusp of being headflow-limited. If the engine is airflow flow limited, then the rpm for peak power will drop and the output will maintain itself close to 330 fwhp. If the engine (head) is not airflow limited, then the output will increase and approximately in a linear way. Put another way, if the engine isn't airflow limited, then you could use a hotter cam and make more power. If the engine is airflow limited, a larger cam won't help.

In the case of Dewey, or Lo-tec, if the stock SP heads were that bad (truly airflow limited) then a cam swap would not have helped them, the engine output would not have improved and the timeslip (trap) would have stayed constant. In both cases, the cam swap helped. And they both altered the exhaust so that should have isolated the heads as the weak link -- and yet each went faster than stock. So the head flow was adequate enough to obtain a gain in performance. The heads might still be the weak link but not from looking at the gains made after cam/exh swap.

It's easy enough to confirm this, and to do it scientifically (something you always strike for). Run a DD2000 (or newer) model using an engine with a seriously limited stock head, like say a 350 v8 TBI with 180 fwhp and the peanut cam using stock swirl port heads. Increase the displacement to 400 cid. Or retain the 350 size and change the cam to something hotter. Or run your Vortec in the example, and jump to 400 cid. I have enough confidence that DD2000 attempts to model physics properly and certainly better than any hand waving in a TGO thread.

Maybe we should get an independent person (not you or me) to run these, so there is no possibility of reporting biased results, thus avoiding deliberate confusion of the facts by either of us. Sounds fair right?



First of all, the word is "scalar". It's usually used in a context opposite of a vector. A scalar has magnitude, a vector has both magnitude and direction.

Using the ratios you suggest would be difficult to do by themselves because none of them (except displacement) is directly-related to engine output. A way to include them, and to do it without expensive engine building and dyno testing, is to perform the A v. B test using DD2000+. You know, engineering modeling, the kind I've been advocating and you've been ignoring. A tool like DD2000 handles the math + physics properly, at least to an order that's appropriate here.



I must work hard at it to be that good. It could also be that the simple math model does a very reasonable job at predicting the outcome, rather than my shady math skills and sleight of intellectual hand.



The 262 v6 is 3/4 of a 350 Jon.

The 229 v6 is 3/4 of a 305.

You blew the math because you made the wrong comparison (you scaled the 262 to a 350, and then took the result and compared it to a 305. What was that term you used above for my math skill?)

Here, let me do it for you:

229 scaled to 305: 110 hp * (305/229) = 110 * 1.33 = 147 hp
305 TBI GM rating: 170 fwhp
(note: the 229 v6 was rated at ~110 fwhp during 1980-83, the nadir of the smog era. It was non-EFI, non hydraulic roller, and non SP head so I wouldn't expect good agreement. hp/cid is only 0.48)

262 scaled to 350: 140 * (350/262) = 140*1.33 = 187 hp
350 TBI rating was either 180 or 190 fwhp

LB4, LO3 and LO5 ratings from Chevy for the same model year (1989) appear here, and the 229 power value came from the first web site I could find. The 350 listed is the copcar engine using the L98 cam. The regular non-police 350 was rated at 180 fwhp @ ~4000 rpm. There are other web sources for this info if anyone really cares to check them.

power to displacement for each: LB4 is 0.53 hp/cid, LO3 is 0.56 hp/cid, and LO5s are 0.514 and 0.543 hp/cid

That's a fairly linear relation of power and cubic inch displacement, even though it's a v6 and 2 v8s, and even though the engines span 262 to 350 cid. That's why displacement scaling works to first order, especially in the case of engines derived from the Gen 1 sbc.

As for the v6 to v8 (262 or 4.3 LB4 scaled upwards to the 350), the 187 fwhp falls exactly between the factory rated power of the civilian LO5 (180 fwhp) and the police LO5 (190 fwhp). That's an error of either +7 hp or -3 hp depending on how you define the truth. Your mistake, well one of many, was scaling the 262 v6 up to a 350, using 140*350/262 to get 187 and then comparing it to a 305 (at 170 fwhp).

So much for the asinine math skills.



IOW people should be more like you, right?

Lo-tec ran as quick in his 3rdgen using a stock SP head Cad LO5 with exh + cam as you did with your $700+ Vortec heads/intake and extensive TBI EFI tuning. With head porting, Lo-tec would have gone quicker. I don't think he wasted his time or his money, even with the lo-po heads. It was a very tidy budget move that resulted in performance as good as yours.... and he didn't even port the stock crap heads.



Like on your car, right? Lo-tec 13.6, you 13.6.

Or you can spend $700+. So it's not a question of the SP heads being worthless, which is how you one-sidedly attempt to paint it --- it's rather what it will cost to replace them (or iron TPI heads) and get equal or better performance.

JPrevost

You advocate the usage of DD2000. Okay, how about their updated version, DD2003. Is that OKAY?
My engine simulated; 334hp at 5000rpm. Only change was to increase the displacement to 400 and with your math I would be making 381hp but guess what, DD2003 says I'll loose peak horsepower and be making only 330hp at 4500rpm.
SOooo.... try digging out of that one.
The real deal is this, your math is crazy. It's great for chit chat around the track but in the real world it means nothing to nobody other than it's entertainment value. For me, this is a tech board, it should be technical, based in reality with very little guessing.

One last note; comparing my poorely ran 13.6 to another is just ignoring more variables. Did it occur to you that the 13.6 was done on full autocross trim? What about the fact that the time was uncorrected for elevation (700ft). Or maybe that during my run, I had 20 degrees of knock retard from the 2-3 shift and it came in slowely to 10 degrees of knock retard at the finish line? Or maybe the fact that I had to lift off the throttle on the 2-3 shift and slowely squeeze into it to keep from hitting the rev limiter (slipping transmission)? I wonder if any of that was something you would want to include? Nope, notta, apparently not. Let's just ignore those variables because there are others that would offset it the other way like the fact that I only weight 178lbs where as lo-tec might be heavier... WTF.
So yes, these heads are still worthless to me and anybody I talk too that says they want to go faster. Have you never heard of the saying, power lies in the heads, the rest is just there to not be a restriction. As in bolt-on swirl port vehicles are enharently slow, comparible to some smog low compression engines of the 70's. Even with a cam and a bunch of bolt-ons they don't perform very well. NJSpeeder swapped to some edelbrocks and bolt-ons with the stock cam and ran a 14.2 with slicks. Not terribly impressive but I'd like so see some other 305 swirl port thirdgens running that with the stock cam.
Air flow limited, give me a break. Every engine is air flow limited when in good tune so don't treat the heads as something special. They're just the most significant part of an engine's power potential.

Thanks for the scalor comment. I learn something new every day. Just didn't expect it to be from you .

I guess there's no convincing you about your ways. Whatever makes you happy. Just know that I'll always be here to contradict you or through salt in a wound . No hard feelings I hope.

GOY

........ I don't have illogical math, or a computer program, but COMMON SENSE tells anyone that a larger engine with the same heads, cam and intake will make more power at a lower RPM than the smaller engine in most cases - unless the heads/intake/cam aren't taxed in the smaller engine - in which case the peak power will be greater and at similar engine speeds when displacement is added.........

JPrevost

If you add displacement without changing anything else the trend is to move the power down in RPM. This happens to make more average power resulting it better ET and higher MPH. You CAN loose peak HP and gain mph!!! 3 speeds in the 1/4 mile means after each shift you dip into rather low engine speeds. Having the added displacement means you're making more hp there resulting in more umph and average power.
Decrease displacement and you can make the same hp if not more by reving higher. The reason you don't see many 327's and 302's in drag cars these days is because drag cars need strong drivetrains... fewer gears is the result. The builders also tend to ignore the RPM range and add valve springs that float or heavy valve train that bounces the valves... put my heads on a 327 and the peak power will go up in rpm but it will be very close to the same power, not much more and not much less.

One story that will soon bring some insight into this myth that displacement = more horsepower; A buddy of mine has a 400 with stock vette l98 heads and a XE cam. When we get it on a dyno we'll see how much more power it makes than a zz4 with the same cam. I told him to save up for larger heads or to port them but listen to me? No, why? Because I didn't give him the answer he wanted to hear. I'm 90% sure he'll make the same power as the same cammed zz4.

GOY

Please don't quote my posts if the reply has nothing to do with me. Nothing you said there is anything new to me.

Greater displacement will generate greater torque production. That is not up for debate. What might be discussed is horsepower. IF the heads/intake aren't taxed by the smaller motor, more torque WILL yeild more horsepower potential in the larger engine when the same parts are put on it, period. If the heads and intake were "Just enough" for optimal high end horsepower production out of the smaller engine - then the larger motor will still produce more torque - AND *maybe* more horsepower, maybe not. It depends how radical of a change there is in torque increase and peak power engine speeds. If the peaks aren't far apart from each other between the motors, but the larger motor produced substantially more torque - it holds a fair shot of showing a horsepower increase as well, but at a lower speed.


There is no other debate to be had. Greater displacement will generate more torque - part for part - and more torque CAN be capable of generating a higher "horsepower number", just at a lower engine speed.

Peak horsepower is inmaterial anyways. Engines don't generate horsepower - they create torque in varying amounts at different speeds. I'd be more impressed in hearing someone make 500 ft/lbs. at 4000 RPM, and keep 80% of that untill 6000, then hearing "I make 700 horsepower dude!"

JPrevost

Ooops.

I'm glad you said power potential and the other thing I see you understand is that peak power means jack squat. Those 2 things are very hard for most people to grasp .

IROCmenace

iTrader: (1)

I like my low end torque SP's.

kdrolt

I already did. I already wrote the answer above, repeated here:

Your statement is only true if you were at the cusp of being headflow-limited. If the engine is airflow flow limited, then the rpm for peak power will drop and the output will maintain itself close to 330 fwhp. If the engine (head) is not airflow limited, then the output will increase and approximately in a linear way. Put another way, if the engine isn't airflow limited, then you could use a hotter cam and make more power. If the engine is airflow limited, a larger cam won't help.


What was the VE at 5000 rpm for both engines?

If the VE percentage dropped by more than the percentage of 400/350, then the power would drop. Which would dovetail with what I said, now twice, in this thread and explain your findings.

The 400 will make more power at low and middle rpms than the 350 (as people here already said) and the reason why is that the VE won't be impaired by the L31 heads. The real question was if the L31 heads would limit the airflow of the 400 as compared to the 350, with all other engine equipment (intake, cam, exhaust) held constant.

To all: that's why I suggested that someone independent run the DD2k+ exercise (not me, not Prevost) so that we'd have an unbiased look at it and with an analysis that explains both sides of the argument.



I won't quote nor repeat the comment that was PM'd to me, but it is common in engineering to use simple math models in the manner I've used. Professors and instructors in that field do it all the time, even at OSU. The simple models don't always work, but then again the user has to be educated enough to know when the answer will be reliable or not. This isn't a class in ICE theory, so most everything here (on TGO) gets done in a simple way, but that doesn't make the method(s) invalid. Analysis is the way to validate or invalidate, and you failed include the details.

I said you'd make 377 hp, in answer to your question, from the gain expected from extra cylinder-filling from a 400 at 5000 rpm if your stock heads didn't hinder the intake flow. You have the VE data from DD2k but you failed to post it, so you failed to explain your results. I had to do it for you.



Your car with L31 heads and what's probably excellent TBI tuning ought to run a LOT faster than 13.6 @ 102+, especially when compared to a similarly-eqipped 3rdgen with stock SP heads. So I would not be at all surprised if you had a lot more in your car that hasn't been revealed. Or maybe your trans was slipping at the time. Or maybe it was the driver (joke)

Like your friends car that ran poorly at the track, your's might not have been running at 100%. Still, it was (and is) amazing to me that Lo-tec ran roughly the same numbers as you, yet he has stock SP heads and you have L31s --- heads that are much better flowing so should run away from the swirl ports.

And the point wasn't really that his car/mods were better than yours; the point was that the SP heads he used were not the junk you've been saying they were, and a reason they aren't junk was that he ran as quick as you did for a lot less money, without making any excuses for any of the differences between his/your car. If he ran 13.6, you ought to run a lot faster than that, right? But you didn't (yet)... Either way it doesn't invalidate what he did, in fact it strengthens the argument that the SP heads are not what you've claimed, because most 3rd genners with TBI 350s would be happy with 13.6 especially if they didn't have to spend much money to get there.



I don't treat them as something special but I do know about the Mach Index and what it means and why it affects performance. That's the ceiling for air flow. Do a search for Mach Index, or search for C.F. Taylor's name, and see who brought that item to the TGO table. It wasn't you. Maybe you'll learn about it someday.



Nonsense. I used to take your posts at face value, but eventually I had my doubts because I couldn't confirm many of your claims. The swirl port head topic was one example among others.

I think you mean throw not through.

I'm tempted to offer advice in reply to the numerous kind words you've had for me, but I think they'll be entirely lost on you --- so I'll skip that. Instead I'll join you with the no hard feelings comment and wish you a great holiday and winter break.

hwp

Fast 355, Just wondering, what do you use for your chip burning and data collecting ? Not trying to take sides because I don't like arguing but there is one more thing that has not been mentioned in the porting old so called junk (tbi's 193's. 416 type) heads and it has nothing to do with money. I like to port heads, therefore the work involved is a pleasure to me ,more fun than work to me especially when I take so called boat anchors and make them perform as well as the store bought stuff. I guess this is because anyone with plenty of money can just buy the horsepower but not just anyone can make it by using there head and their hands. I once ported a 250 six head,left the stock 1.72x 1.5 valves in and had them flow tested. They flowed within 1/2 percent of a 250 head that had 1.94x1.6 valves in them. This was on the same flowbench on the same day.I like the questioning attitude exhibited by Fast 355, Kdorlt, Bill Jones and lots of others. Just another way of looking at things.

Dewey316

Just to add to this again.

I got the 416's put on this weekend. I did some wideband tuning tonight, and got it pretty close to 12.5 - 12.8

Just to show how much better this thing seems to breath. I attached the VE #2 table in my chip, as compared to the one that was in the car before the heads. You can see just how much fuel I had to add in the upper RPM's. When I did this without VE changes, i went very lean above 3500.

dimented24x7

iTrader: (2)

I think another thing that people are doing is concentrating on the intake runner too much. Theres more to the heads then just the intake runners. The combustion chamber will play a big role as well. The newer heads like the vortecs have chamber have a smaller chamber that induces swirl on its own and move the spark plug tip away from the edge of the chamber and more toward the center. This also gives a good deal of area on the underside of the head for squish. Properly set up, that could provide more swirl, flow, and detonation resistance then the swirl ports can.

Some may say to use a 305 head, but depending on the cam and the use of the motor, that may not be an option.

kdrolt

Are these the ported 416s you mentioned in your 14 Dec post in this thread?

And am I reading it right (per your chart) that you are flowing approx no different under 4000 rpm, 10% higher (based on the VE adder table shown) at 5200 rpm and 20% higher at 6400 rpm than you did with the stock 187 SP heads?

The old hp (with stock 187 SP heads) peaked near 4700 rpm (your Nov 17 post, this thread), and the airflow isn't that much higher near that rpm (around 6% better based on the VE adder). So was Fast355 right in his comment about the cam? I know it might be too early to answer that. Thx for the update.

Dewey316

That is not couting the changes in the 3200 rpm cell on the VE #1 table.

I am also going static now, so I added enough fuel to have problems, I have not gotten it sorted out to where it is pulling. From just the initial test drive, I can say, this cam is pulling to over 5k. My guess is that it will be pulling close to 6k, after I get the fueling sorted out. I will see where it goes. I had some winaldl troubls also, so I do not know if I am pulling vacume under the throttle body either.

dimented24x7

iTrader: (2)

Thats a fairly substantial improvement. Its not surprising that the flow doesnt change that much below 4k since the velocity isnt getting near the critical limits in either port when pressure losses start becoming significant. Above that, the pressure losses from the higher velocity and turbulence in the SPs probably starts to set in.

Dewey316

Also note, that I may need more fuel. I am going static now about 4800, I hit 4800 in 3rd gear at WOT, and my AFR jumped to 14:1 (on the WB), adding more fuel did nothing to bring it down, which tells me I can't inject anymore fuel.

I ordered the FP spring from TDS this morning, I'll see if I can the FP up enough to cure the static injector state.

Fast355

iTrader: (2)

Keep in mind that the 416s WILL require more fuel to make the same HP as the 187s did. Just a fact of having a faster burning design is that it typically uses less fuel. For example take a stock TBI 305, put 081s in place of the 187s and see what happens. It will run LEAN due to the 081s lack of the swirl vane, turbulence, and fast burn. Been there and done that. I had to put 18 psi of fuel pressure with 305 injectors in it, just to make it driveable. With prom tuning and the peanut cam the net gain was very little HP under 5,500 and alot more fuel.

It will be interesting to see what happens with the new heads, both at the track and on the dyno.

dimented24x7

iTrader: (2)

The increase in VE above 4k provides clear evidence that the engine is more efficient at moving air, which may very well offset any loss due to less turbulence in the cylinder. While the vane helps, from the flow numbers one can see that its a double edged sword. With stock unmolsted SP's, the edge facing you is alot sharper...

Dewey316

Fast, I have a set of SP's, I'll let them go for a great deal.

Fast355

iTrader: (2)

It would cost more to ship them than I could pick up a pair locally.

Dewey316

I know, it was a joke. Trying to lighten the mood.

Fast355

iTrader: (2)

Sorry, long day today.

I was just simply pointing out that you can't say this much fuel=this much HP or flow.

How is it running now?

Dewey316

Its pretty drivable, waiting for a spring to up the fuel pressure, and then more wideband tuning. My laptop died over the weekend, so I had a friend bring his over. Then my ALDL cable took a crap. (it seems like everything that can go wrong, has gone wrong).

It is plenty rich at idle, and until the coolant gets up to temp, it runs a little rough. Once I can do some proper datalogging, i'll cure that in short time.

It feels much stronger in the upper RPMs, I may have lost something right off idle, the old combo could go in 4th gear from a dead stop, it had so much torque. But it really does pull hard once you get up in the revs a bit. I know how in accurate the butt dyno is, so I will wait to see what happens when I dyno on the 28th.

Fast355

iTrader: (2)

I don't recall the flow numbers that you had from the 416s, but I hope to see you make around 230-240 RWHP with your current combo.

I can say that with a similar hydraulic cam(208/216 @ .050, 114* lobe center, .443/.459" lift , 10.3:1 compression, and a pair of ported 601s I was able to turn out 250 RWHP with a Perfomer RPM spreadbore, BB Cadillac Quadrajet, and Stock 2 1/4" exit Van manifolds-Y pipe-High Flow Cat.

Dewey316

It should be interesting. I'm excited of course, and a bit nervous. I have a history of having problems pop up, the day I am supposed to be at the dyno shop.

Year #1 -- Clogged cat
Year #2 -- #6 plug wire had come undone, and gone un-noticed
Year #3 -- Trying to fix the nitrous, and re-wire in the parking-lot, but I did get a good pull in!
Year #4 -- Cross your fingers.

Well, we are hi-jacking. I figured I would toss in the pictures I took while doing the heads. (they suck, they were taken with my phone.)

kdrolt

Kitch and ME Leigh posted 220 cfm on the intake (stock size valves) and ~160 exh i/e for ported 416s and 081s; stock was 195/110. Stock 187 flowed 165/140 (Fast355 data).

The links to each of those posts are here.

It would be helpful to post the total for the two % increase VE tables, to see how well they compare with the flow data increase (220 cfm vs 165) on the intake side. The flow data didn't improve much on the exhaust (not nearly as much as on the intake side) so that means the the engine has to do some of the work in pushing the exhaust out, so the cam duration on the exhaust probably isn't optimum now that you have a lot more intake.

Dewey316

I ported the exaust bowls and runners much more than the intake, on purpose, to match it better.

When I get the static injector state solved, I will post exactly how much fuel is added.

Fast355

iTrader: (2)

FWIW, my 601s flowed roughly the same as that as well.

kevm14

This is interesting. One thing I learned recently (partly from this thread) is that most TBI engines end up undercammed (for a laundry list of reasons). That means my 96 LT1 cam (not installed) is far too mild.

I just read the entire thread from start to finish and man I'm tired. Time for bed.

ahusted

I find this statement interesting.... Because my stock '97 Z28 doesn't feel undercammed it pulls like a bastard to 5500. With my lame driving I run 14 flat at 100mph.
I am not picking a fight, just pointing out that with better heads small cams can run, but the rest of the engine has to support it.

But to make up for lack of head flow a bigger cam, well tuned, should help, right?

kevm14

Don't forget to read my signature. I have a Camaro, too and I agree. But I think that people (including myself) have to get off the conventional thinking of choosing a cam for TBI. Fast355's 312 is a perfect example of that. It's simple. You choose a cam that will work well with the engine combination, not a cam that you think SHOULD work well with the engine combination. There's a distinct difference there. Sure there's some R&D work for the first guy to experiment, but some of that has been done by a few members of this board. The fact is, people have been largely afraid to do anything remotely aggressive with their TBI vehicles, putting seemingly arbitrary limits on duration, LSA, etc. Add to that the fueling problem and bingo - no power.

But, get a decent cam, maybe some head work, MUCH higher fuel pressure and some good solid tuning (with a good solid ECM solution like EBL) and hey - we might have a decent running engine afterall!

There's no reason to say "hey, put that cam in an engine with a REAL fuel injection system with REAL heads and it'll go up xxx HP" because if it runs well, it runs well, no excuses necessary. If I can get 250-275rwhp with TBI, 193 heads, good drivability and fuel economy, guess what? I'll be a happy camper, regardless of the cam.

GOY

The LT1 intake acts acts as a crutch for the short cam timing in an LT1. It provides plentiful air in a short path so that even if a valve is open only breifly, at higher engine speeds sufficient air can still be drawn in. Without that intake, the engine wouldn't be what it is above 5000RPM.

I personally am a fan of CHP's Vortec TBI build. Their cam was something in the area of 210/214 .510/.520 114LSA. The engine made over 280 ft/lbs at the wheels from 1800-4600RPM, and 257 HP (something in that area) at 5150RPM.

The heads and cam were critical to that build. (Heads flowed 252/181).

kevm14

But what I'm discovering is that I can make a lot more than that much power, without dealing with any of the hassles of a vortec conversion.

Which brings me to another point. Why are some people so insistent that something absolutely cannot be done? Why, also, when it IS done (a few times), the same people retort with "well, you're stupid for doing it." Can't the skeptics at least give credit where it is due and not be dicks about it?

Reminds me a lot of the threads on the Impala SS forum when people would discuss Gen III conversions. A few years ago it was mostly "don't bother, make more power with the LT1 for less money." Now a bunch of people have already MADE the conversion, love it, and a bunch more are researching swaps. Funny how that works. Sure, prices have come down but still.

kevm14

Fast,

Could you do me a favor and model my 9C1 L05 in DD? I have the software but it's not currently installed...

Basically, do you find it realistic that my engine was rated at 205hp @ 4400rpm (same rpm peak as the L05 with the peanut cam I might add) with the L98 cam?

Fast355

iTrader: (2)

Keep in mind this may seem a little high, but DD2000 does not let you model exhaust backpressure. The caprice exhaust was severly restrictive compared to say a truck. The intake system was fairly restrictive as well. I am also using L98 cam specs from an unknown source. With the stock TBI, exhaust, L98 cam, flow from my stock 193s, here you go. The best analysis I can generate in DD.

RPM--------HP-------TQ
2,000-----126------332
2,500-----158------331
3,000-----192------335
3,500-----215------322
4,000-----226------296
4,500-----220------257
5,000-----199------209

kdrolt

FYI:

http://www.9c1.com/brochures/1992/92_1a2.pdf

Using the 1A2 wagon, the non-police LO5 (with peanut cam) was 180 fwhp @ 4000 rpm, 300 fw ftlbs @ 2400 rpm. That non-police engine was the same for 91-93 models.

Now for the 9C1 copcar 350 (yours) with the 773 (pn suffix) L98 cam look here:

http://www.9c1.com/brochures/1993/93_9c1.pdf

Using the police version was 205 fwhp @ 4400, and same torque spec @ rpm.

So on the LO5 the rpms for peak power, and the power itself, were different. HTH.

---

EDIT: on Fast's data above, the power peak occurs at 4000. The power & torque numbers are higher than the factory, but then again I don't know what the accessory losses are in the above.

Powertrain @ GM would have tested the engine(s) in their actual vehicle configuration with all the accessories in place and while using the actual factory exhaust. I dunno if the accessories were running during the dyno tests though (like AC and the alternator charging with a full elec load), though that detail is probably called out in the SAE test specification used.

kevm14

The only thing potentially restrictive about the 92-93 L05 9C1 exhaust would have been the manifolds. There's no way the truck exhaust was better than the 9C1's Y pipe back setup.

Ok, so that's a 9C1 L05 baseline. Since that's probably gross HP, can you also model the civvie L05 with the L03 cam and more choked up exhaust? I'd be looking for only 25hp less with a much smaller cam and much more restrictive exhaust, and the same heads.

Fast355

iTrader: (2)

The truck exhaust is better trust me. 2 1/4 outlet logs that seem to flow pretty good (I am making 275 RWHP though a set right now on a 305), the Y pipe is 2 1/4" and runs into a single 3" pipe. The factory cat on the trucks was somewhat restrictive due to the pellet design. The factory muffler really flows pretty good on the trucks. Some trucks had a single 3" tail pipe, others had dual 2 1/4 pipes. Trucks are allowed to be louder than cars on the noise restriction laws.

The K-vin 350 as installed in a 1992 G20 was 210 HP @ 4,000 and 300 ft/lbs @ 2,800.

The H-vin 305 was 185 HP @ 4,200 and 275 ft/lbs @ 2,400 in the same year G-Series.

Truck ratings are very similar.

kdrolt

I agree. They also didn't have to meet the same noise or emissions regulations as the cars.

The truck LO5s were rated as high as 210 fwhp in 1995, and that was using a cam that was, IIRC, the same as (or slightly warmer than) the peanut roller cam --- but not as warm as the L98 cam.

So if the trucks (210 fwhp) made roughly as much power as the police 9C1 LO5 engine (205 fwhp) when using a smaller cam then I'll argue that the reason was the better-flowing exhaust.

Chris, do you have the actual truck LO5 flat tappet cam spec to compare to the 773 L98 roller cam and the peanut roller cam? I'll add that the roller cams made, by GM's own data, approx 5 fwhp more than they did with the flat tappet. That's based on the Corvette engine rating when they went from flat tappet to roller with no other changes.

kevm14

Wow, I had no idea the L03 had that much power in the truck application. I thought it was 170 in the pickups.

That actually does support that the trucks have better exhaust. At least on the L03. Look at the torque. That's a full 20lb-ft more than the L03 has in the car applications. Though the L05 does not show a torque increase, the HP peak rpm is lower, which suggests a milder cam, meaning that to get to 210hp, it would have to make up the difference with exhaust. Interesting.

So what would be a good cam to use both with ported 193s and unported ones? Maybe something between what you chose and what I have now. Should I forget about using my LT1 cam if I'm shooting for 300 fwhp with unported 193s? I am running LT1 manifolds, cats and a low restriction dual 2-1/2" catback, so exhaust is taken care of.

dimented24x7

iTrader: (2)

From what Ive seen, the tunes where also a little more aggressive as well. Id have to look for sure but they ran them a little leaner then the earlier TBI cars, and I think gave them more timing.

GOY

Trucks had a 3 inch exhaust from the factory - which is another reason I think 3 inch catbacks for Fbodys are joke. (3.5inches is a minimum for a "Performance" mod IMO)


kevm14,
If you think that by putting a set of heads that don't flow as well as 252/181 on a 305, but then using a much larger than 210/214 cam on top that you will create more power, you might create more peak power with a MUCH larger cam, but the head flow is GREATLY responsible for a torque graph as flat as this...


With a set of heads that flows less than those ported vortec's, you will not create the same broad flat torque bar that this engine shows. But you are right, if you are only concerned with peak numbers (AKA - numbers that don't make a car fast) - then a monster cam with less efficient heads might be the trick for you. Just putting a head that flows 30 less CFM on this engine with a bigger cam would NOT produce anything like these results.

Basically, what I'm saying is don't assume that a big cam can overcome a heads short comings for broad (IMPORTANT!) power. I'd love to see the above vortec engine with a 214/220 cam for some more HP, but this is one DAMN good running engine, and the heads were critical - not just cam size. Heads are CRITICAL!


(FYI as a personal opinion - I think a 3.5 or 4 inch exhaust would have generated an additional 10ft/lb over the engine curve and around 15-20HP. No low end torque would be lost - that's a farse anyways. Jesus, in a truck, that same 170HP LO3 would get a 3 incher from the factory, how could you not go bigger "For performance?")