kevm14

Damn. I had a post, but I clicked on a link in Outlook Express and it opened over this window, erasing my post. Gotta love it.

Anyway, I was saying I found some headflow data for stock L31s and Fast355's ported 193s are almost exactly the same on the intake side (call it a wash) and MUCH better on the exhaust. So I decided to model a few things.

Here is a 350 with stock 193 heads, 400cfm @ 1.5in-Hg intake flow (stock TBI I hope?), dual plane manifold, "high performance" manifolds, and the Comp XE268 cam.

Next, the same engine with Fast355's ported 193s.

Finally, the same engine with Vortec heads.

So if someone's willing to port themselves, seems to me that porting their stock heads is more cost effective than buying a set of Vortecs and dealing with the conversion issue.

I'm not sure what the stock TBI flows, but I would like to simulate a stock TBI, a 46mm TBI and a big block TBI. I will say that going from 400 to 500cfm on the intake increased HP by only 10 with the ported 193 heads.

How much lift can 193 heads take with the best valvesprings (not stock), retainers/keepers? Can the guides be cut down enough to run ~0.510 lift? I'm liking this XE268.

I also could use the numbers to the stock L98 cam so I can attempt to build my current engine as a baseline.

BronYrAur

iTrader: (1)

See, this is where I don't buy the flow data from his ported 193's. Don't want to start trouble, and I'm not necessarily calling BS on it. I just see his ported flow numbers saying 220 on the intake and 216 on the exhaust at .500 lift. Now for comparison here is some head flow data of some aftermarket heads out there:

*Exhaust flow at .500 lift*
210cc AFR Race Ready head flows 205 CFM
Brodix Track 1 aluminum head flows 193 CFM
Dart 200 Iron Eagle head flows 172 CFM
Edelbrock E-Tec 200 Aluminum flows 196 CFM
Trick Flow G2 flows 195 CFM

See a pattern here? These are some of the top ranked heads out there, and I keep reading post after post about how great these swirl ports can flow when ported. I simply cannot believe, just because its written on a forum that a ported swirl port head outflows a $1200 AFR race ported head. You have to understand my skepticism with this, so please don't take anything personal. I just don't see those heads outflowing basically ALL similar aftermarket heads (granted the intake side of all these heads flow better just the exhaust) I question whether the same flowing procedure was used on the 193s as was used to obtain all the standard data from these other manufacturers.

GOY

kevm14, I feel you are badly misguided.

Did that dyno calculator ask you what type of piston was used?

I doubt it takes into account quench effects - if it does - how can it make that assumption without knowing the piston top design? Quench is very dependant on the piston used.

The 193 head is inferior to the L31 head. If you want to cram a big cam into a 193 headed engine with serious port work and feel like you will get similar power, feel free too, but you are costing yourself time money and power. Similar port work to a cheap set of Vortecs will gain you massive power gains in an LO3. Hey I'm not saying you can't make decent power with those heads, but I'm asking why start with a major handicap? Just to say you did? Okay, you do that (and say you did), and I'll build fast cars.......... we'll call it even.

irocbirdbuilder

wow it is too late to be reading that much indepth tech notes awhile back i posted about finding hope for the swirl ports, i have been in contact with the guy who is going to do mine i just ahvent had time to pull that apart and get em in, i have other stuff i'm planning on doing all at once, but he told me he could get 30 horses out of them with some porting work, he assured me it would be 30 dyno horses and if i dynoed before and after and didnt come up with 30 he would pay for my gaskets and dyno and rework the heads until i had 30 horses, and yet everyone said it was a waste despite the just under 400 dollar a pair price....i'm still planning on doing it just havent gotten around to it but i have decided to go old school modding, the basics, little more flow into it, headers, cam head work and no computer tuning, i am reading of more and more people running damn nice numbers without any tuning but back to basic modding, i am planning on getting rid of this motor but am waiting as to word if our emmissions testing is going to be done away with since i dont want to spend a ton of cash on everything emmissions legal if they do away with it, so what will it hurt to try the basics

Dewey316

Who are all of these "more and more" people that you talk about?

What data do they have?

This whole thing comes down to who's numbers you want to beleive.

For 3 years now, I have posted time slips, dyno graphs, as much information as anyone has been willing to ask for, etc. I have given people copies of bins I have used, I have posted my spark tables, as a point to show how lacking the stock tune is.

I guess if you want to beleive what people say on the internet, great. But, I would caution you to choose carefully who's advice you take. IMHO, $400 + gaskets, and labor for 30hp is a waiste. I got over 70 HP, with nothing more than a cam, and an intake. and then putting in the time and effort to tune it.

It seems more and more, people are always looking for someone to give them the easy answer, and they wait for someone to provide it. There is always someone around who will back up a wrong position, and make you feel good about your choice. Other people will give you the honest truth, even if it isn't what you want to hear. I really hope you will take the time to properly research everything. I for one, spent hours on the phone with manufactures, and talked with people who have been where I was, and really listened to the mistakes they had made.

Fast355

iTrader: (2)

Now about that cam you run?

irocbirdbuilder

ok but see people on the internet also are saying tuning has to be done and is a must, so why should i believe that? WHat i am getting at is everything is so one sided towards tuning i'm NOT saying All the time and work you have put into it hasnt gotten good results what i am saying is i have sources out here saying yes you can get respectable numbersout of modding a motor without tuning, when i have probaly the best known head guy in colorado saying he can get 30 horses out of the heads, get a cam that will match it perfect combine it with headers and make good power and he slaps a guarantee on it saying there will not be a need for tuning, i'm tempted to lean towards that, just google dave sarno, thats the guy he has a pretty good reputation in denver, and everyone i have dealt with that he has helped with top end work has gotten what he says they will

Fast355

iTrader: (2)

Once upon a time I was able to get pretty decent numbers out of an Un-tuned TBI 355. On the dyno and on paper it looked good. On the street it was a DOG!!! Had a bigger than stock cam so it idled rich, the heads flowed alot better than stock so it ran lean under load. I increased the fuel pressure until BLMs around idle were around 108 and cruise was still in the 140s. I then added a VAFPR to it. That helped in just being able to drive it around. It was a whole lot better once I tuned it!

Dewey316

Then you learn the TBI runs off a preset tune at WOT, so no matter what, it will only inject X amount of fuel at a specific RPM, and WOT. You then learn that for X ammount of fuel there is Y ammount of potential energy. You then figure out, that without properly tuning, you really really really limit yourself, since there is no way for you to get more fuel into the motor.

Now to touch on drivability. I will put out the burdon of proof. You don't want to beleive all the people who say tuning is needed? (irocbird, not picking on you here, this will go for everyone else too.)

I was going to do some tuning this weekend any. I will toss the stock chip in my, and VIDEOTAPE the results. You can all laugh along as my car will not start, and I can not drive it to the end of the block. I will then slip in a custom chip I did, and you can go watch me click of a 13 second run NA (weather permiting, I am in Oregon, we are going on 26 straight days of rain).

I do not keep preaching about tuning just to toot my horn. I do it because I know how bad the car runs without it. And I will be more than happy to furnish the proof.

Dewey316

I will be the first to admin I was wrong after I dyno it in 2 weeks. I am more than willing to try a diffrent cam, I just lack the funds right now, to buy another cam in the name of testing. If you want to donate a diffrent cam, I'll be more than happy to install, and then tune for the new cam.

Fast355

iTrader: (2)

I could do the same with mine. Have you ever seen a TBI engine run with 5 in/hg of vacuum in gear, just smoothly idling at about 800 RPM. Try that with the stock chip and it won't even run, let alone drive. My engine has a huge cam. I was told it would never run with TBI. WRONG! It even has the big cam part-throttle surge around town (no way to get rid of it due to the overlap).

My widebands O2 sensor is out and tuning the BLM method is still leaving something to be desired. The EBL helps alot though.

Dewey, this is my cam

http://cranecams.com/?show=browsePar...tType=camshaft

My WOT shift points are just shy of 6,000 rpm, even thorough Cast Iron exhaust manifolds and a single 3" catalytic converter. Pulls harder than ever.

Fast355

iTrader: (2)

I bet you will see a peak HP increase(better flowing heads), but the RPM probably won't be too much different at peak(running out of cam). My anology here would be like taking some Darts or AFRs, then putting the peanut cam under them. You can make some decent power but the RPM range will be limited.

JPrevost

I've tuned a few over cammed engines and never had the part-throttle surge that you speak of. The only time an engine should surge is if there is sensory feedback that is causing incorrect or over correction. Make sure your AE is good, your timing isn't too high, and your o2 PID isn't over compensating causing the AFR to go way high and way low. Do those things and you should have no surge. You can determine if it's the closed loop tuning by running the engine in open loop. Is there still a surge? You should post over on the DIY-EPROM board, I'm sure it is a tuning or mechanical issue not linked to the cam specs.
EBL helps a lot but it won't cure mechanical issues like intake gasket leaks, oil burning, mis-matched injectors/dirty, weak fuel pump, too much timing, etc. More often than not there is a mechanical problem and not the tunes fault entirely. Fouled spark plugs from running a stock chip is common which then leads to burned plug wires which leads too, lol, now I think we can all appreciate OBD-II in some way or another .

kdrolt

Fast355 (Chris) ought to respond to this, but I will too.

I think if you show the intake airflow along with the exh flow for the heads listed above, you will find that the intake flow on them is (a) substantially larger than the exhaust flow --- which is what those mfgs intended, and (b) larger than 224 cfm. So they get a very nice intake/exhaust flow ratio.

On the 193 ported heads by Fast355, the intake flow was 224 cfm and the exh was 216 cfm: those aren't necessarily balanced numbers.... they just happen to be what Chris obtained.

They would probably work better, in an ideal sense, if the exh flow was reduced so that more room could be made for either larger intake valves, ports, or both... to make the intake flow better. In other words, rebalance the i/e ratio from the 1.04 value obtained by Chris, or the 1.07 ratio of Dyno Don, more in line with the 1.45 ratio of a stock Vortec or to agree with the i/e ratio for the heads you listed above.

Chris obviously can't do that, so he'd probably do better using something closer to a single pattern cam because his i/e is a lot closer to 1.

Aside to GOY: Dewey316's ported plot on p1 of this thread would fit in nicely onto the CHP plot. His car represents the test CHP didn't do: stock heads, cam swap, exh swap, and extensive tuning.

Dewey's curves are smooth and fairly flat (for torque). I don't know if Dewey used the same cam as CHP so I don't know how equitable the comparison is, but for a moderate cam swap it does show what stock LO3 heads + cam + exh + tuning will do vs the 305 with cam, exh, and ported L31 350 Vortec heads. FWIW.

GOY

I can't agree with that. I went back and looked, and "Something" puts a death grip on his plot around 3200-3300 RPM and doesn't let go. It becomes a problem as early as 2700 RPM. He does go a little rich at 3500, but nothing horrible. Running out of cam doesn't look like that on a dyno chart. I would say he could have maintained a greater % of his peak torque for a longer period of time, had "Something" not begun to really kill air flow.

His is a slow run off in torque, as if "Something" is becoming more and more problematic as engine speed increases. Running out of cam manifests itself in more of a "Dent" fashion on a chart, assuming all of the other parts are up to the airflow task. Look at the vortec chart - torque peaks, but trails up high until the cam begins to fail to maintain enough time for propery filling, then the dent occurs. The efficieny is held high due to the heads being adble to maintain substantial airflow at all but the highest engine speeds. THAT was a flat chart!

I wonder what that "Something" that is killing Dewey is......

As far as cams, CHP's was a 210/214 .510/.520 114LSA Comp grind. Dewey's is 206/216 .447/.447 112LSA. The durations are fairly similar, dewey just has a lot less lift and shorter LSA. Either way - that doesn't explain the slow death his engine dies on the dyno (No offense Dewey, I'm just looking and comparing dyno charts is all.)

Dewey316

None taken. If you re-read the thread, I said the exact same thing in one of my first posts.

kdrolt

The death grip you describe is MUCH more visible in a dyno plot of a TPI engine. You want to see the effects of airflow limit as rpm increases, then look no further than a hp plot of a TPI engine. Power keeps climbing and then it plateaus and stays there.

I know there are tons of examples of this on TGO, but an easy-to-find one appears here (admittedly for the wrong engine, but the power curve is representative enough). Look approx 2/3rd into the thread for the stock TPI runners atop a cammed 383.

https://www.thirdgen.org/techbb2/sho...hreadid=273727

Power flattens at 400+ just beyond 4500 rpm and stays flat just above 400 out past 6000 rpm. That's a classic airflow restriction. The engine increases in rpm (which means there should be a linear increase in power at constant VE)..... but the VE drops in equal measure with increasing rpm so power stays constant ---- because the airflow limit on the entire intake has been reached.

I don't think the flow restriction in small-diam TPI runners are going to behave much differently in terms of moving air through the engine, than a restriction of airflow in the head (like the LO3). The engine doesn't care where the airflow restriction is, only that there is one somewhere upstream from the cylinder(s).

Dewey's plot for power doesn't plateau like a TPI engine. It rises to a broad area near 4700 rpm and then it falls off thereafter. I don't doubt the heads are hurting airflow some, but not as much as presumed, as shown by the dyno result and because he's not near the power potential of the heads based on

2.0*165*305/350 = 288 fwhp

using Vizard's estimate for power potential based on head flow, and equated to a v8 305.

Dewey's dyno plot is probably near 250 fwhp right now (208 rwhp), so he's approaching the limit but not at it yet. IOW he'd make more power with a bigger cam even with the LO3 heads. I think that was part, or all, of what Fast355 was implying. The heads aren't great (stock) but the cam is imposing a limit. And no offense to either GOY or Dewey in this, or to TPI owners for that matter. It's a discussion.

GOY

There are some assumptions being made here that are wrong.

First - just because a head can flow JUST enough air to produce 250HP at peak DOES NOT mean that it is efficient at doing so!

It's a scale. Let's say a head flows 250CFM. Do you think it would be more efficient flowing it's maximum 250CFM or only 200CFM? It CAN flow 250, but only 200 of which is required - do you think that will involve less friction and heat? Yes. Will that make it more efficient the further from that peak it flows? Yes! The less taxed the head, the more efficiently it will flow, the more power generated over a broader range. The COUNTER BALANCE of that is when a port is too big and airflow becomes "Lazy." However - in the vortec example from above, that's not a problem because of how the air travels in the heads port and the relatively small port volume. The 193 has a 185cc intake port = lazy airflow+limited potential overall of the head. Bad combination. The L31 with it's smaller port can not only keep air flowing at a higher rate of speed - but manages to flow more air overall! That's a power combination in anyone's book.

So even if the swirl port can flow enough air for a 250HP motor - the efficieny will be hurt overall, as the engine comes closer to the PEAK flow rate. That will narrow a powerband, and kill average power. Average power moves a car, and creates the kind of dyno chart I posted above.

SECONDLY - intake airflow is completely different from head airflow! In the TPI example from above, you are talking about dry air, not wet air like in a head. Take a wet flow intake and compare it to a dry flow intake meant for the same purpose.... completely different runner sizes and lengths, DESPITE the same powerband. A head HAS to flow "Heavy air" or air+fuel. But more importantly is the area the air flows in! In the head air has to make a 23 or so degree bend in 2 INCHES OR LESS in a RAPIDLY narrowing port! That does not happen in wet intakes! On top of it, the head is MUCH hotter than the intake.

For those reasons, the head must flow more than the intake is capable of, because it's more efficient at lower %'s of maximum airflow (as long as port shape and size is kept reasonable) and because it's forcing the air to do more that the intake does, making it less efficient.

Not sure what's not understood there, but it's why race engine builders will spend tens of thousands on heads, but only a tenth that on an intakes, etc.

Secondly - to further illustrate what importance head design is in high rpm power and BROAD power.... why don't we look at the cams. LS1 cams.....
Stock 98-00 LS1 cam
Duration @ .050 198.86 intake 209.25 exhaust
Lift .498 intake .497 exhaust
Stock 01-02 LS1 cam
Duration @ .050 196.37 intake 208.72 exhaust
Lift .464 intake .479 exhaust

We would all consider those "Peanut" sized cams.

If it wasn't for great flowing heads and intake - how could and engine with such a small cam make such great power overall?

Bottom line is this - the less effort it takes to move air through a port at high rates of speed - the more power you can make over the entire operating range.

kevm14

I completely agree. Why the hell do you think I went through all the trouble to create that little Excel utility for injector sizing/fuel pressure? Because fueling is a big problem, even outside of the tune. I can't wait for this EBL setup. First I will get my stock L05 running as good as possible on it (which will hopefully show improvement without touching the engine).

kevm14

I have heard LT1 guys say many times that a lot of those out of the box "race heads" are NOT that good (for the money). They just have a TON of meat for porting and THAT is where they shine (after porting).

kevm14

Fast,

Do you have any more info on that 255rwhp Tahoe running stock 193s? Cam, intake, etc.? I think you said the engine was dynoed on a stand.

Dewey316

as promised. Dyno numbers.

Talk about a rock solid torque curve. the blue run is with the 416's. The red run is the SP heads. (green is my bone stock run from a few years ago).

The numbers here are from the same shop, same dyno. All numbers are SAE corrected.

ShiftyCapone

iTrader: (7)

Wow! Great job dewey. I wonder what he curve would have looked like with stock 416 heads. It looks like after 4200rpm you made a solid 20 more hp. Looks like the two heads almost perform the same under 4200rpm. The SP have a peak torque advantage but and eyeball guess looks like you may have made more average torque with the 416's.

When you tuned the 416's how did the timing and fuel demands change? Was there a huge tuning difference between the two? What about timing?

Dewey316

It took a bit of tuning. Beleive it or not, I'm actualy running less timing at lower RPM's, and a hair more timing above 3k. Fuel is hard to compare. To get the injectors to flow enough, to not go static, I had to up the fuel pressure from 14psi to 20psi. So my VE tables look entirely diffrent now, due to the fuel pressure change. But it is using more fuel a little later in the power band. Funny thing is, the fuel consumption really tapers off after the torque peak at 4200 rpm, but the car still builds more power.

All in all, i'm prett happy. I was hoping for larger peak gains, but the flatness of the torque curve with the 416's, is pretty impressive. I think with the gains above 4200, it will go much faster at the track, reallistly when I'm racing, the rpms are rarely below that mark. All the power I picked up, is in the RPM range, that I run at the track in. The little I did lose, is below the revs I'll use when I'm racing.

vorgath

Never rebuilt a SBC, done some mods but nothing major. My question is .. I got a spare 305 .. yup LO3 .. in the garage

Not planning on doing anything major to it ... but I guess I should ask.. I want to port the head .. port match the ports .. would I even need to replace the valve guides to be on the safe side .. or just leave those alone for now ?

I got titanium valves in the garage but not sure I want to go through the hassle and expense of getting new guides put in the heads (not sure the titanium valves have the standard diameter)

I guess I'll go with the LT1 cam .. cheap *** spring .. tons of tuning

Yeah ya guessed it ... I'm like flat out **censored by Walt Disney and T. Gore and other uhmm "people"** broke so need to go the cheap way .. for now

Fast355

iTrader: (2)

Good work Dewey, glad to see you get some power out of those ported 416s. Guess that goes to show what I have been preaching all along, with the 4,500 rpm redline on these engines in stock form, TPI heads are not the first thing that should be added and should not be added if stock. From 2,500-4,200 the swirl ports made more torque than the 416s (081s are roughly the same) which is good for the street. Like you said the 416s should help you out when you are racing. I have to wonder what would have happened with the swirl ports had you had the A/F mixture 1 pt leaner in the upper RPM band, like the 416s. What would have happened with stock 416s? What about ported swirl ports? Those are just some of the questions are still un-answered.

Dewey, BTW peak torque rpm is typically the RPM where fuel consumption will be the highest. HP is a function of torque and RPM, less torque typically means less fuel, but then the RPM is higher and HP will be higher.

I thought you made a best of 208/272 with the swirl ports (your earlier dyno graph) That is 16 RWHP(224-208) more than the TBI heads. I am sure that over 4,500 it pulls somewhat harder now.

Notice that your power curve is nearly the same until the very top, leads me to believe that your cam is still holding you back. With a different cam and a dual plane intake, I feel you could have more torque AND more HP, quicker track times, with better response and fuel mileage.

kdrolt

I second the good work and follow-through in posting the results.

How much time did you have in the tune you obtained? IOW do you think you have much left that you couldn't extract?



Agreed on the more-power-for-racing comment, especially if you can stay above 4200 rpm in all the upper gears.

Detail: From 2500-4200 rpm, the stock swirl port head made more torque than the ported 416s.... even though the 416s likely flowed a lot better. Thestock swirl ports probably made more torque below 2500 rpm as well, but we can't tell (for sure) from the not-exactly-the-same applications of WOT among the dyno tests.

The differences in ignition timing is puzzling. Stock SP heads beating ported 416s below 4200 rpm doesn't surprise me if the benefit of fast-burn (on SP) overcomes the better flow (ported 416)..... but the faster burn heads should have used a lot less timing advance than the 416s did. Did you have time to even explore optimum timing on both setups? IOW I would have expected the 416s to make optimum power at WOT with at least 34 degs total advance, and the stock SPs to make optimum power will less than 32 degs.



Some.... but I doubt it would have been as much as 20 hp.

OTOH I have to wonder what the power numbers would have been with ported LO3 heads. Everyone by now knows just how poorly they flow unported, yet even up to 4200 rpm with a non-stock cam they stayed even with ported 416s. Even I'm surprised at that.

Fast355

iTrader: (2)

Some more very good questions.

I forgot to mention the timing, I also would have expected peak HP at 32* or less total timing with the 187s. My 081s like 36* even with 9.8:1 compression although the cam is bigger. My other truck with stock 187s/stock L98 roller only likes 22* MAX total advance @ WOT and even then above 3,600 (Cranking compression is 215 PSI)

I know that the A/F mixture would not have made 20 HP difference. But if it made 2-5 HP difference, that is still substantial and part of the overall HP difference.

Dewey316

There me be a HP or two left in tuning. I did all of the tuning pre dyno, with an inovative WB. It starts to go rich right at the 5k mark, i might hold the hp peak for a few extra RPM, and give me a couple more HP at the very end.

Timing is interesting, the SP heads did need less timing at WOT, I'm running 34* with the 416's. I was in the 28* range with the swirl ports. I dropped the timing down in the lower ranges at idle, to fix some surging with the new heads. The only thing I can think of here, is that the swirl ports were more tollerant of extra timing that wasn't needed in those areas. I won't say that those areas of the spark curve were optimal, but the portions that I took timing out of, are not areas you really see the gains on the graph.

Fast -- I think the cam is the limiting factor now. I will also point out, that the heads did shift my power band up, my peak HP is now at about 5200 rpm, instead of the 4600 with the swirl ports. I'll probably be shiftint at 5400-5500 rpm, which is right were Harold told me I should shift with this cam. The torque also doesn't start to taper off until after 4000rpm.

All in all, I think there are a few things to learn from it. The SP heads do seem to show some very good effecience at lower RPMs. The amount of torque I made sure shows that. The HP gains above 4000rpm, show that they are indeed flow limited though, at least when you get the motor to the point, that in needs more flow in some of the RPM range. I was very suprised to see that I really didn't lose much torque at all. There is a 7ft/lbs diffrence in the peak numbers, that really isn't a whole lot, and IMHO a descent trade off, for pickup up 20hp on the top end.

Fast355

iTrader: (2)

I noticed that as well, power improved at all points over 4,200. It is amazing how flat your torque curve really is.

Will you be able to stay above 4,200 RPM shifting at about 5,500?

Finally I still have to wonder about ported swirl ports, any chance you will prep those in the future and try them?

Any chance you will be using the EBL soon?

kdrolt

That's more like it.

Actually if you look carefully you'll see that the red torque curve in the dyno plot (stock SP heads, modded cam + exhaust) peaks at 3000 rpm, the same rpm where you really got into WOT. Look at the air:fuel plot --- you're above 18:1 when the run begins but you don't get under 14:1 until 3200+ rpm... which means you don't know what the peak red torque really is (was) when using the stock SP heads.

So you did lose more than 7 ftlbs. It's probably more like 15-20.

This is a point related to the one Chris pointed out at higher rpms (the red curve would have been higher than shown above approx 4800 rpm because it went too lean).

The blue curve (ported 416s) gets under 13:1 almost right away, so I'd say you really do know the torque curve well in that case, but you don't on the stock SPs, so the difference is more than just 7 ftlbs. And yes I know it's a difference that occurs near 3k rpm, so it's a minor detail in the scope of track and acceleration performance.

And in case anyone cares, the afr on the green curve is above 14:1 until 4500 rpm, so that would explain why the rwhp was so low on the stock engine test.

Dewey316

Pretty close, with a 5speed, I don't drop down as far in the revs, as and automatic would.

Not likely, I probably won't be doing much with the 305 anymore. I have the 327 project to start on next.

I want to. I am just waiting until it comes out. Although the car is running very well how it sits right now. I have a fun little toy, most of the money for the car, is going to go into the new engine. I am still not sure if I want to try for a 4bbl TBI unit, with EBL, or if i am going to go with an aftermarket computer that has 2bar MAP capabilities.

But, knowing how much is involved in this new engine, it is going to tak a lot of time and money, so I will likely get the EBL as soon as it is available.

dimented24x7

iTrader: (2)

I think the lesson here is what people have known all along. the SPs are a good head for low end power on an older motor with stock pistons and such. They provide lots of velocity and swirl to help generate low end torque. Heads with open runners obviously can flow more, and make better peak horsepower since the engine can breath better.

Fast355

iTrader: (2)

Sounds like an interesting project.

BTW, the EBL IS 2-bar compatible. 2-bar sensor on my 305.

kdrolt

IMO, not quite.

If I had polled the TBI group before Dewey's recent dyno test -- asking at what rpm will the ported 416s out-power (and out-torque) the stock 187 swirl ports? -- I doubt that anyone here would have said 4200 rpm. The number would have been much smaller than 4200. I wouldn't have even said 4200 rpm.

Higher power at high rpm for the ported 416s was expected. Better low-rpm power from the stock SP 187s was expected.
I think it's safe to say that everyone did know those two things before the test, and in that I do agree with you.

The stock SPs beating ported 416s from "low rpms" to 4200 rpm wasn't expected by anyone (except possibly Fast355) so it wasn't part of the lesson. That part was new. IMO, FWIW.

Vader

Dewey,

Nicely done. This is s very complete thread, right down to the proof at the dyno. Now if everyone can wrap their minds around the data you'v eposted, it should lends some good direction to future head/cam selection.

Dewey316

Thanks Vader.

I do have one other thing that I am still trying to wrap my head around.

One of the other cars at the dyno, was a 305 TPI car, with stock exaust manifolds, and LT1 cam, and a HSR. We were within 1 hp of each other thru the whole power range, it was scary how close they were.

I can't figure out why he put down just as good of numbers, I have more cam, better exaust, and head work done. I'm thinking that I must be giving up something to the HSR, or the MP injection. I'm thinking it may be time to step up to a 454 TBI unit, and see what happnes with that.

JPrevost

The HSR is a GREAT intake. For all the complaining people do about the log style distribution they can't deny the very real power gains across 95% of everybody's usable powerband.
The other problem might be the code, not air-flow. See how the engine seems to break up at higher RPM... that might be the code, not your tuning or an airflow problem.

kevm14

Wow, interesting. According to my calcs in Tunercat, my L05 gets about 20° max timing at 4800rpm. That seemed much too low, until your post. That's an awfully efficient head to be able to ignite and burn so quickly...

My cranking compression was 170-185 over 30k ago.

Dewey316

Jon,

That very well could be. When I was doing datalogging with the WB, I could not tune around it going rich above 5500.

After many a years of watching various cars dyno, I am very impressed with the stealth ram. If I was going multiport, the HSR would get my nod.

You guy's don't need another beta tester for EBL do you.

kevm14

x2

Twilightoptics

HAHAH That's just funny to me.



John, your car beat out that HSR 305 in torque hands down, and you would hand him his rear in at the track. You'll be able to get out of the hole much faster, as well as better on the shifts.


The cam could be slightly limiting at this point. But you'll be better off with too small a cam, than too big. UltraDyne 272/282(adv) 206/216 @.050 .447 .447 112 LSA (106 CL)

Sounds like it would convert to the XE262 I had in the 350. Size wise (Same cam, smaller engine acts bigger. Sam cam, larger engine acts smaller, etc)

I was just noticing something..... 272 vs 206 duration in the adv vs .050.... that's a HUGE spread, especially for a roller cam. 66 Deg of lag. It should be much tighter than that. My 262 cam was 218/262 avd/.050. 44 Deg of lag. And it was a tappet, which should have a slower ramp yet.

I think there is definitely something in opening that intake valve sooner. You have alot of lag time there. Weird.

My Solid is 267 adv 239.

Dewey316

Most of Harolds roller cams, seem to open like that. The next step up is, 274 which is 210* at .050, with a lift of .492

If you recall though, Ian's HSR went crazy rich in the mid range RPMs, given a better AFR, i think he would have been closer in torque.

Twilightoptics

I still don't think he'll pick up enough to mate with you. Maybe peak number wise. I've seen enough HSR graphs to know that he's not going to get a torque curve like yours lol.

breamrules

The picture of the dyno numbers no longer displays. I would really like to see the curves as I am going to be putting the 416s on a 350 soon and would like a general estimate on what I will be getting. Thanks.