Abubaca

iTrader: (3)

Grim, once again, great post.

I have to once again specify that my opinions are totally theoretical, but none the less, opinions are like a-holes, and I have one.

...you mention a longer duration on the intake side to help the TPI when it falls off. If the TPI starts to choke, all the duration in the world won't help, and if anything, it'll effect port velocity in a negative way if it's too much. The 219 cam has acheived almost legendary status over the years, and it due mostly to the LPE superram intake. There's no argument that the TPI doesn't flow as well, so it would make sense that dual patter (LPE211/219) cam would work well with a TPI. Add to that the rumors that a zz4 like cam was originally intended for the vette L98, the zz9 cam which was TPIS's - "TPI" cam, it seems that the TPI excels with a properly sized dual pattern.

Now make no mistake, NOTHING will make up for a "proper" cam, dual pattern, single pattern or whatnot, and engine combos are almost limitless, so this is really a revolving conversation that'll never end. It's just really cool to discuss different ideas, theories, and experiences.

1991CamaroRslow

iTrader: (3)

ZZ4 cam = great cheap cam. Keep the TPI make a 355 do all the little tricks, port stuff, be happy. Make sure to get a nice big exhaust if you do a single and pick your muffler carefully. This should keep you happy for years to come. This has become an EXCELLENT discussion but I wanted to throw it back on point. Please do continue however as I'm fascinated with this discussion

Grim Reaper

Abubaca, from what I've seen on dynos sheets, when you start to lengthen the duration on the intake, the HP curve with TPI actually continues above 5,000 rpm instead of dropping off abruptly as it typically does.

Yes, the TPI is "fighting you". Typically you see a "flatline" HP curve above 5,000 rpm (instead of rising HP curve if you had a different intake). Eventually the TPI "wins", chokes it off and the HP starts to drop off. But you now extend the HP curve so you are pulling more "useful" rpms (as opposed to just reving it without making any useful power and start going slower).

This can be helpful when you need to "jump" the 1-2 upshift (with the 700R4/4L60). You can now extend the shift point in 1st to get you higher up the power band when you hit 2nd. By playing with the shift points, you can find an optimal "entry point" of the next gear instead shifting based on the "exit point" from the previous gear as most guys do with TPI. Through playing you can find a combo of shift points get your car quicker in the 1/4,

Ultimately, when most guys see the "flatline" HP curve, they want to fix it. Their typical next move is switch to "siamesed" runners which will allow the engine breath better and "build" HP above 5,000 rpm.

(Now you know why I advoacte learning how to burn eproms. For most guys, the modifications never end; they keep wanting to go faster. But now they can tune your engine to take advantage for each of those modifications...but that's another post).

If you want a "fun post", read this one

https://www.thirdgen.org/forums/alte...ning-have.html

I'm still looking for a "crazy person" who wants to try a Miniram & solid roller on a 305 and try running 11s. I know he's out there. I just have to find him.

RaverRacerX

my vote goes for carb style efi manifold=)

dave-92gta

iTrader: (1)

sorry, but to understand your psot i would have 3 days of reading, anywho i was looking at this cam. http://store.summitracing.com/partde...5&autoview=sku
it looks to be ok, the lsa is 110, is this the same as the hotcam or close to it? i was told by many people not to go with a cam that has a single patter. people have told me that a dual petter cam is better because the exhaust port is smaller that the intake port. because of this, a longer duration or larger lift is better to help exhaust flow boosting power.

only going to 5,500 rpm, this cam would work well with a tpi setup like you said grim, any thoughts.

1991CamaroRslow

iTrader: (3)

That cam's not a good match for a TPI engine unless you're very well versed in prom burning. Stick with a wider LSA 112 or 114 is the most common for EFI applications. I think this discussion's pretty neat because of the theory behind why a single pattern cam works well with a TPI engine. Most dual pattern cams are built with a carbed intake in mind and to compensate for the weak exhaust flow of the heads. One thing to keep in mind with this TPI discussion is that the aluminum L98 heads flow MUCH better on the exhaust side than stock iron L98's therefore would call for a different cam unless the heads were ported. From this I would think a single pattern cam would definetly be the answer for an aluminum headed engine but on the iron headed engines with no porting it would seem to me that extra lift and duration would really help them out, not considering the effect on the power band the wider duration on the exhaust side would have.

Abubaca

iTrader: (3)

LOL, I hear ya!
Hotcam is 112. In my opinion, 110 is WAY too tight for TPI, and as mentioned, it can be a bear to tune. I won't say it can't work, but it's certainly not what someone might "recommend". ...and don't take this the wrong way, cuz I'm no expert either, but when straying away from the "norm", it REALLY helps to be an expert. Me, I am NOT an expert, so I don't go too crazy, but it's also why I REALLY like to read as much as possible, kinda like the 3 days of reading mentioned earlier!!!!!
Again, not to debate what is better or worse, but typically the exhaust is BIGGER, not smaller. With the high flow heads of today, an engine can REALLY get rid of more exhaust, so cams have evolved into "dual" patterns, with bigger exhaust to match new head technology.
What's the rest of your set-up? My semi-educated opinion is that the LSA of 110 is too tight. As mentioned, 112-114 is pretty standard. Duration of 224? Eh, maybe just a tiny bit much on the intake? Maybe? Are you running a stock TPI? Modified? If modified, I'd be curios to see a 224/224 cam. Hmmmm.
I don't want to seem like I'm callin' you out, but I touched on this earlier with Grim. (Glenn?) Everything I've EVER read, says that a properly matched system is far and away the best way to make power. You can't "help" a weak part of the motor. If the iron heads only flow "x", then a cam that allows "x" plus 1 amount of air, only hurts the "system". Sure, the TPI flows like crap. You can't magically change that by adding lift and duration to the intake side of a cam. Now ultimately, the question is: where's the line between too much, too little, and just right! ...and for fun, add in port velocity, exhaust scavenging, tune, timing, where you plan to run the car RPM wise, blah blah blah!

1991CamaroRslow

iTrader: (3)

I don't consider that being called out at all, and yes the comment about a matched combo being king is exactly right. However if you look at a flow chart you'll see that up to a point the heads will flow more at a higher lift therefore the added lift would be there to level out the intake and exhaust flow. For instance if the intake flowed 190 @ .400 lift, and the exhaust only flowed say 130 at .400, but when you move up to .500 you get 150 flow on the exhaust. At this point there would definetly be a benefit to adding a larger lift lobe on the exhaust side. This would start to become a null advantage when the heads gave out but on a matched set it could be beneficial.

funkdubie

prolly 1grand past shoulda popped..

dave-92gta

iTrader: (1)

no call out there, just some valuble teaching from someone who knows way more than i do. i agree with you about reading, i have been reading and reading and reading. i have a full setup planed out except heads and cam, and w/e depents on those components. heads are going to be afr 195 or darts maybe. i have a set of vortecs but i dont think im going to use them. now im just learning now. i need a winter car, and im set so start buying parts. thx for everything guys, even though this isnt my post, and i really didnt want to steel it, it sorta happened, sorry. but i learned a lot!

Grim Reaper

I think people sometimes confuse "not optimal" with "won't work". I love using "extreme examples" because it sometimes is best to illustrate a point.

Let's take the L98 as it came from the factory. I've heard many people say that the intake/heads/cam were "matched" by the factory in the fact that they all flowed pretty much the same with each other. Swapping the intake alone or the heads alone didn't really produce major results because the other component couldn't flow anymore. To a large extent, this is true.

But, it's not that a single change is negated by the other part...it's more, you don't get the full benefit of the swapped part until you change the rest. But the change will in fact, produce results...just not as much as it "optimally could" if it were better matched.

Let's take what most people feel is probably the MOST restrictive part of the puzzle, the stock TPI. (Actually, I think the cam is the most restrictive on an otherwise stock engine...and the first place to start).

If the TPI was unable to flow anymore, then swapping that intake onto anyother motor should not produce any more HP than an L98. But, if you swapped the TPI onto the original LT-1 from 1970, that setup will produce more HP than an L98. It is definitely choking the LT-1 and the LT-1 is not producing the power it should because of the "weak link", but that setup will produce more power than an L98.

It's because when they do "bench flows" they only record the number of the part itself. They really need to compare the "total flow" of the system (i.e. intake & heads) and they need to account for the duration of the cam as well. Unfortunately, there is no flowbench that can truly do this...so they flow only one part.

And before you say "but, it is impossible to make the TPI flow MORE"...the real answer is, the TPI never truly flows it's optimal number. When it is bolted to the L98, it is flowing less than it's optimal bench flow number. When you install it on the LT-1, it is flowing closer to it's maximum. Same with heads...the flow numbers are "stand-alone", which they seldom truly attain when bolted with other parts...even if they are all rated the same. What you need is the "flow from the system".

The only way to "test this" is with a dyno. And fortunately, (or in some cases unfortunately), I've seen some pretty bizzare combos using TPI intakes on street rods. This is because the TPI intake is probably the sexiest looking intake ever made by GM. And, many Hot Rodders are old farts (like me), and they now want the "looks" and "decent performance" (but not interested in racing anymore).

I've told them, "you know you make a lot more power if you swapped the intake", and their response is "I don't care, get the most you can out of it". And my response "Just advising, but it is your money .... so make what YOU want (not what I want)".

So while it isn't "matched" it still produces more power than an L98...it's just "less than optimal" and not producing as much power as they could, if they were willing to look at another part (i.e. switch from the stock TPI)...but "it's their money".

Abubaca

iTrader: (3)

I have to say that I followed that entire post to a T!

Skoda101

Grim what part are you specificly talking about extending? the plenum its self or te runners?

Grim Reaper

Great, then I will throw another tid-bit to think about. TPI cannot be properly flowed, because part of the "power" of TPI is from the "air pulses" produced by the reversion through the intake. That is why it is tuned port.

The "pulses" add to the flow at certain points much like "two syncronized waves cresting together" makes a bigger wave and "two waves phased apart" negates the wave entirely. And there is no flow-bench that can properly replicate that.

When we are saying the TPI can't flow anymore, what we are really saying is "the pulses are phased apart" and negating the pulsed waves (and reducing flow). That is why TPI (with a bigger cam and decent heads) will make HP above 5,000 rpm...but it's just a flat-line. Because the TPI doesn't actually stop flowing, the pulses are now working against each other and it hard to increase the flow any more (with modifications such as larger or shorter tubes).

1989GTATransAm

iTrader: (3)

Let me just say that there are at least a couple of efforts here in Southern California to increase the performance of the TPI intake system and retain the outward appearance.

I would think by this summer we should have the results. Maybe sooner on a couple of cars. This will also apply to larger motors such as the 383.

Now for a factory system don't forget the First Injection TPI. I know of one effort being made on that front. From what I have seen posted that should get the job done.

Grim Reaper

In that particular post, I was talking about extending/increasing the intake duration of the cam. Not the actual intake (TPI).

Grim Reaper

Sounds very interesting. Ignoring the "look factor", I know a lot of people who like the "torque characteristics" of the TPI and very happy with a 12 second car (which is easily do-able with TPI).

Don't know if I've seen an 11 second N/A TPI car (SuperRam or siamesed runners don't count)...but I'm sure there is someone out there that has probably done this or getting darn close.

1989GTATransAm

iTrader: (3)

Now don't be a spoil sport. You are right about the Accel. However in our small part of the world siamese runners do count. They also pass the smog test in California.

Whoops I forgot one car has the Accel Superram. However this car will scream. The others are TPI's with SLP runners.

dave-92gta

iTrader: (1)

not yet haha

now the talk of the people here, you can get better preformance out fo your tpi if you do a bit of porting to everything, and a base from edelbrock. one guy i talked to said he can get his car to pull to about 5700 rpm with slp ported runners, plenum amd edelbrock base. now if i stick that with the hotcam im sure you could get it low 12's maybe 11s with the right tranny rear tire combo. dunno, sounds do-able. maybe in 5 years i can give you an answer haha

Abubaca

iTrader: (3)

Be careful what you read! ....if you get into a conversation with someone, even with "typing", and not verbal talking, you can get a feel for what they know, and if they talk a bunch of crap.

One thing I've found about TGO, especially with TPIs, are that EVERYONE has TPI's that pull hard, rev high, run fast, and win races. Amazingly, very few of them have dyno numbers AND timeslips to back it up. 5700 RPMs? SWEEEEET!!!!!! ...but without a dyno graph, it's worthless. Not saying it's not true, just wondering if there's a graph or not. You tell me, if you built a TPI that pulled to 5700 RPM's don't you think you'd have a graph to back it up? I dunno, maybe the guy does, I'm just saying to be carefull what you read.

BadSS

I wouldn't say everyone has TPIs that pull hard and rev high,,, it is pretty obvious by the majority of posts on this board that most don't. When I had the ported stock base and modified SLPs on the car ran, it ran within .05 seconds shifting it at 5300rpm and 5700rpm. Was it "pulling" at 5700??? Well,, the ETs didn't really drop off due to the higher shift recovery RPM,,,, but it leveled on off pretty quick around 5500. If I had a better suited cam for the TPI,,, better exhaust system,,, or better heads,,,, there's no doubt the upper RPM power would have increased and bumped the effective RPM range at least a couple hundred RPM.

The main problem I see now,,, some of these TPI cars are 21 years old. Wiring is shot, electronics are shot, short and long blocks are shot,,,, and you don't know what the other owner or sometimes multiple owners have done with the cars. One guy came into my shop back in the early 90s wanting to get the crap TPI off the car and put a carb on it,,, it ran like crap because there was a 76cc 305 head on one side and 58cc 305 head on the other. If you notice,,,, the majority of the faster TPI cars are relatively low mileage cars or were purchased by the current owners when they were a low mileage car and/or from the original owner and have been well maintained whether they've been hot rodding them or not. When they were new it was VERY,,, VERY common for me to get a 3.23 geared automatic 350 to run high 13.8s (slicks) with basically "free" mods and a couple hundred bucks of parts and a couple hundred bucks for my labor. Most ran in the 14.8 - 14.6 range stock with just a bump in timing on 26x8.5 slicks. The one 305 TPI 5-speed I tweaked ran 14.2s on street tires with the only money spent being a 160-degree stat and K&N filters. It went 14.0s and a couple high13.9s in cold weather at the track on slicks before the clutch gave way. I was far from a “tuner” and during that time the real tuners could get better times than me out of the cars with custom chips,,, since all my times were with the stock chip and old-school tricks.

In proper working condition with the right combination of mods,,, these TPIs would move back then,, and they'll move today if everything is working right. The problem is there are too many not running right causing the board’s norm to be WAY off of what the TPI cars are capable of.

mw66nova

iTrader: (13)

1-2 is at 6K, 2-3 is ~5800rpms...so, it's not THAT high, lol! very conservative gearing too...3.73's with 28" tall tire. went to a 3.45 this year, but with a 26" tire...did that to hopefully make the little 9bolt last a little longer.

as far as going to a miniram...with the hardware and software initial cost being so high and me being a 22y/o with an 8.50/hr paying job, i just can't justify it when the car works...and with the lockup torque converter, i can click off 20+mpg on the highway as it is. so the only thing it might help with is cold starts.

Abubaca

iTrader: (3)

Oh, don't get me wrong, I'm a pretty die-hard TPI guy, and I know there are a LOT of fast TPIs out there. I also know that 5700rpms is possible.

My only point is that for someone trying to research a combo or a way to make better power, they REALLY need to take everything with a grain of salt. If someone can give a legitimate explanation of what they did and why, then by all means listen to their advice. All to often people chime in with what they learned off whoopassperformance.com, and in reality, they have no idea WHAT they run, or why they did it. Just another case of my buddies car did this, or my uncle knows a guy who did that. I'm not doubting what CAN BE DONE, I'm just throwing out the disclaimer that just because it was posted, it doesn't mean it's real!

1989GTATransAm

iTrader: (3)

Right now the moded TPI cars in this area are making peak power around 5200 rpm with a nice gradual decline in power. So shifting in the 5600 to 5800 rpm is best for the most power under the curve. These are stick shift cars. I shift higher with my 700R4 in first because of the big drop in rpm going into 2nd gear.

Like I stated in the earlier post we have some experimenting going on. The goal is to get the peak power higher in the rpm range. With my First intake manifold project I would be very pleased if I can get the peak power up to around 5800 rpm. This would most likely indicate a shift point somewhere around 6200rpm. We shall see as round one should be complete this week. I updated my signature today to reflect the new engine mods.

Grim Reaper

https://www.thirdgen.org/forums/alte...ml#post3186068

Go to that post and look at the graphs that Madmax just posted. It completely confirms exactly what I've been saying...Yes, he's got a flatlined HP after 5,000 rpm (exactly as I've seen on other TPIs). But unlike your stock TPI with a "mild cam", it doesn't drop off but keeps pulling all the way to 5,700 rpm (which I've also seen on other TPIs).

Massive porting of TPI will increase HP because of extra air, but the HP curve will still tend to be flat - but it will be higher. However, "siamesing" SLP runners will both increase HP and change the curve to a "rising" HP curve, instead of the flat line.

I truly feel sorry for you guys stuck with emission testing like California, as you are very limited on your intakes. You must be more creative than us guys who can just slap on a Miniram or a converted single plane intake to run EFI and just rev the snot out of it.

However, the "emission testing" limitation, has also resulted in impressive gains with the TPI intake...much like Nascar has made great gains in spite of "restrictor plates"

1991CamaroRslow

iTrader: (3)

The emissions testers would never catch a siamesed stock base, that could be an avenue you'de want to consider. I'de like to see what siamesing a base does for the power curve on a stockish engine.
Found what I was looking for, from 85MikeTPI
"Now IMHO:
-The stock base mod on a mostly stock motor
should be a nice $0 mode
-For mod'ed motors, a siamesed stock base
will not give you the low-end of a hi-flow
base
-For siamese'ing a base, consider it as
requiring a higher-stall TC (auto trans)
to utilize the benefits
-The siamese mod in no way replaces the all-
out performance of the miniRam, just offers
some of the same dynamics at no cost if
you're already invested in hi-flow TPI.

enjoy
mike"

GregWestphal

iTrader: (1)

I've posted this before, but here is the dyno from my 355 with ported out SLP runners and Edelbrock base manifold:

http://users.erols.com/gcwestph/dynorun17.jpg

and comparisons of various dyno runs:

http://users.erols.com/gcwestph/Dynoruns.html

This also confirms what Glenn is saying about the flatline hp. I ran a 12.47 at 110 mph with this combo, shifting at 6300 rpm. Shifting at lower rpms gave a higher time and lower mph, just slightly.

Rob Wade

Those 195's will be to large for a TPI motor. I would keep it around 170-180 max. The larger intake runners will knock all the velocity out of the bottom end and the LTR's will limit the top end....so you'll have a mismatched combination. Your vortecs are a proven decent TPI head....you just need to purchase the proper base.

D's89IROCZ

Seriously check out the graph on this . A TPI that peaks at 5000 rpm and makes it all the way to 6000 rpm. Here is the origonal thread that blew my mind first time I read it . WHAT a powerband !

Abuca check this out . Complete with graph , etc.


https://www.thirdgen.org/forums/tpi/...ml#post2994417

dave-92gta

iTrader: (1)

Rob Wade. check these out, whats your opinion on them?
http://cgi.ebay.ca/ALUMINUM-HEADS-NE...QQcmdZViewItem vbmenu_register("postmenu_3186704", true);

Rob Wade

I would shy away from them. They are a taller port runner design. You would need to buy a vortec (edelbrock or SDPC, same intake) and then possibly have to modify it. Add to that you still need valves, springs, seals, retainers and locks. They are also set up to run 2.02 valves. More than you need for a TPI motor and more money. Why spend all that money. I still think the 190 cc is toooo large for a TPI motor. I run trickflow 30000005 (summit for a $1000.00) on mine. 175 cc is more than enough for a serious street TPI motor. The angle plugs are a nice benefit also. Makes plug checks/changing a little easier. You said you had some vortecs, right. Save your money and do them up. The only advantage aluminum has for you is 50 lbs. You can use that money elseware. Anyone else want to way in on this?

BadSS

Larger valves help flow as much if not proportionately more at lower lift than it does at high lifts. If anything,,,, you want as large a valve as you can fit for any SBC, and TPI is no different. Actually,, if anything it’s more important with a TPI to get as much flow as soon as possible.

People also confuse volume and velocity - you MUST consider the flow AND the volume when considering which head might have more velocity than the other. The velocity of a 195 AFR head is better than a 163cc stock head at all lift points and has the potential to make over 150 horses over the stock head. Number crunch cfm/cc and see what you get,,, you’ll be surprised that some of these big heads,,, are not too big at all.

You can go with the small valve, small volume, lower flow heads if you want,,, but you’ll end up with the stereo-typical TPI – massive torque and limited HP and limited RPM band. So the question is,,, do you want to build the stereo-type or build something like the new Escalade engine? GM has finally got things right with the new LS series engines. Large high flow heads, small duration cam with high lift, tuned intake, and power from go to whoa. You can get similar power from the old "TPI" if you apply that basic recipe. Or,,, you can continue to build the stereo-typical TPI engine and bitch about the 4500 rpm wall.

Orr89RocZ

iTrader: (20)

agreed! my single owner car was highway driven only...and when i got it, full exhaust and 2800 stall on stock 2.77 gear rearend, i went 13.89 and a few other 13.9x-14.01... on street tires. 13.63 on slicks with abit better gearing now. not bad at all. 12's would be easy to do with TPI..and for some ppl, thats plenty.

TPI's launch very hard with that torque. my car pulls 1.74 60's and has more in it. low 12's could be reached with low trap speeds like 105-108 i'm guessing... as i went 13.6 on a 97mph trap. TPI cars can get decent ET's for the power