I have an idea about on how to save about $850.00 on my top end ..Take my complete TPI system and throw it on top opf my 406.I already have a edelbrock base plate mani and slp ported/macthed runners so...keeping the 406 breathing to 6500 rpm shouldt be too hard.so i wouldt have buy a

-intake manifold $200.00
-air cleaner $100.00
-stubstack $40.00
-770 cfm carb $400.00
-misc $100.00

*I really like the looks of TPI system and to boot it would still look like a stock L98..which would be awesome as a sleeper at the track.I could be like ya..runs low 14's on a good day

Just wanted to know from anyone who has done this or has info on it..any probs i might have..should i have any more p & p ing done done the tpi system..problems airflow areas?
Thanks for any Help!

 

One problem you're going to have is that the 406 will overheat unless you have all the steam holes drilled in the heads.
Another problem will be the inability for all those cubic inches to breathe at higher rpms, even with the SLP pipes. So I would caution you against using too big of a cam. The last thing you want is a hairy cam that comes on strong at 4000 rpm and then drops off at 4500 rpm because the 406 is getting strangled.

If you build the 406 for torque rather than horsepower, there's no reason why the tuned port can't be used on it. But the old rule of combination...combination...combination is so important. Match the cam and compression to the rest of the combo in order to get the most out of your engine.

You should also use the longer 350 connecting rods to bring your rod/stroke ratio up out of the basement.

Basically, I think if you want a 6500 rpm 406, you'll almost have to go with carburetion on a good dual plane like the Edelbrock Performer RPM Air Gap. Or get a good single plane and convert it to fuel injection.

As wonderful a torque-builder as the tuned port is, it just won't give you the high rpms you're looking for.

 

Ok the steam holes are drilled..
very mild cam..barley a .500 lift..
hoping to see 500ish HP at the crank..
already have 5.7 rods..

6500 rpms are set in stone..what do you think the highest it would rev out to?

I'm considering the stealth ram system too...summit has a complete top end system for like 2800 whcih isnt too bad.The tax check will easily cover that.but i would lose the runners which is my fav part of the motor and the savings i was going for

http://store.summitracing.com/defaul...tt=stealth+ram

 

500 at the crank is a VERY lofty goal for a stock TPI system. I think you should more focus on keeping the power band below 4500, instead of thinking of max hp. Any cam that is going to make that 500hp is going to wreak havoc with the TPI. Cool yes, practical, not really.

 

Well the only thing stock on the TPI system is the plenum

the base is a hi-flow edelbrock and the runners are big mouth slp's

IS there any after market plenum for the TPI system?

What do you mean by wrecking havoc on the tpi?

heres the cam im going with

Crane Powermax
.284/.282-509/528


Ive talked with 400 block builders and they've hit the 500 crank hp easiley with the same set up as me..except they have a carb.

*I would think it would easier to hit the 500 mark with a 406 than 350..Are there no ppl in the 500 range?

 

Lots of people are in the 500hp range, but not with TPI. It is a very restrictive setup. I would say that you would need a complete aftermarket intake setup, I think its the superram, maybe, that would make that. Its definately not going to happen with the TPI stuff. At least, no one has done it yet. I think that the biggest problem you will have, is that even that cam is going to want to rev out of the range for the TPI. Two words: Custom Chip. No way around it. Even then I dont think you would come close to the potential of the same setup with a carb.

 

As a system, TPI was designed to give 305's a good seat-of-the-pants feel from the showroom floor. It was never intended, nor does it do all that well, for high RPM, high horsepower performance.

The "T" part of TPI stands for "Tuned". As in, they "tune" the runner length for maximum resonance benefit at a certain RPM. The longer the tubes, the lower the RPM. Shorter runners only help so much. You can check with guys who have dyno sheets, but TPI systems rarely continue to make power above 5000 RPMs, even with all available aftermarket performance pieces. So, putting in a high-duration cam like that will have two effects: 1) Move the power band above the tuned RPM of the TPI runners, and 2) confuse the heck out of the O2 sensor at low RPMs, where the TPI is designed to have its benefit. So, you get the worst of both worlds.

500 HP 400's are fairly common and easy with carb setups. If you want EFI, you're better off with a miniram.

 

Alright..Thanks for the input Guys!
I guess this is why you never see a TPI's making 10 sec runs.

 

You might see a strong 12 second TPI, with a 383 maybe, and good enough traction. 12 seconds is VERY quick for a street car. Only the quickest exotic cars that cost major green get down into the 12's. And you wanna go 10's?

I think to go 10's, what you're going to need is a 572 GMPP crate motor, or a 540 Merlin big block, either that or one humungo roots blower sticking out of the hood.
It takes tremendous power to go 10 seconds in a street car.

Like Ljnowell said, 4500 rpm is probably all you're going to see with the TPI, as it's designed for maximizing torque on a 5.0 engine. I agree that it looks great, and you can bat 5000 rpm with the right modifications on it, and maybe even get close to 400 hp. You see, hp=torque x rpm/5252. To get hp, you not only need torque, but you need rpm too. With rpm so severely limited on a tuned port, it's going to limit hp.

Tuned port makes great torque because of a phenomenon called "Inertial Supercharging". The length and size of the runners are "tuned" for an rpm band most commonly encountered during street driving. What happens is when a charge bounces off the back of the intake valve when it closes, it travels back up the tube and then bounces off the next "charge" coming in, reinforcing it. This reinforced "charge" is timed to reach the intake valve just in time for it to open back up, providing a mild supercharging effect. This timing is "tuned" for idle to about 4500 rpm, and when you combine that with a cam optimized for that band, you get very strong midrange torque.

But the same phenomenon that creates inertial supercharging also restricts its ability to rev much higher than that.

You can get above 5000 rpm with forced induction simply because the supercharger will force feed the engine above the natural tuning resonance...to a point.

You'd be a lot better off if you bolt on a Lingenfelter Superram or a Holley Stealth Ram, or make your own FI with a Victor Jr single plane. Or if you can, run an RPM Air Gap with a carb on top until you can afford better. Then you'll get your 6500 rpm.

 

My goal is to break into the 10's..but i would be happy with a 11 sec flat run..Ive droven a 9sec blown monte, 10 sec 02 tt-ta and 11 sec GN and i was satified with the power the GN had on the street..The others were so not streetable.

i dont want to build this again and again so what ever set up i go with is what im gonna stick with so using a F/I system isnt out of the question either.
Is there a S/C for the TPI/stealth ram?

If not im most likley gonna lean towards a carb and go with a 172 weiand blower...But would have to save for a while on that one...or ebay it.

would a blower fit under the hood of a 4" cowl on the 91 bird?

 

A self-fulfilling prophecy....The reason they're able to get 500 HP easily (which I have no doubt whatsoever of) is because they have an intake that can breathe; as opposed to TPI.

There's no way in hell you're getting into the 10s with that stuff on top of that motor. You most likely won't even get very deep into the 13s. Only the most carefully tuned and optimized TPI motors even touch the 12s. 10s is beyond laughable.

HP is directly proportional to flow: in the simplest possible terms, the time rate of the engine doing work, is directly proportional to the time rate at which it can consume fuel; and fuel consumption is directly proportional to air flow.

You need to make a choice right now, BEFORE you spend a whole bunch of money and get an extremely disappointing slap in the face from reality. Either run TPI; or go as fast as you say you want to.

The best FI systems for high HP are the MiniRam, and the Accel ProRam (basically a big single-plane carb intake with injector bungs cast into it). You'll also need more cam than some FI-compatible street cam.

 

I know this..Im prolly the worst person ever about not making my mind up and sticking with something..It toook me 2 years just to deceide what car to make my "fun" car.

After i get the rotating assy balanced and short block completely built ill make that deceision when i come to that bridge.

 

TPI on a 406 would make a heck of a truck motor for towing. Lots of low and mid range grunt and decent horsepower. It wouldn't win many 1/4 mile races. Light to light would be impressive though especially with a 700r4 w/ stock stall and 2.73 rear.

 

um correct me if I am wrong, and yes he does it with a SC, but isnt willie using TPI and he is in the 11's, and heck is a 305

 

This from the guy who says torque is all important? No I don't want to start this debate, we can agree to disagree. I think you should go carb or stealthram for horsepower, superram if you want good torque. And 10's on a 2wd street car is insane. Honestly I dont get the advent of these hugely powerful sportscars when I get nothing but axle hop in first gear with a 360hp engine.

 

Its all about suspension..theres a guy with a 96 ta with full interior and totally streetable and runs in the VERY low 9's...I raced him once when i didnt know him on the street and he barley left a footprint on the street...and theres quite a few 10 sec street cars around here.

The biggest thing from what guys have told me about hooking up 500+ hp is a 12 bolt or 9 inch rear..The guy with the ta launchs at the rev limiter and doesnt budge the rear..just sticks and goes.

But like i said 11 flat would satisfy me.

 

I spent the better part of the year tuning my car when I upgraded the A-trim to the S-trim.

I got more boost, but I couldn't get the pos to trap higher than 110mph.

The TPI setup was edelbrock base, slp runners, 52MM tb, ported plenum. Infact, everything was ported, the base matched to a 1205 gasket.

I sold the TPI setup on ebay, and started making a singleplane efi setup out of a holley street dominator manifold. (basic 1205 port), vortec truck throttle body, some holley fuel rails, and a spacer made out of t6 alum to addapt the throttle body to the carb intake.

Anyway, got a basic tune for the street. Blms 128 everywhere, tuned WOT stuff on the highway doing 45-65mph wot pulls to get a "baseline".. Took it to the track, ran 119mph every single run for 2 months.

Woulda run faster if I had more fuel too.. Eventually, detonation got the best of it, and I broke two ring lands.

The BEST part was. I sold all my TPI gear on ebay for around $650, and the singleplane setup cost me under $350 to build.

-- Joe

 

Torque IS very important on the street. But a good balance is better. Look what happened when Honda went with only high rpm horsepower and no torque in their S2000. Gutless in street driving but quick only when you redline it.

Kinda what I had with my 427 in the Vette. I originally built it with a great drag race cam. Redline it and it was extremely quick. But driving around town it sucked under 3500 rpm.

I'm "trading in" my huge cam for a more streetable solid roller. It'll still be very fast, but will probably be a lot quicker on the street too, with 80 more lb-ft at 3000 rpm!

In relating to this topic, TPI will give you great torque, but will be severely limited in rpm and horsepower, so you won't have the best balance between torque and horsepower that you want for a street/strip engine. If it's only a street engine and either you don't care or it's going in a truck, then go for it. But you sound like you want a good balance that'll at least get you into the 11's.

I like the $350 single plane FI experiment that the last guy posted. That system obviously breathes much better than any of the other, much more high dollar FI systems commercially available. Another thing I like about it is that the intake is positioned perfectly for making a hood scoop useful for cold air induction.

For a conventional FI system that has the TB facing forward at the front of the engine, any centrifugal supercharger will work fine on it. You've just got the plumbing between the supercharger and the TB to worry about, and most include kits to make that work. I personally would stick an intercooler in that set up too.

Yeah, you'll get 11's probably with a 406, but only if you balance your horsepower and torque for the best street/strip performance, AND optimize your traction.
2WD cars commonly optimize their traction for performance in the 11's or lower. A lot of them are restofied musclecars from the 60's and 70's. Just use some of the technology that they use. Either a ladder bar, traction bar, or 4-link set up, and careful setting of the pinion angle of the diff to start with. Then maybe take a look at changing your springs and shocks for max weight transfer. Then a good set of drag radials.

 

Put a superram on it with the right cam heads and set-up and you can run 10's.

http://www.azzatochips.com/azzato_taylor_chips2.htm

Go to corvetteforum and search for 400 combos in the c4 section.

 

Heres my 406 combo, shooting for 450 hp. 10.5:1, XE274 hyd. flat tappet cam, TFS duttweiler heads and holley stealth ram intake. Should be swapping next spring when MN thaws out.

As far as the mininram, I would rather have the HSR. In the super rod mag the HSR made more hp and tq on average over the MR. The 406 won't lack any torque so use an intake that will breathe.

 

You shouldn't say TPI sucks, as one guy said it's intended for smaller CI motors. It would be great on a turboed 283, 302, 305, 307(I'd go with the 283/302). With TPI you'll need help forcing air into the cylinders. Turbocharging is a sure fire way of accomplishing your goals.

An extreme example would be P. Smith's car. Yeah it's rare, but it can be accomplished...

 

Dude, do want you want but I would have to agree with the majority....you will be choking your motor for air! But, see what the TPI will give you performance wise. You can always switch your induction setup later, that is what I did. I switched to the MiniramIII on my 383 and the car woke up!