Hey I just wanted to know some tips as to get more top end power out of your TPI engine, i mean the low end is kick ***, but im looking for a bit more power with my moving tourque i have the 350 TPI it has plugs, wires, headers-guttedcat-3 inch catback, and a trans-go-shiftkit hell i even have the GT Autoac. functional ram air hood, and intake kit (comes with a MAF sencor) anything else i could do to improve top end preformance is what i would like to know about

 

how about aftermarket runners?

 

You could go with an aftermarket base, and/or runners and port the heck out of everything. Consider siamesing the runners to shorten them. Stock base can be ported, but most aftermarket bases are better right out of the box than a ported stock base.

Or you could go with an LT1 Intake or Stealth ram, Super ram... something with shorter runners. Thats the only way you are going to get some top end back.

 

makes sence, but would that affect any loss of off the line power? or is it all pluses to get those types of modds?

 

Cheapest way would be to get some runners or a cam. Obviously the runners are easier to install. Yes you will lose a little low end but if you can't put that power to the ground it's useless. We have plenty of torque to spare on our TPI motors.

 

True that, we have plenty of low end for a little torque juggling =)

-Aftermarket runners like arizona s&m runners, or edelbrocks.
-Port up your plenum and your base

or for not just 'some' top end over stock tpi, but for lots and lots more:
stealthram, superram, lt1 intakes all are popular options and the superram is actually emissions legal. however these can be expensive (cough superram), they offer vast superiority over stock tpi intakes.

 

I planed on porting my runners, because i dont know if its comon but when i bought the car there are small, but noticable dents in the runners, so if i pulled those out, and ported them, then went with better heads, and parts to go with them, then went with the cam, then i thought about polishing the plenum, and went with one of those holley throttlebodie's im guessing that would help quite a bit right?

 

then i was thinking of going with larger injecters, and better fuel rails....would a more powerfull fuel pump help that at all? or would it not matter because the fuel delivery would only be as much as the injecters would spray into the chamber?

 

You cant really port the runners... they're thin. You can siamese them, but the benefits have been argued and aren't proven except on some of the higher output engines.

For all that work, I'd go with one of the aftermarket intakes.
Even Edelbrocks aftermarket TPI is significantly better than stock.

Psssh, or you can combo all your parts for low end, low end, low end thatd be neat if you get it all to the ground without spinning for all 4 gears lol.

But seriously, if you want to make the TPI higher up in the RPMs, you have to at least replace the base manifold, I wouldn't just port it, I'd REPLACE it. Then I think maybe you can sneak away with ported upper plenum and I'd get a throttle body foil rather than a new throttle body - do a search, no advantage to having a larger TB altho many will keep arguing...

 

before u waist ur money buying anything, u should port the casting wall right behind the ports for the throttle body. my 305 choked out after 5K before i did this and now it pulls right to 5500, and will go to 5750 when im laying rubber. also cut the bottoms off the air boxes and get some K&N filters.

 

The BEST way to get more top end out of your TPI motor is to replace the TPI with a Stealth Ram or LT1 conversion.

 

heh sounds like a plan, but yes suprisingly, on dry pavement, i get virtually no wheel spin, but it takes off like a mother ****er, remember im new with the TPI intake, my old t/a was TBI (its **** and always will be ****) but the step up from the 305 TBI, to the 350 TPI made my arm hairs stand on end and a huge smile to follow, i only hope i get more and more power out of it without losing any street legalness

 

Street legal is easily maintained even into the 11s, if that's your concern you might want to look into the Superram - emissions legal.

 

there no question at all that the STEATH RAM matched to a good cam will easily add about 75-90hp at 6000rpm when properly tuned over a stock TPI, now its true that youll loose some low rpm torque and that some of that gain is due to the TPI just not being able to supply airflow to the engine at that rpm range, (the stock TPI works best in the 1000rpm-3700rpm range and by 4400rpm its severly starving the stock engines air flow) but keep in mind that if you also add better flowing heads and headers the gains are even more impressive. the stock TPI intake barely flows enough air to support 400hp IF EVERYTHING ELSE IS PERFECT, the steath ram FLOWS ENOUGH AIR TO EASILY SUPPORT 600hp if everythings perfect. anything you do to the engine while retaining the stock restrictive TPI will not produce the max potential hp it could have with the FAR LESS RESTRICTIVE HOLLEY STEATH RAMs VASTLY BETTER AIR FLOW .
NEXT TIME you race someone watch the tach. youll notice that the stock engine spends most of its time in the 3700rpm-5500rpm range with stock gearing and an auto trans. that means that your spending most of the time in an rpm range thats at and above the stock TPI intakes upper airflow limit but almost all of that rpm range is within the steath rams 4100rpm-6500rpm airflow range. if youve added stiffer gears or a better cam youll spend even more time in that RPM RANGE btw it takes less than 60hp to cruise at 65mph so thats not a concern with either intake but making max hp REQUIRES the engine to EFFECTIVELY FILL THE CYLINDERS AT HIGHER RPMS, the formula for hp is
(torque x rpm/5252=hp) so if your making torque of 300 ft lbs at 4300rpm with a TPI like the specs on the stock engine show
http://www.ifrance.com/accf-sprtcar/.../specs/89.html

thats about 250hp, move that same 300 ft lbs of torque up to 5800rpm (well above where the stock TPI can supply air but easily in the potential of the STEATH RAM) and your at 330hp (80hp above stock)
add a cam and better flowing heads and headers and another hundred hp is potentially available

 

Yes but emissions - he said he wants legal stuff. The HSR is indeed very badass, but it just isnt legal in a bunch of places (like las vegas) =(

Thats why I think you should look at the Superram, though more expensive that's what I'm aiming at for myself since I am also concerned with emissions. I figure I drive a 350 - the least I could do is obey emissions requirements =P

edit: and the Superram is just about as mighty as the HSR IMO

 

So is the TPIS Miniram not emissions legal?

 

The TPIS miniram doesn't have EGR provisions so it's not smog legal

 

Someone was talking about mating the SDPC intake base maifold (for vortec heads) with the superram plenum/runners.

This is also a good option, even if you aren't going to go with superram, you could mate a good aftermarket base manifold with large tube runners like arizona s&m's or slp runners, and prep your stock plenum.

There are combinations that will seriously add top end without refinancing your house - lol

If you are creative, you can probably put together a good base/plenum&runners combo for significantly less than Superram whilst still keeping emissions legal. I'd go for used stuff, cause who gives a crap if air has already flowed through it?

 

...hell i live in New Jersey NOTHING is leagal here when it comes to automotive laws the laws here are as tight assed as anyother place youll find i guarente you that

 

Siamese the stock base, hog out the plenum, maybe even add better runners and hog them out too. Retains legality and will pull pretty well up to 6000 RPM if everything else is set up accordingly. I bet an LT1 cammed, siamesed and ported TPI, with even cleaned up stock heads (obviously aftermarket heads would be better), with a nice CAI and exhaust system would make a very nice budget combo....

But the bottom line is that you need to set a budget and go from there. If you have a lot of money your options are truly endless. If you have a little bit of money your options are still quite plentiful.

 

A stock LT1 cam would work nice for that set-up?????

 

Well, it would work much better than the TPI one, and I am referring to a budget build.... Those cams can be had for pretty cheap. And keep in mind that plenty of bolt-on only LT1s run well into the 12s with that cam....

 

I was planning to port out a stock base connected to some SLP runners to a ported plenum for more top end power. aside from all this talk about opening up the TPI system... what are some other route one might take to increase top end power?

I'd like to hear about those ideas as well. Like what other aspects of the drivetrain?

Thanks

 

Thats just it - if you don't do something to the Stock TPI or get an aftermarket setup - you won't see top end gain! This is the {choke point, bottle neck, weak link} etc whatever you wanna call it. Needs to be fixed before you go anywhere else if top end is your first priority.