tpi questions

[Ishmael]

I'm thinking about adding tpi from a trans am to my small block. I'v never even looked at a tpi engine in person but it seems like an ideal way to make good power and add fuel injection without having to move to a new engne platform. I've got somme questions though. Are the heads the same as vortec heads or some other kind of center bolt or could I bolt the intake up to regular heads?
How does the ignition work?
Could I use the computer and fuel pump out of a trans am or would I have to run an aftermarket computer and pump?
Does the tpi intake dictate the kind of cam to be run?
Will the factory intake support 450- 500 hp or a supercharger?

[BonzoHansen]

while you wait for an answer maybe prowl here: http://www.thirdgen.org/techboard/tpi/

[Ishmael]

Thanks, those guys are really data heavy but I guess they gotta be which gave me one more thing to think about. I've also found out that they can make 500 hp naturally.

[86Cutlass383SR]

Scott, I replied to your PM but here's a good read on TPI's and various other systems.

http://www.compcams.com/Community/Ar...?ID=1737510521

A stock based TPI can support 500 ft/lbs of torque but not HP. The runners are too long and too small diameter to support higher rpm power. TPI motors are torque motors but can be made to flow higher HP with the right parts and mods.

There is a LOT of info available on the ThirdGen board. With enough digging you can see whats needed for anything from a stock TPI upgrade, which aftermarket system would be better for you, and even how to modify stock or aftermarket parts. Some guys in Calif. have to stay emission legal and can still pull some amazing HP out of these.

[Samckitt]

I'm thinking about adding tpi from a trans am to my small block. I'v never even looked at a tpi engine in person but it seems like an ideal way to make good power and add fuel injection without having to move to a new engne platform. I've got somme questions though. Are the heads the same as vortec heads or some other kind of center bolt or could I bolt the intake up to regular heads?

The heads are not Vortec heads, they are pre-vortec, pretty much standard Chevy heads. The Vette heads are better, they are 58cc, aluminum & "D" port exhaust. In 87 they went to center bolt, prior to that they were the same perimeter bolt.

How does the ignition work?

Ignition is just like that of the TBI & Computer controlled quadra jet carbs. It is either external HEI coil, or coi-in-cap HEI that timing is controlled by computer.

Could I use the computer and fuel pump out of a trans am or would I have to run an aftermarket computer and pump?

I don't see any reason why you can't run the computer & fuel pump, if you can get it mounted in your tank.

Does the tpi intake dictate the kind of cam to be run?

Probably, stock TPI intake falls off in the 4-5K range. (I think)

Will the factory intake support 450- 500 hp or a supercharger?

I doubt it.

[MonzaRacer]

OK with aftermarket TPI parts 500hp is not unthinkable. If you use reasonable expectations they do run well.
Upgraded throttle body helps, if your ok with doing more on your own you can go one of 2 ways TPI with full computer control, or FI only and let a standard HEI control the ignition.
Now as long as your at least slightly tech savy and like doing as much your self as possible check out www.bgsoflex.com. The Megasquirt II or Megasquirt II and extra will do either.
For the cash Megasquirt is one tough setup over spending $3k to $5k on other stuff.
AS for fuel injection fuel pumps you can either swap a newer pump/pickup setup into a stock tank, but you should look around a salvage yard for a damaged tank and get the cup that the pump sits in,,,or look at the newer ones that use the plastic housing around the pump. Installing a new top on the tank is one way to adapt newer pumps, but I am working on doing it with out major cutting. YET my Monza Tank is going to get modded to center it mor under the car anyway,,,sooooo.
Now one way to adapt to later intakes is to have a machine shop drill and tap the intake side of the heads, and install pipe plugs, remachine then redrill to newer pattern.
I have also installed studs in the older heads and simply bent them so the newer intakes fit.
Basically I have set up several cars with TPI fuel only, it works same as other but only runs fuel, heck I have 2 running 6 cyl ecms. There is no knock control, just fuel.
WE have one working with an add on wide band but re going to switch to a different WB as this one is too slow.
If you want FI actually think about using an LT1/LT4 intake and a remote thermostat housing and pull the cross over from the back of the intake, better flow and more options too.
You cna get the buy that mods point distributors to make a points dist into an HEI use the 7 pin module and tada your FI. The intake wont know any different, and yes the intake needs some machine work/mods.
I for one intend to use one on my 283, and I am building a wasted spark DIS conversion setup that can be used on any V8, the "kit" is almost done.

[Ishmael]

Thanks for the responses guys. I had thought about getting an LT1 out of a 96 buick but it seemed like even more of change from what I have now. I also like the thought of only having to switch out the intake instead of the whole engine as mine has just been rebuilt.

[Ishmael]

I'm revisting this thread as my summer comes to a close. I did some other work to the car and never got around to fuel injection. Its wierd that I always think I'm going to work on the car all summer and I haven't touched it in a month.
Anyway, new question: is there a difference between tpi from an 87 and an 88?

[Samckitt]

If there is any difference between 87 & 88 it is very little. Only thing I know of that may be different is the deletion of a cold start injector, & somewhere along the line they went with a speed density system instead of Mass Air Flow system.

[ArtosDracon]

TPI is great, I've built several TPI engines, though all but one have been smaller than a 350. The smaller CID engines don't run into the same top end losses as 350+ do so they can make great power and torque with fewer mods.

If you want 500hp on a 350 TPI your best bet is vortec heads with a matching LIM from edelbrock and finding a set of SLP runners. The SLP runners combine two runners together so each cylinder can draw through two runners at a time, it helps keep air velocity steady and increase flow. I would recommend modifying the LIM as well so that the dual runners blend together in the LIM instead of hitting a wall at the LIM, you can do the same at the UIM as well, but with smaller results.

I've seen one person actually move the injectors inboard a bit and angle them more towards the intake valve for better attomization, but I tend to doubt that really brought appreciable returns.

For ignition a DIS is really the way to go, even a wasted spark set-up wil be notably better than even a MSD 6AL controlled HEI, but much more complicated.

A stock EMC should work just fine, but depending on your engine mods, you'll probably want to get a custom chip burned for you.

[Scott Parkhurst]

Touch base with a shop that specializes in TPI engines..

..like TPI Specialties? LOL!

www.tpis.com

Great guys/great shop. I work with them on a lot of my own stuff...they do good work.

[avewhtboy]

There are extrude honed runners out there for the factory TPI manifolds which allow more air flow, could search for a set of those as well. Not sure what the max horsepower rating is for them.

[funcars]

There is a TPI manifold called a superram that pushes the powerband rpms up. It has larger shorter runners and a larger plenum. You can make 500 hp and good torque if you get everything right and you will need to retune. You'll need a wideband sensor and datalogging capability to go along with it.

You can run a stock TPI computer and re-tune it yourself - they are cheap and fairly bulletproof. Aftermarket systems are a little easier to tune directly with a laptop, but that is available for TPI too. Like the other guys said look at thirdgen for more details. Start with the DIY PROM forum stickies.

Good luck

[86Cutlass383SR]

I run the SuperRam on my 383 and you wouldn't believe the added torque and power it gives. And, there is one for sale here in the for sale section if the guy still has it. Not mine. If you want one it will have to be used as they no longer make these.

87 & 88 were basically the same. 89 brought the deletion of the cold start injector. 90 was the year they dropped the MAF and went with Speed Density.

[Ishmael]

I was thinking a stroker with a stealth ram on a built sbc and maybe some late 80s accessories. It just seems like by the time I have everything needed to the stock system I would be as far ahead with the holley system.
I've lloked into LT1, I've thought about a stroked sbc or pontiac with aftermarket efi. I'm considering an LS2 or similar. I figured out I only need about 450 but 500 is a nice round number. I keep coming back to about $10 000 all in. I did just find an ls2 from a tbss for $2500 though. The more I research this the more I don't know which way to go. What are your thoughts gentlemen?

[ArtosDracon]

If you're starting from scratch and aiming for 500hp for 10K I would go LS. Ten years ago that wasn't an option because there weren't anywhere near enough of them to be a good value, but with how many are being chugged out by GM every day and the fact that they've got them in everything from the Malibu to the Corvette to the 2500s, they're just to reasonable to not get IMHO. And even if you go with an iron block out of a truck you'll be well ahead of most TPIs except for the L98 vette engine, and even then, big aluminum intake is going to weigh more than the composite on the LS, so you'll get better fuel management, more parts, easier power and less weight with an LS.

[Ishmael]

I've also got to consider install costs and the ls is going to be the most.