I have a 92 RS that is currently a TBI system with the 305. I am currently building a 383. I also have a complete TPI setup (mass airflow). Which setup would be most practical? I know staying with the TBI would be the easiest since it is already set up that way.

Like everyone else, my goal is to get the best performance.

Thanks for you input!

 

okay well how about this will the ecm compensate for the larger displacement engine? Will the tbi injectors be able to feed the 383?

The combo will produce 425hp.

 

I am surprised that there are no diehard TPI or TBI gearheads that have spoken up yet.

 

Re-pin your harness and go with the TPI!

 

I see in your signature you are in germany. Where at?

Thanks for you input. This is not something I am doing this weekend... So I have some time to decide.

 

well I recently did the tpi swap on a 92 rs. thing is both stock tpi and tbi will choke that 383. now if you swap to tpi so you can run multi-port setups like superram, HSR and the like you will be better off power wise. you could stay with the tbi but you will come up short in a few areas. for the 383 your stock fuel pump will not be strong enough. if emmisions aren't something you have to deal with, I say get yourself a good carb intake manifold, throttle body adaptor, aftermarket tbi unit for big blocks, and a couple other little things to increase you setups potential. the only reason I went to tpi is so I can stay emmissions legal (plus it looks cool). if that had not been a factor I would have built a tbi setup on steriods.

 

Emissions are not a deterant for me.

I do have a aftermarket TPI fuel pump. So whichever way I go it will be used. I dont have the specs here.... can look them up.

I was thinking about staying with the TBI just to keep it simple. I wasnt sure how much that throttle body would restrict the engine. Do you know what the cfm rating it is?

What about the ECM parameters?

The good thing is that the previous owner had added the nice exhuast but kept the stock manifolds on it.

 

425 hp is possible with tbi. With either system you will need an after market intake and larger throttle body.

Stay with the tbi because it will be cheaper and work. Get a bored throtle body (2.125", and it can be done with sleeves) and a good intake. 90 lb injectors and 20 psi of fuel pressure will feed the engine.

You will need to tune a good chip to get the max hp with both systems.

 

For the throttle body you mentioned where do you get it bored? Or is there a ready to go throttle body you can buy?

Thanks!

 

holley makes a throttle body but it is only a two inch. check on ebay for others.

http://cgi.ebay.com/ebaymotors/ws/eB...category=33550

http://cgi.ebay.com/ebaymotors/ws/eB...category=33558

The second link will let you use any good 4 bbl intake you want.

 

Your forgetting something, TPI just looks friggin cool under the hood

 

I'm a little confused. You abandoned TBI because TPI offered an emission's legal alternative? There are plenty of aftermarket TBI intake manifolds that are EGR equipped....

 

was the other driving factor

 

 

For me its a toss up. The TBI is a speed density setup and with the cam I am going to use the vaccum at idle will be 15...

The TPI I have is mass air flow so that is a little more user friendly. As far as performance upgrades.

 

Don't give up on the TPI quite yet. I've got this one making decent torque and still pulling when shifting at 6,800 RPM:



It should also get reasonably good mileage, due to the TPI fuel metereing and Highway Fuel and Spark enabled in the programming. I know a MAF setup shouldn't run that well, but it does. Somehow, it just isn't right. But, it can be done. Get a programmer and some PROMs, and start tuning. The TPI might be worth the extra effort. You're going to be on the edge of adequate flow with a stock TPI, but the HSR or converted LT1 intake can solve a lot of that problem.

 

Vader, it's bad enough that the stock TPI can't breath as it is, but did you have to go and throw a 10,000lb load on top of it? J/K

 

Strange how it still makes torque at 6,000 RPM. For a TPI and MAF, it seems to defy logic. They're stock runners, too.

 

A couple of years back I was with a friend driving in his 1989 Corvette (auto/stock)... and I was very impressed with it's mannerism's on the highway. It too pulled way passed 4,000 RPM, and he kept assuring me it was completely stock. I believe him.

However, I wish my old L98 performed like that when I first obtained her. It took porting, porting and even more porting, and I still couldn't catch him up high (and this was even after I geared her to match). She kept falling flat on her face passed 4,500 RPM. Yet, with the Stealthram, this immediately solved the problem. I guess this is why I'm constantly pointing fingers at the stock intake...

As for that car of your's, I'm very jealous. She's a beauty. I know she's a different make, but I would see myself airbrushing a small (in script) "Christine" on both fenders.

 

I have the TPI in my monte SS and I love it compared to the carb set up... I have not ran it at the track since I installed it but it pulls great to 5500.

I need to get some updated pictures of under the hood.

 

Those cars (the Monte SS) should have came from the factory with Tuned Port Injection (a 454 version of it wouldn't of hurt either)....

 

yeah a big block would have been nice.

I thought about going that way when I was re-doing it. I changed my mind because of the inventory of SBC parts I had.