LeeCross

I'm currently building a 383 stroker and installing a tpi unit on it. I'm not sure which route I need to take as far as what computer or wiring harness I need. I still have the 2.8 MPFI harness and computer from the original engine. I didn't know if either could be altered or what I needed to do. The tpi unit I have is set up for The MAF. Any help is appreciated.

utilityguy2

iTrader: (1)

more details please. unlikely the harness and computer will do you any good.

LeeCross

I'm going to be running a cam that is bigger than normal and with the block being bored over and having a longer stroke, plus running larger injectors. I didn't know what kind of problems I would run into as far as programing for the computer I would need or what. I have read on here that the MAF setup is a little for forgiving to mods but I don't think a ecm for a stock 350 would run ok with all that. I know this setup has be done before, I'm just not sure of the specifics.

utilityguy2

iTrader: (1)

That's where the programming comes in. All of that can be done in programming.

vetteoz

iTrader: (13)

Stock TPI ECM is fine ; it is the tune on it that determines how it will run
All you need is a competent tuner;
unless your cam is too radical, most likely one of the online tuners already has the tune for it

When selecting cam , Be aware EFI prefer LSA 112 or greater, too much overlap can give tuning problems.
Also TPI ( designed for a 305 ) on a 383 is going be to rev restricted so look for hi lift ( head dependent )
but short( ish ) duration

You might be interested in what a alternative intake can do for performance
http://xtremecarzone.com.au/index.php?showtopic=386

utilityguy2

iTrader: (1)

Tuning for a modified motor needs to be done on the car, preferably on a dyno. There is no pre-made tune for anything other than a bone stock motor with all original equipment. Some chip companies will try to tell you theirs is for such and such but the fact is, every engine is different and a tune on one engine may not be so good on another engine of same size but different characteristics. TPI will have some flow problems for your engine but that all depends on what your intended use is.

vetteoz

iTrader: (13)

Many of the better online tuners can get a custom tune close on 1st try; after you send them a datalog they fine tune it
Plenty on here and other forums are very happy with their online tune; esp given they don't have access to a local tuner
who plays with these ancient systems
.Most only do LSX tunes now

utilityguy2

iTrader: (1)

Good Luck with that.

vetteoz

iTrader: (13)

For this tuner nearly 10 years of happy 3rd Gen customers inc some way from stock engine setups
which you say they are only capable of tuning


https://www.thirdgen.org/forums/afte...-helped-w.html
https://www.thirdgen.org/forums/afte...thumbs-up.html
https://www.thirdgen.org/forums/post...585-post7.html
https://www.thirdgen.org/forums/tpi/...cmforless.html

utilityguy2

iTrader: (1)

Checked them out. nothing different than others such as hypertech and superchip or the ones I sell. Basically minor spark change and lower fan on for a 160 thermostat. Not a custom tune by any means. Custom tuning takes a lot of time I'm still working on mine going on 6 months with probably 10 hours of logs. If I had a dyno would probably take about 4-5 runs to get close.

vetteoz

iTrader: (13)

You are sadly misguided
They get the same feedback across many forums
http://forums.corvetteforum.com/1557799124-post9.html typical

Ask the real tuning gurus in 3rd Gen DYI Prom or DFI
https://www.thirdgen.org/forums/diy-prom/
if a off the shelf Hypers*it chip is the same as PCMforless custom tune and see the response you get

Maybe you just want to promote what you sell ?

utilityguy2

iTrader: (1)

Maybe you have some interest in PCMforless? I don't sell or promote so called "performance chips". Just trying to help the guy out with some reasonable advise. You may do the same. It's up to him to decide what's best for him.

vetteoz

iTrader: (13)

We are not talking " performance " chip but a custom tune tailored to his actual engine.
My comment was based on the fact that unless he has a radical combo ;
a online tuner has most likely already done a tune on a similar engine combo and be familiar with what is required

utilityguy2

iTrader: (1)

What I've found is that no two engines are the same. A tuner can provide you with a starting tune but you must provide the final tune. Of course many people are happy with a engine that runs OK as far as they can tell. Nothing wrong with that either. I think the poster has gotten his answer and doesn't need any more "advice" At least from me.

tealcamaromanrs

fast ez-efi retrofit kit(self tuning) capable of about 550hp or so. thats what i got on my 383 tpi

vetteoz

iTrader: (13)

Is fuel only
No electronic control of spark

tealcamaromanrs

true but i purchased a distributor that handles adjusting the timing and the timing curves. its a msd

The Devastator

I did this about 5 years ago. I built a 10.8:1 383 with iron eagle heads, and an extrude honed and port matched stock tpi unit.

I used a 7730 ecm and harness with 30pph fuel injectors. I got a custom tune through TPICHIPS.com. It worked VERY well it took three datalogs and retunes through him to get it dead on. Chip cost 250 bucks back then. I only paid for the one chip. The retunes he did for free.

If I had it do do all over again I would have gone with the accel DFI like I did with my big block swap. Made my life infinately easier. A thruster DFI system for TPI costs about 1400 bucks and most tuning shops (decent non specialty shops) tune accel.

The motor I built made 570ft lbs of torque BUT it only made 390 hp. She was vicious in first and second gear but ran completely out of steam at 4250 rpm. In retrospect it would be perfect for a DD gas mileage combo or a truck engine, but it really needed a superram or stealth ram to utilize the Iron eagle 185 heads it had on it.

I am currently rebuilding this engine for a lower (9.0:1) compression and a cam with less duration for a 1978 oldsmobile delta 88 project.

Don't expect ANY power above 4000 rpm. We had to advance the camshaft 4 degrees and clearance the connecting rod-intake lobe clearance to get my big roller cam to work in the powerband of the intake.