Hi guy's and girls, hoping you can help. I have a 91 Z28 TPI with a 383, vortech blower, and lots of other goodies. I am trying to find a company that can build me a custom chip to tune this baby in. I've checked with various dealers like Diablo, Hypertech, SuperChips and all say that they don't deal with this year model. So can anyone point me in the right direction, or tell me which chips they use?

I have contacted Jet Performance and they say they can burn them, but I'm trying to get more options, and more information,

Thanks

 

The only way you will get an engine such as that properly tuned is to do it yourself. Another option may be if you can find a shop that really knows what they are doing. It will be expensive though.

The DIY method is the best. No mail order chip will ever be even close.

RBob.

 

i agree...find someone local or be willing to drive. i have tried them all as well as tpis which claimed to be the best. they cost me my new engine with their useless parts.

do it yourself or be willing to work for it to get it right. do not go over the counter generic and do not go mail order. it can't be done.

 

Aye I wasn't planning on doing a generic chip or anything by any means. I've had the car of a dyno, and planned on using dyno information on the fuel and such along with all my parts to burn a custom chip designed for all the addons I have for my car.

As far as I've ever been told there's really know to tune the ecm on the 88-92's, the chip was the only way. Is this not true?

I've never heard anything bad about TPIS. I've talked with them several times in regards to things going on with my car, and have not seem to get any bad information yet. But I will be cautious.

If there is modifications I can do to the computer myself I am more than willing to learn and do it myself, my problem is I'm just not finding any information on doing it.

 

Maybe you can answer this question, it's "one" of the biggest reasons for me wanting to have the custom chip burnt. Based on everyone I've talked too, Accel, TPIS, Chevy Racing, AZ Speed and Marine and several other speed shops around the country for the motor I'm running, and the boost I need a MINIMUM of 30lb injectors.

The biggest I can get in there now without puffing mad amounts of rich black smoke even at idle is 24lbs. I currently have 24's in there, and on the dyno it was showing about 12 points, which I've been told is about a point too rich for my setup. Yet everyone still insists the injectors are too small.

I ordered an adjustable fuel pressure regulator tonight which I will install this weekend and see if that doesn't help some of this.

If anyones got any ideas or things I can do please post and I will deffinately follow up.

So far I've built my car from the ground up, when I first started I had the shop doing the work, but I came to realize if I was going to own a street car, especially one to drag race with, I was going to have to learn how to do this stuff myself.

Thanks again

 

About the 12:1 at idle and smoke, yes, very good possibility. I would imagine that you have also stepped up the cam (duration & lift) over stock. What happens is that this will lower the volumetric efficiency (VE) of the engine at lower speeds. In return the ECM not being programmed for this change will be injecting too much fuel.

On the other hand a stock 350 TPI runs 22 #/hr injectors. A 383 @ 14 PSI boost will easily double the level of HP of the stock 350. Hence the requirement for larger injectors.

In order to handle the larger injectors there are two parameters in the EPROM for this, first in the flow rate of the injector, the second is the engine displacement. This wil allow the fueling calculations to take both of these into account. Currently the ECM thinks that the displacement is 350 ci and the injectors flow 22#/hr.

Then for the idle the (and everywhere else in the RPM/load range) the VE table will need to be adjusted. The items that require changing are located within the EPROM. There are editing utilities available just for this purpose (free ones at that!).

See this link and hang out here and at the DIY_PROM board. It'll take a bit to get the hang of the lingo. Just don't get discouraged.

https://www.thirdgen.org/newdesign/tech/promintro.shtml

RBob.

 

Another thought, as you start getting familiar with doing the chip tuning consider changing to the $58 mask. A mask is the actual software that runs in the ECM. The $58 mask is used in GM Turbo cars/trucks (SY/TY/Sunbirds/GrandAms). It will handle 1 bar (edited: not 2 bar) of boost when used with a 2 bar MAP sensor (easy to get and cheap).

There are a couple of harness to ECM pin changes to make, but they are minor. There is a ton of info here on TGO on using the $58 mask in your vehicle. And it will run in your current ECM ('730).

RBob.

Edit: just noticed a mistake, a 2 bar MAP sensor will handle 1 bar of boost (not 2). The first bar (so to speak) is from vacuum to atmospheric. The second bar will be from atmospheric to 14.7 psi of boost (1 bar of boost).

 

i can not get into it for legal issues and sway you any one way. i can however warn you and tell you to be cautious. no one company can do it over the phone. to do it right they will need the car to make subtle changes in real time. tpis in my opinion as well as many others can not tune worth a damn. same goes for the many other large companies who claim to do things.

i wish you luck in your search and hope you do enough research to help you avoid these or take a chance on winding up loosing alot of money. this is of course if you need a really specific tune and your not just slightly modding a tpi car. in which case you may not get close but some of these companies can help you get in the ball park.

do a search and read this site, you will learn more in a few weeks then any other way possible and be alot more aware of what your getting into. there are alot of smart guys here that know there stuff.

good luck as it's not a fun battle.....

 

I will deffinately check into that site and modifying the eprom myself. I was always told that in the 92 and down you couldn't modify it yourself, hence why I was looking for a chip.

Being that I can modify the fuel curve, and the displacement of the engine that will probably suit my needs. Those were among my main concerns. Also the fact that I'm running the blower now, but if I can used the modified mask as the other post stated I will deffinately look into that too.

I really do have the desire to learn and do myself. So I thank everyone who's giving me input on this subject. The reason I came to this forum with my problem was because I know theres a wealth of knowledge here, and should I get stuck I have some backup to rely on.

What erks me as you said was that alot of these speed shop are in it for the money, and don't know as much as they claim. They're worried about getting their money. Besides where I live there's no decent speed shops close, and to have to drive across country anytime there's a problem is not possible.

Thanks again, keep the info flowing. I'm sure I will have more questions for you all as I get deeping into this.