My 1987 GTA has a rebuilt (stock) 350 TPI with about 20,000 miles on it. The only aftermarket stuff I can see so far are a larger than stock MAF and a K&N filter. For this summer I want to add a dry NOS system at the Throttle body 'cause although it's fun to drive, it lacks real GTA power. I don't want to break or melt anything so, what is the limit on this configuration? I may put a new fuel pump and adjustable regulator on it, but how far will I get with the stock injectors?:lala:

 

actually you won't be able to get away with a dry nitrous shot on a TPI, the computer won't compensate for lack of fuel, and youll burn it up. correct me if lm wrong but l think there are only wet systems manufactured by nitrous companies for the TPI. NOS states in their instructions that you can get away with running a 150 shot with their kit #5151.

l got away with running a 150 shot on my TPI 305, ran many many bottles through it, and it held up just fine. l ran it with 72,000 on the clock.

 

Thanks Mouse. That's the kind of "first hand" answer I was looking for. I checked out the #5151 kit and it looks like just what the doctor ordered.

 

the block learn multiplier and integrator portions of the ECM have enough adjustment to self learn the new fuel values from the O2 sensor for a 22 to 24 switch. as a matter of fact I helped a guy put a votech A-trim (back when that was all there was) on a 89 iroc 350 and we put motorsport 30# injectors and it still learned them but it was getting close to its max internal self adjustment according to the scan software we had at the time. I like the 51xx series dry systems from NOS on TPI cars, but only to around 100 hp then I switch to wet flow (not particularly ideal on the tpi intake either). these systems use a special device to crank up the fuel pressures on the injectors and the junky ones GM used on the TPI cars (like the rochesters) can lock closed at these pressures and a dangerous lean condition can result. the ford injectors have a higher pressure lock threshold. that why I like to install 19# stang injectors on the 305 cars with the same setup or with blowers.

 

B4Ctom,
You sound like you know the ECMs. Are you saying that if I install the NOS setup we've been discussing, I'll be integrating it with the pressure regulator somehow? (That's great!) So when it sees a request for the juice, it can bump up the fuel pressure while the ECM is lengthening the pulsewidth? Do you think the stock (22#?) injectors on my 350TPI will handle the 150 shot? Any chance I'll lock the injectors at these levels? What's your theory behind switching to a wet system at 150 shot? Thanks for your input. I have lots of years of wrench turning under my belt, but when it comes to altering the factory engineering for performance, I still benefit from those who have firsthand experience.

 

Actually mouse you can get away with a dry nitrous kit on a TPI. You are tight about the stock computer wont give enough fuel to compinsate for the nitrous. But if you get a chip with as much greater fuel curve or you can get a computer controlled nitrous kit. Like the one from Venom Performance. They have one of the safest nitrous kits that I know of today. I helped a friend install it the other day and it is easy to put on too only about 2 hours. The kit comes with a small computer module that ties into each injector. And ties into the throttle position sensor. When the computer knows you are at wide oprn thorttle it provides more fuel to the engine. So to your question you can run a dry nitrous kit you either have to get a new chip to go with it so you can compinsate for the nitrous. Or you can get a computer contorlled one like I just put on a buddys car. I hope this helps you out in some way.