I have a 1987 Iroc-Z 305 TPI. (G92 package).

Mods that I can remember:

3.48 Gears
65mm BBK Throttle Body
K&N Cold Air Intake (Stock dual intake that came with G92 package)
Dynomax Cat-back Exhaust
Edelbrock Shorty Headers
CraneCam Mild Camshaft -

Link to Camshaft: http://www.cranecams.com/product/car...detail&p=24201

Now my question is, where should the fuel pressure be at? It has an aftermarket fuel gauge/regulator I'm just wondering what I should be setting it at..

 

i have mine set to 41psi with vac. line hooked up. about 47psi with it disconected (simulation of wot).

the magic number i think is 43.5 psi but cant remember if its with vac. line disconected or not?? These injectors are designed around this pressure.

 

hmm.. I looked at the gauge while the car was running.. seems to be somewhere around 37psi or so. Too low?

 

37 psi with line connected is about stock. Adjust to about 44 psi with vac line connected or the easier way would be to adjust to about 50 psi with it disconnected and that will set you near 44 psi with the vac line connected.

 

Alright will adjust it tomorrow thanks for the info.

 

for the guys running a psi guage! after i turned my car off yesterday i noticed my fuel pressure dropping down gradually to 10psi over about 2min period. in the past my pressure would hold strong for like a half hour.

does this sound normal?

 

No that sounds a bit quick. You may have injector that is starting to leak. My will hold pressure for hours after I turn the car off.

 

I finally had a chance to go out and adjust the fuel pressure. First of all, the Cranecam AFPR is a PAIN to adjust. I had to loosen the bolts on the runners that bolted it into the plenum and pop the back end of it up so I could even turn the screw because the nut was stuck on the plenum.

Anyways.. I just adjusted it a little, bolted the runners back on tight to the plenum and it's now at 41-42 PSI ish up from 37 PSI at idle. At first it smelled a little gassy from the engine, but it went away pretty quickly. I took it out for an aggressive drive & smelled no gas whatsoever in the car, but I can smell gas when I'm behind the car around the exhaust. I just wanna make sure I don't run rich.. so should I still go bump it up to 44 PSI?

 

The fuel pressure is only one part of the whole air/fuel delivery and combustion system.

To properly tune your car, you are going to need to get a EPROM burn for your car and setup.

 

Hmm. how much PSI can the stock injectors handle anyways?

 

My Return line was jammed up when I bought it, and blew out fuel pressure diaphragm when i put a gauge on it was running 75 psi- lol - not good but just gives you an idea they are pretty tough.

 

Damn, 75 psi? Well then I won't be worried about that.. good to know.


Regarding this.. When I bought the car the owner gave me a chip that he bought and never used with the car. Here it is:

http://www.summitracing.com/parts/HYP-127052/

Should I even consider using this thing?

 

38 psi, stock at idle.

 

i would try using it! i know a few members dont like "general mail order tunes". this chip will not tune to its full potential but should be better then the stock one. you have a mild cam right?

 

I'll go ahead and give it a go then! In the instructions it says to use 93 octane? .. is that normal? But , yea I have a mild cam. Here is the cam I have:

http://www.cranecams.com/product/car...detail&p=24201

 

The chip must have a pretty aggressive timing curve then. higher octane gas wont knock as much as standard 87 octane.

 

Yeah I have not a clue about the chip. He said he got it with the car.. I looked it up looks like it matches this car, but I'm assuming it is made to work with a all factory motor. Ah well, so I suppose I am going to give it a go and see how it turns out. I'll use 93 octane just for testing purposes when I do it though.

 

you should double check with the tuning board on tgo, im no expert when it comes to tuning.