94 Z/28 with A4. Bone stock ran 13.8. Changed to 3.73 gears, ran 14.1. Put BFG drag radials on. still ran 14.1.
Now for the big question......

We installed AFR 190cc heads, TPIS ZZ9cam, 1.5 rr, Hooker LT headers with ORP, 52mm TB.

With fuel pressure set at 41 psi, the car ran 14.15!!!! GRRRRRR

Took the K&N filter off, and cranked the fuel pressure reg in 2 turns, ran a 13.85

No SES light on.....

What is up here? What to check next? Shouldnt this combo be good for mid 12's ?

Thanks in advance

 

It's hard to tell without knowing what kind "mph" traps you used to get before, and what mph you're getting now.

Is your car missfiring?
got any codes?

leo

 

Also have you had any tunning done? If so who did it? When I did my hotcam kit, I only gained 1mph in the 1/4 mile and wasn't really much faster at all as far as ET goes. After pcmforless.com tune I gained about .4 and 4mph in the 1/4.

Aaron

 

We gained about 2 mph in the 1/4, with the new mods. From 96 mph, to 98 mph.

No misfiring, havent checked for any codes

Shouldnt the engine be capable of 400-425 FWHP with these mods?

 

41 pounds of fuel sounds too low for a heads/cam car. Mine is set to 47 pounds and back when I had heads/cam/headers I had it set at 45...

The PCM probably does need a tune too.

 

those are some huge mods for no 1/4 mile differance..id get the car dyno'd or checked out after the install

 

Using stock injectors with that fuel pressure?
Also, can we tune the PCM ourselves with the right software, and a laptop?

 

theres definetly something wrong with the car.


get scanned for codes, and get dyno'd.

 

Anyone know of a reputable tuner in the Minneapolis, Mn area?

 

PCMfor less does great work and is probably much cheaper than anyone around. Madwolf also does tuning.

Joe

 

I have a Hypertech "programmer". How does that differ from what a tuner like PCMforless does?

 

Greatly! I had one of those...they do almost nothing. They don't change the Air/Fuel ratio from my understanding. People mostly use them for gear changes ect... PCMforless would be like dynotuning without the dyno or wideband.....in other words....they change the same settings.

Joe

 

First things first...

1. Check the condition of the engine with a compression check. If it's low, or you have too much deviation between two or more holes (10 - 15% lower), then you've probably got ring trouble.

2. Assuming the compression checks out... Check the installation of the cam with a degree wheel to make sure it's in there correctly. You could be of tooth on the chain and not realize it.

3. What altitude are you at? 98 MPH is WAYY low for heads/cam in good shape. If your at a high altitude, then you need to correct your times to see if your truely in line or not.. I've got home ported heads and a CC305 with a 3.73 gear and I run mid 12's @ nearly 110. Not the best, but not the worst either...

4. Lastly, assuming everything else is cool, you need to check your tranny. You may be slipping and losing a lot of time..

Hope this helps..
Dave C.

 

Speaking of the transmission.....can a non lockup convertor be installed in place of the lockup? and if so, what are the pros/cons, besides the cost difference.

Thanks for the replies, you guys are tremendously helpful !!!

 

Hey, I would recomend calling TPIS. They can tune your computer. Have you ever checked out the Monnesota F-body club? Check us out. www.mnfbody.com