I put this question on the drag racing forum as well, but it really is a TPI question more than anything. Besides, no nearly as many guys browse that forum.

Went to the 1/8 mile track Friday night after getting my Accel intake base and adjustable fuel pressure regulator installed. Set the fuel pressure at about 44 psi, which I think is about where the stock one runs. Results were slightly worse than my last outing.

The averages for the 3 or 4 runs bewteen most recent and time before that went like this

before - 60' = 1.9800, 1/8 mi = 8.7173, mph = 79.26
after - 60' = 2.0239, 1/8 mi = 8.7826, mph = 79.05

Not to big a different, but consistenly slightly slower, especially on the 60' times. I assume the Fuel pressure was basically the same since I set it at the factory setting, so the difference was the larger base. I've always heard that running superram (especially the plenum and runners) will result in better top end with slightly poorer low end torque. Do you think this is the case here. It would show up in the 1/8 mile and 60' times I guess.

Ive done mods since I bought the car about 1 year ago and each mod resulted in better times until now

nothing, 1/8 = 9.47
tuneup and fast chip = 9.25
Cold air intake = 9.24
Nitto drag radials = 9.12
Cold weather ( ok I had no control over it) = 8.86
Borla Cat back and 52mm TB = 8.71
Accel Base and AFPR = 8.78

Any thoughts? When I reset the timing after replacing the distributor it ended up a little higher than before. Before I was running 8 deg btdc and I was trying to set it at that, but when I tightened the bolt it went up to about 9 deg. I didn't think that would make a big difference. It was a cool evening Friday as well.

 

Did you remove the vacuum hose from the AFPR and plug it while setting the pressure? If so then try raising the FP in 2psi increments and do a few runs.
There are too many variables so say for sure that your car is slower, do you not have a 1/4 mile track around? That is a better indicator of HP.

 

Edit ---- I read you other post - there's way to many unknown variables. I thought you might be lean,,, but if you're at 50# without vacuum on the regulator,,, it's less of a chance. I'd check for vacuum leaks - at the heads, runners, and plenum - first. There's a good chance adding the intake to the stock heads wouldn't give you a lot anyway - especially if you're running the stock runners??? Could very well be the diffence in track conditions - weather and / or track prep.

 

Different ambient conditions (air temp, air pressure, humidity) will cause variation in performance. Worse traction (tires spinning more at the line? too low of a stall converter?)

Rule of thumb, for every tenth of a second lost at the 60 foot line, expect to loose 2 to 3 times that at the big end.

 

I will check for vacuum leaks, I was wondering if the stock runners and gaskets would seal good against the larger base. The outside diameter of the stock gaskets are not much bigger than the openings in the base. At any rate I ordered some SLP large runners so when they get here I will put them on and try again.
by the way, am I supposed to measure the fuel pressure with the vacuum hose on or off, and if off, is it supposed to be plugged? I get 42 psi running with the hose on, and 50 psi with the motor running and the hose off, not plugged.

 

Vacuum hose off and plugged