Ok, so here's the deal, last night I went to the local 1/8 track for some test and tune. Last time I had been was last October where I ran consistent 8.80's @80mph. Last night my friend tags along with me with his 95 T/A auto bone stock besides a moroso CAI and possibly a flowmaster catback(we don't know for sure but its very quiet). His car has 40,xxx miles while mine had 84,xxx miles. I have mods in sig and have recently done a full tune up (opti, plugs, wires, fuel filter etc...) I ran consistent 8.9's around 79-80mph. I thought this was good considering I ran close to the times before but was shocked when my friend ran 9.1's to begin with then brought it down to 8.9's as well. We both ran on street tires and we have about the same driving ability. How is it possible that my friend ran almost identical times with just a CAI? I honestly don't think I suck that bad at driving, also, looking at the timeslip we have nearly the same 60' and 330. I would think with my exhaust setup I would have at least some advantage. so I'm beginning to wonder if something isn't quite right with my car, that or my friends car is just unusually fast(which I doubt because another stock lt1 camaro ran 9.0's all night long). The only things I havent replaced are my o2's. Also, I've always had a long start problem since I bought the car and I think it may be the fuel pump on its way out. I just don't understand why other cars with fewer mods are running the same times as me and feel so much stronger. It's very frustrating and I dont know what to do. Any input would be greatly appreciated.

ME
R/T .674
60' 2.140
330 5.865
1/8 8.949
MPH 79.85

My Friend
R/T .618
60' 2.079
330 5.864
1/8 8.990
MPH 79.03

 

I'm guessing you need a custom tune in order to take advantage of your headers. I don't know anything about the difference between 94's and 95's, but I don't think there was any major performance difference.

Next time you're at the track, you drive his car and let him drive yours. At least three runs each. That might clear some things up, too.

-Jake

 

You don't need a tune for headers. Some cars just run better than others, nothing you can do about it but buy more goodies. It looks like your car is not trapping quite as fast as it should for your mods. Your friend did out 60' you and that is why he ran the same times as you with a little bit less power.

 

One way to find out. Dyno it. Dyno your friends car too.

Your long start problem could be the problem if it's caused by a leaky injector. I doubt your pump is going bad but your long start could also be caused by the check ball not holding at the pump. 2 easy ways to help pinpoint the long start problem. When you fire up the engine at a time you know the long start problem will occur, first tun KOEO key on engine off for 4 seconds. Then turn it off. Now KOEO for 4 seconds again. Do this 5 or 6 times and then try cranking the engine. If it starts much better than before, you know the fuel is draining away from the fuel rails.

If that doesn't help the problem the very next time you try to start it, hold the throttle wide open and then try to start it.

It still would not be a bad idea to monitor the fuel pressure while your driving under varying conditions.

 

You didn't say what gears are in each car. If he's got 3.42s and you don't, it's explained. Good Luck

 

what gears????

 

Umm, the rear axle ring and pinion. Depending on year and options, it varies between 2.73 and 3.42. In the 1/8 mile, I'd guess a bone stock 3.42 car would beat a 2.73 car with intake and exhaust mods. 1/4 mile race would help equalize, but they're running 1/8. Notice the friend has a quicker 60' time, but is caught by the finish line. Gears or sticky tires make the friends car quicker, even though cas0484s car is faster. Either that or somebody doesn't know how to launch. J/K

 

We both have 3.23's. What concerns me is the trap, I always was under the impression that your trap speed was an indication of power. Therefore, if we are trapping about the same mph, our cars are about the same, power wise. Which doesn't add up due to me having headers and a catback and him not. Anyhow, I finally hooked up my fuel pressure gauge yesterday and with the KOEO, the pressure jump to 40psi then drops very fast to 10 psi then slowly drops to zero. i guess this would explain the long start. Once the car finally starts, the fuel pressure sits around 35psi and drops to 30psi while im cruisin, didnt get to do a wot run yet but this seems kinda low. Any ideas?

 

Why don't you and your friend swap cars for a few runs! Might be interesting for both of you.

T

 

Don't worry about it. Your car is .8 mph faster in the 8th, which is closer to 2-3 mph faster in the 1/4 mile.(at least from my experience) That puts you at around 20 more rwhp than him. Just for reference, when I added my 1.6 rr's, my 1/8 mile trap speed only went up by 0.6 mph, but the 1/4 mile trap speed was 3 mph faster. If you would have raced him for a full 1/4 mile, you would have won by a fair margin. Plus, his 60' time was 0.6 sec faster than yours which gains hime close to a full 0.1 seconds in the 1/8 just because he launched better than you. If you both had your 60' time, he would have run closer to a 9.1 1/8th.

Just for reference, when I had very similar mods to you (MAC mids, catback, and cai) my times were as follows:

R/T .629
60' 2.148
330 5.963
1/8 9.033
MPH 81.58
1/4 13.8
MPH 101.8

... but I have a M6 and put more power to the rear wheels, so my traps are a little higher because of it. Your times are fine. Don't worry.

Dan

Dan

 

It's time for a fuel pump my friend. I had the exact same pressure readings last week when I hooked a gauge up to my car. I just installed the Racetronix pump this morning and it's a brand new car! Midrange torque is better, and it feels like I picked up ~30 HP above 5K. You may have a leaky injector as stated above because of that pressure drop, or possibly a bad check valve, which you can test when you replace the pump.

 

I am thinking of going with the Racetronix pump myself. Is it a direct replacement for the stock pump or is modification required? I'm planning on only buying the pump itself and not not the wiring harness.

 

i believe the racetronix fuel pump is a direct replacement.

I drove the car with just the fuel pump and not the harness for about 1500 miles, it ran great.

I just recently put the harness in, not really sure if it made a difference or not though.