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View Full Version : Need better 1/4 mile times



SCaddict
08-28-2004, 07:23 PM
I went to the track last night and was a little disappointed. This is what I ran...

R/T .706 (that sucked)
60' 2.356
330' 6.696
1/8 10.260
MPH 69.35
1000' 13.337
1/4 15.932
MPH 84.64

I thought with mods I would be in the low 15's. Any ideas why I am running so slow? I think I might install an intercooler fan for next time as my car seems to drop off halfway down the track. If I want to run high 14's does that mean I need to pick 100HP to do so? I am running at 3600 feet! Should I launch from idle or from around 2000 rpms. My car is a 90 with an AOD.

pearl95sc
08-28-2004, 08:53 PM
A bigger TB and/or MAF would probably help somewhat. Although you have an OD pulley, the amount of incoming air is limited by the smallest bottleneck in your intake tract. Also, get a shift kit, or the lentech valvebody upgrade. You will feel the difference. I did one in my 94, and with 4 people in the car, it will still get squirrley into 2nd gear at full throttle.

As far as racing is concerned, with my 94, I launch from around 2200-2600 rpm. Depends on how tacky the surface is. I get minimal spin going this route. Kinda gotta play around with that. Even though you may get some spin, its better than falling and getting a worse than normal driving takeoff.

Conan56
08-28-2004, 09:11 PM
Try a 5% pulley the 10% is a bit much on a stock Intercooler

Shockwave
08-28-2004, 09:25 PM
Try a 5% pulley the 10% is a bit much on a stock Intercooler


I don't think the 10% is too much for 3600 feet altitude.

tim
08-28-2004, 11:05 PM
Dont feel bad the first time I ran my car it was slower than yours with mods. I didnt notice if you had exhaust mods. If not they will help a lot. I went from 14.958 to 14.30 with pulling the a/c condenser out, i.c. fan on a stock i.c. and drag radials. With tires I launch at 2300. the lentech valve boby lets you shift where you want. The bfg drag radials are on sale at tire rack for $112 each a real steal. Good look and keep trying. One more thing, you may want to try a 5% pulley till you upgrade your intercooler.

SCaddict
08-29-2004, 12:25 AM
I have full exhaust. I just can't believe that I am still near 16 seconds. The car seems to go good for the first little bit and then kinda goes flat. That is why I am thinking of an intercooler fan, maybe the intercooler is getting heat soaked.

tim
08-29-2004, 01:35 AM
Thats what mine was doing. Get the fan. Before you put it on put your hand on the intercooler and piping going to the intake. Then put the fan on and do the same thing. I would guess the differance is 35 or 40 degrees. One of the cheapest and most efficent mods you will make. Tim

SCaddict
08-29-2004, 02:13 AM
I am going to do an intercooler fan and hook up a manual switch so I have full control over it. I guess it is time for the AR.

Big Cat Davo
08-30-2004, 04:18 PM
That is a little higher than what you were expecting, but that is usually how it happens. You 60' time is pretty decent for street tires. My best 60' on street tires is 2.2. My best run in Calgary was a 15.17 ran last October, right at the end of the season at a SCCoWC Alberta gathering. I can think of two things off the top of my head that is killing your times, but more likely it is not one or the other, but a combination of the two.

1. I think you are pulling timing on the top end, pretty harsh. It is wither from running lean or from heatsoak. I wul dhead over to Toma's he is a cool guy and chages like 60 bucks for a baseline pull with AF ratio. That should give you an idea of what is going on. Either you are running lean and pulling timing or you are heatsoaking the IC bad and pulling timing. How much boost are you seeing with the 10%? I don;t imagine that it is too bad. I run a 5% and only see 13 PSI at 2300 feet.

2. Your tranny is slipping and/or shifting poorly. Like I said before, you get out of the hole not too bad, and the 330' time, if I can recall, is also consitant with my Calgary runs that were under 15.5. But your MPH and all you times after that are way down. It could be that the Tranny is in need of some work, be it the clutches or whatever. A shift kit may help, but if you have mod money to burn then a Lentech Valve body will really help those times. Oh, and how are you shifting . . . just putting it into D and letting the car do it, or using the effective but tranny eating 1-D-1 shuffle.

Hope this helps a little, and don't get discouraged. My first passes in the Cat with the gutted stock exhaust and the 3.27's netted me solid 16.6's. I eventually worked it down to 15.9's before I started the other mods. I am sure that with a little more seat time you will improve. The track was very slick Friday night, my buddy John in his 30th TA pegged the Rev limiter after is his two shift even with DR's, the track prep was poor.

Dave

SCaddict
08-30-2004, 06:35 PM
Dave,

Ya, the track was very poor! My buddy has a GTA and he ran 2 seconds slower on the left then he did on the right, and it was not driver error. People were losing traction half track. Some almost hit the wall. Today I removed the A/C condensor and i can't believe how much more air will hit the rad and intercooler. I think that will help me a fair bit.

Big Cat Davo
08-31-2004, 09:49 AM
I look forward to seeing the results. I think i will be going with a shorted AC condenser, rather than none at all. You going to be running Friday again? Oh and my buddy got you on video, if he gets around to encoding it I will let you know.

Dave

007_SuperCoupe
08-31-2004, 10:34 AM
Double check for vacuum leaks. They will cause you to be quite a bit slower than you think...It slowed me down over .5 in the 1/4. Higher elevation will probably cause that number to be bigger.

SCaddict
08-31-2004, 11:34 AM
Dave,


I will run in 2 weeks. I am going away for this long weekend. I will post the results.



007 supercoupe

I have no vaccum leaks but the elevation is killing me.

007_SuperCoupe
08-31-2004, 11:45 AM
Dave,


I will run in 2 weeks. I am going away for this long weekend. I will post the results.



007 supercoupe

I have no vaccum leaks but the elevation is killing me.



You may not think that you do, but it is worth double checking. Trust me on that. My cars have had vacuum leaks at the top nut on more than one occasion, after I had resealed them. I finally got tbird88's gaskets and haven't had too much trouble since...just the top nut loosening up gradually causing another leak...Doesn't hurt to double check.

Big Cat Davo
08-31-2004, 11:57 AM
Have a good weekend buddy, a will watch the boards for your results. I should be back in Canada in October some time. If race City is still open I will bring the Cat out to play.

Dave

XxSlowpokexX
08-31-2004, 12:16 PM
Did you rebuild your differential when doing the gears? 9 out of ten SC's I seen run at last years MM&FF shootout were in need of a diff rebuild.

It also sounds like timing is being cut out. My car was doing the same thing at one point. WHat kind of boost are you getting?...I'd still give the larger pulley a try

Coast to Coast SC
08-31-2004, 12:29 PM
Your times are nowhere as bad as you think. The NHRA correction factors for 3600 ft are .9562 for ET and 1.0465 for MPH. Applying these gives you a 15.234@88.58. Don't worry about your RT's they don't add to your ET. Work on getting that lauch down into the 2.2xx range and you'll like the results. Also between runs, get some bagged ice on as much of the intercooler and pipes as you can. Lastly be sure to get rid of all the heavy stuff that you can. A toolbox, spare tire, jack and a cooler can add a tenth quite easily. Good luck next time.

Anthony

Micahdogg
08-31-2004, 02:04 PM
Mac CAI
ASP 10% Overdrive Pulley
Ported Exhaust Manifolds to 2.5" to 3" to 2.5" Pipe
Magnaflow Mufflers and Resonator
SCI Jackshaft Pulley
180 Thermostat
BHJ Balancer
SCI Underdrives
3:73 Motive Gears

Your short time is killing you. 2.3 anything sucks. Cut it down to the 2.1 range and you'll be easy mid 15's. You must be experiencing wheelspin with 3.73's and that bad of a time. Do you empty your trunk, run with less gas in the tank, etc...? I would also disconnect your accuators from the front shock towers. You'll be amazed at how just another inch of lift helps plant the rear better.

I'd work on the launch.

Micah

David Neibert
08-31-2004, 02:25 PM
I don't really think wheelspin was his problem...but I could be wrong.

I know from PMs we have sent each other that the car wasn't allowed to cool or iced down before racing, and we all know that racing a hot car can add a 1/2 second to your ET.

Another thing was launching at 2600 rpms on a stock converter. Any torque mulplication from the converter was lost because stock stall is 1800-2000 rpms, and standing on the brakes and throttle only make an already heat soaked motor hotter.

There is no need to go over 1100 rpms when launching unless your running on street tires and trying to reduce wheelspin. The whiplash effect of the converter flash stalling at around 2400 will really help get that heavy car off the line. If your spinning the tires, I would first try reducing the air pressure to about 25 psi, if your still spinning I would suggest rolling into the throttle instead of flooring it.

The quicker you allow the engine to rev up the harder/quicker it will launch (even if tires are spinning some). Holding your foot on the brakes is just heating up the motor and killing bottom end torque.

Considering the mods, altitude and the items mentioned above, I think the car did pretty damn good.

David

Big Cat Davo
08-31-2004, 03:13 PM
I am sure Dave N. can give you some really good advice on launching the Auto, it is something I have no experience with, so will not comment on. The reason SCaddict is dissapointed is our mods are very similar and I am almost a full second faster.

The biggest reason that wheel spin and the 2.3 three 60' time did not throw big flags for me is that I have a lot of exerience on that track, and the track prep sucks big time. Us Canadians seem to get hosed on the track prep, ask XR7 Dave about the Track prep out in T.0.

To me, the big indicator that something may be amiss is his MPH. Our mods are almost identical, I have a fuel system (38's, 255lph FP and the 75 MM MAF to with it) that I do not make the power for yet, and he has underdrives that I do not have. The only other differance is the 5 speed vs the auto. You would think we would be pretty close. My best MPH in Calgary is 92 and change. His is 84.

I think Dave N, may be on to something. I ice the crap out of my Blower and IC.

Dave

SCaddict
08-31-2004, 08:08 PM
Big Cat Davo,

Believe me, I am listening and doing everything that David Neibert has to say. He has been very helpful to me. If your buddy could get the video for me it would be great! I would love to watch it on tape. To answer your question I am getting about 11psi at 5000rpms here.

Damon,

I did rebuild the entire rearend. Including trac-lock and all that jazz.


Coast to Coast SC,

You mean I have to get rid of all the dead bodies in the trunk! Why didn't someone tell me before.

Micah,

I am going to work on my short game a little and launch like David N. has suggested.

tim
09-02-2004, 05:30 AM
Just a thought first time at the track 15.958. on a motor with lots of mods. Pulled the a/c condensor. Added a i.c. fan and a set of bfg drag radials. 15.30. Pulled off the front sway bar and the a/c compressor. Also cleaned up my dragging front breaks. 15.154. Keep tweeking. Next is a double intercooler.

Jeremy_K
09-02-2004, 12:11 PM
I went to the track last night and was a little disappointed. This is what I ran...

R/T .706 (that sucked)
60' 2.356
330' 6.696
1/8 10.260
MPH 69.35
1000' 13.337
1/4 15.932
MPH 84.64

I thought with mods I would be in the low 15's. Any ideas why I am running so slow? I think I might install an intercooler fan for next time as my car seems to drop off halfway down the track. If I want to run high 14's does that mean I need to pick 100HP to do so? I am running at 3600 feet! Should I launch from idle or from around 2000 rpms. My car is a 90 with an AOD.
i ran a 16.1 the other night with the same 60' time as you and trapped at 85.something MPH. my R/T was much better I don't remember exactly it was like .05. you killed me at the 1/8th though my 1/8th is always in the 10.38-10.40 range. it's these damn AOD transmissions. They suck on the top end. i'm gonna try an IC fan and exhaust. what elevation are you at? i'm around 5200' at albuquerque.

SCaddict
09-02-2004, 02:40 PM
NMXr7SC,


I am at 3600 feet. I believe that my biggest problems are heat soak and bad launching.