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poor 1/4 mile times

13K views 45 replies 24 participants last post by  SpeedDoc 
#1 ·
I ran my car at the track a few weeks ago and was dissappointed. I have no mods beside a blitz nur-spec muffler section and a TXS BOV. I ran a 14.73 as my best time. I know it's not my driving. I had great 60 foot times and the like. It was a rather hot day and I didn't have any ice to cool my intercooler between runs. Is it possible that the temp and conditions that day are the reason for my slow times? I don't know the elevation but the temp was around 85.
 
#29 ·
Just bought an 05 WRX like a month ago. Ran it at SCO Nights last Saturday. Best run was a 15.02, 91 MPH, 0.2 RT and around 2.0 60 foot, Bone Stock. I've been doing 7000 launches, where I basically step on the gas till it hits red and bounces back and forth. Then dump on the 3rd yellow. How much of this can the stock gearset handle before I replace it? Do you guys think it's better to ease out instead of dumping like that? Can you explain some more launching techniques? Also, only one person responded to the question about shift points. Is it the general consensis that around 6.5k is the right place to shift?

Thanks for you help.
 
#33 ·
IBAUCLAPlaya,

Out of 3 runs, on 2 of them I did a little nose dive after the launch. Also, I don't think I quite have a feel for my shift points yet. I'm pretty new to racing so I still need tons of practice. I bet if I had more experience I could've ran at least a 14.8. A well experienced driver could've ran a 14.6 i bet. So yeah, that's probably not that great of a time, but I'm gettin there :cool:

How much stress can the gear set take from launching? I mean, I'm completely stock right now, until this weekend. As for launching though, I'll look around for more descriptions on how to do it safely without stripping my gearset. Unless you guys don't mind explaining again. ;)

Thanks for the info guys
 
#34 ·
Yesterday, I ran a 14.3 @ 94 with only tanabe catback and turboxs BOV, two mods that aren't going to help me. My 60' was 2.0.. i was happy.. It came on my third run.. i quit after that, figured i couldnt get too much better, and nothing broke so it was a good day
 
#40 ·
sumdumgoy said:
Any particular reason? Would be cool to hear pros and cons of both methods.
shifting at redline versus shifting just after peak power output:

the theory behind shifting at redline is that the faster your crankshaft is turning when you enter a new gear, the faster you will get to max power output at that gear.
*Less Bog*

the theory behind shifting at or right after max power output is that since your car makes (for example) 170HP at 5800rpm, but 150HP at 7000 RPM, you would not want to spend any time at 7000.
*More Average Horsepower*

at least that is how I see it.

all that being said, when I shift at 6000 versus shifting at 7000, I do better at the track...
 
#42 ·
Rain_Racer said:
shifting at redline versus shifting just after peak power output:

the theory behind shifting at redline is that the faster your crankshaft is turning when you enter a new gear, the faster you will get to max power output at that gear.
*Less Bog*

the theory behind shifting at or right after max power output is that since your car makes (for example) 170HP at 5800rpm, but 150HP at 7000 RPM, you would not want to spend any time at 7000.
*More Average Horsepower*

at least that is how I see it.

all that being said, when I shift at 6000 versus shifting at 7000, I do better at the track...
That makes perfect sense. I guess the trick is knowing where your max power points are. Any secret to knowing that. ** sorry for the noob question ** When I got dyno'd or all the dyno's I've seen done only do 1 gear, is that correct? If that's true, is the power curve the same for all the gears or would it be different?

leewmlds,

Is there anything specific you noticed that changed about your driving to get you to those numbers?

thx
 
#43 ·
sumdumgoy said:
That makes perfect sense. I guess the trick is knowing where your max power points are. Any secret to knowing that. ** sorry for the noob question ** When I got dyno'd or all the dyno's I've seen done only do 1 gear, is that correct? If that's true, is the power curve the same for all the gears or would it be different?

leewmlds,

Is there anything specific you noticed that changed about your driving to get you to those numbers?

thx
well my shift points came from the fact that my local 1/8 mile strip is never crowded on test and tune days, I have probably made 40 passes, just dont launch hard, let your intercooler cool off between runs, and your car can handle LOTS of runs in one night.

*trial and error*

but as for a good rule of thumb just try to notice when your car stops pulling hard, and when you know if you shifted it would pull harder, it is all about torque to the pavement... well at least for the first 1/8 mile.

really the biggest secret is that knowing your car can mean the difference between a 16 second 1/4 mile and a mid 14s time. Practice makes perfect.

Also the first gear ratio sucks a lot on a WRX so I shift to second at a lot lower an RPM than I shift into third.
 
#45 ·
Cosmo said:
That's the beauty of launch control. I don't have to let off the gas to shift. It limits your RPM's to a pre-set limit (5500 rpm in my case) when the clutch is depressed. So, your throttle body stays open and the turbo stays spooled in between shifts. I noticed a difference of about 1/3 second from not using it to using it.
Yes, I'm looking forward to wiring up a lauch-control mod in my car in the coming weeks that will do just what you explained. It'll act as a "stutterbox", and will allow me to shift without lifting. Oh, how nice that's gonna be.
 
#46 ·
WRX Tranny

Rain_Racer said:
well my shift points came from the fact that my local 1/8 mile strip is never crowded on test and tune days, I have probably made 40 passes, just dont launch hard, let your intercooler cool off between runs, and your car can handle LOTS of runs in one night.

*trial and error*

but as for a good rule of thumb just try to notice when your car stops pulling hard, and when you know if you shifted it would pull harder, it is all about torque to the pavement... well at least for the first 1/8 mile.

really the biggest secret is that knowing your car can mean the difference between a 16 second 1/4 mile and a mid 14s time. Practice makes perfect.

Also the first gear ratio sucks a lot on a WRX so I shift to second at a lot lower an RPM than I shift into third.

I picked up my '05 WRX last night and am wondering what can be done about the 5sp. Even with the Subaru short-throw shifter it seems a little sloppy and you can drive a truck through the ratio spacing. I'm used to the sublime 6sp in my '01 S2000 and might consider swapping out the 5sp for the 6sp from the STi but am wondering if there's a cheaper "fix." Any suggestions?

ab
 
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