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View Full Version : Things that could be affecting my 60' times



SCrazy
10-01-2012, 03:18 PM
My 60' times tend to range from 1.62 to 1.67 they have been in this range for a coupld of years now and I've been on a bit of a mission to cut them down. My car has a trans break but the time will fall into this range whether I'm footbreaking of leaving off the transbreak.

Last time I measured my car it weighted 3650 with me in it. It has 27" tall tires and 3.73 rear gears.

Since I've been on this mission I've added rear air bags to reduce squat, added a roll bar to stiffen things up.

Last year I had a 3800rpm stall converter and used to leave off the transbreak at about 3400 rpm....I was convinced I need a restall on the converter.

My converter is now 4500rpm stall and I was leaving at 4000rpm+.

Nothing I've done has made a significant change to my 60' times so I'm looking for new answers.

I suppose I could change the gears to 4.10 or something but I'm trying to hold off on this option until I need new tires.

Could there be a tuning solution where the motor just isn't pulling hard enough coming off the line.

Could my alky injection be coming on too soon or too hard at the line and wetting things down too much.

Any comments or other suggestions.........

This thing will pull both front tires when it jumps off the transbreak then it just doesn't go like I'm hoping for.

XR7 Dave
10-01-2012, 06:33 PM
Too much alcohol too early will kill torque. Try tuning the car without it, and even if you feel you still need it down track, just try some 1/8 mile stuff without it. Or maybe even try to set it up so it comes on only above 5000rpm.

Kevin Leitem
10-01-2012, 07:47 PM
At what rpm do you have full timing? But i would agree with dave. Or I would ditch the meth and run full race gas. I would recommend VP MS109. Its oxygenated and unleaded. It will not harm your oxygen sensors

XR7 Dave
10-01-2012, 07:49 PM
I also think you should upgrade to the 4" intercooler. Won't help your 60's, but it will help your cooling. CX Racing has the exact same core in 4".

Kevin Leitem
10-01-2012, 07:53 PM
Also i just found out that my msd was still holding the two step on a little till i shifted into third. I couldn't figure out why my AFR was jumpy in 1 and 2 but when I shifted to 3 it cleared up. Then on sunday it started to happen in third. Didn't use 2 step on a pass and it cleared up and reved much higher and quicker.

SCrazy
10-02-2012, 07:44 AM
Thanks for the replies.

I don't recall the exact voltage the meth is triggering but it corresponds to around 3500rpm at WOT so it is definately running while I'm on the transbreak waiting to launch.

I believe the timing is currently set so that it has full timing at 5000rpm and above then steps down in 1deg increments for the next couple of cells down chart so at 4000rpm on the transbreak it should be getting close to full timing.

With this car now almost exclusively a track car I think if I changed the IC it would incorporate some kind of water based system although I currently never see IATs above 90 or so.

I've toyed with changing fuel to straight VP-109 as well.....I guess my biggest hesitation about that route is not being sure what I would need to do to the tune to accomplish this.

XR7 Dave
10-02-2012, 09:06 AM
Thanks for the replies.

I don't recall the exact voltage the meth is triggering but it corresponds to around 3500rpm at WOT so it is definately running while I'm on the transbreak waiting to launch.

That is definitely a problem.

neverfastenough
10-02-2012, 09:08 AM
Im trying to get my brain running, is there a way a relay could be used to kill the snow pump when the transbrake is active..........

CMac89
10-02-2012, 09:23 AM
I say ditch the meth if you're gonna use race fuel. The bigger intercooler is also a good idea. Both of these will allow you to run more timing. Other than timing, scaling the MAF curve a few percent will be the only changes you need to make to the tune.

Other than that, the things that will allow you to 60ft better is power, a looser, more efficient converter, and a good suspension setup.

1MTNCAT
10-02-2012, 09:32 AM
I say ditch the meth if you're gonna use race fuel. The bigger intercooler is also a good idea. Both of these will allow you to run more timing. Other than timing, scaling the MAF curve a few percent will be the only changes you need to make to the tune.

Other than that, the things that will allow you to 60ft better is power, a looser, more efficient converter, and a good suspension setup.

And................More gear and tire and less rotational weight if possible!! Lighter wheels??? ;)

DrFishbone
10-02-2012, 12:00 PM
Too much alcohol too early will kill torque. Try tuning the car without it, and even if you feel you still need it down track, just try some 1/8 mile stuff without it. Or maybe even try to set it up so it comes on only above 5000rpm.

I wondered about that. I'm using a boost-referenced controller on a temporary basis, so as soon as there is power to the rear wheels, it's already running. My 60's were all just a little slower than the past. The car didn't bog any though.

SCrazy
10-02-2012, 12:56 PM
I would certainly not say mine bogs at launch....in fact it hits hard....but it then just doesn't accelerate as quickly as I would expect. Gonna have to play with the meth setup.

1MTNCAT
10-02-2012, 08:55 PM
I would certainly not say mine bogs at launch....in fact it hits hard....but it then just doesn't accelerate as quickly as I would expect. Gonna have to play with the meth setup.

I'm not that familiar with the stuff but it does make sense. That certainly should be included in your plan to improve the 60's to see how the car reacts along with the other things.

BLOWN38
10-07-2012, 10:14 PM
Brian, I set my meth up to come on at about 4v and max at 4.5v trying to get some better 60's at the shootout. I don't really know if it helped but it kinda seemed to pull harder. I had a noise in the rear all day, so not sure if thats what slowed my car. Something was up as most of you guys where catching my times. But I did have my quickest time of the day on the 2nd to last run. And it didn't have much of an effect on the ACT's when I changed it.

Basically I set it to where the MAF voltage was when the car hit 3rd gear. So after I reset it it would come on about 4500 rpm instead of instantly where it used to be at about 3v which is about 2300 rpm.

ACT before the change on first run of day started at 104 and ended at 124. After the change 2nd to last run of day which was my last full pass ACT started at 116 and ended at 132.

I also run 103/104 race gas.