hey im new to this site, but i've heard alot about it. some of you guys know me from FTW.

anyway, a couple of months ago i went to the track with only a chip, cold air and a boost bypass. i ran a 13.1 with 1.9 60ft. i wasnt happy untill i get into the 12s. so i bought 3.73 gears, traction bars, and the 90mm MAF unit to help me get there. i took the Chip to JDM to get reburned for the new mods. i went to the track the following week and i ran 13.3 -13.6 all day with a 2.2 60ft time. some poeple told me it was the chip, and some said it was my cold air intake. my filter was real dirty and it was for an 80mm MAF. what do you guys think??

the temp was about the same. (55*)

i bought the bigger JDM cold air intake, and got Jim to reburn my chip. do you guys think im in the 12s?

 

If you 60 ft times were 1.9 you can compare the time slips. The filter size won't matter without added boost. What is the mph?

 

Yeah, your 60 foot times got slower.....

Your answer is.......

Traction bars and or slicks!

I have the same problem, no traction.

 

Yeah, you lost .3 in the 60' so that is the bigest factor since the most important part of the 1/4 mile is in the first 60' (IMO). Compare the MPH, what was it before and after? It will give you some idea.

 

i have traction bars. it was barely chirping off the line.

 

yysenhimer, the 13.1 was 105mph and the 13.3 was 102mph.

 

i know the 60ft time make a big difference... what do you guys think brought it down?? shouldnt it have went up with the mods i did?

 

how was the humidity? have it dyno tuned, it may be too safely tuned.

 

If you went down 3 mph it may be the amount of timing and air fuel ratio. It could have been too high and Jim lowered it or something else.

 

Almost the same thing happened to me...kinda. On my 01' Bolt i had a diablo chip burned by JL, JL Ram air kit, boost bypass and that's it. I ran a 13.06@ 103 mph. About a month later I installed a JL 3# pulley and denso plugs, and Bassani cat-back, and had my chip reburned for everything. Went out and the best I could muster was a 13.1@106mph. My mph went up, but my 60 ft times were consistently 2.1-2.2. I have some Nitto DR's now, so we'll see what happens. Plus I had my chip burned for cold weather, and after a short drive after cleaning the inside of my tips, they're coal black in like 20minutes. So I know I'm a little too rich. I'm sending the chip back soon for a summer reburn. CA gas sucks though, oh well. Call JDM and talk to him about the chip, good luck!

 

Hmmm...most likely the burn on the chip then unless there is some other problem. I have seen dirty air filters affect times and mph but I don't know about by that much. I would say call JDM and ask them about the burn.

 

I say the timing also Chef

Mine seems to run better w/more timing @17 degrees.
Right now I'm only at 15/16 and lost MPH also. (on Gas Runs)

Example
Last Yr (old Program w/17 degrees) filter-chip-n-4lb


Now this yr (new program w/15-16 degrees) filter-chip-n-4lb

#66 Lost 3MPH

Here's one where I gained a tenth and yet I'm still down on MPH
#47


I'm trying to have my timing re-done now. I'm gonna try 18 degrees for gas, and 16 for Nitrous.

I can't wait for the Predator to come out so I can tweak it myself.

But my (2) 12.0's @ 112+ MPH on Juice are still keeping me going for now.

 

Rob,

You are comparing apples to oranges. I assume the first run was at your local track. Besides the weather difference of the first run being in late October and the others in April, Cecil is known for being a quick track. Also, it looks like you were on tires unless you are cutting 1.75 short times on the F1's. Putting tires on not only changes the 60', but it changes the mph at the big end. I am not doubting you saying that you have lost et and mph with less timing, but maybe it is not as bad as you think.

 

I was chasing my tail for a few months in a similar situation. I kept increasing timing on my programs because each week at the track i was loosing a tenth here and tenth there, while all the while i was increasing my 60 ft times and adding mods.

First it was thought that there was a fuel problem. Then there was the " wtf did my boost go "... In the end, the problem ended up being the head gasket. Not saying this is your problem, but when your truck starts requiring over 20 degrees of timing to make up for lost times when all the other variables are all in line with previous bests, its something to look into.

It required oil falling on the ground to notice the gasket problem.

I hope you get it sorted out. It can be quite disturbing and frustrating.

 

Was one of the added mods in between the track times those wheels and tires? Big heavy wheels will slow you down. Plus the tire size (diameter) will reduce your overall gear ratio, hurting performance.