trailor

Ok last year, I went to the track on a perfect night. Track was prepped, weather was wonderful, etc etc. My power-adding mods were LT's w/ O/R H pipe, 75mm TB, JLT short ram intake piping & filter, and a pretty basic tune from Delta Force (Sniper) Special Forces w/ 93 octane and +2* on the Global Spark Modifier. I was running sumitumo htr-z II street tires (had maybe 3k miles on them). My best of the night was a 13.98 with a 2.2 60', while my friend ran it to a 13.88 with a 2.1 60'.

Since then, I have put on b/w 5k-8k more miles on the car, plus I have added a PP 75mm "Upper Plenum" Elbow, 4.10 Motive gears, UPR Adjustable LCA's, MM Panhard Bar, 24lbs injectors, 180* thermostat, and made a tune practically identical to my old one from special forces, that accounted for the 24lbs injectors and 4.10 gears (tried to write a tune in commando that also accounted for the 180* t-stat and fooled with some other spark advancement settings, but it didn't run right, so i tossed it). I also decided to add a bottle of Gumout Octane Booster since I still had about 3.5 gallons of 87 in the tank. Still ran on the same street tires. I welded up one of my two torque boxes (ran out of time for the other one). I also removed the quad shocks, as I was told they were no longer needed with aftermarket LCA's. Still had some wheel hop on small burnouts....

STILL ran a best of 13.98 w/ a 2.2 60'! The weather was about 15* hotter than last time, and a good bit more humid. Track was still prepped, even better and sticker however than last year. A different friend of mine who has more seat time with mustangs than the other guy consistently ran a low 13.9 with a 2.1 60'. I understand that the heat and track conditions make a difference, but I can't believe that with 4.10s and LCA's I would be running the same exact times. Any ideas with what's going wrong here??

TRUEBLUE3934

Higher temp and more humid air will effect your power output!!!
I agree that the 4.10 gears should have dropped your ET a little, even with street tires. You don't mention what your Trap Speeds were both times out. That typically will reflect how much power you were making, unless you had significantly different weight between the two outings.
Give us just a little more information...

oxfordgt

For 1 you didn't add anything that would have given you anymore power. Second you added LCA's and 4.10's but still ran street tires. LCAs really don't do much unless their custom made and not in the stock location. Adding the 4.10s with street tires canceled out any benefit the LCA could have given you.

trailor

trap speeds this year and last year were both between 102-104mph. my 13.98 run yesterday had a trap of 102.69 to be precise, and i also had a 14.08 run with 103.9 trap. can't find my slips from last year, but it was in the same range. the weight was practically the same. i added the weight of the PHB, but removing the rear sway bar and having lighter LCA's with the quad shocks and their mounts removed should have just about cancelled each other out.

oxfordgt, i was under the impression that the LCA's would help with better launches and grip, etc. even with street tires. i was still losing traction on all my shifts, mostly, however, on my 1-2, in which i tried to compensate with some feathering. if what you say is correct, i would be very relieved, because i was thinking something more serious. still sounds kinda weird that the drastic difference in feel of 4.10s wouldn't net any gain in 1/4 mile times...

oxfordgt

Slap on some drag radials and you'll go faster.

I would have done upper control arms before lowers. A mustang suspension is designed for highway driving not drag racing, you have to change the geometry for any real improvement and basic $100 uppers and lowers like from MM or UPR won't do it.

trailor

i am currently in the process of changing the geometry, once i install my torque arm there will be no need for UCA's. just having trouble coordinating times with my welder. hafta get the FLSFC's on first... after all that work is done, i will be getting smaller rims and DR's. still, i was hoping to have seen some gains before that time..

TRUEBLUE3934

4.10 gears should have helped your ET's a little, even with the street tires (unless you now have another gear shift which could offset the gain somewhat). You can't take full advantage of the additional torque multiplication without sticky tires, but the car will pull harder all the way thru each gear with 4.10's.

Your slower ET but higher trap speed tells me that you had some wheel spin on that pass.

Don't fret over the results just yet. I would almost bet that you were making a little less power, but made up for that with the gears. Definitely get a custom dyno tune made to optimize your set-up! I'm guessing that you are giving up some benefit from your mods right there.

DRs will absolutely help drop at least 0.5 off your ET(probably more like 0.75).

trailor

yeah, i do need to do some digging into my tune, trying to work out the kinks. i'm guessing the "canned tune" from special forces just ain't doin the trick. i'll fool with it more in depth once i hook up my wideband. thanks for the reassurance, i just got so discouraged seeing the same results, after seeing some people on here gaining up to several tenths of a second on just a gear swap. i knew the weather wouldn't help either, but man... just a disappointing track day.

oxfordgt

Wrong unless you are into road racing. Torque arms are not for drag racing.

trailor

i went for the PHB & TA setup bc i wanted an overall better performing vehicle. that simply can't be accomplished with aftermarket UCA's (Jazzer's guide gives a simple explanation as to why). with the PHB & TA, the upper control arms no longer funtion properly, and are thus removed, changing the stock 4-link suspension to a 3-link. i understand that it won't net me great benefits for drag racing, but it still should provide some, based on my research.

EDIT: The info pages on the torque arms offered by MM and Griggs both mention increased dry/wet traction, as well as better launches at the strip and improved traction under harsh acceleration: MM's TA page and Griggs' TA page