Right now on motor, My car makes 600-640 to the crank, and I am running 28-11.5-15 hoosier qtp's and a 3.73 rear gear. My car won't do any better than 1.70's in the 60 ft, and that is leaving at around 3500 rpm.
My question is do I need to go with a smaller tire or different gears?

 

My mustang with a carbed 6 liter and trex cam, th400 and 3.73s using a tight 4500 Revmax converter would hit 1.5s, this was using a 26x10.5x15 ET drag, so I surely say get a 26" tall tire.

This was all motor.

 

Could it be my nitrous converter, I know it's really tight.

 

Could it be that I have a 3600 nitrous converter?

 

What kind of car? What tires? What is your tire pressure? Any mods on your rear suspension?

 

Do you have a transbrake, or are you foot braking it to 3500? I would assume that is on a transbrake. So in that case, with the 1.70 sixty, is that dead hooking, or are you spinning some? Just trying to add this all up, back when I was running my car N/A, it was TH400, 3.50 gear, 28" MT tire, 379whp. I would transbrake launch it at 3200, and it would only pull a 1.81 sixty. I decided it needed more gear, so I swapped to 4.57's, and the next time out, nothing else changed, 1.63 sixty, still dead hooking. So then I decided it needed more power, and I went back turbo... ET's to be determined soon. lol

 

What ET and mph does the car run?
And how much does it weigh?
How many cubes?

I wouldn't switch to a shorter slick. Tall tires just hook better, the contact patch is longer.

Also, cars tend to go quicker if you don't foot stall it to the max.

My 700hp rat had same trans with 3.73 gears. I ran the quickest leaving at 1800rpm. Converter flashed to near 4500. Tires were 30" and the 60ft in the high 1.30's.

You might need a diff converter and maybe a 4.10 gear. I think the conveter would have the biggest effect.

Hey Jordan.

Ron

 

Haha, hey Ron! Fancy seeing you around here!

 

My car is full weight, less spare tire, and battery in trunk, I'm running hoosier qtp's 28-11.5.15at 11psi and skinny tires in front. It seems like it doesn't matter If I use the foot brake @ 1900-2000 rpms or trans brake at 3500 it doesn't 60ft better than a 1.70, and I'm not spinning. Right now in the 1/8th I'm running 7.55-7.65 @ 92-93mph, I also figured out that if I hold the pedal to the floor with the trans brake it won't go past 4k rpm's, should I just launch that way?

 

How many pounds is full weight?

 

Sorry I have no idea, I never had it weighed.

 

You did any changes to you set up? Any updated results?

 

My vote is on the converter. I'd also avoid going to a smaller diameter tire.

 

you might try more gear in the trans-2.75 1st ATl

 

Will the car be sprayed? If so have you sprayed it?

You can't have both motor and nitrous and be perfect. However, it sounds tight enough for 2-300 worth of nitrous.

 

Here is an update, so I had my car weighed and it weighs 3758 with me in it. this was the last pass I made with a 200 shot on a 295/55/15 mt et sreet radial.

 

that was leaving on the trans brake @ 3400 rpm and ramping in the nitrous from 60% to 100% over .65 second on the progressive controller. I now have RADIAL PRO tires but haven't tried them yet. What do you guys think? Thanks for all the help!!

 

Well its a lot better thats for sure.