I just returned to the track after about a yr of not drag racing.... waiting till I could put in billet shafts. Now I need help from those with more experience!

Previous best was 14.2/104 in idea conditions with very light power breaking and 285 tires.
Since than have changed two things (other than billet) ..... Twin turbos and 315 tires.

Ran 13.13 sec/102 mph in 100+ temperature and a quartering 15 kt. headwind, with 20 psi launch and a 1.75 sec 60' time. Far from ideal conditions .... even had 200 lbs extra in the truck bed.

With these times... are the 35" tires hurting me all that much??

Rj

 

RJ, Your 60' times are great, but I think you need more injector. I've cut a best of 13.47@ 99.?? mph on stock shafts. With those 60' times you have a 12 second truck, easy. Tires are probably slowing you down too.

 

Thanks...I'm sure I can be in the 12's with better conditions... and better preparation (I still had low octace washer fluid in my bottle).

I guess my real question is.... If my tires aren't hurting me off the line, as proved by good 60' times, can they be hurting me much further down the track??

Isn't the main reason for stock sized tires....a good jump off the line? Don't larger tires actually help on top end?

I guess the only way to know is to try it....just don't have another set of wheels lying around!


RJ

 

larger tires help you off the line (less spin), then hurt you on the top end to a certain degree. You have to find a happy medium on tire size, I would say 285's on your stock rim size.

 

RJ........... Where was your rpm at through the traps. If at or right near redline, I would say your good. Banging the limiter at the 1000ft mark or so will slow you down a lot. 1.75 is a good 60ft, there is room for better but not much. 1.69/1.72 is smokin, not to many get faster than that. Everyone has a different opinion but I would use rpm as your gauge, max rpm right before the traps is good.

Fred

 

RJ, I've pulled a best of 1.66 on 285s at 23 psi but usually pull 1.75 leaving at 15 psi on 285s. I'd say the tires are hurting you some. And you know any headwind is going to hurt these billboards we drive. My 12.84 pass was with a 1.66 60 foot and a 8.21 1/8th. For bracket racing I usually leave at 15 psi and run consistent 13.0s in the 1/4 with an average of 8.30 in the 1/8 mile. I'm planning on dropping back to 265 Nitto's to see if my times will improve even though I think the truck looks better with 285s.

 

Thanks guys!
RPM at the 1/4 mile pole was my only real concern because I'm only 2800 rpm at 110 mph. Thought higher might be a little better.

With 4x4 launch...no worries about spinning on the line ... but I did get a "chirp" going into second, as the boost got up past 50 psi

I'll try some 285's when I get the chance and see how they do!

RJ

 

Thanks MC, Please let me know your results with 265's. Will be very interested. Look forward to meeting you at your July get together!

RJ

 

i watched a 98.5 short bed quad 4x4 run deep in the 12s last week, stock turbo with a big set of injectors and a comp. running on a set of 265s if i remember right. but the weather was nice, around 70 degrees, this was in michigan.

 

RJ,
I'll trade you your tires for my 285's

Still, a nice run.

~Rob