JClaw

Not a f-body but I had to ask anyway.

Would you guys bother with 15" nittos on a very light car (2300 lbs or so with me in it) with maybe 300rwhp and very aggressive gearing? They have 275/50/15 or 275/60/15.

Is it harder to hook a 3500 lbs car with 450rwhp or a 2300 lbs car with 300rwhp, all else being equal?

WhiteSSP

Lighter is always better.

CrawlinWS6

iTrader: (41)

The lighter the car, the less amount of weight on the tires, causing more traction issues.

BlueSix

If you're drag racing this 2300lb, 300rwhp, aggressive geared car i'd put a full slick on it.

JClaw

Yeah I might look into that... Im gonna see what it MPH's on street tires first.

But does the fact that there's less power required to run the same ET in a lighter car outweight the lesser amount of "thrust" on the tires?

11SECSS

iTrader: (199)

My car is some what light around 3200 and making about 340 rwhp. I know the 17" MT drag radials slowed it down compared to a 17" Nitto drag radial .But the best times came from a 15" ET STREET tire.

Bitemark46

I would say it depends of where the CG is. But I would opt for the light car w/ 300rwhp. Less weight = less stress on drivetrain parts. But the good thing w/ a light car is you can actually add some weight and be faster. Alot of guys that race in NMRA are way under the class minimum weight so they stick 50lb weights in the trunk and the car comes in right at or just over the legal limit. -Mark

JClaw

Why do you think the MT's slowed you down? More rolling resistance?

Also what is your trap speed @ 3200 lbs/340rwhp? Does 3200 lbs include you?

That's interesting... The car is a stripped '89 240sx with a VQ35 up front. I actually weighted the complete engine on a bathroom scale. It weights 260.

Weight distribution should be something like 48/52 or 47/53 because the stock engine weights a ton compared to the VQ. So the CG should be further back.

I haven't finished my swap yet but here's what it looks like in an S14 with stock suspension:



Beleive it or not the motor is in the car, just the hood missing!

11SECSS

iTrader: (199)

My trap speed with the 15" is high 116 and best of 117.10 with a 1.61 60ft
My trap speed with the 17" MT is like 113 with a 60 of 1.69-1.72 11.9x-12.0x
My trap speed with 17" nittos is 114 witha 60 ft of 1.63-1.66 11.8x-11.9x
I also tried some BFG's 17" and went 114 with a 60ft of 1.64 11.8x

I think the MT hooked really good and the car bogged of the line then couldn't keep up out the hole plus the few extra pounds of the tires hurt it also weather was about the same conditions . The weight is close to that with me in the car.

JClaw

Wow... whatever I choose it's definately going to be a 15" tire.

Gary Z

Although you describe two cars with nearly equal power-to-weight ratios it is unlikely that all else would be equal. Your question reminds me of a heads/cam F-body compared to an LS1-powered Miata. Getting either to hook would require experimentation. Because of its shorter wheelbase, the Miata needs a better driver.

JClaw

I'm kind of new to RWD cars in general; why is a shorter wheelbase car harder to launch?