TRUEBLUE3934

Thanks man!
Yes, when I go to the track I remove the front swaybar, passenger seat, and rear seat bottom. When I arrived home with the car on day one, I popped the trunk and took out the spare and jack before I even went into the house. The dog bone on the rear end housing is off, since it was tuned for the stock gears anyway. The windshield washer tank is empty and I try to arrive at the track with right at 1/8th tank of fuel. I always put my 17x8 factory wheels and tires on the front (because they weigh ~7lbs each less than the 17x9 I run on the street). I also mounted my DRs on the other pair of 17x8s to keep weight down a little. The 38lb battery is now located in the right rear corner of the trunk. That is all of the weight changes that I can think of...

You are correct about the reduction of rotating mass. Especially at an average working radius of approximately 10". I am told that a decent pair of skinnies and tires are around 25lbs each. The 17x8's I run on the front now are 42lbs each. A reduction of around 34lbs of rotating mass should produce a measurable improvement. However, I am asking for someone to help quantify the improvement for me. There is not a good/easy way to calculate the improvement in advance. At the end of the 1/4, they will be rotating around 1475rpm. However, the majority of that accelleration actually takes place in the first 6 seconds or so. The rate of accelleration declines pretty quickly after that. So trying to accellerate the wheels from 0 to say 1100rpm in 6 seconds is a significant task. Having only 59% of the mass to rotate/accellerate is a big improvement.

KillJoy

Don't forget also the reduced friction, as your going from a ~245 to a ~165 tire. I usually average about .3 and 2-3mph

TRUEBLUE3934

WOW!
That is more than I had thought with my most optimistic estimate!!!
That may change the direction I chose to go in search of lowering my ETs some more. I'd really prefer to stay all motor and leverage that set-up, but I thought that I had pretty much exhausted what my budget would get me there. I was figuring spray might be about all I had left for options.
Thanks for the feedback!!!

Anybody else have results they can share with me???

5.0kid

back when i was running 10s i got about .12 out out of running skinnys vs a standard size wheel, if you dont already own some the cost of the wheel and tires is not worth the gain; you would be better off buying cheap dry shot or if you can afford it wet shot plate kit or nozzle kit

TRUEBLUE3934

Thanks for your input 5.0kid!!!
Those gains are probably more in line with what I was thinking I'd see. You were accellerating those wheels quite a bit harder than I will since you were running 10's. Realistically, it looks like I would see ~0.1 reduction in ET.

I figured the gains could not be too great because I just don't see guys ranting and raving over getting a set of skinnies. If they made a real nice improvement, I would expect to see more discussion about them. A set of skinnies would cost me about 75% of the up front costs to get a wet kit and accessories, but with only about 15% of the ET gain.

Thanks guys!!!

KillJoy

My timeslips don't lie..

With weld 15x8's in the rear on a 275/50/15 and 17x9 fr500's in the front with a 275/40/17 I cut a 12.77 @ 109mph with a 1.7XX 60'.

With the same rears, but now 15x3.5 welds with a 165 front runner in the front, the car went 12.4 @ 111mph with a 1.6XX 60'

WolfRugger52

Both the rotating weight and the reduced weight up front will help tremendously, hence why every proper drag racer runs them. But also you've gotta remember the rolling resistance is nearly zero compared to a wide sticky tire that you most likely run on the street for handling. As for time, I would have no idea but should be a bit if you can launch it.

Drag Racer Dave

I agree with the other post in here that weight/rotating weight will make a positive difference to your et. The other advantage of a “skinnie” is the reduced surface area of the tire that is on the track.

To that point my 96 GT is mostly stock (I am the original owner). The car will run consistent 16.000 all day everyday at Bandimere Speedway (~5800 ft with out alt adj). Nothing to brag about et wise, but I launch the car at 2500 and shift at 5000. Also I am a bigger guy and the car is in full street trim. My 16.000 are with the front tires at 35 psi.

Last fall at the last test and tune day I ran three passes 16.000, 16.00 and 16.010. I then over inflated my tires to the mfg max 55 psi. The car then ran 15.90 – 159.905 for rest of the day (12 more passes).

So for anyone that wants to pick up cheap et, you may want to look at taking the front tires to the max mfg psi. Bandimere has several air stations around the track so changing psi is really simple.

Yes I am well aware of all of the weight tricks that have been discussed in this thread and others, but right now my experiment is to run the car as is. What I am hoping to do with this car over the next season is add a bolt on or make a change and report back to the forum what the gain in et is to help those contemplating making a purchase to see what the bang for the buck is.

TRUEBLUE3934

More details KillJoy...
Were both of these passes on the same day? Do you have the timeslips to find out the 60' times to the 1/1000? Did the car consistently run high 12.7's with stock fronts and consistent 12.4's with skinnies? Is the 2mph gain also a consistent change? I'd hate to draw any significant conclusions from just 2 isolated passses. I ran 3-4 passes at 12.76-12.80 the same day I ran my 12.5 pass (no changes to the car, just got a better 60' on that pass and possibly a "majic" combination of shift points).

I'd love to get that kind of improvement from skinnies, but I'm looking for all the details for assessment AND additional feedback from others to help build a consensus on the magnitude of improvement.

If I can build further evidence of 0.25 second gains with skinnies, I will absolutely do them. I'm hoping for input from additional users.

5.0kid

No problem always trying to save people money by giving my expereinces out ive been through about 7 different motor combos running 13s all the way now to 8s. and about 5 different trans combos as well.

Now brother who has a 106mm turbo on his 350 95 camaro has full size stock wheels on all 4 with a pair of 295/60s on it ran a 9.20 on the foot brake with no suspension mods or weight reduction, he put a set of drag lights on the front and went 8.95