I think it has a lot to do with how fast your car is.
A 12 sec car may pick up more than a 10 sec car.
The faster you go the more it's going to take to go faster.

 

Well consider me schooled then! I was gonna buy a set of dedicated light weight front runners but I guess right now it isn't worth the cost.

 

Indeed. Seems most here overlooked that.

 

Or called ..... The point of diminishing returns

 

My first race car was a 14 second 1956 Chevy wagon, Jr Stocker. Crager Super Tricks (very light spun aluminum, 4" wide) & Moroso fronts were MUCH less than a tenth quicker than stock 15" steel wheels and 6.70 15" street tires. Nowhere near a tenth.

 

[QUOTE=VandykeT/A;17389757]I know a lot of things effect et but generally speaking if I'm running a Torque Thrust II with a 275 on it now, how much should I pick up going to a 3.75 skinny? Anything like .1 or close to it?[/QUOTEo

I think going from this set up to a lighter 15" rim and some skinny you could see close to a tenth.
Especially with a lite front runner.

 

My replica z06's weigh nearly 50lbs a piece. Again, there is more to it than just saying you'll go a tenth quicker or .04 or whatever. Too many variables to make any claim.

 

Word, if it didnt make a difference, why the hell everyone runs them?!

 

Run them and tell us your results, I think you will still be surprised!

 

Here is what I gained with skinnies... Same day at the track..




Stock Rally wheels and 245/60/15 BFGs, 55lbs each


Weld Magnums and hoosier 185 radials, about 27-28lbs each.



Proof is in the pudding. I have done this test several times.. Normally gains 1 tenth and 2 mph every time.



On my C5Z, my CCW drag pack knocks 70lbs off the car, and with the 26" ET Streets, I gained 11 mph at the strip compared to running stock 17x9.5 Speedlines all around with 275/40s up front and 28" M&H Racemasters on the rear.. Granted the 28"s were killing the 3.42 gears with the stick and most of the gain in mph was from proper gearing to the power band.. But yes, it gained 11mph with no other changes..

Needless to say, the 28s were sold..lol

 

So, what are you going to call that? A tenth?
You picked up almost as much between your two passes with the skinnies as you did changing to them. Only valid test in that case (we call it A-B-A testing) is to change back to see how much it slows back down, then average the difference. If you trailered the car your fluid temps warming up will account for much of that difference.

 

Why oh why do you run skinnies then?

 

If you were building a real race car would you be dumb enough to put ugly, heavy, factory tires and wheels on it? I hope not.

Not everything we do to a race car is done with the thought "This will be worth another tenth."

 

I do it to match the rear wheels

 

GM has some of the better factory wheel designs out there but I guess that is an opinion. What does heavy have anything to do with anything? Its just funny that you say skinnies are worthless yet you have them as well. Your reasoning behind it, even better. Why don't you do back to back to back to back to back to back testing since no one else is qualified to?

Mine don't match

 

I didn't say they are worthless, but not worth a tenth. I have drag raced with NHRA for over 50 years. I have tested more than you ever will. You don't get fast by guessing at ****. You have to learn how to test correctly, or you will never be faster than anybody else.

 

**** got serious!

 

Nah, you just don't go to the track, make a pass then throw the new part on the car and call the next couple of passes the results. Everybody I race with make a few runs to make sure the car has settled in, and stopped picking up. They most always pick up after getting the engine oil warmed up (can make a big difference) get the Trans fluid up to temp (higher than normal street driving) and gear lube warmed up. Many racers have heaters in the trams, eng oil pan, and even the rear end. The only way to know for certain how much something is worth is A-B-A testing. I have never found more than 5 hundredths swapping fronts like that. Since he picked up almost half his gain AFTER the tire/wheel swap, it appears that is about what he found. That car isn't real consistent.

 

Well it sure is hard to notice the difference in ETs with skinnies unless your vehicle is dialed in perfectly and launched at the same RPMs all the times. Transmission temps, oil temps and weather has a big influence also. Not trying to get all Albert Einstein up in here, LOL, but thats just my opinion.

 

Who won?