NSFW

I realize this depends on a LOT of variables. I'm most interested in what it takes with stock '02 C5Z gearing. And Dunlop Z2 tires in stock dimensions. And 68F. And assuming all drivers are spherical and frictionless... But really, any examples would still be interesting. I'm just looking for a rough idea of what it takes.

And horsepower numbers would still be interesting, if that's what you know best.

The reason I ask is that I figure that I won't get a whole lot of value from having much more, so this would probably be a good goal to use for planning upgrades.

Thanks!

dbgoodwin

I've known cars that stick in 2nd with 500 foot pounds of torque, and those that spin with 200.

I would say as a generic opinion 500 at the tire in these cars should hook in 3rd

c4cruiser

I have a Vortec supercharger in my '02 coupe and with 450 RWHP and 405 ft-lbs of torque, I can light the rear tires up in 3rd after getting RPM's up around 3000 or so. The tires are Goodyear GS-D3's in Z06 sizes.

Of course there would be variables. The Z06 M12 trans has a slightly different 3rd gear ratio (1.43 in the Z06 and 1.30 in coupes) but the diff gears are the same at 3.42. Weight will play a part too (Z06 is about 130 lbs. lighter than a coupe) as will tread compound, tire temp, air temp, and the road/track surface.

dbgoodwin

Shaolin Crane

That's about right with a 3.4" stroke and 7-9psi

djmlax89

My tires are probably around 35% or so on F1 Supercars, but I usually get some wheelspin on a hard shift to 3rd on a warm road. Mostly stock 03Z with bullets, halltech and ECS tune. I'm sure it'd dead hook with better tires.

Kingtal0n

it goes

engine rotating torque -> transmission torque multiplication -> differential torque multiplication

The torque you have at the rear tire in 1st for example is well over 1000ft*lbs of leverage. Likewise I could spin the rear tires in 3rd if I had a 100 ft*lbs of torque at the engine but it went through a 10:1 differential gear or something crazy

Gordy M

The easy way to light up the tires in 3rd is to use old worn tires. The loss of friction of hard tires makes the torque needed to break loose much lower.

Mike94ZLT1

LS1's have a 3.622" stroke, and regardless, 7-9psi should make a lot more than 405 tq to the tires. Plenty of guys are hitting his numbers with bolt-ons and a healthy cam.

c4cruiser

The blower is set at 7 psi and outside of a Corsa cat-back exhaust, the engine has no internal mods. Stock cam, stock exhaust manifolds, stock heads. It does have 42 lb injectors. Wish I could find the dyno sheet that showed the power curve and what RPM, but I do recall seeing the 405 figure.

Shaolin Crane

Blah, I always forget they have a small bore. I was figuring with a stock cam though, either way that's not off base.
That's what I thought.

Quickshift_C5

My car has about about 640ft-lbs of torque (550rwtq), and it won't spin the tires in 2nd if I quickly feed the throttle in. If I stand on the pedal instantly, it'll spin if I'm 3k or below. Every other gear dead hooks no matter what. This is using Toyo R888's in 305/30/18.

UNLIMITED408

My stock 04Z with street radials will spin and get violently sideways powershifting into 3rd. Since I put 19" CCW's wrapped in 305/30's it will still get sideways but not as bad.

Sea level and rowing gears might help some

knewblewkorvette

I don't remember what my 98 had for tq but she had 767 rwhp. That thing could easily break the tires loose in 3rd. Damn right scary when you are doing 80-90 mph.

I was under the impression the more wore down the tire, the more surface contact it has. The more contact, the better the traction. This is of coarse is not true when it is wet though.

dbgoodwin

Kingtal0n

Thats another thing. I can get 650rwhp from a dynojet and 480rwhp from the same car on a mustang dyno. The number is useless, irreverent, unless you give correction factor specifics or are using an actual dynojet to dynojet comparison (because dynojet always has the "known" roller weight)

NSFW

I'm not looking to compromise my car's performance, I'm trying to get a sense of how high I should aim when choosing upgrades.

NSFW

I tried to list all of the variables I could think of....

You got me. I missed that one.

Kingtal0n

In real drag racing where the engine is setup for high rpm performance, all you care about is finishing in 1:1 transmission gear and as much rear differential as possible to get you to the end of the 1/8, 1/4, 1/2, or mile run. Or whatever.

For example, a 3000lb vehicle with 500 horsepower, if it can achieve 6000rpm then the ideal rear gear is around 3.88, but if the engine can go to 7000 the gearing can be steeper like 4.50. Higher gears multiply torque better, and cause the engine RPM rate of change to increase (The differential of RPM is the rate of change of RPM). It means the engine will also go to a higher RPM faster which is good when the engine is setup for high RPM drag racing conditions.

If we put a 4.5 in the rear with only a 6000rpm redline, however, the engine will max out speed before it can finish the 1/4 mile. So just imagine trying to do a 1/2 mile with a gear like that. It would be maxed before even going halfway.

Check how easy and quick you can do the math these days:
https://www.motivegear.com/wp-conten...alculator.html

NSFW

I should have mentioned in the beginning that I'll be using this car for road-course lapping days. Not racing, just lapping. It might get drag raced once or twice just for grins, but I really don't care what times I end up with.

I'm just looking for some examples of what it takes to spin the tires in third gear on a reasonably well set up car. Summer tires, around 200-300 treadwear, Set up for road courses.

Again, just because I won't get much benefit from spinning the tires in fourth. If I have enough to spin the tires in third, I'll have enough. So I'm wondering how much that takes.