jahudso2

My car is the same way with 3.73s. I can't brake the tires loose from a roll. I think part of it is that everyone buys their 20" bling wheels and then they have no tire sidewall for traction. If you have the stock 17s, the tires have enough sidewall to absorb the power and keep you planted.

mygt500

Even if he didn't it would only affect the speedo/mileage and not the rotation as the gear is mechanical......
Though I have no sidewall I have great traction for 20's and being 285 wide helps (sure the added weight makes it harder to spin too) but to be honest who wants to spin anyway...other then for fun and burnout contests if you spin you lose....dont care how much HP the car makes if it doesn't get to the ground then whats the point.... JMO

alsGT

I had 4.10s installed a couple of weeks ago. I went through the 3.73 vs 4.10 decision like most. I read so many posts about tire smoking spin that it made me nervous to choose the 4.10s.
Don't believe it. I have the stock Perelli's on 17" rims.
I can dump the clutch and spin right through 1st, power shift and spin through most of second. But it is easy to take off very hard and not spin.

I even asked the question on one post: Will my tires spin from a roll?
The response I got was: "There is something wrong if you don't".
Bull. I am extremely happy with the gear choice. If anyone else is struggling with the decision, get the 4.10s, don't believe the hype about excess tire spin.
Al

Norm Peterson

A torque converter does a couple of things that either aren't normally done with a mechanical clutch or can't be done at all with one.

The first is the ability of a torque converter to allow engine rpm to rise somewhat independently of road speed. That's the "flashing" mentioned, when you nail the throttle the AT car's engine rpm will rise with little or no initial change in road speed, putting the engine up where it's putting out more torque. This you could perhaps simulate by riding the clutch and letting it slip under power (you'd have to really love the stench of burnt friction material, really hate your clutch and want to kill it off as quickly as possible to be doing this).

The second is that by design of the elements inside the torque converter (things like curvatures of the vanes), internal fluid flow can be made to multiply torque under some conditions. You can not duplicate this method of increasing driveshaft torque with a manual clutch, period.


Try stomping on it from a first gear roll at 4000 rpm or so. That's about where max torque lives and would be your best bet for getting wheelspin.


Norm

Riptide

Just to be safe last night after I got done reading a couple posts in this thread I went out and checked my clutch again. Did the 5th gear roll at 35mph and stabbed the throttle. Nope. It's fine. Just bogs like it should.

Guess I'm confused at this point as far as whether the car is behaving as it should or if something strange is going on. I'm seeing mixed experiences with some of these replies...

Without having another car to test against mine with exact same mods then I guess theres nothing I can do to get down to the bottom of this. If the car traps OK in the 1/4 and seems to run perfectly fine what else am I supposed to make of this.

FWIW - I have no doubts the car will spin easier now from a dig than it would with the 3.55 gears previous.

EDIT: Thanks for the info Norm. I don't know if DA complicates this but I'm usually driving in a 4000+' DA.

Norm Peterson

I imagine that it does. I'm down around 100' or so above sea level (pretty close to the Atco drag strip in NJ if you can find a DA for that place).


Norm

thewarmachine

Our cars have no power at low rpm. You can't just let the car roll in 1st with no gas, then step on the gas and get it to spin tires. It Won't Happen! You HAVE TO drop the clutch with plenty of a rev.

Riptide

That's what I figured but it is contrary to what many people have stated on this forum regarding the 4.10 gears on stock tires.

Also, they still wouldn't break loose from a 3000rpm roll either. Which is starting to get into the power band. I haven't had a chance to try Norm's (4000rpm) suggestion though.

thewarmachine

You should go above 3000 rpm because that is the point where our car lunges. There is a noticeable lunge at 3000 rpm when accelerating. I think I'll contact Brenspeed and get them to fix this. It is stupid. I want a continuously changing power band...not a jump at 3k rpm.

Riptide

I may be wrong about this but from my understanding due to the design of our engines (being OHC) they make torque at a higher rpm than a pushrod engine like the LSx. Therefore, it's a design issue. They can't just tune it out for you.

Only "fix" is to get a twin screw blower. That will start making significant torque down low.