Drag Racing Tech - Do slicks provide the same grip spinning at higher speeds?

As title says, between spinning them at low speed (in 1st gear) and spinning at higher speed (in 2nd gear), is there difference in grip and acceleration?
On our crap tarmac my 1st gear (in manual 240SX) is completely useless, so I thought why not start in 2nd, but was afraid that faster spinning slicks would provide less traction.
So, do they loose grip?

it will probably bog and reduce the wheel spin.

Never done it, but I see that as a big stress on the clutch if it dose pull the motor down with traction

Yes, but assuming it will not bog down and destroy clutch, will faster spinning slicks loose much of their grip?

I'd look at trying to fix the suspension before you try leaving in 2nd gear. That's not going to work out too well unless the gearing on that car is insanely low in first gear.

Make it hook, adjust the shock settings, move some weight back in the car, get rid of the insane amount of camber gain that those cars have when the rear suspension compresses, to help keep the whole tire in contact with the pavement, that would probably make a world of difference.

I'd look at trying to fix the suspension before you try leaving in 2nd gear. That's not going to work out too well unless the gearing on that car is insanely low in first gear.

Make it hook, adjust the shock settings, move some weight back in the car, get rid of the insane amount of camber gain that those cars have when the rear suspension compresses, to help keep the whole tire in contact with the pavement, that would probably make a world of difference.

Excellent advise! try and stay away from the "Band aid" approach as much as possible.

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It's definitely a crutch, but if you can't pull timing or adjust launch enough, you do what you have to do??
Leaving in 2nd will have less torque multiplication, so it will definitely help hook.
Same reason why we have custom gear sets, sometimes you just can't control the big multiplication or wide ratio.

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Leave at a lower rpm?

I'd look at trying to fix the suspension before you try leaving in 2nd gear. That's not going to work out too well unless the gearing on that car is insanely low in first gear.

Make it hook, adjust the shock settings, move some weight back in the car, get rid of the insane amount of camber gain that those cars have when the rear suspension compresses, to help keep the whole tire in contact with the pavement, that would probably make a world of difference.Why exactly it won't work well? I'm at the traction limit in 2nd gear too, so by starting in 2nd I eliminate gearchange in the beginning, gaining A LOT. If only slick would provide same grip when I spin it in 2nd gear, I should gain.
"Make it hook" - I wish, but easier said than done. I couldn't find drag shocks for 240SX. Weight distribution is 54/46. Camber is fine, more or less

Leave at a lower rpm?Too much of a risk to bog down with tiny 110ci engine. And when turbo "switches off", run is finished :)

perhaps seeing this video you will understand how bad our official track is.
700HP Evo destroying 1100HP purpose-built dragster.
http://www.youtube.com/watch?v=M-S5VK4kjGc

I thought people put turbo ls motors in those little cars... so I'm sure they are making twice the torque and hp that the little 4 banger is and I'de imagine they are hooking them up.

JL is saying that IF the car hooks in second, which it probably will b/c its probably going to bog, it will more than likely break something.... and that will probably be the clutch.

like gconnoyer said... leaving at a lower rpm/less power level would probably be a better thing to try.

next time you go to the track just give it a few different tries... worst case scenario you blow the clutch up, or break something in the back.

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Like I said, you do what you have to do.
When I couldn't get my car to work with a 2.48 1st gear, and I did everything I could to the car & launch, I went to a 1.76 gear.
It worked much much better, but cost $4000.
Leaving in 2nd is free, and if it works until you can try something else, go for it.
I couldn't leave in 2nd, with a turbo 400 so I had no choice but to build a different trans.

Good luck,

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I thought people put turbo ls motors in those little cars... No, these little cars actually have their own motors...
so I'm sure they are making twice the torque and hp that the little 4 banger is and I'de imagine they are hooking them up.you have to understand tracks are different
JL is saying that IF the car hooks in second, which it probably will b/c its probably going to bog, it will more than likely break something.... and that will probably be the clutch.Well actually I wasn't hoping to dead hook in 2nd, instead I wanted to spin quite a lot till it gets to at least 5000rpm, because bogging down on such small motor means loosing instantly

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Like I said, you do what you have to do.
When I couldn't get my car to work with a 2.48 1st gear, and I did everything I could to the car & launch, I went to a 1.76 gear.
It worked much much better, but cost $4000.
Leaving in 2nd is free, and if it works until you can try something else, go for it.
I couldn't leave in 2nd, with a turbo 400 so I had no choice but to build a different trans.

Good luck,

.yepp, I will try to do that once it gets warm (it's snow here now).
BUT I have to plan mods ahead. If I learn that slicks don't loose much grip spinning, than I'd plan to start in 2nd and change main gear accordingly.
If I learn they loose much grip, then... I don't know what to do then :) because as I said you can't afford to bog down in turbo 110ci :)
but anyway I'm spinning like crazy already. 1st is useless.

Move more weight backwards... that's the only thing you probably can do that's going to help.

I don't know what it is about those cars but they are terrible at hooking up period, regardless what is in it for a motor.

The only other thing I can think that may help you is a slipper type clutch, and changing the rear end ratio out for something alot longer. Make 1st like 2nd and then put a slipper type clutch in so it won't fall on it's face.. an inherent problem with all 4 bangers.

Move more weight backwards... that's the only thing you probably can do that's going to help.

I don't know what it is about those cars but they are terrible at hooking up period, regardless what is in it for a motor.

The only other thing I can think that may help you is a slipper type clutch, and changing the rear end ratio out for something alot longer. Make 1st like 2nd and then put a slipper type clutch in so it won't fall on it's face.. an inherent problem with all 4 bangers.yes but HOW to move it? I've moved battery, nothing more to move... I can only add weight near rear bumper.
But again, by putting longer ratio diff I will spin tires more. Will they loose a good amount of traction when spinning faster?

No you won't really spin them more, the friction to ground should get the car moving more.

There are adjustable shocks out for that car look around on the ricer forums they are there, you'll have to lower the back of the car some to get it shifted back, pull more weight out of the front, move stuff to the back (battery if it's not already, etc). Lower the rear of the car, may have to minitub it if you have a bigger tire on it like in your sig pic, pull the tires in if you have to, hell put a taller slick on if you are going to minitub, and increase the traction that way.

Another thing you could look at doing is lowering the front as well so it has more downtravel in the suspension which will allow more weight transfer when you launch it. The car's probably like every other one of those cars I see it doesn't transfer weight for shit and then blows the tires off like mad.. sound about right?

Another trick you could do with that car, go get a small windshield washer pump and a small resivoir and while you're doing your burnout, engage the pump and spray some VHT on the ground in front of the tires... old school street racing deal but it does work.

No you won't really spin them more, the friction to ground should get the car moving more.

There are adjustable shocks out for that car look around on the ricer forums they are there, you'll have to lower the back of the car some to get it shifted back, pull more weight out of the front, move stuff to the back (battery if it's not already, etc). Lower the rear of the car, may have to minitub it if you have a bigger tire on it like in your sig pic, pull the tires in if you have to, hell put a taller slick on if you are going to minitub, and increase the traction that way.

Another thing you could look at doing is lowering the front as well so it has more downtravel in the suspension which will allow more weight transfer when you launch it. The car's probably like every other one of those cars I see it doesn't transfer weight for shit and then blows the tires off like mad.. sound about right?I would either spin them more, or bog down, no other option
lowering both rear and front doesn't make any sense to me I'm afraid.
And no, minitub is a bit too crazy, not a stockish car in my view :)
edit: yes it does blow tires immediately and it doesn't transfer weight, you can see it very good in those short videos

Lowering the front, if you can without losing any weight (lower the front and rear) will give the front suspension more down travel from ride height, effectively allowing more weight transfer to the rear tires, this will help with traction.

Does the car have any anti squat built into the independant rear suspension? If so can you get rid of it so the rear will squat more, effectively also transferring more weight?

These are the things you have to do to get the car to leave. Or, put a lower ratio rear gear (3.73 to 3.55 for example) in the rear end, and put a slipper clutch in the car. This way when you let it out it doesn't grab so hard and bog the motor, and the longer gears will let you actually use some of first with the slipper clutch more effectively.

If you already have every posible thing moved to the back of the car, can you shift the motor rearwards in the engine bay at all? Even if it's only 2 or 3 inches that's still enough to help, just have to relocate the motor mounts and trans mount, and shirten the drivehsaft.

What about the radiator, can yo go smaller with that, or run it off a water tank instead of a radiator? If so then you can put the water tank, about 5 gallons would be plenty for an engine that size, and put that in the back of the car as well.

Lighter front suspension, brakes, wheels, anything you can do to get the thing to want to pull the front end up off the ground is absolutely going to help this situation. Hell move the drivers seat back and extend the pedals and steering column so you've sitting more in the back of the car.

Some out of the box thinking will be needed most likely to get the car to leave but it's possible.

It looks like you might have lowering springs on the car. If so, they have to go, and be replaced with some factory springs/shocks for better weight transfer.

While getting the alignment after replacing shocks, make sure they take all the negative camber out of the back they can to put it close to zero.

IF that doesnt help enough, add 100 lbs to the rear bumper. Or do both.

Al

I would put a double adjustable shock on it so when the rear squats it can be held down, so that the weight won't transfer back off the rear so easily. ANY rear camber at all is no good, get rid of all of it, and get the stuff out so it's not going to gain any during the suspension travel.

That rear camber change, is one of the major issues with any independant rear suspension car and drag racing. One of the main reasons it will never work as well as a solid axle will.

Lowering the front, if you can without losing any weight (lower the front and rear) will give the front suspension more down travel from ride height, effectively allowing more weight transfer to the rear tires, this will help with traction.hmmm, I don't quite understand this, did you put that right? Do you want me to lower the front?
Does the car have any anti squat built into the independant rear suspension? If so can you get rid of it so the rear will squat more, effectively also transferring more weight?

These are the things you have to do to get the car to leave. Or, put a lower ratio rear gear (3.73 to 3.55 for example) in the rear end, and put a slipper clutch in the car. This way when you let it out it doesn't grab so hard and bog the motor, and the longer gears will let you actually use some of first with the slipper clutch more effectively.Yes it has anti-squat, people use some bushes to raise the rear subframe, I don't know how that works though
Slipper clutch is cosmic money I guess? Which are burned quite easily while you learn to setup it
If you already have every posible thing moved to the back of the car, can you shift the motor rearwards in the engine bay at all? Even if it's only 2 or 3 inches that's still enough to help, just have to relocate the motor mounts and trans mount, and shirten the drivehsaft.
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Lighter front suspension, brakes, wheels, anything you can do to get the thing to want to pull the front end up off the ground is absolutely going to help this situation. Hell move the drivers seat back and extend the pedals and steering column so you've sitting more in the back of the car.Not moving motor, but you know, I thought about making pedals longer somehow and sit more to the back :)) But as I calculate, my own weight only makes very minor difference if moved back even 3"

It looks like you might have lowering springs on the car. If so, they have to go, and be replaced with some factory springs/shocks for better weight transfer.

While getting the alignment after replacing shocks, make sure they take all the negative camber out of the back they can to put it close to zero.

IF that doesnt help enough, add 100 lbs to the rear bumper. Or do both.

AlYes I'm going to try stock springs/shocks (although I don't understan why JL-WS6 wants me to lower the car...)
And yes, I'm going to add weight in the rear too!

If you have multiple rev limits available I have used another approach. I had three timers that started counting when I let the clutch out, each one engaged a rev limiter. The first one was 4500, second was 5500, third was 7500. I would adjust the times out to let the tires catch up without bogging the car while always running full throttle. I wish I could have had a slider clutch, but nobody made one. This method kept the boost up for me and controlled the wheel speed, albeit a little crude!
JL wants the front lower to increase pitch rotation time before the front tire hits travel limit. You would want a long spring with lots of coils that stores alot of energy.

Kurt

No multiple steps either... Not even 2-step :)