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Old 03-31-2003, 03:33 AM   #1
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Dump the clutch or slip it?

I'm running ET Streets, road race suspension (not much weight transfer, etc.). I am pretty consistent, but don't seem to be improving much.

60' times average in the 2.oh's, but I squeaked out a 1.89 as my best to date.

Are you dumping the clutch at a certain rpm, or do you slip it out?
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Old 03-31-2003, 10:21 AM   #2
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Dump the clutch.

Explain your burn out procedure, tire pressure, launch RPM, and are you spinning or bogging?
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Old 03-31-2003, 06:03 PM   #3
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I agree with 351 Stang. I too have ET Streets. I launch at about 5000 rpm dumpting the clutch. Gets me around 1.70 - 1.75 60' times. This is with the front swaybar on.
Roll through the water and do about a 10 second burnout or however long it takes to get some pretty good smoke from your tires. Roll to the lights, stage, rev and dump. You will be pleasantly surprised when you get your first case of whip lash. I know I was.
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Old 03-31-2003, 06:41 PM   #4
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Quote:
Originally posted by 351 stang
Dump the clutch.

Explain your burn out procedure, tire pressure, launch RPM, and are you spinning or bogging?

I do about a 5-6 second burnout, enough to start seeing a little bit of smoke, but not much. Then I just let off the brake and come out of it. As soon as they catch, I put in the clutch, brake, and stage. I could probably burn out a little bit longer.

I've been leaving around 3 grand, but probably not spinning. That's probably my problem, I'm probalby bogging but it is hard to tell.

I have been running 15 psi in them. Since my car is set up more for road racing, I have big brakes and cannot fit 15 inch wheels on it. So I am running the 26x10.5 16's. That probably hurts a little bit with the lower sidewall, but I'm stuck with that size tire.

I guess with over 500 hp I'm concerned that I will get too much wheelspin if I leave at 5000 rpm, but with both of you dump it, that's what I'll try. If I get a little bit too much wheelspin, then I can just adjust the rpm and try again.

Any guesses on what rpm with around 440 rwhp and 422 rwtq? I know I'll figure it out eventually, but I'm hoping to get somewhat close and adjust from there.

Looking forward to that first whiplash!!!

Practice, practice, practice...

Thanks to both of you for your advice.
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Old 04-01-2003, 08:49 AM   #5
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What rear end gears do you have? For 3.73 or higher I suggest that you do a burnout in second gear. Make sure you keep in it until smoke rolls off the entire tire. Don' t smoke out the grand stands, but if you just get a wisp of smoke it's not long enough. Stage and complete your run as quickly as possible. Drive around the water and back into the water box. This will keep you from tracking water from the front tires. Don't run your AC at the track due to the condenstation. Don't follow some ricer in an Integra........follow a race car with big rear tires. Ricers always leave water on the track. (see above for stupid reasons)

You never mentioned what kind of clutch you were running. If you are running a centerforce clutch or similar "street performance" clutch, it could be slipping. I smoked my centerforce my first pass on 10.5" ET Drags. I never had a problem on Nitto Drag Radials, but as soon as I added the slicks......instant slip. It took me a couple passes to figure out what was happening. I only have 380 RWHP (but it's all under atmosphere)

Have someone watch your car during launch. I mean really watch it. Have them look and see if you are spinning.

If you are spinning then improve your burnout and play with tire pressure.

If you are not, you are either burning up your clutch or bogging. If you are bogging, raise the launch RPM. You should be leaving at least 5000 RPM.

I suspect your problem is a insufficient burn out, followed by too low of a launch RPM. If you throw in some water on the track from a rice-boy, then you get crappy 60' times.


Even with a stiff suspension you should be able to pull 1.6X 60's with no problem. You could pull the front sway bar and if you have adjustable struts loosen them up.
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Old 04-01-2003, 12:19 PM   #6
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Quote:
Originally posted by 351 stang
What rear end gears do you have? For 3.73 or higher I suggest that you do a burnout in second gear. Make sure you keep in it until smoke rolls off the entire tire. Don' t smoke out the grand stands, but if you just get a wisp of smoke it's not long enough. Stage and complete your run as quickly as possible. Drive around the water and back into the water box. This will keep you from tracking water from the front tires. Don't run your AC at the track due to the condenstation. Don't follow some ricer in an Integra........follow a race car with big rear tires. Ricers always leave water on the track. (see above for stupid reasons)

You never mentioned what kind of clutch you were running. If you are running a centerforce clutch or similar "street performance" clutch, it could be slipping. I smoked my centerforce my first pass on 10.5" ET Drags. I never had a problem on Nitto Drag Radials, but as soon as I added the slicks......instant slip. It took me a couple passes to figure out what was happening. I only have 380 RWHP (but it's all under atmosphere)

Have someone watch your car during launch. I mean really watch it. Have them look and see if you are spinning.

If you are spinning then improve your burnout and play with tire pressure.

If you are not, you are either burning up your clutch or bogging. If you are bogging, raise the launch RPM. You should be leaving at least 5000 RPM.

I suspect your problem is a insufficient burn out, followed by too low of a launch RPM. If you throw in some water on the track from a rice-boy, then you get crappy 60' times.


Even with a stiff suspension you should be able to pull 1.6X 60's with no problem. You could pull the front sway bar and if you have adjustable struts loosen them up.
Awesome into, 351 stang. Thanks!

To answer your question, I have 3.55's, I do my burnout in 2nd gear, and I have a Ram900 clutch. I don't think it is slipping, on the contrary, it doesn't quite slip enough. Really chattery! No A/C, I removed it. I don't usually back into the water, because it seems like at some tracks (Bakersfield is an example) they run pretty quick and 'everyone' drives through the water. It is a pretty light amount of water, however.

Thanks again for your help, guys. You probably took some wear and tear (and frustration on my part) out of how long it will take me to get better. I think I need a slightly longer burnout, and more rpm. And more practice.
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Old 04-01-2003, 12:24 PM   #7
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Quote:
Originally posted by 351 stang
What rear end gears do you have? For 3.73 or higher I suggest that you do a burnout in second gear. Make sure you keep in it until smoke rolls off the entire tire. Don' t smoke out the grand stands, but if you just get a wisp of smoke it's not long enough. Stage and complete your run as quickly as possible. Drive around the water and back into the water box. This will keep you from tracking water from the front tires. Don't run your AC at the track due to the condenstation. Don't follow some ricer in an Integra........follow a race car with big rear tires. Ricers always leave water on the track. (see above for stupid reasons)

You never mentioned what kind of clutch you were running. If you are running a centerforce clutch or similar "street performance" clutch, it could be slipping. I smoked my centerforce my first pass on 10.5" ET Drags. I never had a problem on Nitto Drag Radials, but as soon as I added the slicks......instant slip. It took me a couple passes to figure out what was happening. I only have 380 RWHP (but it's all under atmosphere)

Have someone watch your car during launch. I mean really watch it. Have them look and see if you are spinning.

If you are spinning then improve your burnout and play with tire pressure.

If you are not, you are either burning up your clutch or bogging. If you are bogging, raise the launch RPM. You should be leaving at least 5000 RPM.

I suspect your problem is a insufficient burn out, followed by too low of a launch RPM. If you throw in some water on the track from a rice-boy, then you get crappy 60' times.


Even with a stiff suspension you should be able to pull 1.6X 60's with no problem. You could pull the front sway bar and if you have adjustable struts loosen them up.
Awesome into, 351 stang. Thanks!

To answer your question, I have 3.55's, I do my burnout in 2nd gear, and I have a Ram900 clutch. I don't think it is slipping, on the contrary, it doesn't quite slip enough. Really chattery! No A/C, I removed it. I don't usually back into the water, because it seems like at some tracks (Bakersfield is an example) they run pretty quick and 'everyone' that does a burnout drives through the water. It is a pretty light amount of water, however.

Thanks again for your help, guys. You probably took some wear and tear (and frustration on my part) out of how long it will take me to get better. I think I need a slightly longer burnout, and more rpm. And more practice.

p.s. - it took me 14 attempts, and opening and closing my browser twice to post this. A new personal best.
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Old 04-01-2003, 01:18 PM   #8
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I bet the Ram 900 series clutch hardly slips at all. I was considering that clutch and went with a Mcleod Revlock disk instead. It's a similar metalic compound disk. There's not much slip in mine either.

With that info it sounds like you could be bogging off the line and then spinning when the car comes back into the powerband.

Try to watch the tach or datalog a run (if you have something that will do it). I bet your RPM drops to 1000 RPM after you drop the clutch and causes a bog. If the tires aren't heated enough they could then spin after the car got back up into the 4000 RPM range.

I had a bog that I couldn't get rid of after I installed my Mcleod disk. The car really hooked up, was under geared (3.70's), the clutch wouldn't slip, and I bogged like hell with my peaky naturally aspirated power band. A swap from 3.70's to 4.33's cured the problem.

I doubt it's a gearing problem on your car.
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Old 04-01-2003, 01:56 PM   #9
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I have a feeling that I am just too timid off the line. The tires are new, and I'm used to 500 ft. lbs. of torque on street tires. When the car is cool, it will break the tires loose on a third-gear roll-on, and it weighs over 3500 lbs.

I'm going out to Bakersfield for the Fast Ford event in April, and I'm going to try to make at least three runs, and use different rpms on each. Maybe 3500, 4000, then 4500, and find the one that works the best.

I think you are right, it's launch rpm. I doubt that I am spinning, just a little bit too timid. and not giving it enough rpm, and probably not letting the clutch out fast enough.

Thanks again for your time. I'll post some results after the Bakersfield event. I know with almost a 119 mph that my car should run 11's with a better launch.
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Old 04-01-2003, 09:59 PM   #10
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All I can say is that by dumping the clutch, it is extremely hard on the car and you could break something! Just my thoughts.
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Old 04-01-2003, 10:29 PM   #11
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Quote:
Originally posted by badgerk
All I can say is that by dumping the clutch, it is extremely hard on the car and you could break something! Just my thoughts.
yes, dumping at 5,000+ can do some damage, but thats the risk we all take to go as fast as we can . best thing to do is weld up the tourqe boxes and have SFCs in the car before the damage comes... of course even then there are no guarantees.

on ET Drags (or ET Streets) slipping the clutch on the launch will ruin it fast. if you dont dump the tires will grab harder than the clutch and the disk will get smoked. it only takes one wrong launch to destroy a otherwise perfectly good clutch.

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Old 04-02-2003, 09:33 AM   #12
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Quote:
Originally posted by badgerk
All I can say is that by dumping the clutch, it is extremely hard on the car and you could break something! Just my thoughts.

I never thought of that.


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