Is my DS slowin me down?
01-14-2007 | 01:46 PM
#17
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From: Ocala, Florida
Chirp is achieved due to the kinetic energy of the drivetrain, spinning at a higher RPM than needed for a given speed/gear, being suddenly dumped to the wheels. That kinetic energy gives you a brief but large torque spike while the clutch is engaging and pulling the revs down. That torque spike is limited by the capacity of the clutch, not the torque of the engine. So, if you lighten the rotating inertia significantly, it will be harder to chirp the tires. As you mentioned this has to do with the diameter in the case of the driveshaft; it's not really the mass(weight), but the moment of inertia, that counts.
I don't really know, but I doubt if the aluminum DS moment of inertia is significantly lower than stock. Moment of inertia is dependant on the mass times the SQUARE of the radius the mass is rotating about. So, a small increase in diameter can offset a significant mass reduction pretty quickly.
I don't really know, but I doubt if the aluminum DS moment of inertia is significantly lower than stock. Moment of inertia is dependant on the mass times the SQUARE of the radius the mass is rotating about. So, a small increase in diameter can offset a significant mass reduction pretty quickly.
01-14-2007 | 01:49 PM
#18
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From: Hell was full so they sent me to NJ
The tires "chirp" because the stored inertia of the faster moving clutch accelerates the mass of the rotating assembly from the clutch on back. Reducing the inertia of the rotating assembly behind the clutch (e.g. - aluminum DS) would make it easier to "chirp" the tires.
01-14-2007 | 01:58 PM
#20
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From: Ocala, Florida
01-14-2007 | 02:56 PM
#21
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From: Rochester Hills, MI
The tires "chirp" because the stored inertia of the faster moving clutch accelerates the mass of the rotating assembly from the clutch on back. Reducing the inertia of the rotating assembly behind the clutch (e.g. - aluminum DS) would make it easier to "chirp" the tires.
01-14-2007 | 05:15 PM
#23
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From: Tallahassee & Jupiter,FL
well this has been a interesting thread so far, and I really dont gauge the performance of my car by chirping tires, its just weird that it did it everytime, no matter what at WOT when shiftin to 2nd. Sounded cool but threw me all over the road so it got annoying pretty quick, so I do like it being gone. Its just weird that everyone says that it should chirp more if anything and I just thought it weird and nothing did change, tire pressure, temp, ect... but thanks for all the comments so far everyone. i think i might just throw the steel one back in for a day and see if anything changes
01-14-2007 | 05:18 PM
#24
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From: Tallahassee & Jupiter,FL
01-14-2007 | 05:27 PM
#25
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From: Tallahassee & Jupiter,FL
01-14-2007 | 05:49 PM
#26
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From: Sweet home Chicago
I thought the chirp was due to the sudden increase in torque to the drive train, when trans shifts to the next gear and the engine drops in revs to where its torque is higher... ??
If true, this would have meant that the aluminum driveshaft, software than steel, would absorb a bit more of this shock due to the trans shifting, so there would be less shock left over to break the tires loose...??
(Almost) sounds right, doesn't it?
If true, this would have meant that the aluminum driveshaft, software than steel, would absorb a bit more of this shock due to the trans shifting, so there would be less shock left over to break the tires loose...??
(Almost) sounds right, doesn't it?
01-14-2007 | 06:22 PM
#27
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From: Rochester Hills, MI
T/A Bob - For some cars, probably. But in that case I think there would also be enough engine torque at that same RPM/gear to do a roll-on tirespin. I was speaking of an M6, but the sudden engine RPM change is providing a burst of power to the wheels with the A/T during a shift, too.
As to the effect of the aluminum DS being less stiff, I really don't know. I suppose it could reduce the peak shock load, and make it harder to snap the wheels loose. Good point.
As to the effect of the aluminum DS being less stiff, I really don't know. I suppose it could reduce the peak shock load, and make it harder to snap the wheels loose. Good point.
01-15-2007 | 12:14 PM
#28
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From: Ocala, Florida
01-15-2007 | 01:47 PM
#29
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From: Davie, FL
You told him you were running 3/4 of a turn? That's ****ty man, being lazy= more work. I did the same thing with my pushrod length after i had the heads milled. Cost me ****ing up the valve seals to do it the correct way.
01-16-2007 | 02:22 AM
#30
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From: Ocala, Florida
I'm gonna re-adjust them after I do the installed height, from what I measured its off a good amount so this way I'll atleast know its done right.