race shifting

the unknown · Post by **the unknown** » Wed Dec 10, 2008 4:21 pm

my car has been acting kinda weird whenever i drive it fast. i watched the tutorial video about upshifting on this site and figured that i should shift the way greg shifts in the video when i race. i try to shift that same way and i make sure to bring the clutch together before getting on the gas. but whenever i dump the clutch after i shift, the clutch engages pretty harshly then the car shudders. ive driven other cars and the clutch doesnt engage as harshly as mine. i think that my clutch may be damaged cuz my car is pretty old and im pretty sure its still got the stock one. i have a new exedy clutch waiting to go in anyway but i wouldnt be surprised if there was something wrong with my technique. maybe u guys could help me with this problem. how do u guys shift when u race? lemme kno if u have any thoughts about this.

AHTOXA · Post by **AHTOXA** » Wed Dec 10, 2008 4:28 pm

Shifting for acceleration at near redline will cause the shift to be harsh because you're trying to complete it as fast as possible. So when you're going all-out I would not expect to be as smooth as regular driving.

DrNick · Post by **DrNick** » Wed Dec 10, 2008 4:29 pm

When you "race", it's a given that you're sacrificing smoothness. Other than that, by "dumping the clutch," do you mean just sidestepping off of it, or doing a fast (but controlled) release? Even if you're doing some spirited driving, a fast AND controlled release shouldn't be causing major issues if you're timing the upshift/release correctly.

Before we go any further though, what kind of car are you driving?

the unknown · Post by **the unknown** » Wed Dec 10, 2008 4:40 pm

i drive a 91 acura integra with a cable clutch. i figured that race shifts are gonna be rough, but my clutch seems to engage harder then in other cars ive driven. my friend let my drive his srt4 and whenever i dumped the clutch in that, i didnt seem as harsh. same with my other friends 03 golf, and pretty much any other manual car that ive driven. plus my car shudders whenever i dump the clutch; i dont really kno what could be causing that. btw i dont side step the clutch, i just do quick controlled release. another weird thing; whenever i dump the clutch in lower rpms it shifts fine. maybe the prob will go away when i install the new clutch and flywheel. maybe the one thats in there now is just beat to shit.

the unknown · Post by **the unknown** » Wed Dec 10, 2008 4:40 pm

or i may not be timing it correctly...

fa22raptorf22 · Post by **fa22raptorf22** » Wed Dec 10, 2008 5:18 pm

There are two ways you can race shift.

1) The nice way 2) the harsh to driveline way

1) Shift like normal, but at or close to redline depending on your powerband.
Go WOT and as you reach the shift point, either drop the throttle totally or almost all the way off. Push the clutch all the way in, shift straight from gear to gear, let up on the clutch controlled and fast. You will soon figure out how much throttle to have as you let the clutch off. If you are all the way off, when the clutch gets let out, the car will begin rapid deacceleration as the car drags on the engine. You want just enough that the engine spins the same or about the same as the tranny speed.

You can also drop the clutch really fast if you wait till the rpms have dropped, thereby stopping the shudder.

2) Powershift. Push the throttle to the floor and hold it there. When you are maybe 500 from redline: push the clutch, shift and drop the clutch as fast as humanly possible. Your goal is to complete the shift before you bounce off the rev limiter. This is hard on the driveline, but it is a race isn't it?

I use method 1 because I like to be nice to my car.

Watch this for the WOT upshifts
http://www.youtube.com/watch?v=klMur6TPkrM

Post by **jomotopia** » Wed Dec 10, 2008 5:21 pm

you can shift fast without powershifting, and if you are trying to accelerate and shift as fast as possible then timing is out the window. if you run a gear all the way to redline then the revs are going to have to fall pretty far for the next gear and waiting on them is going to defeat the purpose.

WOT to redline, dump throttle/slam clutch, rip the shift, dump clutch/slam throttle. it won't be smooth and it will be hard on the equipment.

if you're saying that the clutch grabs harder than other cars then to me that rules out the clutch being worn out because if it was worn out it would have a soft and sloppy engagement.

gizmo · Post by **gizmo** » Wed Dec 10, 2008 5:45 pm

Does your car have a single, dual, or multidisc clutch? If you've only driven multidisc clutch cars, and your car happens to have a single disc clutch, that would account for the harshness.

I think the main point of concern here is the shuddering.

Everyone has carefully explained that "racing shifting", for want of a better term, can be harsh in itself. So be mindful of that...

But that harshness should not be coupled with shuddering!?! A race shift should be accompanied by one good old fahsioned jolt without then being followed by several smaller aftershocks, correct?

the unknown · Post by **the unknown** » Thu Dec 11, 2008 12:47 am

ya ur right gizmo...there shouldnt be any aftershocks after the main jolt, but whenever i dump the clutch very hard/fast, that is wut happens. only in my car though. im pretty sure it has a stock single plate clutch. but all the things u guys are telling me make sense. i watched that youtube vid of [keiichi tsuchiya maybe?] driving the hachiroku race car. i made sure to pay very close attn to his feet during shifting. it looked like he wasnt dumping the clutch as wildly as i was. his was quick and controlled. my clutch dumps were quick, but not so controlled. so i went out and tryed shifting the controlled way. it worked, but sometimes i got on the throttle a bit too early and did not get the instant pitch change from the engine after the shift. should i think of race shifting as just a really fast seesaw motion? and is there such thing as dumping the clutch too fast?

the unknown · Post by **the unknown** » Thu Dec 11, 2008 12:49 am

oh and i havent driven a car with a multidisc clutch yet...

the unknown · Post by **the unknown** » Thu Dec 11, 2008 12:53 am

im trying to run through all the worn parts that could cause the aftershocks; worn motor mounts? or maybe worn diaphragm spring in the pressure plate?

gizmo · Post by **gizmo** » Thu Dec 11, 2008 1:03 am

are you sure it's not a multidisc clutch? single disc clutches, in high horsepower cars, just don't seem to slip.

the unknown · Post by **the unknown** » Thu Dec 11, 2008 1:12 am

ha ha the motor is a completely stock 130hp b18a. the clutch is single. besides dont multiplate clutches engage alot earlier in the clutch pedal travel? my clutch engages half way up and feels kinda soft when doin regular launches. how do you dump the clutch by sidestepping anyway? is that what keiichi tsuchiya is doing in the youtube vid posted above?

gizmo · Post by **gizmo** » Thu Dec 11, 2008 2:06 am

it's my understanding that single disc clutches are used in racing applications, particularly ones with high horsepower engines, because they are reliable at high RPMs. Trouble with them, again to my understanding, is that they're difficult to slip. Many a driver has dented a fender trying to drive their racecar onto the trailer...

he doesn't sidestep, he's moving his foot onto the "dead pedal" and resting it there temporarily so that he doesn't wear the clutch's teeth by hovering his foot over the pedal.

Post by **jomotopia** » Thu Dec 11, 2008 10:46 am

the unknown wrote:should i think of race shifting as just a really fast seesaw motion?

yes

and is there such thing as dumping the clutch too fast?

depends on the situation really.

StandardShift.com

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