Heel Toe Shifting
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Joined: Feb 2000
Posts: 1,445
From: Seattle, WA
Originally posted by brain
Are you guys sure you are double clutching? yes.
I do not see the point at all. It appears that some of you may be referring to general rev-matching. you're right that there is a difference, but my post above kind of addresses that issue (I saw the same stuff you probably saw when posting this).
When you downshift, you push the clutch in, blip throttle quickly and move shifter to desired gear. Are you actually letting out the clutch with the shifter in neutral, and then pushing it in again? If so, WHY? I do not see ANY benefit to this. Am I missing something on it? It's a requirement for dog-leg trannies, but "can" be used in a syncro tranny to limit wear on the syncros... at th expense of time taken to shift gears (see post above for details).
On a side note, its funny as hell if you don't match revs and drop it from 5th to 3rd, and then floor it. It makes the tires slow down a second, and chirps them. yeah, first the syncros get fried while you try to force it in gear, then the engine does some serious engine braking, follwed by a WOT run which of course shifts weight all over the place and breaks the tires free for a chirp.
Rough as hell on the drivetrain I'm sure, but still makes people think the car is fast as nuts. My buddy used to do it in his 14 second mustang all the time. yeah... that's just called bad driving.
Are you guys sure you are double clutching? yes.
I do not see the point at all. It appears that some of you may be referring to general rev-matching. you're right that there is a difference, but my post above kind of addresses that issue (I saw the same stuff you probably saw when posting this).
When you downshift, you push the clutch in, blip throttle quickly and move shifter to desired gear. Are you actually letting out the clutch with the shifter in neutral, and then pushing it in again? If so, WHY? I do not see ANY benefit to this. Am I missing something on it? It's a requirement for dog-leg trannies, but "can" be used in a syncro tranny to limit wear on the syncros... at th expense of time taken to shift gears (see post above for details).
On a side note, its funny as hell if you don't match revs and drop it from 5th to 3rd, and then floor it. It makes the tires slow down a second, and chirps them. yeah, first the syncros get fried while you try to force it in gear, then the engine does some serious engine braking, follwed by a WOT run which of course shifts weight all over the place and breaks the tires free for a chirp.
Rough as hell on the drivetrain I'm sure, but still makes people think the car is fast as nuts. My buddy used to do it in his 14 second mustang all the time. yeah... that's just called bad driving.
Registered User
Joined: Feb 2000
Posts: 1,445
From: Seattle, WA
Originally posted by Freebird
On the Jerico which I think is mandated for road courses by NASCAR, Ive seen many in car shots of drivers downshifting without H-T. What am I missing? IE syncros. Even if it has syncros You'd think they would still H-T.
On the Jerico which I think is mandated for road courses by NASCAR, Ive seen many in car shots of drivers downshifting without H-T. What am I missing? IE syncros. Even if it has syncros You'd think they would still H-T.
The rev-matching (or close to it) that you mention is the reason double-clutching is used... crashing gears when their close eats them pretty quick (same applies to sycro trannies when the rpm isn't even in the same range... just try to downshift from redline and you'll have a tough time even getting it in gear on a syncromesh tranny... syncro's don't elliminate the rev-matching, they just make the range much greater.
With the bugets of today's NASCAR teams I imagine double-clutching is probably not used due to the time delay. As you said though, a crash box driven like this tends to pop out of gear when the dogs get hammered repeatedly.
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Joined: Aug 2002
Posts: 195
From: In a meeting
Originally posted by Steve in Seattle
no syncros in NASCAR to my knowledge. I know Jasper makes trannies for NASCAR teams as well so I doubt there's a specific manufacturer. I believe the requirements are for no more than 4 gears, the final of which must be 1:1.
The rev-matching (or close to it) that you mention is the reason double-clutching is used... crashing gears when their close eats them pretty quick (same applies to sycro trannies when the rpm isn't even in the same range... just try to downshift from redline and you'll have a tough time even getting it in gear on a syncromesh tranny... syncro's don't elliminate the rev-matching, they just make the range much greater.
With the bugets of today's NASCAR teams I imagine double-clutching is probably not used due to the time delay. As you said though, a crash box driven like this tends to pop out of gear when the dogs get hammered repeatedly.
no syncros in NASCAR to my knowledge. I know Jasper makes trannies for NASCAR teams as well so I doubt there's a specific manufacturer. I believe the requirements are for no more than 4 gears, the final of which must be 1:1.
The rev-matching (or close to it) that you mention is the reason double-clutching is used... crashing gears when their close eats them pretty quick (same applies to sycro trannies when the rpm isn't even in the same range... just try to downshift from redline and you'll have a tough time even getting it in gear on a syncromesh tranny... syncro's don't elliminate the rev-matching, they just make the range much greater.
With the bugets of today's NASCAR teams I imagine double-clutching is probably not used due to the time delay. As you said though, a crash box driven like this tends to pop out of gear when the dogs get hammered repeatedly.
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Joined: Jun 1999
Posts: 2,368
From: OR
A while back, I watched, I'm pretty sure a Nascar roadcourse race on TV and they had an interior camera's on the pedals and the driver(forgot who) at the same time, split screen. It was pretty neat..
most of the time he drove two footed.. left foot on brake and right foot on gas... and he also snuck some quick shifts without using the clutch.
Also, (i'm guessing for the really big brake zones) he heel-toed.. left foot on clutch, right foot on brake and gas..
Now, doing this to the pace of an actual race in traffic, his feet literally looked like they were dancing all over the place!
It was amazing! Even the TV commentors laughed and wondered if he ever got his feet mixed up!
most of the time he drove two footed.. left foot on brake and right foot on gas... and he also snuck some quick shifts without using the clutch.
Also, (i'm guessing for the really big brake zones) he heel-toed.. left foot on clutch, right foot on brake and gas..
Now, doing this to the pace of an actual race in traffic, his feet literally looked like they were dancing all over the place!
It was amazing! Even the TV commentors laughed and wondered if he ever got his feet mixed up!
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Joined: Feb 2000
Posts: 1,445
From: Seattle, WA
Originally posted by Ken S
most of the time he drove two footed.. left foot on brake and right foot on gas... and he also snuck some quick shifts without using the clutch.
Also, (i'm guessing for the really big brake zones) he heel-toed.. left foot on clutch, right foot on brake and gas..
most of the time he drove two footed.. left foot on brake and right foot on gas... and he also snuck some quick shifts without using the clutch.
Also, (i'm guessing for the really big brake zones) he heel-toed.. left foot on clutch, right foot on brake and gas..
I'm told that straight-cut gears are much easier to pop out/in on the fly, but without a REALLY solid feel for where the RPMS need to be you'll probably bang it up pretty good. Syncros probably help alot with this, but with dog-rings its like ignoring the double-clutch with the engine attached.
Musta been a blast to watch... we need to see more of that "driver skill" focused coverage on TV (I could care less about arial views of dots circling a track). I'll admit I tried clutchless shifting my T56 once or twice... but it ain't fun, and there's no way is H3ll I could figure out how to pop it in gear under any decent amount of throttle.
Last edited by Steve in Seattle; Apr 15, 2004 at 08:31 PM.
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Joined: Feb 2000
Posts: 1,445
From: Seattle, WA
Originally posted by quick
NASCAR guys rarely if ever shift gears once they get out of the pits, except for the few road course races they run. They put the car in top gear and leave it there....
NASCAR guys rarely if ever shift gears once they get out of the pits, except for the few road course races they run. They put the car in top gear and leave it there....
)Besides... didn't you see Days of Thunder? Tom Cruise was shifting gears every time they showed his car! That tranny musta had at LEAST 25 gears.
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Joined: Feb 2000
Posts: 1,445
From: Seattle, WA
Cool article on Nascar from the driver's perspective: http://www.nascar.com/2003/news/cnns...d_aroundtrack/
11 turns in the road course at Sonoma (Infineon Raceway)... shifting gears like a mad man.
Here's one talking about the 1 or 2 shifts most NASCAR crews pull at a tri-oval track (like Daytona... but this one's specifically about the 2.5 mile Pocono Speedway): http://www.catchfence.com/html/2003/rs060603.html
looks like NASCAR allows 5-speeds now (or did in 2003 at least). anyone know what the current regs are?
11 turns in the road course at Sonoma (Infineon Raceway)... shifting gears like a mad man.
Here's one talking about the 1 or 2 shifts most NASCAR crews pull at a tri-oval track (like Daytona... but this one's specifically about the 2.5 mile Pocono Speedway): http://www.catchfence.com/html/2003/rs060603.html
And yes, I said shifting gears. But, it’s an oval you say! Yes, but with such different turns and different length straights, in order to get the most out of the car, drivers will have to shift at least once a lap, and most will shift twice.
They will use one of those special Jerico five-speed transmissions, that requires little effort to shift and no clutch work necessary.
Keep in mind they are traveling near or better than 200 mph as they enter the first turn, so it’s either tap the binders or drop it down a cog to keep up those RPM’s upon exit of the corner.
Most will do the big downshift, and then upshift upon exit. Then, it’s off to the Tunnel Turn which does not have a lot of banking to keep you on the track. Once you make it through that tricky bit, it’s off to the final and a very flat turn three. Downshift before the turn, carry it wide near the wall, catch high gear right at the start/finish and you’re off for yet another long lap around the Pennsylvania course.
Up and down shifting at such high speeds and sustaining high R’s for long periods all adds up to several blown engines on the day, you can count on it.
They will use one of those special Jerico five-speed transmissions, that requires little effort to shift and no clutch work necessary.
Keep in mind they are traveling near or better than 200 mph as they enter the first turn, so it’s either tap the binders or drop it down a cog to keep up those RPM’s upon exit of the corner.
Most will do the big downshift, and then upshift upon exit. Then, it’s off to the Tunnel Turn which does not have a lot of banking to keep you on the track. Once you make it through that tricky bit, it’s off to the final and a very flat turn three. Downshift before the turn, carry it wide near the wall, catch high gear right at the start/finish and you’re off for yet another long lap around the Pennsylvania course.
Up and down shifting at such high speeds and sustaining high R’s for long periods all adds up to several blown engines on the day, you can count on it.
Last edited by Steve in Seattle; Apr 15, 2004 at 08:28 PM.
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