vitoal18t Posted January 27, 2006 Share Posted January 27, 2006 I want to know how most people use their clutch when heel-and-toe downshifting into a corner. Say we are approaching a 35mph hairpin (mid apex) in 4th gear at 100mph. When I watch in car videos I see people engaging the brakes and rowing through the gear box downshifting from 4th to 2nd (4-3-2, on this car 1st gear redlines @ 30MPH). Do most people double clutch when downshifting, single clutch, or just press (a) (disengage) the clutch, hold it in and go 4-3-2, blip throttle, engage the clutch. (b)Or do people double clutch into every lower gear, so going from 4-3 double clutch, 3-2 double clutch again. ©Or 4-3 single clutch as a regular downshift (since most cars have synchros), 3-2 single clutch. I was always under impression that it is a good idea to double clutch with every downshift (that's what I do when I have fun in my car), but I am not sure I can downshift 4-3-2 (double clutching into every gear) faster than my car brakes 100MPH-35MPH under 100% braking. Maybe I still double clutch and downshift too slow. Please advise! -Vito Quote Link to comment Share on other sites More sharing options...
GAC Posted January 27, 2006 Share Posted January 27, 2006 Here's the procedure as you approach a corner: 1. Get on the brakes firmly, but smoothly with the ball side (left) of your foot on the right side of the brake pedal. 2. Push the clutch in. 3. While still pointed straight ahead, and with your foot still on the brake, roll the right side of your foot onto the gas pedal to blip the throttle. 4. Select the gear you want to be in for the upcoming turn. 5. Let the clutch out. 6. Ease your foot off the brake pedal and onto the gas as you begin your turn-in. This is the basic procedure...different tracks, corners, cars, styles, etc will favor it a bit differently. Quote Link to comment Share on other sites More sharing options...
Kolia Posted January 27, 2006 Share Posted January 27, 2006 Here's the procedure as you approach a corner: 1. Get on the brakes firmly, but smoothly with the ball side (left) of your foot on the right side of the brake pedal. 2. Push the clutch in. 3. While still pointed straight ahead, and with your foot still on the brake, roll the right side of your foot onto the gas pedal to blip the throttle. 4. Select the gear you want to be in for the upcoming turn. 5. Let the clutch out. 6. Ease your foot off the brake pedal and onto the gas as you begin your turn-in. This is the basic procedure...different tracks, corners, cars, styles, etc will favor it a bit differently. Exactly. Let's all note that it's pointless and time consuming to row thru all gears when we can just go directly in the needed gear. Quote Link to comment Share on other sites More sharing options...
loudes13 Posted January 27, 2006 Share Posted January 27, 2006 I disagree about pointless. It's rare to have to downshift multple gears, but your synchros were not designed to to go 5 to 2 or 4 to 2. The reason for hpde is to learn finer points like that. I've even had the opportunity to demonstarte double clutch downshifting, which saves synchro wear, and is necessay with some gear boxes. Quote Link to comment Share on other sites More sharing options...
Kolia Posted January 27, 2006 Share Posted January 27, 2006 I disagree about pointless. It's rare to have to downshift multple gears, but your synchros were not designed to to go 5 to 2 or 4 to 2. Errr... No. The synchros are not connected with each others. Open a gear box and see. On a six gear tranny, gears 1-2, 3-4 and 5-6 typically share the same fork, but that's all. Double clutching will help speed up the shafts in there and is a good technique to master should you ever need it. Rowing thru gears might sound cool, but it's just that many more occasions to upset the car. The only time you would have to do it is if you're driving a car with a sequential gear box. Of course, it can be boiled down to driving style. But I've yet to see a top level driver recommand doing it. Caroll Smith and Ross Bentley both agree on the "skip gears if you can" technique. edited: 'cuz it seem I couldn't count to 6... Quote Link to comment Share on other sites More sharing options...
vitoal18t Posted January 27, 2006 Author Share Posted January 27, 2006 I see....Thank you for the info! Just Press the clutch, blip throttle, select the gear and let out the clutch!! Sounds good, but I have more questions. Blipping throttle is in step 3, selecting gear is in step 4. Is there a reason to blip the throttle before gear selection? Engine is not connected to the transmission at this point. I guess the single reason is to blip before selecting gear is because it takes time for engine to rev up. Thank you! -Vito Quote Link to comment Share on other sites More sharing options...
Kolia Posted January 27, 2006 Share Posted January 27, 2006 Blipping throttle is in step 3, selecting gear is in step 4. Is there a reason to blip the throttle before gear selection? Engine is not connected to the transmission at this point. I guess the single reason is to blip before selecting gear is because it takes time for engine to rev up. It takes place almost at the same time. It's easier to catch the engine while it's slowing down from higher rpm. And it's a fail safe should you get mixed up, get the gear in and blip as you let go of the clutch. It also prepares you for the next step of learning to down shift: double clutching. Bliping while the engine is driving the rear wheels is bad... (Don't ask how I know that...) Quote Link to comment Share on other sites More sharing options...
vitoal18t Posted January 27, 2006 Author Share Posted January 27, 2006 So you say... "next step double clutching". Do you feel that it is necessary on a street car? Double clutching doesn't make you any faster. It saves synchros I agree. I guess by next step you mean that a lot of purpose built race cars don't have synchros and you must double clutch in order to down shift, otherwise it will just grind. Right? Quote Link to comment Share on other sites More sharing options...
Kolia Posted January 27, 2006 Share Posted January 27, 2006 Double clutching is not necessary on a synchro transmission. You’re right. Worst case scenario, you might hit the dogs head on or it just needs to speed up, the synchro will bounce a bit, you jiggle the stick and pop it in on the second try. No real problem. If this happens while you’re braking at the limit, preparing to trail brake into a turn, it might surprise you. You might unsettle the car and go wide. You shouldn’t crash because you where not driving 10/10, but you’d have blown that curve that time. When I skip gear, I want to be sure the gear will get in the first time. So I plan ahead, take a bit longer to do a double-clutch down shift that I’m sure will get in and instead spend my attention on nailing that apex. Quote Link to comment Share on other sites More sharing options...
ek_brandon Posted January 28, 2006 Share Posted January 28, 2006 double clutch = fast and the furious just dump that shit and hope the you dont go to like 12000rpm like donna or edo did this year in honda challenge... kinda funny to watch the incar though... Quote Link to comment Share on other sites More sharing options...
bsim Posted January 28, 2006 Share Posted January 28, 2006 In case I missed it in one of the lengthy posts above, the point of 'blipping' the throttle is to match the (higher) engine speed of the lower gear. Try shifting from 3 to 2 when slowing down. As you drop the clutch, you'll feel the engine 'jerk' as it jums in revs to match the lower gear. You do NOT want that to happen when you're threshold braking into a corner. The added drag on the drive tires will cause them to lose grip and/or lock up. Bad, terribly upsetting the car. So, when you blip the throttle, you're bringing up the revs to match the downshift - BEFORE the downshift occurs, drop the clutch, and it's smooth as silk. After the 1000th practice - of course. Quote Link to comment Share on other sites More sharing options...
Eric J. Posted January 29, 2006 Share Posted January 29, 2006 Much of the advice here is good and already hashed out, but I'll a tiny bit more: - I, too, don't see any point in rowing through all the gears unless it helps your rythm somehow. Some people do this just to more finely monitor the deceleration by keeping track of the revs. Many people, including me, skip gears and, as mentioned previously, just select the gear you want to be in for the corner. Rowing through the gears is, IMHO, a bit of additional wear and tear that isn't really beneficial for me. - Sometimes it's good to adjust technique to take better care of the equipment, especially if you have a ton of money invested in a tranny or a clutch system. Double clutching _may_ have a small benefit in taking care of the tranny, but for synchronized trannies the benefit is going to be pretty small. - Matching revs in the downshift (which is pretty much the point of heel-and-toe technique) helps to keep from upsetting the weight transfer balance of the car _and_ also helps prevent damage to the torque straps in the pressure plate. Unless you like changing clutches (it's a bear to do in my car), matching revs is your friend in many ways. Quote Link to comment Share on other sites More sharing options...
peerless Posted February 1, 2006 Share Posted February 1, 2006 I myself have been practicing the 'heel/toe' on the street and have been getting pretty good at it. I come into the corner at the speed limit, about 40mph. Heel toe down to 2nd and into the throttle coming out of the corner. My BMW has a natural oversteer to it so I have to be kinda careful as the ass end likes to slip. I have been getting used to it and countersteer accordingly. I have been 'rowing' through the gears, ie 4-3-2. I think I might try just going from 4-2, as it does seem kinda pointless to bring an extra gear into the mix when you are slowing down so rapidly under braking. Still need more practice. I understand the heel toe downshifting but have never understood 'Double Clutching'??? Is this a Honda thing?? Do you press the clutch in to disengage, then release in Neutral, and then clutch again to bring it into gear??? Why?? Shit it takes to long just to go 4-3-2 coming into a corner. I hear people saying to conserve synchros and stuff, but to be honest if your that concerned about your transmission then maybe you shouldn't be racing?? I really need to get to a track event this year. Quote Link to comment Share on other sites More sharing options...
Kolia Posted February 1, 2006 Share Posted February 1, 2006 ...I understand the heel toe downshifting but have never understood 'Double Clutching'??? Is this a Honda thing?? Do you press the clutch in to disengage, then release in Neutral, and then clutch again to bring it into gear??? Why?? shoo-shiddily-diddily it takes to long just to go 4-3-2 coming into a corner. I hear people saying to conserve synchros and stuff, but to be honest if your that concerned about your transmission then maybe you shouldn't be racing?? I really need to get to a track event this year. Yes. When double cutching, you release the clutch in neutral, then blip the throttle (give it more gas than regular blipping), depress the clutch and pop in the lower gear. Why? The simplest way to explain it is that it “loosens” the synchros and “rev match” the internals of the transmission. I take my car’s transmission as example. The synchros are splinned on the main shaft who is connected to the wheels. All the synchros are always spinning at the same speed as the drive shaft. On that same shaft, all my gears are free wheeling at their own speed. These gears are driven by their sister gears on the counter shaft. That shaft is driven by the engine via the clutch assembly. ( can post a drawing tonight from my Nissan tech manual) When I depress the clutch, no power is sent to the counter shaft but it is still being driven by the main shaft (connected to the wheels). While I’m moving the shifter to neutral, the synchro disengages from whatever gear I was in. The counter shaft is then spinning on it’s own momentum (ie slowing down pretty fast). I then keep on moving the shifter to the next gear and the that synchro starts to engage. The synchro has a cone that acts as a mini clutch to speed up or slow down the gear it getting into before locking the dogs into it. Going plus or minus one gear is fine, the speed differences are minimal and the synchros “mini-clutch” doesn’t have to work hard to match the speeds. Jump a couple gears and now the speed differences are much bigger. Keep in mind that the synchro is not speeding up (or down) only the gear you’re getting into. It’s actually driving ALL gears through the counter shaft assembly. That’s a lot of work for a tiny metal ring… If I put the shifter in neutral, release the clutch and blip, I will speed up the counter shaft and all the gears to a speed closer to what it will be inside the tranny. I’m rev matching the tranny and the engine instead of just the engine. And my 300hp engine has a much easier time doing it that my small synchro. Does it makes sense? With a picture it will be clearer… Quote Link to comment Share on other sites More sharing options...
Eric J. Posted February 1, 2006 Share Posted February 1, 2006 Old trannies (i.e., from the 30s, 40s, 50s, especially truck trannies) without synchros required double clutching just to engage the gears. Some race trannies with straight-cut gears, no synchros, etc., also shift more easily if double-clutched. As Kolia described, it can help with some wear issues, but with a synchronized tranny it's probably not going to make much difference. If you've got $$$ invested in the tranny you may be more inclined to double-clutch, but it's also doubling the wear on the throwout bearing and sleeve. It's a good talent to have when driving antique cars or trucks, though... Quote Link to comment Share on other sites More sharing options...
Kolia Posted February 1, 2006 Share Posted February 1, 2006 If you've got $$$ invested in the tranny you may be more inclined to double-clutch, but it's also doubling the wear on the throwout bearing and sleeve. Not if the double clutching is used in lieu of rowing through multiple gear shifts! Total number of clutching cycles will still be less. Ah ah , okay, I’m being smart guy now… Quote Link to comment Share on other sites More sharing options...
Eric J. Posted February 2, 2006 Share Posted February 2, 2006 If you've got $$$ invested in the tranny you may be more inclined to double-clutch, but it's also doubling the wear on the throwout bearing and sleeve. Not if the double clutching is used in lieu of rowing through multiple gear shifts! Total number of clutching cycles will still be less. Ah ah , okay, I’m being smart guy now… CVT, man! The only way to fly... Quote Link to comment Share on other sites More sharing options...
vitoal18t Posted February 2, 2006 Author Share Posted February 2, 2006 Another thing about Double-Clutching. Go 65mph in 3rd gear. Remember exact RPM your engine is at. Shift into 5th and stay @ 65 MPH. 1). Do a 5-3 Downshift, "single" clutch and blip throttle, select 3rd gear. Notice the effort of the shifter. Depending on the car and shifter you need to kinda help it into gear. 2). Now do the same thing, 5-3 Downshift @ 65MPH, but this time double-clutch and match exact RPM when your engine will be in 3rd gear. Now shift and notice just how smooth shifting is. It slides like hot knife through butter and the shifter practically gets "sucked" into 3rd gear. That's because gear and the dog ring (I think it is called a dog...hehe) are going at the same speed. Synchro doesn't need to do any work to get gears up to speed. You can downshift without using your clutch, just double clutch and do exact rev matching and the shifter will go in, no need to use the clutch at all. Of course it is very hard to get every time and very harsh on your tranny if you mess up. I try that sometimes, but very rarely. Only at slow speeds, when I am sure I can get it right. The original idea behind my post was to find out how many people double clutch on the track, and how many people "row" through gears. Sounds like very few "row" and some double clutch under certain conditions. To be honest style of downshifting depends on the car. For example my 1.8T Jetta with 23ish LB flywheel and drive by wire throttle is not very eager to rev, so downshifting is more difficult. Focus with 27ish LB flywheel, but regular throttle cable and louder exhaust is much easier to rev match and revs a bit quicker. I also drove a Focus with a light flywheel, either 7lb or 12lb (don't remember exactly) and it was a true pleasure to downshift in that car because just blipping the throttle revs jump up virtually instantly. Thank you! Quote Link to comment Share on other sites More sharing options...
loudes13 Posted February 3, 2006 Share Posted February 3, 2006 I still believe that the synchros were not designed to select 2 or 3rd gear after a 120+ straight (like road america, corner 5 or 12). Grabing 4th, matching revs, engaging the clutch, then doing the same in 3rd is still technically easier on the synchros. Street synchros are just designed to smooth out single shifts on the street. Mix HP use, 120+ straights, >100k miles, and your technique matters. As above, you can feel a diff when you properly match revs to road speed. It's not that hard, and helps those synchros last forever. Quote Link to comment Share on other sites More sharing options...
kinkyllama Posted February 3, 2006 Share Posted February 3, 2006 You can downshift without using your clutch, just double clutch and do exact rev matching and the shifter will go in, no need to use the clutch at all. Of course it is very hard to get every time and very harsh on your tranny if you mess up. I try that sometimes, but very rarely. Only at slow speeds, when I am sure I can get it right. In my car you dont have to double clutch before downshifting... all you have to do is match the revs almost perfectly and it slides right in... if you try to put it in when the revs are a bit off though it'll grind or just wont go in. I drive a 04 suzuki forenza w/ currently stock tranny Quote Link to comment Share on other sites More sharing options...
GAC Posted February 3, 2006 Share Posted February 3, 2006 You can downshift without using your clutch, just double clutch and do exact rev matching and the shifter will go in, no need to use the clutch at all. Of course it is very hard to get every time and very harsh on your tranny if you mess up. I try that sometimes, but very rarely. Only at slow speeds, when I am sure I can get it right. In my car you dont have to double clutch before downshifting... all you have to do is match the revs almost perfectly and it slides right in... if you try to put it in when the revs are a bit off though it'll grind or just wont go in. I drive a 04 suzuki forenza w/ currently stock tranny Do you track this Suzuki? Quote Link to comment Share on other sites More sharing options...
Eric J. Posted February 3, 2006 Share Posted February 3, 2006 I still believe that the synchros were not designed to select 2 or 3rd gear after a 120+ straight (like road america, corner 5 or 12). Grabing 4th, matching revs, engaging the clutch, then doing the same in 3rd is still technically easier on the synchros. Street synchros are just designed to smooth out single shifts on the street. Mix HP use, 120+ straights, >100k miles, and your technique matters. Or just wait and downshift to your selected corner gear once you've decelerated to the speed for that gear. I don't think very many people skip gears without decelerating first, but if they do, you're right that it's harder on the equipment. As above, you can feel a diff when you properly match revs to road speed. It's not that hard, and helps those synchros last forever. Yup, but I don't see how skipping gears aggravates that. Quote Link to comment Share on other sites More sharing options...
kinkyllama Posted February 3, 2006 Share Posted February 3, 2006 Do you track this Suzuki? Yeah. Why? Quote Link to comment Share on other sites More sharing options...
Kolia Posted February 3, 2006 Share Posted February 3, 2006 SHOBoy you beat me to it. When I skip gears, the lower gear is engaged at the end of the braking zone, just like when rowing. So instead of 5-4-3-2, I go 5-wait-wait-2… Quote Link to comment Share on other sites More sharing options...
GAC Posted February 3, 2006 Share Posted February 3, 2006 SHOBoy you beat me to it. When I skip gears, the lower gear is engaged at the end of the braking zone, just like when rowing. So instead of 5-4-3-2, I go 5-wait-wait-2… This really is the way it needs to be done. Discussion over on this particular point. Quote Link to comment Share on other sites More sharing options...
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