How to DOUBLE CLUTCH and WHY - Starring Ian's Heel & Toe Shifting
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- เผยแพร่เมื่อ 1 มิ.ย. 2024
- Rev matching is not enough for a smooth transition when down shifting. A true double clutch matches the input and output speeds of the transmission. The heel & toe technique gets the engine speed to match the trans. Do all three and you have lap time perfection. This is the most comprehensive explanation as to why. So many people don't get this right, so Ian and I try to explain. We even show the transmission internals and what spins and when. Ian also describes how the synchros work and how to take care of them while going fast.
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Intro
Stripped Shell Introduction
• Porsche 911 Longhood C...
1
Drivers Fender Backdate, Unfold short hood edge, Make Signal Box Parts From Flat Sheet
• Backdating My Porsche ...
2
Drivers Fender Signal Box, Shape Bottom Portion w/ Bead Roller
• Porsche 911 Metal Fabr...
3
Drivers Fender Side Patch Panel Hammerform, TIG Weld Signal Housing
• CNC Machined Hammerfor...
4
Drivers Fender TIG Weld Side Patch Panel, Add signal housing triangle piece
• TIG Welding Sheetmetal...
5
Passenger Side Fender Backdate, Additional Content From Driver's Side
• Modify Your Short Hood...
6
Shorthood to Longhood Conversion, Form Outer Skin Edges And Weld On
• Project Porsche 911, L...
7
E Wheel and Form Longhood Inner Skin w/ Handormed Strength Rib
• English Wheel Metalsha...
8
TIG Weld Outer and Inner Longhood Extension
• Porsche 911 Restoratio...
9
Longhood Front Seal Custom Bracket
• Porsche 911 Carrera RS...
10
Rear Backdate, Remove Rear Impact Bumper and Valence
• Porsche 911 RS Tribute...
11
Lead Rear Valence Corners, Rear Latch Panel Backdate
• Porsche 911 Outlaw Bui...
12
Hybrid Steel License Plate panel & Fiberglass Rear Bumper, Custom Panel Brackets
• Porsche 911 Build - Hy...
13
Custom Aluminum Rear Bumperettes, Solidworks Design, Cut on CNC machine, Rear Flare Trial Fit
• Old Porsche 911 Resto ...
14
Form and TIG Weld Custom Rear Aluminum Bumperettes, Rear Bumper Complete
• Old Porsche 911 Resto ...
15
SC to RS Flare Comparison, Photoshop & Sheetmetal Conversion to RS
• How to Spot a SC Fende...
16
Tack Weld Passenger Side RS Rear Flare, Remove Undercoat, Align Flare
• How to Butt Weld a Ste...
17
Weld Passenger Side Flare, TIG VS MIG, Planishing, Weld Distortion, TIG Arc shots
• Porsche 911 Build - We...
18
Align Body Panels, Hood gaps, Adjust tub with dumbell, Repair Rocker, gap tool, Windshield fit check
• How to Align Body Pane...
19
Fill 20+ Holes, Mirror, Washer Jets, Rockers, Gas Filler, Antenna,
• How to Fill Holes in Y...
20
Remove Rear Window without cutting seal, Kick Method
• How to Remove Porsche ...
21
Remove Decklid Bumps and adjust Gaps & Fit, Add Weld material to edge
• Porsche 911 Decklid Pa...
22
Weld Pssgr Fender Support Panel, Lead Hood to Fender Gap, Weld Fender Edge to Reduce Gap
• Perfect 3mm Door Gaps ...
23
Build quality, Improve Panel Fit, Lead Passenger Door Gap, Lead Rocker to fender gap, Drivers Door
• Who Doesn't Want High ...
24
Drivers Door Alignment, Fill Rust Pits with TIG, Lead Drivers Door Gap, Adjust Front Fender Signal Fit,
• Panel Alignment Nightm...
25
Discovered Rust in Suspension Pan, Spot Weld Drilling, Tram Guage Mounting Points, cut out pan
• Rust Repair is HARD on...
26
Suspension Pan Repair, remove suspension, Cut Latch Panel for Oil Cooler, Check Squareness
• Suspension Pan Replace...
27
Align and Weld Suspension Pan, Spirit Level to remove twist, Kettle Bell Hits to Tweak Position, Rosette Welds
• 911 Suspension Pan Wel...
28
Re-Align Hood/Tub after Suspension Pan Install, Repair rust on gas tank panel,
• 911 Gas Tank Panel Rep...
29
Gas Tank Support Welded In, De-rusted with Electrolysis Bath, Reshaped pan edge, Final welding
• How to Simulate Factor...
30
Simulate Factory Spot Welds, Rosette Plug Welds, Pencil eraser on primer
• How to Simulate Factor...
31
Convert Drivers Side Flare to RS Profile and Repair Rust Damage
• Porsche Restomod - RS ...
32
TIG Weld Drivers Side Flare, Remove Failed Undercoating in Wheel Well, Planish and Metal Finishing
• 911 Restomod | This is...
33
Strip Paint from Car and Prep for Epoxy Primer, Strip it disc and paint stripper
• How to Beat the Ugly O...
34
Epoxy Prime, Project Review and Cost Reveal
• My Cheap Porsche Gets ...
35
Rear Coilover Gussetts & X-member strengthening plates, Golf Ball Dimple Dies For Speed Holes,
• How To Make Your Porsc...
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Tom, I think in your video you are answering a question that MANY have, but never asked. Your video should go viral!
If anything goes viral, it will be the super short version, ha ha. This longer video is really good information though. I hope many people see it, but also try it.
I usually start by teaching people that your transmission has a gear no one counts. Neutral is a gear. So double clutching is selecting neutral gear releasing the clutch and then shifting to the next gear 3 N 2 N 1.
Once you think of neutral as a gear of its own it helps drive
Good call. Neutral gets some love
This is great! I have been looking for specific material like this on the difference between a traditional 'heal-toe' (called a 'blip' here) and a double clutch downshift. It seems like you are saving wear on not just the Synchros, but the Throwout bearing as well.
I noted how Ian likes to compare the smoothness of a good downshift to being "like an automatic transmission" but in most automatic transmissions you get a noticeable "lurch" when forcing it to downshift! So I would argue it's actually better than an automatic with the exception of maybe a DSG transmission where each shift is about as seamless as it gets.
Thanks for the great video
Thank you, this video has created some great discussions and a place to share information. You are right that downshifting an auto causes a lurch. I guess it's all about the timing of when you downshift. Ian says to downshift just before you turn into a corner to prevent an over rev. But I guess most autos won't allow an over rev.
Anyhow, thanks for watching and sharing your thoughts. Always welcomed👍
I've watched many videos, but no one has explained it as well as you have... will have to watch many times! THANK YOU...!
Thank you! This video was not for the casual observer. It's a difficult topic and too much information for some.
Some of my videos with lots of talking are not well received, but Ian really knows what he's talking about. It was hard for me to edit, because I had to cut stuff out!
We hope this video gives you all the information you need to practice and see for yourself.
Nice... that was the way I was taught to drive a manual transmission by my neighbor, a gentleman named Chuck Milligan, who raced along side "Old Yeller" in what Chuck called "Specials" in Southern California SCCA racing
When I first bought my 83 911 with its 915 transmission I quickly realized it had a few synchros or worn dog teeth and needed a rebuild by modern standards. My dad taught me how to double declutch, and 27 years later the same transmission (with no repair) has been just perfect. Synchromesh is not a performance optimization, it was a driver comfort aid (do less work and have similar results). Problem is similar is not the same, and the synchros wear, and as they do, the results change. Double declutching does not change over time. Great vid!
Ian really knows how to be kind to the transmission and clutch. I'm so glad we were able to do this video together to keep double clutching alive for those who are willing to learn.
Eye opener. I’ll practice double clutch from now on. Thank you, Ian and Tom.
Perfect!
In 1947, Porsche patented the split ring synchromesh system.
Amazing foresight!
I was doing cruising Neutral->Gear wrong for years (i.e. no gear selected while car is still rolling, then into gear). I would clutch in, rev match, select a gear, clutch out. Reminding myself why double-clutching exists corrected me. Correct order to not wear synchros is rev match, clutch in, select a gear, clutch out.
I refer to weight transfer often. Sometimes I will say" that is a weight transfer " and I don't say an unwanted or disruptive weight transfer . I am sorry for not explaining the difference of un wanted and disruptive weight transfer VS the smooth and required W/T
Everything we do as an input to the controls will effect a weight transfer , as the driver we need to manage the amount and effect of the W/T. Steering and brakes , throttle , passengers , moving in the seat , Shifting , clutching , turbo on boost, or off boost, ECT all effect weight transfer . I hope this helps . Ian
This was very educational on all levels, great info on what causes clutch wear as well.
Thanks, this was another power packed information video!
The theory for the downshift is 5th gear at 130mph to a 40 mph left turn , apply the brakes , they are made to slow the car better than anything else . My point is to speed regulate to the exact speed you need .
The double clutch downshift only needs to happen once 5th to 2nd , when to do it is very important . How do you know when to do it?
No matter what the turn the system is the same . The downshift needs to finish with you removing your hand from the shifter and place it on the wheel and immediately start your turn in
To make this easier, you can get a gas pedal that is wider on the bottom and adjustable side to side. I have my gas pedal close to the brake pedal so I can brake and blip while I’m downshifting. I also have a very precise shifter. I’d don’t use any of the factory parts, and my shift rod is above the tunnel as my shifter is raised closer to the steering wheel. I have zero play in my shifter and 2nd and 3rd are spring loaded to center (901 close ratio transmission). The factory shifter is sloppy, even with all new bushings, and a monoball at the input shaft. I went to a Wevo, which was better, and replaced that. I got my new shifter from Hargett. And I believe the gas pedal too. For some reason he is not making the shifter anymore. It has a reverse lockout, as it is easy to nick reverse when shifting from first to second. I like the fact that I can just drop my hand less than half the distance to the original shifter, and it is very hard to miss a gear.
Great tips Rod and thanks for sharing. Pedal setup is important for sure. My stock 1989 911 is practically impossible to touch the gas pedal while braking. My yellow car has a custom pedal box that allows for a much better driving experience.
I will be doing some experimenting with the shifter too. Thanks for sharing your experience.
Bless you Ian, what a wonderful way of explaining of synchronizing the engine speed with tire speed (drive shaft) and way to regulate it through the left foot double clutching (until it becomes a muscle memory).
Indeed, thanks Ian!
Down shift...vroom !!!!🥰 Loved this vid... thank you guys❤
Ok, first of all the drag racer with the cigar in his mouth clip was amazing...haha...but not as amazing as this episode. Very informative! I now have a more complete understanding of the why and the how of double clutching. Nothing but great stuff here on this channel. Thanks Tom and Ian!
Grumpy Jenkins is awesome, right! Thanks for the kind words too. Ian shared lots of good information here.
THANK YOU for educating everyone was to WHY and the importance of weight transfer. Gotta keep our cars balanced.
Great explanation, use of open trans , and in car video. You hit a home run with this video.
Thanks Todd, we had fun working together and we are still talking about the nuances of how the input shaft mass effects the cars weight transfer.
Great video!!! Thanks Tom and Ian!
Great video, thanks
My dad taught me to lightly press the next gear without shoving it in, then letting it pull itself in when ready. I wonder if that's the dog teeth synchronizing (this is on the dump trucks)
This is good advice. The light pressure allows the synchro to match the speeds and then the dog teeth are happy to fall into place. There's actually a bit of a snap fit that keeps the gear engaged.
Thanks mann for this awesome video!
It is so valuable to be able learn from such experienced drivers as a beginner.....
My pleasure!
Holly molly, that just blew my mind!... thank you for sharing.
So much good information by Ian👍
I don't understand why at 2:40, some of the gears spin when you spin the input and some spin during the output spin. Shouldn't all 6 gears always be in a constant mesh?
Also, if I understand correctly, the purpose of double clutching going UP a gear is so that the motor slows the layshaft, as opposed to single clutching where the layshaft will rapidly slow down and put the speed difference into friction of your synchros?
And lastly, while double clutching while shifting down a gear, don't you have to decide between "wear on your clutch" or "wear on your synchros" because you can't let out the clutch and pop it into gear at the EXACT same time? What do you prioritize? I assume you don't want a lurch, therefore, there is SOME amount of wear on your synchros because you pop it into gear slightly early.. And it makes me wonder how a non-synchro shift would work. It's almost like you have to triple clutch if you want 0 wear because the time it takes between getting "in gear" and finally releasing the clutch.
Thanks for going in depth with this video.
Thanks for your thoughtful comment and I'm so glad you are pondering this topic.
It's true the gears are always in mesh, but they all can't be connected to their shaft at the same time or the trans would be locked up. The dog teeth are what lock a gear onto its shaft so it can transfer power. The slider engages the dog teeth and usually sits between two gears of different diameters.
During an upshift the layshaft speed doesn't change much because it's connected to the wheels. The input shaft needs to slow down to speed match the new gear ratio. This naturally happens due to the oil drag in the trans. That is why double clutching is not as beneficial on upshift.
Down shifts are different because we are trying to increase the speed of the input shaft which it naturally doesn't want to do.
It's possible to shift any transmission without depressing the clutch at all if you get the speeds just right. I don't recommend this because it's difficult to do and if you don't get it right the dog teeth will suffer. It's just an example of zero wear in an ideal case. As long as you match the engine speed and let the clutch out quickly the clutch will last a long time during gear changes. Most wear is from a dead stop in first gear. Don't pre rev too much in any gear.
As for synchro wear, double clutch definitely helps if done properly on down shifts. On my car you can hear the synchros complaining or whining if don't do it right.
Hope this helps.
Such a great explanation and an excellent demonstration! If you’re interested in making it, I’d love to watch a video about suspension tuning and how roll bars, spring stiffness, damping, and alignment impact performance/handling characteristics. I’m in the process of replacing rear sway bar mounts that got utterly destroyed, most likely on a pothole, and while I like to think I have a decent idea about them and spring rates and damping I’d be curious to hear from someone with the practical experience and a driver’s know-how. Such a great video, thank you for it!
Thanks, I'd love to make a video on the effects of suspension components and alignment. For my car, the first thing to do is alignment and new tires.
Then I will add the adjustable anti roll bars. And then coilovers?
Each time I make a change I always want to understand what the effects are.
This won't be a single video, but maybe I could do a consolidation video after all is said and done.
Really good stuff thanks
Thanks, it was a LOT of information.
great footwork! l call it double clutch heel n toe downshift 😁
Say that three times fast, 😂
Great Video. Thanks Tom and Ian. I can't wait to try out my new knowledge. Also, very Jealous of Ian with a 911T in addition to Kermit! I can't tell if it is Tangerine or Red. Tom, you should have at least introduced the car. We all noticed it was not Kermit...
Kermit is undergoing some upgrades! In the engine department I think, My car is too loud to record video, so Ian borrowed this tangerine beauty from a client. Ian does have several 911's though. One is a 72! This video could have easily been over an hour long! Sometimes the car is just a teaching tool, ha ha.
Gentlemen, that was the best lesson on that subject I've ever heard. Thanks!! Also, thanks for including the Tremic. My XJ6 is currently a three speed auto (😫) but as soon as the budget allows, It's going manual. I regret not practicing more in the 23 years I had my Miata. LOL. Again, awesome video. Cheers.
Thanks Jeff, I feel like I'm making your to do list longer. First Webers and now a manual trans...
@@GarageTimeAutoResto They were already on the list. 👍
Nice information
So nice of you
@@GarageTimeAutoResto keep the good work up bro👍❤️
I think shifting from 1st to 2nd without double clutching, the lay shaft rpm can be much higher than that of the output shaft. And this is not good to the synchro. Am I right?
Yes, this is true. The lay shaft is spinning faster on an upshift. This is why it's best to shift slowly instead of ramming it into gear.
This is true for every shift as the input shaft needs to be roughly 1500RPM less.
Thanks for an very informative video! I must say after trying the double clutch technique it is an enjoyable process. I was wondering if Ian’s Porsches in the two videos have stock Porsche shifters?
Yep all stock in the shifter dept . The Tangerine car is a customer car . I will be changing the torsion bars to a softer set up , also the tires will go to 60 series, it's way to stiff. I agree it is great fun to pay attention to your driving technique and enjoy the drive . As Tom and I have mentioned the pedal adjustment is very important as well . Thanks for the interest
In my '14 2.5L scion tc, there's quite a bit of space between accelerator pedal and brake pedal, making the heel-toe downshift quite difficult if not impossible to incorporate into daily driving. Without being able to heel-toe, is everything else regarding double-clutching (every shift) & rev matching still completely applicable and beneficial?
I've always had a hunch that double-clutching is a good habit, not only in terms of synchro wear, but performance. It's certainly more smooth when done correctly on both up and down shifts, despite everyone telling me it's a waste of time and not necessary unless I have an 'old car' or my synchros are worn-out. I've found when driving in the snow or rain double-clutching to be exceptionally helpful perhaps because as you've pointed out there's a much smoother weight transfer - which inevitably helps to a more apparent degree on slippery roads...
Thank you so much for sharing your wisdom! Perhaps after I master the double-clutch on these stock pedals, I'll consider replacing them, so I can start using the heel-toe...
I think it's beneficial for sure and a good habit to get into on downshifts.
Rev match is the most important thing for weight transfer because the rotating inertia of the engine/flywheel is much higher than that of the input shaft and components.
People that say double clutching isn't necessary are saying that the input shaft inertia doesn't matter.
Double clutching does the best job of matching all the components speeds, but like I said the engine speed is the most important.
@@GarageTimeAutoResto In regard to specifically upshifting, on newer cars (past 20 years), generally speaking, would you say that a perfect double-clutch on an upshift will always be better/smoother than a perfect single-clutch on an upshift?
Think about the speeds of the various parts. When upshifting the engine and input naturally are slowing down to match the axle speed.
So there is no performance benefit on an upshift, unless you want to practice.
Downshift is a different story because we need to speed up the engine and the input shaft. We can blip the throttle to speed up the engine, but we can only use the driven wheels to speed up the input shaft.
nice video! What happens if I blip the lay shaft with a rpm much higher than the output shaft? Would I still be able to upshift smoothly without wearing the synchro?
Thanks! On an upshift you want the RPM of the lay shaft to drop to match the RPM of the output. This normally happens naturally and there is no need to blip on upshift
I drive an '85 with a 915 trans. I noticed that shifting down from 4 to 3 and 3 to 2 is perfectly fine without doing any double-clutching. However, upshifting is generally more prone to some (minor) grinding, especially when shifting at low RPMs. Also, when shifting down from 2 to 1, I need to blip the throttle to prevent it from grinding, but this can be without double clutching as well. Both these behaviors don't make any sense to me. Any thoughts?
Does the grinding stop when you shift slower?
Your synchros are probably worn more on one side than the other. This makes sense because upshifting is much more common.
All you can do for the time being is shift slowly and wait for the engine rpm to drop before clicking into gear (shaft speeds to match)
Downshift into first isn't recommended above 5mph in my opinion.
Double clutching is helpful for smoother downshifts and to prevent synchro wear.
@@GarageTimeAutoResto Ah of course, didn't think of the inbalance in wear. Thanks. When warm, and at higher RPM (4000+] they upshifts are quite smooth, and actually seem to be better when done fast.
Wow, it was all about mechanical sympathy, but when weight transfer came into play it got very real
Great in-depth video! My car's second gear syncro grinds when I am trying to shitft quickly, so I have to shift slowly and put less pressure on the shifter to avoid a grind. Could a good double clutch be faster than a single clutch with my worn out syncro?
Yes a good double clutch be faster than a single clutch with my
worn out syncro , but remember you need to allow for the two speeds to match each other , then the gears will engage. Certainly the double clutch will save the trans from more damage . Thanks for the interest
@@iancarpenter2334 so basically shift as you normally would right? but always come to NEUTRAL before going to another gear
correcT?
@@christophercolumbus8944 The best way to practice all shifting is to slow it down for all shifts , up or down . Speed is not the goal , but efficency of the shift
thanks for the interest, Ian
@@iancarpenter2334 thanks, Ian but clutch in to Neutral clutch out, clutch in 2ND gear clutch out?
clutch in to Neutral clutch out, clutch in 3rd gear clutch out? and so on?
i did try doing it slow but nothing happened i know it has to be somewhat quick without hesitation so i am working on that.
Wow
do you have to blip the throttle when double clutch downshifting?
Yes, but it doesn't need to be a rapid blip. You want the revs to match the lower gear you are downshifting too.
This means you can hold your revs there instead of stabbing the throttle.
Tom, so is it not recommended for a Porsche to not be driven without the clutch like my motorcycle and formula cars?
Dave , that is correct . For most efficient shifting use the clutch.
The motor cycle has a constant mesh style , as well the formula car has a dog style shift engagement
@@iancarpenter2334 thanks for the clarification Ian. Sometimes people don’t get the differences in their transmissions.
@@Royalerp31m If you were in a situation where your clutch cable broke or anything to prevent the clutch from opperating , you could turn the engine off, put the car in first gear , then turn the key and start the car and drive away in first gear . It would also be possible to shift the gears without the aid of the clutch, without doing any damage to the car or trans . That is a lesson in itself
Haha I actually taught myself to double clutch because if that other video.
Ha ha, great!I've been practicing too.
5th or 4th directly to 2nd (after completing braking) seems odd. Downshifting sequentially with little dbl clutch blips is what I have been doing for many years. Doesn't this use engine braking & reduce brake wear?
The brakes are so good on these cars they don't really need any help from the engine. I'd rather replace brake pads than synchros.
Well. If your going from 80km/h to then having to get down to 20-35km/h for a 90 degree turn your not actually going to go down every gear now are you?
Brakes are cheap and easy to replace. Clutch and syncro wear is much much worse! Even with good bliping and nice downshift there is wear on components that are not the clutch disk. Dubble clutch helps but still allot of wear on the clutch components.
I daily have to go top gear (5th) to 4th. Engine brake and small amount of brakes down into 1.2K rpm or lower. Then from there blip into 2th gear like nothing. Since at that point the gearbox is just about right for a 2th gear.
Since going from 4th to 2th at that point is like going from 1th to 2th. Just that you have to give RPM to let the engine match.
It is called eco driving having the RPM go low, since when engine braking (even if at low rpm) the real win is that the engine do no burn fuel! Since it is taking away emery to slow down! So all the way from 80km/h to 30km/h it do not burn anything outside of RPM matching with the throttle.
Really with dubble clutch I sometimes go from 5th gear into 2th if going slightly down hill and really rev the engine high enough to meet 2th gear. But that is more or less getting into 1k RPM and then dubble clutch up to 3k RPM or so to meet 2th gear. If holding the clutch in it is possible to go from 5th into 1st gear too. But that is just not a good ide.
It has all to do with RPM and road speeds. Gears are just a modifier. Go from top gear into 2th gear at 80km/h and the RPM is going NUTS. But at 40km/h with dubble clutch not so much. And from 4th to 2th at 40km/h you might as well forget dubble clutching and just blip and time it right. Since the RPM and road speed are just about right for a 2th gear.
Problem with syncro gearboxes is the wear and possibility of a to low gear get selected without you knowing and releasing the clutch ending in a OVER REV.
@@TheDiner50 The theory for the downshift is 5th gear at 130mph to a 40 mph left turn , apply the brakes , they are made to slow the car better than anything else . My point is to speed regulate to the exact speed you need .
The double clutch downshift only needs to happen once 5th to 2nd , when to do it is very important . How do you know when to do it?
No matter what the turn the system is the same . The downshift needs to finish with you removing your hand from the shifter and place it on the wheel and immediately start your turn in
This is why modern racing with automatic transmissions/sequential gearboxes is boring to me. These devices take a lot of the skill out of driving.
I agree whole heartedly!
I did this and it didn't work I don't think THEORY or watching videos is going to help it is an aposteriori way of learning
I did this with double clutching and just going into the lower gear WHILE blipping car just goes into throw up mode
Ian said that it takes lots of practice and I think he is right. No one is going to get this down in a day.
You never said what double clutching is....lol. its synchronizing the speeds. You never said how. Maybe its at the end. Im inly 10 min in.
Ok. Sorry. You explained it at 19:30. Ty
Thanks for watching patiently. Lots of passion and experience talking in this video.
Double clutch isnt useful or necessary on anything made in the past 40 years so
It makes a difference on synchro life and results in smoother downshifts on early Porsche transaxles for sure.
They don't use the borg-warner style synchros that actually work better.