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Downshifting into corner

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Old 04-26-2018, 12:04 PM
  #21  
GodISmE
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Originally Posted by mhoward1
I don't believe engine braking slows you down any faster. braking is limited to tire traction and braking bias. So as long as all 4 wheels can apply braking force to the limit of tire traction then that is the maximum you can apply. It doesn't matter if the force is applied by the caliper or the engine.

I don't have data to support this in a Z car, so I can not prove it but I do have supporting data in other cars.

So if X is max force a tire on that corner to take, which component would you rather apply that force? The brake pad or the clutch disc?
Believe it! Plus it saves your brakes.
Old 04-26-2018, 12:26 PM
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mhoward1
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Originally Posted by GodISmE
Believe it! Plus it saves your brakes.
but kills the clutch.

Do you have the data behind this?
Old 04-26-2018, 01:20 PM
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GodISmE
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Not if you heel&toe. No data, butt feeling and lap times

- 5th to 3rd with heel and toe
- 5th to 3rd with heel and toe
- 4th to 2rd with heel and toe
- 5th to 3rd with heel and toe

Last edited by GodISmE; 04-26-2018 at 01:27 PM.
Old 04-26-2018, 02:07 PM
  #24  
jcrick
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Originally Posted by GodISmE
Believe it! Plus it saves your brakes.
Why would you want to save your brakes? They are designed to slow you down.

Engine braking(early downshifting) is not faster at slowing the car down. You risk shocking your driveline and damaging your engine/transmission. Risk over-revving the car. And you also risk rear lockup.

I brake and wait on my shift. I find the car more stable with a delay in shifting gears. I tend to go through the gears but will skip if necessary. And sometimes it is necessary

Reading this thread I see a few posts that have me think that some people are braking with the clutch pressed in. Am I the only reading that? Because that would be a big NO NO!
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Old 04-26-2018, 02:43 PM
  #25  
mhoward1
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Originally Posted by GodISmE
Not if you heel&toe. No data, butt feeling and lap times

https://www.youtube.com/watch?v=Qh3YmFAcDp0 - 5th to 3rd with heel and toe
https://www.youtube.com/watch?v=eGgCehz92cY&t=3s - 5th to 3rd with heel and toe
https://www.youtube.com/watch?v=kZZsOrGkSrM - 4th to 2rd with heel and toe
https://www.youtube.com/watch?v=TWrY86rTPzQ&t=2s - 5th to 3rd with heel and toe
no offense meant but butt feel tends to suck. I use to own a competition data company and have data from 100s of drivers and races (including my own) , many who are pros. The data shows that as long and the brakes have enough power to lock each wheel and the bias is set correctly then it that’s all there is. It’s the tires that stop the car, not the brakes. They just provide the resistance. If you have a difference when heel toeing then it might be you are lifting a bit on the brake to blip the throttle.

Data aquisition is now cheap, I recommend using it for anyone learning or looking to improve. The pros use the data all the Time.
Old 04-26-2018, 03:30 PM
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mhoward1
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So it seems I accidentally lied. I do have 350z data on one of my archive drives. I am pretty sure Bryan Settle, Randy Probts, and John Evan’s data is in there. I’ll see if I can find it and post some of it here.
Old 04-26-2018, 03:35 PM
  #27  
guitman32
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Originally Posted by jcrick
Reading this thread I see a few posts that have me think that some people are braking with the clutch pressed in. Am I the only reading that? Because that would be a big NO NO!
No, that was incorrectly inferred by several in this thread since it was mentioned by mhoward1.

The process of skipping gears, even if you choose to row down and only rev match at the last shift, shouldnt result in more clutch-in time. If it does then it needs to be done quicker or the driver needs to adapt a different technique to help deal with the situations where this conversation is relevant (high entry speed, short brake zone approaches). It is mostly a motion to help keep your mind in sync.
Old 04-26-2018, 11:00 PM
  #28  
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I run though each gear. One to not over rev which I have done before. And second to use each gear as a gradual engine brake. Like above if you practice enough 5-4-3-2 will not slow you down at all. It just takes time to gain the confidence to heel toe during breaking.

I learned by heel towing daily driving to each stop signs and stops light at normal/slow driving speeds. If you’re very novis I’d just learn down shifting to stops with out the brake, then learn to heel toe, then initiate heel toe later and later to gain the speed and accuracy to down shift in a fast but controlled manner.

I’m sure I’m far off some guys here but it’s now second nature to me on and off track, as well as in my work trucks.

Just always remember take it slow, and perfect practice makes perfect. Forced or bad practice makes bad habits. Like I said take it slow and light try to learn at stop lights. Then bring it to the track when you’re running 70%, then 80% then before you know it you’re doing 110% and not even thinking about it.

Last edited by CK_32; 04-26-2018 at 11:08 PM.
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Old 04-27-2018, 08:31 AM
  #29  
JMII
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Originally Posted by jcrick
Why would you want to save your brakes? They are designed to slow you down.

Engine braking(early downshifting) is not faster at slowing the car down. You risk shocking your driveline and damaging your engine/transmission. Risk over-revving the car. And you also risk rear lockup.

I brake and wait on my shift. I find the car more stable with a delay in shifting gears.
Same here. I brake until the RPMs drop low enough to safely go down into the next gear (leaving myself some margin for error). Because as mentioned if you drop too quick you'll over rev, destabilize the car and/or break the rear end loose due to all the weight being on the nose.

Engine braking works fine on the street when you are coasting to a stop, because the RPMs are much lower and you not standing on the brakes. With slow moving traffic ahead I find a downshift is often enough to bleed off excess speed to avoid touching the brakes at all. I tend to still tap the brakes however to alert the driver behind me to the fact that I'm slowing down.
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Old 04-27-2018, 11:11 AM
  #30  
GodISmE
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Just learn the damned thing (h&t) and stop making excuses lol I still butcher it sometimes but it will eventually pay off.
Old 04-27-2018, 12:44 PM
  #31  
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Originally Posted by jcrick
Why would you want to save your brakes? They are designed to slow you down.

Engine braking(early downshifting) is not faster at slowing the car down. You risk shocking your driveline and damaging your engine/transmission. Risk over-revving the car. And you also risk rear lockup.

I brake and wait on my shift. I find the car more stable with a delay in shifting gears. I tend to go through the gears but will skip if necessary. And sometimes it is necessary

Reading this thread I see a few posts that have me think that some people are braking with the clutch pressed in. Am I the only reading that? Because that would be a big NO NO!
I don't think we are all on the same page with terminology. It is my understanding that if you are braking while the clutch is out, you are "engine braking". I was taught early on to leave the clutch out when braking during performance driving. It does make a difference. Obviously clutch in if the wheels are going to stop.

I always brake with the clutch out and I use heel toe when I downshift. I just don't hit every gear on the way down as it would require me to clutch in additional times as opposed to just one and it seems unnecessary.
Old 05-02-2018, 05:41 PM
  #32  
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if you are not good at heal toe.

https://www.auto-blip.com/
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