Opinions on downshifting
 

What are some of you guys opinions on downshifting? Mostly after coming out of a long stretch. Is it ok to skip gears as long as you don't over rev or bind the rear tires? Also if you still go threw the gears is it ok to clutch in once and rev match threw the rest of the gears and clutch out? I do realize that not going threw the gears can wear synchro more. But that's racing/ tracking.

At Road Atlanta for me on the long back stretch I was averaging 135mph with a couple of laps at 140 if Istayed it just a little longer and wanted to brake harder and later which at this point is a slight down hill into a chicane. Well being I heel to toe (pretty good at it) being I don't have SRS. At 135mph and 6th gear coming to the chicane (in which third gear is perfect for this apex) I was braking hard clutching in and holding to I slowed alot then rev match to third which workes perfect for me lap after lap. Seemed so natural. But should I be practicing this differently? I'm going back in two weeks with a bunch of hand notes and want to be ready. I know I need to learn this but interested in your opinions.

I guess it would depend on how your brakes are holding up, how hard you want to stop, and you skills (including dealing with a lot of things at once, at speed)...

id row through the gears just to let the motor do some of the braking, and save some of the brakes.

i would also be willing to bet that you could brake later and stop harder if you use the motor as an aid.

if you feel safer just holding the clutch in and focusing on braking, i'd continue doing what you're doing. :tup:

Why are you going through the gears if you don't engage the clutch?

Why would you wear out synchros if you don't go through the gears?


synchros should only come into play when you push the lever into 'gear'... if you're rev matching, it will save wear on the synchros.. but if your not releasing the clutch, why bother?

I didn't say I was doing that. I said if. And many drivers even pro do this when carrying high speed into a short braking zone. I've seen plenty of videos showing both ways. And the reason I'm asking is I believe that by going threw the gears it may slow down the engine and transmission speed to a little bit more suitable speed to make engagement smoother while also preserving the tranny. That's why I'm asking to understand the variables. I'm just making points of what could be. Just want to hear from experience members with track time there input.

Skipping is fine as long as you rev match. Attended a lecture with Peter Krause at VIR and he specifically addressed it, nothing wrong with it and less work

Good to hear Mike. So have you been converting back yet? Going to miss you in two weeks.

are you sure you werent watching them blip through a sequential?

on one end of the trans is the diff... on the other end is the motor... if you don't release the clutch and tie the two together, they won't slow each other.


my bottom line... ideally, if you can blip, brake and clutch through all the gears, you will stop faster (if you are smooth enough)... but most importantly, do what feels comfortable to you... if you're jerking the car while braking, it is much worse than just keeping the clutch in... but don't bother rowing through gears if you're not releasing the clutch... it either makes more useless work for yourself (rev matching) or put useless wear on your synchros... just skip from 6 to 3...

but what do i know...

How r u in 6 gear @ 135?

He said approaching 6th I believe which sounds about right!

Don't you generally not want to be engine braking on track?

'generally'? hard to say.

in corners.. no.. in a straight line.. why not?

let's say my brakes are cooking and I have only a few laps to go... do i let the engine do some of the work?

on the other hand... let's say my motor/trans is running how and I only have a few laps to go... do i just hold the clutch in and let the motor idle while i brake?


I would say try learn to do everything.. if you can be comfortable with it, and it works.. great. if it sketches you out while braking.. don't do it.

but as far as i know (in regards to the OP)... there is no point in going thru gears if you don't release the clutch... and synchros won't wear out by skipping gears.

Double clutch and avoid engine breaking.

My vote would be that you should be engine braking anytime you're foot-braking. If you want to skip a gear to save some work and attention-span that seems fine, but I'd still leave the higher gear engaged until you're ready to make the jump IMHO. I don't really see how holding in the clutch and braking in neutral is helpful to any aspect of the process.

seriously?

Double clutch - Wikipedia, the free encyclopedia

Brakes are cheaper than clutches!

^^ doesnt get it...


You only NEED t o double clutch if your transmission does not have synchros. Double clutching doesnt help on a syncronized transmission (which all modern cars have)

Engines are for going, not for stopping. How fast you can stop is determined by the tires and the available traction. You can easily reach the threshold of the tires using just brakes so the engine won't help you stop any faster. All you are doing is adding stress and wear to the driveline. Brake pads are cheap and that's what they're for and they'll stop you faster than any engine will.

I hit every gear on the downshifts, but it's a matter of preference. If you're going to skip gears on the downshift, then keep in mind that your rev-match will need to be a higher blip than if you hit every gear (the rev difference going from 5th to 2nd is more than 5th to 4th or 4th to 3rd or 3rd to 2nd) - so it's either a bunch of small blips or one big one.

I'd also recommend leaving the car in gear until you're ready to do your one big blip. If you're clutching to neutral, then you're blipping the engine from idle which will require an even bigger blip - much more opportunity for a mis-match and chirping the rear tires which can lead to a spin.

too much fast and furious...

This was defiantly what I was doing. I wouldn't clutch to neutral ever. And I have down pretty good. All and all I wanted to be assured it was OK.

I hope you knew what double clutching was before you read that Wikipedia article. I'm not saying you have to double clutch with a synchronized transmission, but I promise you that you will reduce synchro-wear if you do.

wikipedia just taught me how to drive a stick.

but i bet you will also reduce synchro-wear if you just only use 2nd and 5th gear.

Obligatory: Vin Diesel Rips Paul Walker (The Fast And The Furious) - YouTube :)

In any case, it is factually true that even on a modern transmission, using a double-clutch technique (in addition to normal rev-matching) will make the engagement smoother. When combined with heel-toe on a downshift, the extra release-push cycle on the clutch pedal mid-shift (while the stick is transitioning through N) basically serves to "rev match" the front side of the transmission to the engine revs you're blipping up to for the next gear. I only ever tried this playing around on the street a bit, I have no idea if it's practical.

Either way, the whole double-clutching issue is orthogonal to the basic questions about skipping gears on downshift (although as you skip more gearing, double-clutch might become more worth it).

Just buy an automatic

If your lazy and want less reliability. :stirthepot: Also add SRS on rop of that also.

Guilty as charged!
We'll see. In the long run I expect the 7AT to need a rebuild before the 6MT does for sure. In the short term though, I've flogged the crap out of mine for 3 years now without issue, with the only upgrade being a very small extra cooler for the fluid. Whereas with the 6MT guys, we've already seen issues with clutch slave cylinders and some aftermarket flywheel failure stuff.

It would be faster than double clutching down each gear at all the corners. I thank vin diesel for the tip

It would be faster. But being all this would happen during the braking transitions it wouldn't matter.

Apples to oranges.

You must have either a really long braking distance or really quick left foot to double clutch the car down to the gear you want

I don't personally double clutch ever. I was just pointing it out.

Only Vin Diesel, F&F fanboys and truckers do

Where's my hipster trucker hat when I need it? :P