I've been battling with myself over this and I've looked all over the internet on how healthy this is for the car.


Now I know the importance of rev matching to keep wear off of the synchronizers and this and that but.. Something confuses me and I want to make sure that what I'm doing isn't going to hurt the car.


So here's the scenario.


I'm cruising on the highway at 60MPH in 6th gear. My RPM is around 2200..

Slow traffic is in my lane and the left lane is clear for take off.

My foot is in the gas and I'm boosting to pass, I'm at around 65mph now and about 2500rpm

I

1.) Put clutch in without letting off gas
2.) Shift from 6th to 3rd to get in power band
3.) Release clutch at around 5000RPM to rev match without ever lifting off gas to keep boost.


This is basically a rev matched downshift right? I'm not doing anything damaging as long as I'm nailing the rev match. Tell me otherwise if I am!@


Thanks!!

 

If you are smooth, it's perfect.

My version of that (I drive a Justa) is a double-clutch downshift from 6th to 4th under similar circumstances.

Timing is everything though, huh...

Cheers,

Charlie

 

Nothing really wrong here. Just press the clutch down very deliberately and release it just as fast. You don't want to be slipping the clutch at that high of engine speed, especially since these cars don't have bulletproof clutches.

 

You all need to learn how transmissions work.

Rev matching does absolutely nothing to reduce wear on ANY transmission part. It sort of helps prevent wheel lock up from bad shifts. (Reving with the clutch in as you shift)...

A double de clutch, done correctly, will eliminate any synchro wear, and wheel lock up. (clutch in, shift to neutral, clutch out, rev to correct rpm for the lower gear, clutch in, shift to lower gear, clutch out.) This action lets the input shaft spin the lay shafts of all the rears, and matches the RPM of the engine to the wheels/gear selected.

 

LOL - thanks Teach!

 

Like richard said: The rev matching will do nothing for your transmission. You might get some synchro wear doing your 6-3 (or other downshifting combos) eventually. Doing that every once in a while is fine, but not something you want to do consistently. I would also recommend finding out what transmission fluid you are running. The MINI service where I am uses automatic transmission fluid when they flush (so old ladies don't have harsh shifts on cold mornings). Swap it with some good manual transmission fluid so your synchros are nice and coated. It will be a pain to shift on colder mornings but you will spare the synchros from trivial wear and tear for a bit longer.

Also doing a double de-clutch as Richard suggested would be a good idea when your doing acceleration like that on the highway as it will preserve the synchros better. Might be a bit tedious to do it on a track where a simple heel-toe will suffice around a corner, but heel-toe will wear on your synchros after a while. Better to have your clutch or brakes wear out than to ruin synchros. That gets expensive.

 

Good info.

While we're on this subject..
What type of MT Fluid is recommended for the MINI?
Is a "tranny flush service" a simple drain/refill or is there more involved?

 

I use Redline MTL. A little thicker than stock but smoother shifts. Go easy on shifts in very cold weather for first shift or two until trans fluid warms up.

It is a simple drain and refill job and takes just under 2 quarts of fluid. I changed from factory at 1,200 miles (breakin flush) and I change ever 30,000 miles. There is no filter in a manual trans and I don't buy the"lifetime fluid" argument. Clean fluid gets rid of normal abrasive particles (from gear wear) in the manual transmission fluid and keeps the synchrnos happy. This will keep car shifting easily - even at higher mileage.

Good luck. I used a funnel with tubing to make it easier to refill the trans. from above. Car needs to be level and you just refill until it overflows the refill hole.

 

so is no one else going to mention how terrible an idea it is to shift from 6th to 3rd @ 5k, and how that's completely out of the efficiency range of the turbo?

 

I think someone just did.

 

SO the turbo isn't boosting at 5k rpm in 3rd gear?

 

Oh it is boosting, but with regards to efficiency is what psichick was referring too. There is a chart for every turbo that shows efficiency of the compressor.

This is not ours, but just a quick google to show what everyone is referring to.


I will be honest, I am not too sure where you want to be but the turbo on our cars is pretty decent from the low end and give great torque. You will get more hp at higher RPMs, but that may not be what you need to acceleration and gain speed. This is all speaking from more of a physics reference. Ideally here we are talking differences of fractions of a second and in traffic that isn't a huge deal.

 

So maybe a shift to 4th and release at 4K? Please forgive my ignorance. I did try to use an efficiency calculator and I did see a picture of this.

 

Rev-matching on downshifts isn't about watching the tachometer. It is about precisely using the clutch and accelerator pedal to match the engine revs to the ratio of the next gear you're selecting to ease strain on the clutch and drivetrain, and figuring out how to do this by feel. If you do it correctly, it will be as smooth as glass. The car won't jerk during the process and the downshift will be as smooth as that of an automatic transmission, and the engine won't abruptly change speed when you reengage the clutch because it won't need to. It's something that requires practice.

Back to watching the tacho. Probably not a good thing, especially not in traffic, as the original poster described, unless one does it with peripheral vision only. If you're focusing on the tachometer, perhaps you're not watching traffic around you as closely as you could be. Rev-matching is a seat-of-the-pants deal. You just figure out how to do it. And every car is different, because gear ratios and throttle response - the tools you're working with - differ from brand to brand, model to model.

For a good example of this sort of thing, seek any one of a number of YouTube videos dealing with Nurburgring. Here's an example. This driver pretty much has it figured out. Note that the sound isn't too good until about the 1:30 mark.

Not trying to be snarky. Hope this is of some small help.

 

I use redline oil in my car and when I contacted redline they told me they do not make a manual tranmision fluid that meets the spec for the r56 mini s. This was less then a year ago? has this changed or did you just put it in?