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-   -   Spirited driving fail? Over rev? (https://www.ft86club.com/forums/showthread.php?t=118695)

Pepper86 05-19-2017 03:07 AM

Spirited driving fail? Over rev?
 
I was trying to exit the freeway with "authority" and go from 6th to 4th at 70~ish. When I did so: to my surprise; it felt like I hit the brakes glanced down and saw 7k+ rpm I think it was around 7100-7200rpm but I for sure hit the rev limiter as it felt like I hit the brakes, and the engine cut out. I am sure I clutched as it is an instinct. Granted all of these event happened in a matter of seconds(or less). I am an experienced driver with some track time, so I have a decent understanding of this. I swear I went to 4th, but it is impossible for the car to hit 7500rpm in forth at any where less than 100mph if I am not mistaken. So the only other option is that I went into 2nd? Which means that I over revved? I have the Toyota 86 now which has the slightly higher final drive of 4.3~ and @70mph~ in 2nd gear is around 8500-9k(rpm)? That sound about right? I am trying to figure all of this out as like I said this all happened really fast.

FR-Sky 05-19-2017 03:23 AM

Thats call money shift lol.
I don't think you over rev, because our 3rd gear max speed is 83mph, 6th to 4th at 70mph is totally fine.

swarb 05-19-2017 03:26 AM

Quote:

Originally Posted by Pepper86 (Post 2912890)
I was trying to exit the freeway with "authority" and go from 6th to 4th at 70~ish. When I did so: to my surprise; it felt like I hit the brakes glanced down and saw 7k+ rpm I think it was around 7100-7200rpm but I for sure hit the rev limiter as it felt like I hit the brakes, and the engine cut out. I am sure I clutched as it is an instinct. Granted all of these event happened in a matter of seconds(or less). I am an experienced driver with some track time, so I have a decent understanding of this. I swear I went to 4th, but it is impossible for the car to hit 7500rpm in forth at any where less than 100mph if I am not mistaken. So the only other option is that I went into 2nd? Which means that I over revved? I have the Toyota 86 now which has the slightly higher final drive of 4.3~ and @70mph~ in 2nd gear is around 8500-9k(rpm)? That sound about right? I am trying to figure all of this out as like I said this all happened really fast.

Is this your first manual transmission car? How much experience do you have?
Did you more the shifter from 6th as up and then left then down, or up and then down? It would auto center and only up and down movement is needed. If you did the up,left,down movement, you probably went into 2nd.
Did you rev match/blip the throttle?
Shifter springs would help a little in the feel department.

stevesnj 05-19-2017 09:33 AM

I love the 6th to 4th downshift in this car, the engine loves to rev and passing is enjoyable doing the 6th to 4th downshift on the highway

stevesnj 05-19-2017 09:35 AM

Quote:

Originally Posted by FR-Sky (Post 2912895)
Thats call money shift lol.
I don't think you over rev, because our 3rd gear max speed is 83mph, 6th to 4th at 70mph is totally fine.

Just a mis shift, the computer did it's job to cut power. Everyone hits the limiter or missis a shift. Enjoy and don't sweat it.

celek 05-19-2017 10:24 AM

If it was truly 70MPH you have nothing to worry about...

TommyW 05-19-2017 10:39 AM

You hit 2nd. That's how you over rev and ruin motors. The rev limiter doesn't help with downshifts that are missed. 5th or 6th to 2nd can happen very easily. That is the downshift that is super important to get right with this shift pattern so gotta be mindful when doing so.

Detroiter 05-19-2017 11:40 AM

Quote:

Originally Posted by TommyW (Post 2912978)
You hit 2nd. That's how you over rev and ruin motors. The rev limiter doesn't help with downshifts that are missed. 5th or 6th to 2nd can happen very easily. That is the downshift that is super important to get right with this shift pattern so gotta be mindful when doing so.

The limiter does help you on downshifts. In events like this when the engine hits red line the fuel cut rev limit is so harsh that it has a great chance of locking up the rear wheels. This will stop your engine from being forced to rev higher as the wheels won't be spinning any faster than it is. I've seen it happen on many different rwd cars. Never being on that I was driving I should add:D

Sportsguy83 05-19-2017 12:08 PM

Quote:

Originally Posted by Detroiter (Post 2913009)
The limiter does help you on downshifts. In events like this when the engine hits red line the fuel cut rev limit is so harsh that it has a great chance of locking up the rear wheels. This will stop your engine from being forced to rev higher as the wheels won't be spinning any faster than it is. I've seen it happen on many different rwd cars. Never being on that I was driving I should add:D

I have to disagree with you on this one. A long time ago when I was younger and stupid, I was racing and shifted into 2nd while trying to shift to 4th, and completely trashed an engine, pistons melted, rods broke, all kinds of shit because there was no rev limiter in the world that stopped the engine from revving to 10K+.

Detroiter 05-19-2017 12:22 PM

Quote:

Originally Posted by Sportsguy83 (Post 2913027)
I have to disagree with you on this one. A long time ago when I was younger and stupid, I was racing and shifted into 2nd while trying to shift to 4th, and completely trashed an engine, pistons melted, rods broke, all kinds of shit because there was no rev limiter in the world that stopped the engine from revving to 10K+.

I guess I didn't write what I meant very good:bonk: What I meant was that it can help in some cases. I could imagine shifting to over rev a engine past 10k would probably cause tragic things to happen no matter if the wheels could lock up from the limiter or not.

I'm guessing the times I've seen it was when the miss shift resulted in the engine only trying to rev slightly past the limiter allowing the wheel lock up to slow the car quickly enough to get it back to the usable RPM range. Also could be that I've seen it happen most on MX5's which being extremely light could allow for the wheels to lock up easier, atleast that's what I'm thinking:iono:

Sportsguy83 05-19-2017 12:24 PM

Quote:

Originally Posted by Detroiter (Post 2913035)
I guess I didn't write what I meant very good:bonk: What I meant was that it can help in some cases. I could imagine shifting to over rev a engine past 10k would probably cause tragic things to happen no matter if the wheels could lock up from the limiter or not.

I'm guessing the times I've seen it was when the miss shift resulted in the engine only trying to rev slightly past the limiter allowing the wheel lock up to slow the car quickly enough to get it back to the usable RPM range. Also could be that I've seen it happen most on MX5's which being extremely light could allow for the wheels to lock up easier, atleast that's what I'm thinking:iono:

Yea it makes sense. I guess it depends how far away from the Rev limiter the misshift takes the engine, and I bet the lightweight MX-5 helps.

JD001 05-19-2017 12:39 PM

Oh noooo, not another MT thread about changing gears...


https://ae01.alicdn.com/kf/HTB1.NucJ...nt-b-Munch.jpg

churchx 05-19-2017 12:48 PM

Hmm, is clutch also drive-by-wire in ours, or only accelerator? If yes, i can see ease to impement safeguard in ECU to not allow engaging it untill rpms drop to safe range even with pedal depressed.

Detroiter 05-19-2017 01:01 PM

Quote:

Originally Posted by churchx (Post 2913055)
Hmm, is clutch also drive-by-wire in ours, or only accelerator? If yes, i can see ease to impement safeguard in ECU to not allow engaging it untill rpms drop to safe range even with pedal depressed.

No our clutch is hydralic. I'm pretty sure there is no cars using a clutch drive by wire system, or at least I've never heard of one before.


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