JTso

iTrader: (2)

I was test driving my car with one of the local members today, trying to demo the Hondata reflash and the results of some of the mods. I was cruising at approx. 80 mph in 4th gear and downshifted to 3rd then floored the pedal. The car threw us back to our seats (what a feeling! ) and I continued to bring the rpm close to redline, then proceeded to quickly shift into 4th. It had to be at least 95 mph. With all the excitement, I mis-shifted into 2nd instead! The next thing I knew, the engine roared and the rpm ran all the way to 8000 rpm, it might even ran over that slightly! I quickly pressed the clutch and put it back to the proper gear and coasted, while listening for unusual sounds.

The rev-limiter didn't seem to help for this particular situation due to mis-shift. Everything seems to be fine at the moment but I will keep monitoring for any signs of problems.

peter_bigblock

I did the same thing hammering it coming around an entrance ramp doing about 65. I was WOT in 3rd and mis-shifted into 2nd instead of 4th. It was really momentary, I hit the clutch and was off the gas right away but it still roared to 8,000 or so for an instant.

That was maybe 2,000 miles ago and I haven't noticed any detrimental performance/noises/effects from the gearbox or engine. Don't think a one-off mis-shift is going to do any lasting harm, though I'm going to practice Dan Martin's shifting technique to make sure I don't do it again.

Mis-shifting sucks!

04_K24TSX

How's your idle? Any unusual vibrations coming from the engine? I'd check the engine's compression to see if any valves might be slightly bent. If you were in redline in 3rd gear and shifted into 2nd, you must have went past 8K rpm. Keep us updated.

Alin10123

Hmm... revlimiter shuold've kicked in anyways. Maybe the limiter is set so that you can be up there for a split second but anythign longer it'll kick it back. Or maybe you just hit your clutch before it had a chance to launch back.

drunkenbuda

WoW, i wish i would have heard that. What is your next mod gonna be?

Dan Martin

Rev limiter doesn't do anything for mis-shifts, it only limits throttle-based overrevs. In a mis-shift, the wheels are spinning the engine so there's nothing the computer can do. You'd need a electrohydraulic clutch like in an SMG system to be able to prevent that from happening.

fdl

^^ what he said

A split second at 8000 should be fine IMO.

JTso

iTrader: (2)

Just finished with a compression test and all cylinders are 165psi +/- 2psi, which seems to be perfect. I guess I got lucky this time. The engine is now officially broken-in.

04_K24TSX

Man, your lucky. I guess honda's cylinder internals can stand some good abuse. If you would have done that with my old car (celica gts), say bye bye to your valves. Then again, we're talking 9K+ rpm.

sauceman

Happenned to me too, the almost exact same thing, and the engine withstood it admirably. https://acurazine.com/forums/showthr...ight=mis-shift

Haven't ovverrevved it again since.

dom

Only JTso would get the compression checked

kurt_bradley

He's not the only one. Then again, I also have all the equipment at my disposal.

The engine should be fine. A quick blip off the chart isn't good, but it won't kill it. The engine has a sustainable point of revs that is definately higher than even where Hondata sets the new rev limiter. Though not much higher.

I actually gave my car a decent couple of rolling starts from 5-100 over the weekend. It was great. I hit the 7600 point a few times through those runs, but I usually try to just hit it at about 7300-7400 to play it safe. I hate the cutoff. I think the car thanked me in its own special way afterward. We had a couple AZ members come to town over the weekend to check out Austin. They seemed to enjoy the car too.

More info and a few pics from the weekend can be found here.

vwong

JTso, you're very lucky. Are you sure the rev only went pass 8000 rpm slightly? You must've caught it rather quickly. I mis-shifted also in my Prelude during a track event. From the original video clip, I could see the tach needle went way pass all the marks, and was pointing at the 6 o'clock position. I estimated that it revved to at least 10k rpm. I was able to drive it for another 9 months before I spun a bearing. When we took apart the motor, we found all 8 exhaust valves bent.

JTso

iTrader: (2)

I'd like to think it only went pass 8000 rpm slightly, but from the sound of the engine, it sure sounded like higher. It happened so quickly that my first reaction was to press the clutch then look at the tach. It was at the top of 8K, so it's quite possible that it went up much higher than I originally thought, especially I was shifting at the higher redline with the Hondata reflash.

LannyM

I would surmise that you didn't engage the clutch long enough to bring the engine up to speed. As soon as you heard the engine winding up, you declutched. If you hadn't the result would be this:





Over 11k in 2nd gear (1.88) at 95. Of course, you would be rapidly slowing down before it reached 11k anyway.......talk about engine "breaking" (sorry, bad pun intended.)

But, you probably caaught it before it got much over 8k, which hopefully wouldn't be an issue for a second or two. For once thank goodness for that crazy 1.88 second gear. The RSX-S runs a 2.13 second gear with the same 4.76 final drive; in the same circumstance it would spin to 13k

JTso

iTrader: (2)

Interesting info LannyM.

Arcticcl9

I have never overreved by misshift, but one time I downshifted too early from 4th to 3rd gear right before a freeway offramp (yeah, I was going quite fast), and I saw the needle go up to 8k rpm before I pushed the clutch back in again. I drove slowly he rest of the way, trying to listen for any strange noise or vibrations from the engine. This happened a long time, and I have no problems so far, so everything is all good The K24A is a pretty tough engine, but if you screwed up more than once it might just explode on you.

nahooneyya

i've done that in my my old civic before..

ran fine after...

xizor

you didn't mention that part in your other post

good to hear your engine is doing good jtso. driving a 6MT really does require good shifting technique, if I get lazy I find myself mis-shifting sometimes, luckily I'm not doing it at redline.

afici0nad0

laziness...

no mis-shifting yet, but jerking from time to time...

early morning drive while still half asleep is killer....

05_TSX_GP

best wishes to your engine JTso!

Would anyone care to point me to the thread explaining Dan's shifting technique? I haven't had any problem with the 6MT... maybe I have just been lucky

Canyonball

Good thing no damage occured. Last time I heard this happen, it was some kid who blew his GSR engine. I was working at ACura at the time and had the guys change my oil on my freshly SC'd 'Teg. It so happened to be April fools day and those bastids took some of the kids engine shavings and put them on my "old filter" and said something was wrong with my engine!!! My stomach sank as I thought about how I just voided my warranty.... next thing you know...
"APRIL FOOLS!!!!"

lol @ those bastids! They got me good though, I'll never forget it.

Oops, sorry about the rant, glad your K24 is cool!

yfin

What about the fault codes on the ECU? It has registered the over-rev.

You might want to get it cleared to avoid issues with the dealer if there are warranty issues.

calgary_tsx

i also missed the 3-4 shift once 2 years ago, and once a few months ago, but I dont think it did any damage, I was not clutched out fully either time, however tach was at 8k

iamhomin

Ouch. The worst mis-shift for me was from 5 to 4, @65mph. Which wasn't bad at all..

iamhomin

I've heard something about that too.

IneedaTSX

Ha, I had the exact same senerio happen to me in a prelude, only I wasnt so lucky....I ended up blowing the head.........Looks like the TSX God's were on your side...lol

vwong

You're talking about the post on the broken crankshaft? Well, the mis-shift was in December 2003. The spun bearing (leading to 1st motor rebuild) was September 2004. And the broken crankshaft (leading to 2nd motor rebuild) was June 2005.

05_TSX_GP

Holy crap!!! Are those rebuilds on your TSX?

vwong

No, it's the Prelude.

05_TSX_GP

Still a big OUCH. Take good care of your TSX engine

slats

I'm not the fastest driver (nor do I try to be) so I actually shift a little more deliberately when at WOT. My only mis-shift in my new Accord was at lower speeds and I clutch before the tach came close to redline.

Slats

mrsteve

iTrader: (1)

Palm down while shifting

97AcuraCL

you now have a code on the car's computer that says you've over-reved. and the dealership will try to void your entire warranty because of it...

if you deal with a bunch of pricks like the people at Fountain acura.

If however you work with a decent dealership like Ferman Acura, they'll gladly do a compression test for you to be sure that you didn't do any seriously permanant damage

either way, sorry to hear about the mishift, lol shit that musta been embarrasing.

97AcuraCL

JTso has joined the club of worst fuckups ever huh sauceman? lol thank god we've got some well built motors.

JTso

iTrader: (2)

Worst fuckups? Don't think so... We are members of the elite 8000 rpm club and sauceman is the club president, since he did it first.

05_TSX_GP

sauceman had mis-shifted and over-revved on his TSX before? And his engine (no big repair or rebuild?) is still running this strong with this high mileage? indeed!!!

05_TSX_GP

Has sauceman taken the weekend off from AZ?

I am really curious about his over-revving mis-shift and the engine reliability that he is still enjoying Just like to hear a confirmation from him

NightShredder

I guess this happens to the best of us. Just this weekend I mis-shifted and quickly realized my error and got the clutch in before 7100 RPMs. Felt like a dumb ass though.

CJams

It's about time you drove that thing to work Johnny!