Mis-shifted Into 2nd From 3rd At Wsid!

[R33Turbo]

hey guys, just went to WSID and was happy with the time i pulled 13.75 with only a cat back and 10 psi boost...HOWEVER, the last run i shifted from 3rd gear redline into 2nd gear, would this of damaged my car engine (such as pistons working too hard?) or would the rev limiter cut it off even if u shifted from 3rd to 2nd???

wat are the possible damages i coulda done??? cuz my car runs alright but just paranoid man

[gt-ahhh!]

hey i saw your car! i wasnt competing, but i would like to in a few weeks, 16th methinks.

didnt see the mis-shift, and im no techhead but i have heard it can do all kinds of things such as valve-bounce, the piston coming up and smashing into the valve. of course that is just heresay, if its running fine i shouldnt be too concerned.

not like that poor bmw that got towed. or whatever it was that shat its guts up the end and delayed proceedings.

ill race you if i see you there again. mind you im expecting mid 12s with a 230-240rwkw R33.

[R33Turbo]

HAHAH nah its alright i wouldn't wanna race ya...u can race the gtr's mate...

but the thing is i thought the rev limiter woulda cut it off so i woulda been safe? or am i just lucky the pistons didn't fly out?

[paulr33]

if its driving ok and no smoke or bang noises etc its probably ok

[skylinekid]

if u shifted to second from 3rd wen u were on the limiter id be more concerned about ur gbox and driveline hence a massive compression lock usually... but if u had sticky tyres well i dont know but i wouldnt have thought it would have affected ur engine much cept for pinging of limiter

[R33Turbo]

yep the gearbox is actually quite fine imo...

i didn't have sticky tyres, i only had some low profile "roadster" tyres at rear...and wat do u exactly mean by driveline issues?

i shoulda mentioned before, i did smell something badly right after it happened whether its the clutch or brake pads i don't know but there was no smoke or bang noises...

[gt-ahhh!]

but the thing is i thought the rev limiter woulda cut it off so i woulda been safe? or am i just lucky the pistons didn't fly out?

well the way i figure it, if you let the clutch right out, there is nothing stopping the engine from doing say 10000rpm. the rev limiter wont prevent this, it only cuts the spark (or fuel?) in an attempt to drop the revs. remember, if the tyres are going 150kmh, this speed is transferred through the drivetrain, and then to the engine. in 2nd this would = 10500rpm.

this normally results in compression skid, where the tyres lock up, or the engine doing 10000rpm momentarily lol.

[gt-ahhh!]

i shoulda mentioned before, i did smell something badly right after it happened whether its the clutch or brake pads i don't know but there was no smoke or bang noises...

hopefully that was your clutch slipping. best possible result! burnt clutch smells like shit, i daresay thats what it was.

[inthisglass]

yeh mate, your engine will be fine but you just gave your 2nd gear cog and your drive train a bit of a work out

if its still driving fine then dont worry too much

[R33Turbo]

oh alright thanks ALOT GUYS! just bloody paranoid after that....

but yeah like u said the tyres did lock up and made me skid~! so does that mean the rev wouldn't of gotten to 10000rpm? or it still would have and kinda stuffed up my pistons u reckon?

oh yeah another thing is, when i tried to step on it on 2nd gear after i mis-shifted, the rev went up as if the clutch was slipping, i thought that was the rev limiter kicking in? or is it really just a clutch slip?

Edited April 2, 2008 by R33Turbo

[gt-ahhh!]

but yeah like u said the tyres did lock up and made me skid~! so does that mean the rev wouldn't of gotten to 10000rpm? or it still would have and kinda stuffed up my pistons u reckon?

oh yeah another thing is, when i tried to step on it on 2nd gear after i mis-shifted, the rev went up as if the clutch was slipping, i thought that was the rev limiter kicking in? or is it really just a clutch slip?

yes the revs probably did get up to 9-10000. i think its worse for your valves than your pistons, but if something let go it would probably have happened instantly and been catastrophic. so dont do it again lol.

revs going up, but not speed, is generally a good sign of clutch slip.

[R33Turbo]

okay...well just to make sure i haven't damaged anything what method would be the best to see if i have done any damage? Compression test or leak down test?

[Equinox]

No real way of knowing if you weakened your valvetrain. Just hope for the best.

This is probably the most common way that healthy engines pack it in, miss-shifts.

Edited April 2, 2008 by Equinox

[10MinuteCar]

why don't you give it another run? because if the valves did bend due to the mis shift then wouldn't the performance be affected in a bad way ? or maybe not? can someone correct me on this?

[trism]

like already said, if it did damage, itd be very noticable

[gt-ahhh!]

like already said, if it did damage, itd be very noticable

agreed. think rattling, loss of power, knocking, plumes of smoke, oil leaks.

[R33Turbo]

thanks for the input guys. well im taking it in for a compression test tomorrow to make sure, but apparently to find out for sure i need to pull apart the head

*sigh* shouldn't of went to WSID tonight

Edited April 2, 2008 by R33Turbo

[ztuned]

check ur front bar.

nah seriously its happened to me a few times and nothing happened, the car will heal itself it somethings wrong, just don't worry bout it lol

[The Mafia]

LOL @ anyone saying the rev limiter would have stopped it.

Of course it doesn't. All it does is cut fuel.. If the engine is being forced to rev harder, then nothing is going to stop it..

[Sydneykid]

SoSK did similar, 4th to 3rd instead of 5th. Result 12 bent exchaust valves, no compression, engine no run. If the engine still runs OK, then chances are you got away with it, consider yourself very lucky. A leak down test will confirm that everything is OK.

Cheers

Gary