Hey guys,

I had a situation over the weekend where I had to humble a modified Bimmer. In all the excitement of it, at one point I downshifted to 3rd and revved it all the way to 7000. I saw the tach needle bouncing back and forth for a little bit then of course I shifted again.

I am just wondering if you can do damage to your Z by over-revving or is it fool-safe??

Thanks,
Mike

 

You probably just hit the rev-limiter....everything should be ok. The only way to really damage the engine would be to downshift into a lower gear that physically over-revs the motor, such as going into 1st at 80 mph. In that case, the rev limiter can be of no help!

 

The rev-limiter kicks in at 6600 in the Z, hitting it should not do damage.

 

If there was any damage done to it, you would've known already. A pushrod would've probably bent. But, looks like you're ok.

 

Smokin............
Listen for strange ticking noises for a while...............

From WHAT you described you DID, you DID mechanically overrev the engine........( you came from a higher gear, into a lower at excessive rpm's).
The rev limiter does NOT work in these scenarios...........

There are top speeds( for every gear) where you CANNOT downshift into, or you will produce the same results as having UNINTENTIONALLY gone from 4th to 3rd, or 4th to 2nd............

Bad things happen.................

Get you're manual out, and read the speeds at which you are allowed to downshift into before the overev happens............ :eek:

 

Thanks for the info, I am sure I over-revved, not hit the rev limiter.

What does it mean if I hear strange ticking noises (did not hear any afterwards though - but I didn't drive hard after that)?

Mike

 

Mike,
These dudes are pretty tough.........
As long as you are not hering any strange or NEW sounds that were not there before, you are probably ok...........
Just pay attention to the engine, and any thing that is out of the NORM.......from what you have seen/heard thus far.
IF you bent a pushrod/s, you would most likely be hearing some noises, and or a seeming loss of revability, and smoothness..............
If you had damaged a valve(bent), you would know pretty much right away.......
Personally, I think the LS6 engine is built to take a FEW trips to the 7k range without unwinding........
Be aware, that the overev (since you went to 7k) is/has been recorded in you're lil' GM black box.......and GM with a special set up will be able to read this IF & when you had a major mechanical problem FROM this episode......
If the car is running strong NOW, I wouldn't sweat it........just drive on as usual.........
From what I have read, most dealers will warranty this ONCE, and then you get to pony up the $$$$$$$.
Best of luck, I think you will be a/ok.......and wouldn't worry further about it.......
;)

 

Not safe in the circumstance you describe.

 

Unless I'm missing something, the only way to get to 7000 rpm is by downshifting at the wrong time .. Under acceleration the rev limiter should stop you at 6600. As others have said, if you're not hearing wierd noises or experiencing reduced performance, you're probably ok .. but I'd be careful in the future about your downshifts. Valves and pushrods can be a pretty expensive repair.

 

If it was only 7000 rpm dont go loosing sleep 7500+ starts becoming a concern.David Smilovic

 

The only way to over-rev beyond what the limiter will allow is (as you found out) to downshift and force the issue, at which point the limiter is of absolutely no use - the laws of physics take over, and the engine has to spin at the rpm needed for the selected gear.

Sounds like you are OK, since there is no apparent evidence of damage - but I wouldn't make a habit of it... :eek:

 

Others have over revved on downshift, and if they had damage it was immediately apparent.

 

MAKE sure you clear any errors in the DCS, it will log an error if you hit 7400 (tach max) and the dealer will be able to see that error. I dont know if the computer keeps a permanent log that we cant see or clear. :nopity

 

From what I have leaned from my scan tool is, the PCM stores a snap-shot of the car's info when an error occurs. This can be cleared with the scan tool. I found it useful when trouble shooting be tranny problem on my 00 SS.

Rick

 

Thanks guys for the great information!! Okay how do I clear the computer code?

Mike

 

Trust me you can't fool a dealer I have seen this before a customer took a 99 fixed roof out for a test drive and came back saying he had to stop and get gass and must have gotten a bad tank because it's not runnin correctly, Well when I pulled the heads and saw several hits on the pistons from the valves not to mension several bent valves it's pretty easy to see what happened, used car department paided for the repair, this time and I'm not so sure we would have made the customer pay for it if it had been his car but I will tell you if damange was done you would know it by now and there is no way you would be able to fool the dealer(unless they where that bad and in that case you may not want to use them) and by not saying something some guy may speen a lot of time trying to figure out what's wrong, I didn't I pretty much had a hunch something was up a simple compression test told me it had to comeapart and the rest was history.

David Fulcher

 

You need a scan tool of some kind. Autotap or the one I use is http://www.obd-2.com. It is inexpensive and works great. You will need a lap top.

Rick


[Modified by forloop, 3:35 AM 3/8/2002]


[Modified by forloop, 3:35 AM 3/8/2002]