Rev limiter 8300? and 1st to 2nd grind during

[nsxrock]

My car doesn't hit the rev limiter until it is well past the 8000 mark.

Is this normal? I seem to think that my other NSX's bounced of the limiter right at 8k.

Also, I did some G-Tech runs today and the car grinded on my 1st to 2nd shift. That has definitely never happed to me in my past NSX's. The clutch was all the way in.

I shifted as fast as I could and I could not only hear but feel the grind from first to second.

I remember a review of a 2000 NSX that grinded on the 1st to 2nd shift as well.

Does anyone remember what article that was...?


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James
2000 Red/Tan
South Florida http://members.aol.com/flnsx

[This message has been edited by nsxrock (edited 01 August 2002).]

 

[NoClgDeg]

My rev limiter kicks in at 8300 as well. I think this is normal.

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91 Red/Ivory #2061

 

[nsxtasy]

Originally posted by NoClgDeg:
My rev limiter kicks in at 8300 as well. I think this is normal.

I believe that it is normal for the rev limiter to kick in when 8300 is indicated on the tachometer. (Mine does.) However, I am not sure whether the tachometer is designed to be accurate, or if, alternatively, 8300 is designed to be indicated when actual revs are 8000.

 

[Number9]

Keep in mind that for each car, indicated RPM may be different from actual. During NSX dyno day some years back, it appeared that indicated RPM for NSXen tended towards optimistic and actual was lower. Rev limiter kicked in, according to the dyno typically between 7900-8000 RPM, while the tach tended to indicate something on the order of 8.3k rpm.

 

[nsxtasy]

Clearly a case of great minds thinking alike and writing posts simultaneously.

 

[BadCarma]

Originally posted by nsxtasy:
I believe that it is normal for the rev limiter to kick in when 8300 is indicated on the tachometer. (Mine does.) However, I am not sure whether the tachometer is designed to be accurate, or if, alternatively, 8300 is designed to be indicated when actual revs are 8000.

I beleive it was on Dalis site that I read the rev limiter did indeed kick in at 8300 but the tach was accurate to plus or minus 300.I believed the minus part right off but it was not until I hit my rev limit at 8500ish that I believed that much swing.hell I kept running it to what at a glance looked like 8500 and no limiter kick in.I thought perhaps mine was not working or had been tweaked by the previous owner or even that he had chipped the ecu and raised or eliminated it altogether.I did not know what it felt like to hit it until it happened.unfortuntly like twice in a week.but I know the tach is not 100% calibrated or it is but the calibration level is 300 +-
david

 

[5inchfatlip]

How high has everyone actually gone too....I totally totally swear that mine went over 9000RPM the other day...it was a botched shift from 3rd to 4th on Nitrous, which is activated by full throttle...I'm not sure what happened, but once I got the shift into the neutral gate the RPM's shot up like I have never seen...
I let off the gas right away and it went to idle...I thought I blew it, but it's ok...it this possible...?? It looked like someone had flicked the needle on on of those kiddie board games...

 

[5inchfatlip]

anyone on my issue??

 

[nsxtasy]

Originally posted by 5inchfatlip:
How high has everyone actually gone too....

I usually just go to redline. A couple of times I've accidentally hit the limiter at an indicated 8300.

Overrevving (exceeding the cutoff, such as when downshifting) is a VERY RISKY THING. Bad, bad, bad...

 

[sjs]

Originally posted by 5inchfatlip:
anyone on my issue??

If your ECU has been modified the limiter may be disabled. In that case it is entirely possible that you hit 9k in neutral. If it didn't break right then you should be fine. I don't know what goes first on a stock NSX, but the weak link for most cars is that they will "float" the valves. This means the valve springs can't close the valve fast enough. That can lead to several problems including the piston coming up to hit the valve. Another weak point is asking cast pistons to change direction that quickly, but if it's fine now then you probably didn't hurt anything.

I've hit the rev limiter more than a few times and it's no big deal. That's why it's there, safely below the danger point. I suspect the valve train is good to 9k, but the cast pistons probably aren't and the power curve falls off anyway. If it were me, I’d run it up to 8+ in 2nd to see if the limiter works.

 

[5inchfatlip]

thanks for the replies everyone- I've hit the rev limiter on differnet cars, not on the NSX though, I'm still kinda scared right now......I've also been told the needle just popped like that but the rev limiter actually did kick in....I don't think anything happened since I drove 15miles home after this...I'm still wondering how the revs shot up when I passed the neutral gate, it couldnt of been extra nitrous seeping out right???

 

[BryanZublin]

I measured the tachometer accuracy on my 1992 NSX a few years ago and also when the fuel cut (ie. "rev limiter") engages. The rev limiter engages at a measured (actual) 8000 RPM and the tachometer indicates 8300 RPM.
Bryan Zublin

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Zublin Engineering
http://www.zublin.com

 

[matteni]

The original post was about the "grind" from 1st to 2nd. I experianced this tonight during a hard shift. I have shifted hard many times and have not experianced this before.

Car is a 91 with 43k miles. Stock gears and stock clutch. Must be "normal". Sometimes at a light I have trouble getting it into 1st too. Probably related...

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Nick M

91' Red/Black with Many Mods
99' Honda Odyssey with Many Kids

 

[DocL]

Originally posted by matteni:
...Car is a 91 with 43k miles. Stock gears and stock clutch. Must be "normal". Sometimes at a light I have trouble getting it into 1st too. Probably related...

Grinding and difficulty geting into any gear on a consistent basis is not "normal". A few times I have grinded the gears, but that was because I wasn't paying attention and I let the clutch out before completing the shift into the next gear. Furthermore, I have never had a problem getting into first or any gear. It sounds like your clutch is probably on the way out, and the continued grinding may be damaging the gears in the transmission.

What does everyone else think?

 

[matteni]

Aren't all our clutches on the way out - if you really think about it? ;-)

Maybe I didn't shift perfectly. When it won't go into gear I can feel the gears like they are not perfectly aligned. It is not a clutch engagement problem but more of a random occurrence when the gears are "on top" of each other - if that makes sense or is possible.

As for the clutch - no overreving or any of the other typical symptoms. FYI.

 

[DanO]

Originally posted by 5inchfatlip:
How high has everyone actually gone too...

While I was getting used to my short gears and R&P at the track I was quick on a downshift or two and exceeded 8500…maybe close to 9000! Yikes! As far as I can tell, there were no adverse effects to the engine, just the driver. From what I’ve heard over the years, the weak link in the NSX is the oil pump gears.

DanO

 

[scott]

The grind is very probably your synchro. Double clutch and this will tell you if it is. If you get a smooth shift on a double clutch then bad synchro. If not then it could be cable adjustment or some other lower probability item.

I had the same problem and replaced my synchro. Problem cured.

 

[robr]

just sounds like the 1-2 synchro is shot. my 4-5 syncro is shot so i always have to double clutch, not nearly as inconvenient as the 1-2 though. im not sure i could live with that one

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