I'll bet that got your attention!
Rev Limiter
Phlat Black Guru
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Joined: May 2001
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From: Back In RI...............
Originally posted by Speedraser
Luke,
I'm curious -- why would you hit the limiter in neutral?
OT: I guess the Superformance had a 351 Stroker... Very cool.
Luke,
I'm curious -- why would you hit the limiter in neutral?
OT: I guess the Superformance had a 351 Stroker... Very cool.
Thread Starter
Banned
Joined: Nov 2003
Posts: 856
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From: San Diego
Todd - I was waiting for someone to actually think that through and realize there should be absolutly no reason to be on the limiter in neutral 
I was upshifting and I guess I just didn't have it all the way into gear, it popped out and as I released the clutch and hammered the throttle, well, you know the rest...ZING right to 7k.
..how witty
I was upshifting and I guess I just didn't have it all the way into gear, it popped out and as I released the clutch and hammered the throttle, well, you know the rest...ZING right to 7k.
Originally posted by Phil McGrath
Luke "never lifts"
Luke "never lifts"
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From: Williamsport, MD
I always figured it was relatively "safe" to hit the rev limiter under accelleration. On those spirited bursts I occassionally over-peg it in first trying to close that big gap between 1st and 2nd. I've never felt like anything was strained - more like you just stopped accellerating at that predetermined line. If fuel is cut off at that point - which in practical terms is more like on-off-on-off-on-off as you bounce the rpms into that wall, what could get damaged? I wouldn't think any cam, rocker, valve, crank type parts should be hurt - but perhaps you could create a strange lean fuel condition with the on-off that creates a less than ideal environment inside the cylinders and even to your O2 sensor?
I once missed a shift in my 78 911SC and "bumped" first for about a 10th of a heartbeat at "the wrong speed." I don't think the engine had time to get pulled up to wheel speed, but it sure scared the hell out of me. The engine never missed a beat. Absolutely bulletproof.
I once missed a shift in my 78 911SC and "bumped" first for about a 10th of a heartbeat at "the wrong speed." I don't think the engine had time to get pulled up to wheel speed, but it sure scared the hell out of me. The engine never missed a beat. Absolutely bulletproof.
Intermediate
Joined: Sep 2013
Posts: 37
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This thread is awesome.
I love this forum and my new 993, sorry to resurrect an old thread. I hit the rev limiter today twice; in 3rd at about 90 and 4th at about 130. Anyone else notice a high pitched whine at about 6700?
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Instructor
Joined: May 2008
Posts: 163
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From: sussex United Kingdom
,
I don't worry about it any more, its normally just the passenger wanting me to slow down :-)
Pro
Joined: Nov 2012
Posts: 609
Likes: 30
From: The Blue Ridge Mountains
I've read a few past threads about bouncing off the rev limiter, and am aware of everything associated... I know it's not a good thing, especially if it happens under load, ie. mechanical over-rev which no limiter can protect you against. My question is this; how tuff are these motors ? Lets take the mechanical over-rev out of the scenario. If you hit the rev limiter with the car in neutral, can it handle it ? I've read the limiter kicks in just over redline (7K). Is the 993 motor stout enough to handle this every once in a while ? Thanks in advance.
As per Pat Williams/Memphis an engine can be over-rev'd by missing a gear - well, we all know that. If I remember correctly the valves in a standard 993 engine are designed to handle up to 8,000 RPM's - anything higher than that could result in a bend valve. How do I know? My 993 is scheduled for an transmission rebuild to shorten the gear ratio similar to the G50-21 and before I could take the car to Pat my engine started to develop an unusual clicking sound. That itself could be just a bad lifter but its also misfiring...
I hope I'm not going to face a complete top end rebuild and no, I did not miss a gear! But I did hit the rev limiter under load for sure last time I drove her...
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Joined: May 2001
Posts: 9,662
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From: Solana Beach, CA
If you want to avoid the rev limiter going up, get a digital dash such as RLCracing.com You shift on the pre-programmed shift light. However, If you shift from 5th to 2nd, on a down shift, your revs are going over 10,000 and you will bend some valves...
RL Technical Advisor
Joined: May 2001
Posts: 11,870
Likes: 75
From: Portland Oregon
The valve springs, rod bolts & rods are not designed nor ever intended to see that kind of RPM, even accidently. Valve to piston collisions are common and worse.
That's just one reason why Porsche set the rev limiter at 6750 RPM on these cars.
I'd strongly advise anyone NOT to use the rev limiter as the shift point otherwise they will spend an inordinate amount of money at some point. Installing an Autometer recording tach with shift light is FAR less expensive.
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Joined: May 2001
Posts: 9,662
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From: Solana Beach, CA
Once you
Have a shift light you'll wonder why you didn't do it years before. I am partial to the MicroPod unit from rlcracing.com, with digital read out for oil temp and pressure, data derived from sensors....
