Rev Limiter
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From: San Diego
Rev Limiter
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.
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Can't answer your question completly but I have bounced off the limiter a few times in both my 993 and 964. This happens to me only at the track. I don't think its that big of a deal. I think the biggest danger to the car is the "money shift" over revving from a missed shift.
Jamie
Jamie
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The "Money Shift"..
Just as we have seen in other Porsche cars, an accidental down shift from 5th to 2nd, is not healthy. I have a friend who did this, spun the motor up to an estimated 10,000 RPM on the Rev charts...needless to say, he has all new exhaust valves. In addition, while the motor was apart, he got new valve guides, and just for insurance, he had the heavy duty valve springs installed.
In the heat of battle, I have bounced off the rev limiter a few times with no apparent ill effects. A BIG shift indicator light would be an excellent way to avoid this. I have a friend with this mod on his 993 TT car. I have been told that this is not easy to wire on the 993 NA car, hmmm, go figure.
In the heat of battle, I have bounced off the rev limiter a few times with no apparent ill effects. A BIG shift indicator light would be an excellent way to avoid this. I have a friend with this mod on his 993 TT car. I have been told that this is not easy to wire on the 993 NA car, hmmm, go figure.
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From: Indianapolis
Agro,
There is a pretty big difference in bouncing off the limiter under load and under no load. My understanding is that these engines are remarkably stout, so I wouldn't worry too much about the occasional rev limiter occurance, under load. I would advise strongly against hitting the limiter when unloaded, if at al possible.
Just my $0.02
There is a pretty big difference in bouncing off the limiter under load and under no load. My understanding is that these engines are remarkably stout, so I wouldn't worry too much about the occasional rev limiter occurance, under load. I would advise strongly against hitting the limiter when unloaded, if at al possible.
Just my $0.02
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From: New Jersey
I believe Eric in Chicago had a shift indicator light in his n/a 993. I have given it some thought as well. The added benifit is that you will stay in the power band more effeciantly. That is to say I believe the peak HP is a bit lower than redline. It always takes me a little by suprise when I hit the limiter but I am oh so glad its there.
Jamie
Jamie
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From: San Diego
Thanks for sharing guys.
Neil - can you pls expand on why hitting the limiter under load is better than bouncing it with no load ?
Martin - MSD makes these cool little gadgets called RPM activated switches. When you hit a predetermined RPM, the switch activates whatever you want, shift light, window, door locks, etc...I agree a shift light would be nice for those fast 2nd gear corners...But the motor slows down towards redline in the higher gears so it's pretty easy to just glance down. A nice BIG red light next to the RPM guage would be cool though...
Thanks again guys - keep it coming. I'd like to hear how many of you have bounced the limiter without incident.
Neil - can you pls expand on why hitting the limiter under load is better than bouncing it with no load ?
Martin - MSD makes these cool little gadgets called RPM activated switches. When you hit a predetermined RPM, the switch activates whatever you want, shift light, window, door locks, etc...I agree a shift light would be nice for those fast 2nd gear corners...But the motor slows down towards redline in the higher gears so it's pretty easy to just glance down. A nice BIG red light next to the RPM guage would be cool though...
Thanks again guys - keep it coming. I'd like to hear how many of you have bounced the limiter without incident.
Drifting
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From: La Jolla, CA
Agro1,
I have bounced off the rev limiter multiple times over the years. I am not sure whether there is damage or not but the car has been running at tracks (auto-x, DE, and TT) since 1997. Seems pretty tough to me.
I have bounced off the rev limiter multiple times over the years. I am not sure whether there is damage or not but the car has been running at tracks (auto-x, DE, and TT) since 1997. Seems pretty tough to me.
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Dan - Yes, I did. I'm gonna start a thread later detailing everything about the car, Hergesheimers, Truspeed, etc...with a couple photos. But in short, it's awesome. Absolutly love it and the LWF is fantastic. I wouldn't say it is for everyone, but if you like to drive, and drive the 993 the way it was designed to be driven, it is great. The power is much better. Getting rid of that heavy DMF just allows the motor to rev very very freely...More to come.
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From: FF county, Connecticut
Ditto what Jamie said, I hit the rev limiter over 4 times in one day (and loving it) in 3rd gear doing probably 100 mph, at Lime rock just last week.
It was very mild and smooth, not a sudden jerk at all unlike some americans I have driven.
It was very mild and smooth, not a sudden jerk at all unlike some americans I have driven.
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From: FF county, Connecticut
Originally posted by JKW993
I thought our cars only have a rev limiter under load. Once you hit the rev limiter fuel is cut to the engine. If you are in neutral or downshifting there is nothing to stop your engine from over revving. Am I missing something?
I thought our cars only have a rev limiter under load. Once you hit the rev limiter fuel is cut to the engine. If you are in neutral or downshifting there is nothing to stop your engine from over revving. Am I missing something?
But in Neutral, as in reving the engine while standing still, it will sense the high RPM and cut fuel ... reducing the rpm.
Oh, but make sure your nitro is turn off :-)