Sooner

Need some info on potential damage from hitting the Rev Limiter. I was out for a rather spirited drive yesterday and hit the rev limiter twice. 1st time was in second gear during a pass, I was so focused on looking ahead for traffic, I hit the rev limiter then immediatley shifted to 3rd.

2nd time was in 4th gear, again looking ahead didn't think I'd get near it, but briefly felt it then shifted to 5th.

I assume it's there to protect the engine, and that hitting the limiter will do no damage on an ocassional basis. Is this correct?

Thanks in advance.

the_buch

No harm done if you bump into it occassionally by mistake (assuming you're all warmed up), that's what it's there for, but I wouldn't make a habit of it or run along bouncing off of it ...

Tom W

Yes. Occasionally bumping the rev limiter will not cause damage.

You WILL damage your engine if you cause it to over-rev on a down shift (where the rev limiter does not help).

Howdy993

Brian -

I've seen rookie drivers hit the rev limiter lap after lap at DE events. It can't be a great thing to do on a regual basis. I think your initial thought is probably accurate, occasionally hitting the limiter is not a terrible thing but, its something I'd learn to avoid.

Your neighbor Steve Weiner will probably chime in with very sage advice. Can anyone tell me if the 993 limiter retards fuel or spark?

Thanks

ZombiePorsche44

If you could damage you car by hitting the rev limiter, what would be the point of having it?
F-1 and most upper end race cars in lots of race series use rev limiters to regulate the pit road speeds so the driver doesn't have to match the revs to the gear as his/hers only way to keep from getting a stop n' go penalty or worse.

In theory, you cannot damage your engine by hitting the rev limiter while accelerating, but, I wouldn't drive around for extended periods while your engine stutters.

As mentioned by Tom W., the biggest NO NO to keep in mind is, should you hit 3rd instead of 5th while down shifting at 150 mph or hit 1st while trying for 3rd at 80mph, you will cause an immeadiate overrev that will more than likely slam some of your expensive valves into the more expensive pistons and destroy precious bits your engine.
Be familiar and accurate with your gear box and pay special attention to your down shifts, there is never a need to hustle through the gears while braking/downshifting, the speed will dictate when to drop another gear.

I have seen lot's of blown motors from drivers who got in too big of a hurry downshifting while trying to overtake under brakes or just did it due to fatigue.
No matter what the reason, I guarentee it will be really expensive to remedy that split second mistake.

ZP44

Crimson Nape Racing

Hmmm..... hitting the rev limiter in 4th gear, that was a spirited drive!

Sooner

Ummm...yeah it was to say the least! First chance I've had to really onpen her up. Very Deserted back raod...no oncoming traffic & more importantly no driveways, intersections etc.... I had the car on the track last week but only hit about 115, yesterday I hit 140.

That was plenty fast for me & something I only do on Very rare ocassions when conditions are right.

slapshot

I ponderd that very thought too Crimson. In 4th? That would mean you were going at least . . . . Ha!

amfp

You would know rather quickly if you caused any damage. IMO, 4th and hitting the limitator is really on the edge and you need to try watching the tach more. Most important is not over reving when downshifting. There is no limitator for that, and it will quickly bend your valves.

Doc V.

Exceeding the rev limit by using the throttle creates a range 1 overrev, and the rev limiter will protect the engine. However, exceeding the rev limit by increasing the engine's rpm by, say, botching a downshift--by shifting from fifth gear to first gear at 120 mph, for example--creates a range 2 overrev which will damage the engine.

____________
PCA National Instructor
BMWCCA Certified Instructor
Skip Barber Racing School Multi-year Participant

Mark in Baltimore

Unfortunately, we don't have quite the same technology as F1 cars. Hitting that rev limiter, as has been already mentioned, is okay on a very occasional basis, but it is unnecessarily hard on the engine and should really be avoided at all costs. Ask Steve Weiner what he thinks of bangin' up against the limiter.

The rev limiter is no substitute for common sense, mechanical finesse and basic attention to driving.

soltino

Fifth to first at 120 <?>

tino

Mark in Baltimore

Known as the "money shift".

ZombiePorsche44

Mark in Baltimore,
I know the technology in these cars and was not advocationg hitting the rev limiter on every up shift. I was just stating that if you do hit it momentarily, it will not harm the engine, that is, unless you keep your foot to the floor and hold it.

You quote "The rev limiter is no substitute for common sense, mechanical finesse and basic attention to driving" is a good piece of advice but I would also like to add that an AutoMeter race tach with programmable shift light can be a good investment too.

ZP44

PiB993

Had to search for a thread like this with my 993TT. I haven't audibly heard the engine "bounce" off the limiter but a few times I was a bit scared if the car had a limiter because it spins up/revs up so fast and the redline is relatively low compared to more modern cars. Accelerating hard in 3rd then slowly backing off the throttle I was shocked how close I was to redline and wondered if I may have passed it. Glad to know there is a limiter now. The cars soo much faster than anything I have driven I'm inclined to watch the road and not the tach when giving it the beans . . . . but I guess it is directly in front of me.