roadsleeper

Hi all, this sounds like such a newb question, but I never do this on any car except for my Cayman...

This only happens to me on track and on B-road drives where I stop looking at the tach and rely on listening to the engine for when to shift. Which is exactly the problem... the 3.4l block sounds like it could rev for another 1 - 2,000 rpms when I find myself bouncing off the rev limiter.

The million $ question: Am I damaging my engine when I hit the rev limiter like this?

cviles

Nope.

I could leave it there, but I redline (or near it) my car at the track all the time. My car has 20,000 miles on it now and between 2-3000 of those are track miles. Not a single problem with the engine.

Just make sure you give the oil time to warm up before you nail it and you'll be fine. Boxsters don't have oil temp guages, so give it a couple more minutes after the coolant reaches 175 or so and you'll be fine.

SD987S

Assuming you've properly warmed up the car the rev limiter is doing what it should be doing and preventing you from damaging the engine.

What you are doing when boucing off your rev limiter is creating "events" in the car's PCU that can be read and possibly be used against you in a warranty claim. A 987S owner from another board needed his transmission replaced and when he went to the dealer they reviewed the events with him as grounds for voiding the warranty. In that instance however, the tranny was ultimately replaced under warranty. The events are graded on a scale by severity/duration.

Mike Murphy

The engine can be bounced off the limiter during shifting, but I would not hold it there for any extended period of time. As soon as you hit the limiter, or .1 seconds before, you should be shifting into the next gear.

I choose to shift 500 RPMs below the limiter on my 125,000 mile 911 because I am not that fast on the track to notice the extra 500 RPMs so it's not a benefit to me.

roadsleeper

Thanks for the very helpful replies everyone

Cviles - Agreed. I really wish our cars came with oil temp and pressure gauges...

SD987S - I assume PCU is the same as ECU? Out of curiosity, do you know if these events can be erased from the ECU's memory? I'm running an aftermarket chip, so I figure if I get it reflashed, it should wipe the car's memory... is that right?

murphyslaw1978 - Yes, I'm definitely up a gear the moment the limiter kicks in... It obviously feels / sounds really odd when the engine hits the limiter, so my first natural reaction is always to back off the throttle a bit and go up a gear (all for drivetrain longevity!)

Thanks again all!

fast1

The 6 ranges for a Boxster can be broken down as:
Range 1: 7300-7500 RPM
Range 2: 7500-7700 RPM
Range 3: 7700-7900 RPM
Range 4: 7900-8400 RPM
Range 5: 8400-9500 RPM
Range 6: 9500-11000 RPM

Range 1-3 will not do engine damage. At range 4 and higher, engine damage is likely. I can't see how a range 1 incident (hitting the rev limiter) would be grounds for denying a warranty claim.

I'm running an aftermarket chip, so I figure if I get it reflashed, it should wipe the car's memory... is that right?

Some of the after market chip manufacturers replace your OEM chip, so I would expect that as far as DME is concerned you start with a clean slate. On the other hand replacing or reflashing chips is grounds for voiding your warranty.

roadsleeper

fast1 - Thanks for the reply. Forgive the ignorance, but what are these ranges you mentioned? I understand ranges 1-3, as these seem to be the maximum operating ranges of the current watercooled flat six engine. But ranges 4-6 sound more like figures an F1 car would be putting out.

Yes, potential loss of warranty was a foregone conclusion when I chipped the car. I actually spoke to a prominent chip tuner from the UK and found that Porsche even equips certain markets with a bolt that has a self-shearing head which holds the ECU in place. In other words, if some one tries to remove the ECU without the proper tools, the bolt serves as a tamper seal.

fast1

I understand ranges 1-3, as these seem to be the maximum operating ranges of the current watercooled flat six engine. But ranges 4-6 sound more like figures an F1 car would be putting out.

Actually F1 engines run at 18K+ rpm. Ranges 4-6 can only be hit on a 987 when missing a downshift, i.e., downshifting into 2nd instead of 4th. A rev limiter will not protect you on a missed downshift, and damage is very likey at those engine speeds. That's why I always insist on a DME report before I purchase a used sports car with a mnual transmission.

roadsleeper

fast1 - Wow, I didn't even think the engine would survive to rev to 11,000 rpms without completely exploding... Thanks for the info!

HHPorscheTech

Yep, fast1 is right the new boxster/ cayman/ 997 all have 7 diffrent igniton ranges based on rpm, and damage to the engine should not occur at the lower range. Also there is now way to erase that information in the DME (engine computer) the only way to get rid of those is to replace the DME. Which is unneccessary based on the information that you have given. Not to mention that the new Porsche scan tool can tell if the DME has been replaced on the car.

Mike Murphy

Yikes, what next - black boxes? Yep.

roadsleeper

Isn't that where it's headed though? Our cars carry more computing power than the average commercial aircraft, and with memory hardware getting smaller and smaller, it's a simple matter of adding 1 or 2 GB of memory to an ECU and voila, your car can remember what you do to it and rat you out!

Mike Murphy

Actually, I think it would add value to have a PC in the car - powerful enough to run applications, such as GPS maps, cell phones, internet, etc. For example, I just bought a Garmin StreetPilot 550 GPS and the thing comes standard with 2GB of memory.

fast1

it's a simple matter of adding 1 or 2 GB of memory to an ECU and voila, your car can remember what you do to it and rat you out

That could make radar detectors obsolete. All a cop would have to do is observe a car that appeared to be going too fast, and then simply stop the car and execute a quick download to get your speed. Print a copy of the download along with the speed and date and time, and you would have to get a dam good lawyer to beat that one.

Macster

The last few seconds before air bag or safety restraint system deployment is usually recorded/saved to non-volatile memory and can be obtained through dealer's service.

Very likely if your vehicle has some form of traction control, accident avoidance, lane deviation control, braking assistence, etc. ditto.

Engine overspeed events and engine run time since last DTC clear and many other events/times/counts are already logged in non-volatile memory.

What's lacking is details -- in most cases for most cars -- on how to access this absent taking car to dealership service.

Sincerely,

Macster.