From my understanding, there are some flash programs that increase the rev limiter by 500 RPM or so without any other changes (internal or otherwise).

Does this sound correct? If so, is it safe to increase the rev-limiter by 500 RPM on stock internals?

 

6750 is stock. I set ours to 7100 unless the customer specifies other wise .

 

Do you think setting it at 7100 will affect longevity of the engine? How high do you think it can be set with stock internals?

Also, I take it this will increase top speed (if one is inclined to test this out!)

 

I don't think it will increase top speed by itself, because you will need more power
to get more revs at top speed. Longevity depends on how long you stay at high
RPMs. Essentially, yes, but how much is debatable. I heard recently of a guy who
had a type-R Honda of some sort, and he drove it around, even on the highway,
between 6000-8000rpm the whole time because technically that was where the
most power was. LOL! Even just cruising at 55mph (which takes about 25hp).
His motor lasted about 10k miles.

 

I thought our cars bumped up to the rev-limiter in 6th. Hence, I figured a few hundred extra RPMs would allow a few more mph on the top end ...

 

I'm not sure, but because top speed is such an obvious marketing target,
Porsche surely tuned the RPMs and gearing to get max power when it
needed it to get the max speed. Just bumping the rev limiter up isn't
going to give the car the large amount of added power needed to push
the car any much faster. And even if so, then that's not your worry.
You're not taking your car to top speed, are you? The worry would be
when/if anyone exercises the higher RPM limit in daily repeated blasts
in first gear on on-ramps etc. Heck, it wouldn't be hard at all for Porsche
to have the rev-limit be different in different gears, and to make it
higher in 6th if that helped make a higher sell-by top speed number.
The question becomes why/when do you want to use a higher top-RPM
limit, and probably for most such defined purposes, the practical solution
might be to make a small gearing change instead.

 

ever need to worry about stages of over-rev during PPI if u decide to sell the car?

 

So a higher limiter - say 7100 like Tony said is ok, as long as you don't spend most of your time at the upper end of the range?

The top speed question was a theoretical one, but I suppose it's possible that Porsche put the revlimiter exactly where the car tops out.

However, what's the point of increasing the rev-limiter then. Does changing gears at 7100 RPM vs. 6750 give you a performance difference that you can feel?

20C4S - I imagine that if the rev-limiter is increased and you spend any amount of time close to the new redline you are going to register 1000s of Type 2s over the course of a few weeks of spirited driving!

 

I imagine the reason for increasing the rev limit is because you hit and surpass optimum fairly quickly thus creating type I revs in the ECU...raising the limit potentially gives you a larger window...but not sure if tis is true...the ECU still may register Type I's?

 

I don't think the ECU is intelligent enough to adjust the parameters for Type 1 and 2 if the limiter has been raised. As a result (I think), you would register Type 2s everytime you're over 6750. I'm not sure what would trigger a Type 1 - maybe when you bump into the new raised limiter?

Does this sound right?

 

Dreamtripper, et all:

Yes, the ECU is dumb and will record everything over 6750 as a Type 2.
JR

 

Sorry, I should have included that the ECU is REALLY DUMB and it will:
Record any time the rpm hits 6750 as a Type
OVER 6750 as a Type 2.

Doesn't matter what softeware program you get.

It shouldn't hurt your engine a bit. The technology of these engines goes back to the good old 930s, more like the GT1s, and are pretty stout. I personally like 7000 for a redline [using stock rods/fastners]. If you need/use it depends on how strong your particular engine pulls at higher RPM. Since a lot of the cars on this list get hot rodded, I imagine there is a lot more advantage to the extra RPMs to take advnatage of better breathing.
jr

 

Part of the 'use' of over-reving (for me at least) is sometimes it is better to keep your foot in it approaching a corner (during racing at a track) as opposed to making the upshift when you will be making the downshift right away. I know my limiter is bumped to 6950 or so with a UMW flash.
Just my $.02

 

I thought it only recorded it if it hit the actual limiter and the clutch disengaged. So if the limiter has been increased, then the ECU won't send the signal to the clutch to disengage for that split second, so I don't think it would record, but this is just a hypothesis.

 

I would say the ECU is too smart to be tricked into changing it's
cause-for-concern limits, just because someone changed it's
when-to-kill-the-throttle programming.

Just because someone gets/makes a faster car, that doesn't
change the maximum speed the driver can safely drive at either.

Anyone who wants to present their technical expertise and analysis to
establish that the safe-for-the-motor RPM limits set by Porsche are
demonstrably over-conservative for a stock-internals car, is welcome
to do so here. Do include information about the range of tolerances/
differences that can exist in different stock motors, that may allow XXXX
rpm in one motor, and destroy another after 5 minutes cumulatively in
another.

For a turbocharged motor, more revs means immediately more power,
and sometimes makes for a car that needs fewer gear changes on a
given course. That's why it's so seductive. It *does* increase stress
on internal parts and more heat and friction. Parts that were designed
as light as possible for minimum reciprocating mass at XXXX rpm maximum
may be too light for XXXX+YYY rpms, and may respond by gradual
stretching/bending that first steals back the power gained, and then
starts an irreversible failure process that may proceed thereafter even
if you never go to XXXX+YYY RPMs again. Hardware doesn't heal itself
like a teenager in the weeks after after a rash act with his skateboard,
so I would think YYY times before second-guessing Porsche on the
durability criteria for it's motors. But heck, if you are willing to take the
risk and have the money to rebuild when/if it blows up, go for it. I would
*love* more RPMs! It would absolutely save me serious time in some of
my races to be able to avoid an upshift near the end of a short straight,
followed by an immediate downshift under braking and turn-in, but I am
not going to risk my motor as-is. If/when it gets rebuilt, I will get all the
upgraded parts I can find that will make the motor stay happy with more
RPM, and then go for that extra YYY.

Joe