Could a light weight fly wheel affect a DME (over rev report)?
07-23-2018, 07:49 PM
#1
Could a light weight fly wheel affect a DME (over rev report)?
Found a high mile 997tt I was looking at for a DD while the others sit in the garage while I stare at them.
It has a ton of over revs even in the highest ranges. No way the car wouldn't have blown up 50x by now if it were correct.
A Porsche mechanic told me it is not accurate because of the fly wheel that is in it.
Any thoughts guys?
It has a ton of over revs even in the highest ranges. No way the car wouldn't have blown up 50x by now if it were correct.
A Porsche mechanic told me it is not accurate because of the fly wheel that is in it.
Any thoughts guys?
07-23-2018, 08:41 PM
#2
Burning Brakes
I don’t know if a lwfw would do it but a tune that raises the rev limiter could although 4 and 5s would still be unusual.
07-23-2018, 09:56 PM
#3
Technically speaking, a lwfw would make it way easier for the engine to hit over revs, because it will rev higher and faster, when compared to the original clutch/flywheel. But in this case, the over rev report would be correct.
07-23-2018, 09:57 PM
#4
Drifting
I could see it going both ways - a heavier flywheel would have more inertia and keep spinning into over rev territory, while a lighter flywheel would rev up faster and maybe over rev if you're still gassing it when you shift.
Rambler is right about the tune complicating things as well.
Finally, I'd be curious to see the actual report based on your "should have blown up 50x by now" comment. A lot of people seem to be under the impression that 100 range 5 over revs mean the engine's about to throw a rod any day now but that is almost never the case unless the money shift just happened 30 seconds ago.
Rambler is right about the tune complicating things as well.
Finally, I'd be curious to see the actual report based on your "should have blown up 50x by now" comment. A lot of people seem to be under the impression that 100 range 5 over revs mean the engine's about to throw a rod any day now but that is almost never the case unless the money shift just happened 30 seconds ago.
07-23-2018, 10:19 PM
#5
Rennlist Member
I could see it going both ways - a heavier flywheel would have more inertia and keep spinning into over rev territory, while a lighter flywheel would rev up faster and maybe over rev if you're still gassing it when you shift.
Rambler is right about the tune complicating things as well.
Finally, I'd be curious to see the actual report based on your "should have blown up 50x by now" comment. A lot of people seem to be under the impression that 100 range 5 over revs mean the engine's about to throw a rod any day now but that is almost never the case unless the money shift just happened 30 seconds ago.
Rambler is right about the tune complicating things as well.
Finally, I'd be curious to see the actual report based on your "should have blown up 50x by now" comment. A lot of people seem to be under the impression that 100 range 5 over revs mean the engine's about to throw a rod any day now but that is almost never the case unless the money shift just happened 30 seconds ago.
07-23-2018, 10:55 PM
#7
Burning Brakes
Thinking about this some more, even if the lwfw allows the rpms to rev up more quickly, all this would mean is that you will reach the rev limiter more quickly when accelerating in gear but bounce off of it no differently than with the regular flywheel, hitting ranges 1 and 2 (which are not really over revs but hitting redline). In other words, I don't think the computer would override the rev limiter because of the flywheel.
And if there was a money shift(s), I don’t know how the flywheel would make any difference in terms of hitting ranges 3-5 on a money shift.
And if there was a money shift(s), I don’t know how the flywheel would make any difference in terms of hitting ranges 3-5 on a money shift.
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07-24-2018, 07:42 PM
#8
Interesting. Let’s say you’re completely stock/OEM, and decided to for a spirited 2 hour mountain run and bounced off the rev limiter 20 times. What DME levels are those and what’s the big f’n deal?
Ive yet to hit a rev limiter in the 911, but I’ve hit the rev limiter by accident with my 420HP S2000, that revs crazy fast and hard to catch, a thousand times when I was younger. That’s what’s it there for, to prevent any damage. I’m at 175K miles on the same motor and she drives like a dream and rips.
Ive yet to hit a rev limiter in the 911, but I’ve hit the rev limiter by accident with my 420HP S2000, that revs crazy fast and hard to catch, a thousand times when I was younger. That’s what’s it there for, to prevent any damage. I’m at 175K miles on the same motor and she drives like a dream and rips.
07-24-2018, 08:21 PM
#9
Burning Brakes
Interesting. Let’s say you’re completely stock/OEM, and decided to for a spirited 2 hour mountain run and bounced off the rev limiter 20 times. What DME levels are those and what’s the big f’n deal?
Ive yet to hit a rev limiter in the 911, but I’ve hit the rev limiter by accident with my 420HP S2000, that revs crazy fast and hard to catch, a thousand times when I was younger. That’s what’s it there for, to prevent any damage. I’m at 175K miles on the same motor and she drives like a dream and rips.
Ive yet to hit a rev limiter in the 911, but I’ve hit the rev limiter by accident with my 420HP S2000, that revs crazy fast and hard to catch, a thousand times when I was younger. That’s what’s it there for, to prevent any damage. I’m at 175K miles on the same motor and she drives like a dream and rips.
07-24-2018, 10:06 PM
#10
There's no harm in hitting the rev limiter which will register Range 1 and sometimes 2 on the DME report. These are fine and even PDK will register 1s and 2s. The point of this thread was OP's question about whether a lwfw would cause there to be a ton of range 5 ignitions which are generally much worse since they occur well over the redline/rev limiter and possibly caused by a bad misshift which the computer can't stop.
07-24-2018, 11:23 PM
#12
Drifting
I've seen way worse reports than that, on cars that by all measures are running fine years later and never "blow up."
What are the total operating hours?
What are the total operating hours?
07-25-2018, 09:03 AM
#13
Burning Brakes
