Red Line Equal Over Rev?
Rennlist Member
Joined: Apr 2006
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In a 911, shift at redline. Period.
-td
Race Director
Joined: Sep 2012
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From: SOcialist republic of CALifornia
When the time delay for the shift is considered along with the HP drop, NOT shifting is sometimes the correct thing to do, even if it means potentially bouncing off the rev limiter.
There are also times when upshifting is not the appropriate thing to do because your hands are otherwise occupied.
And, though admittedly I can count the number of times it has happened on one hand, bouncing off the rev limiter in fifth is the less terrifying option vs. manning up and trying to ****** 6th...
There are also times when upshifting is not the appropriate thing to do because your hands are otherwise occupied.
And, though admittedly I can count the number of times it has happened on one hand, bouncing off the rev limiter in fifth is the less terrifying option vs. manning up and trying to ****** 6th...
Three Wheelin'
Joined: Nov 2014
Posts: 1,575
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From: Swedish expat in Latvia
Drivning the car hard means you will inevitably hit the rev limiter now and then. I see this as normal in a Porsche.
No harm. It's just cutting fuel before risk of engine damage.
No harm. It's just cutting fuel before risk of engine damage.
Three Wheelin'
Joined: Feb 2014
Posts: 1,550
Likes: 8
From: Greater Philadelphia Area, USA
It's better to be realistic, and approach life that way. So, while being technically correct is nice, being realistic results in things such as rev limiters.
You can exceed redline on a downshift and be fine, if it's mild and in range. So, it looks like the use of over revving in this thread needs to be better defined.
Downshift over rev = spinning the engine past its design limits, according to previous posters, but this isn't the best and most consistent use of over rev
Over rev report = captures even those ignitions in ranges which are safe and could be from a slight run past red line (thanks rev limiter) and downshifts which land in a gear which over revs the engine, including ones that land in safe and unsafe ranges.
A blown downshift can trigger an over rev ignition count and be harmless if it's in the lower range.
That's why reports are interpretive.
You can exceed redline on a downshift and be fine, if it's mild and in range. So, it looks like the use of over revving in this thread needs to be better defined.
Downshift over rev = spinning the engine past its design limits, according to previous posters, but this isn't the best and most consistent use of over rev
Over rev report = captures even those ignitions in ranges which are safe and could be from a slight run past red line (thanks rev limiter) and downshifts which land in a gear which over revs the engine, including ones that land in safe and unsafe ranges.
A blown downshift can trigger an over rev ignition count and be harmless if it's in the lower range.
That's why reports are interpretive.
Race Director
Joined: Sep 2012
Posts: 10,424
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From: SOcialist republic of CALifornia
You can also use the hour indication to get an idea of whether have anything to worry about (when you're checking out a potential purchase)... (Note:ignition ranges for my '99 are much more simplistic with just 2 ranges; later cars that have several additional ranges.)
If the car has 2,000 operating hours and shows 25 range-2 ignitions at 750 hours, you have a pretty good idea that the previous owner wasn't consistently blowing shifts and endangering internals, and I would also be willing to believe that in the intervening 1250 operating hours any issues caused by the over-rev would have made themselves known by now.
On the other hand, if you see thousands of range 2 ignitions and the most recent were just one running hour ago, it's wise to be skeptical.
If the car has 2,000 operating hours and shows 25 range-2 ignitions at 750 hours, you have a pretty good idea that the previous owner wasn't consistently blowing shifts and endangering internals, and I would also be willing to believe that in the intervening 1250 operating hours any issues caused by the over-rev would have made themselves known by now.
On the other hand, if you see thousands of range 2 ignitions and the most recent were just one running hour ago, it's wise to be skeptical.
Last edited by 5CHN3LL; Mar 31, 2016 at 12:47 PM.
Rennlist Member
Joined: Nov 2009
Posts: 3,162
Likes: 537
From: PNW
You can also use the hour indication to get an idea of whether have anything to worry about (when you're checking out a potential purchase)... (Note:ignition ranges for my '99 are much more simplistic with just 2 ranges; later cars that have several additional ranges.)
If the car has 2,000 operating hours and shows 25 range-2 ignitions at 750 hours, you have a pretty good idea that the previous owner wasn't consistently blowing shifts and endangering internals, and I would also be willing to believe that in the intervening 1250 operating hours any issues caused by the over-rev would have made themselves known by now.
On the other hand, if you see thousands of range 2 ignitions and the most recent were just one running hour ago, it's wise to be skeptical.
If the car has 2,000 operating hours and shows 25 range-2 ignitions at 750 hours, you have a pretty good idea that the previous owner wasn't consistently blowing shifts and endangering internals, and I would also be willing to believe that in the intervening 1250 operating hours any issues caused by the over-rev would have made themselves known by now.
On the other hand, if you see thousands of range 2 ignitions and the most recent were just one running hour ago, it's wise to be skeptical.
Keep in Mind, his Range 2 is different than our range 2. In a 997, range 2 is simply bouncing off the limiter with a bit of gusto.
Rennlist Member
Joined: Jan 2014
Posts: 4,070
Likes: 371
From: Chicago, IL
You can also use the hour indication to get an idea of whether have anything to worry about (when you're checking out a potential purchase)... (Note:ignition ranges for my '99 are much more simplistic with just 2 ranges; later cars that have several additional ranges.)
If the car has 2,000 operating hours and shows 25 range-2 ignitions at 750 hours, you have a pretty good idea that the previous owner wasn't consistently blowing shifts and endangering internals, and I would also be willing to believe that in the intervening 1250 operating hours any issues caused by the over-rev would have made themselves known by now.
On the other hand, if you see thousands of range 2 ignitions and the most recent were just one running hour ago, it's wise to be skeptical.
If the car has 2,000 operating hours and shows 25 range-2 ignitions at 750 hours, you have a pretty good idea that the previous owner wasn't consistently blowing shifts and endangering internals, and I would also be willing to believe that in the intervening 1250 operating hours any issues caused by the over-rev would have made themselves known by now.
On the other hand, if you see thousands of range 2 ignitions and the most recent were just one running hour ago, it's wise to be skeptical.
Burning Brakes
Joined: Mar 2016
Posts: 1,066
Likes: 222
I found this a useful resource to help understand the different ranges - http://www.911virgin.com/porsche/rev-range-information/
So for a 997.2 Range 1 and 2 are below the Rev Limiter, 3 and 4 above but not necessarily a deal breaker, 5's and 6's warrant closer enquiry....
So for a 997.2 Range 1 and 2 are below the Rev Limiter, 3 and 4 above but not necessarily a deal breaker, 5's and 6's warrant closer enquiry....
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