What are acceptable rev ranges? Are 1s, 2s and 3s OK? Or are none OK?

Opinion seems to be 1 to 3 OK, 4 to 6 not OK. UK OPC practice appears to be Porsche Warranty will be granted for cars with revs in ranges in 1 to 3. For cars with 4 to 6, warranty is subject to checks, and may be refused.

Thanks.

 

I think 1 and 2 ok. 3-6 start to increase risk of damage. Warranty information seems about right.

 

I hope this helps:

RANGE 1 Maximum engine speed exceeded; engine damage very unlikely.
RANGE 2 Maximum engine speed exceeded; engine damage unlikely.
RANGE 3 Maximum engine speed exceeded; engine damage possible.
RANGE 4 Maximum engine speed clearly exceeded; engine damage probable.
RANGE 5 Maximum engine speed very clearly exceeded; engine damage very probable.
RANGE 6 Engine damage has generally occurred.

 

If you accelerate hard and bounce against the rev limiter a few times will you definitely trigger a Range I?

 

No, I hit the rev limiter a bunch times, no over revs.

 

I copied this from a previous posting here for a 997.1. I am certain it pertains to .2's as well:


Damaged unit parts due to high engine speed.

The information below is intended to help you to evaluate engine damage, which may occur as a result of one or more overspeed events. You can also use the values entered in the VAL to improve the assessment process for granting pre-owned car warranties, for example, and to examine entitlements for carrying out repairs under warranty.
Engines are designed to operate at a maximum permitted speed. This engine speed is not exceeded when the vehicle is driven normally. However, driving and operating problems (e.g. “changing to the wrong gear” on vehicles with manual transmission) or manipulation (e.g. tuning) can cause the maximum permitted engine speed to be exceeded when the vehicle is driven.
Overspeed events are stored in the DME control unit. The following values are also recorded:
- Number of ignition attempts in each overspeed range 1), and,
- Status of the hourmeter during the last overspeed event 2).
1) Overspeed range = Defined rev ranges with classification of expected engine damage, e.g. engine damage possible, ... probable, ... very probable, engine damage has generally occurred; see section ⇒ 'Rev ranges'.
2) For technical reasons, overspeed events are entered in a preset time interval. As a result, there may be entries in a higher rev range (e.g. range 2), while no entries are stored in the lower range.

Typical faults and symptoms as a result of overspeed events may include the following:

* Damaged valves and/or pistons (impact marks on the valve, valve impressions on the piston, valve bent).
* Cylinder liner damage (even “piston seizure”).
* Damaged or displaced connecting rod bearings.
* Loosened or loose fastening screw(s) on the crankshaft pulley.
* Loosened or loose fastening screw(s) on the camshaft gear.
* Loosened or loose connecting rod bolts.
* Cracked timing chain(s).
* Changed timing.
* Irreparably damaged clutch elements (pressure plate and/or drive plate).
* Vibrations and/or engine imbalance due to irreparably damaged clutch elements.
* Vibrations around the transmission.
* Defective synchronisation.

Information
If such faults or symptoms are present together with engine damage, the VAL that was created must be checked for overspeed entries.
If overspeed entries are found and if the difference between the current hourmeter and the status when the last overspeed event was recorded is less than 50 operating hours, there is a high probability that the damage was caused by overspeed event(s).
The value “50 operating hours” should be seen as a guide. The possibility of engine damage occurring much later due to previous overspeed event(s) cannot be ruled out.


Rev ranges - 997 GT3:
Create the VAL before deleting the fault memory. Overspeed events are documented as follows in the VAL:
Rev range 1: 8,400 -1 ... to 9,200 -1
⇒ Maximum permitted engine speed exceeded; engine damage possible.
Rev range 2: 9,200 -1 ... to 9,400 -1
⇒ Maximum permitted engine speed exceeded; engine damage possible.
Rev range 3: 9,400 -1 ... to 9,600 -1
⇒ Maximum permitted engine speed exceeded; engine damage possible.
Rev range 4: 9,600 -1 ... to 10,000 -1
⇒ Maximum permitted engine speed clearly exceeded; engine damage probable.
Rev range 5: 10,000 -1 ... to 11,000 -1
⇒ Maximum permitted engine speed very clearly exceeded; engine damage very probable.
Rev range 6: over 11,000 -1
⇒ Engine damage has generally occurred.
Information
Before starting engine repairs and submitting a warranty claim or granting a pre-owned car warranty:
In the event of overspeed events in range 4 – 6, we recommend that you contact the Technical Hotline before starting repairs or granting a pre-owned car warranty in order to find out how to proceed and agree on warranty entitlements.
"

 

this is very helpful.

where is this from?

car I'm interested in has a reading of 13 in rev range 1 at 27hours. Car has now done about 6000 miles and is just under 3 years old.

 

What you need to watch out for is a fair amount of over-revs in ranges 3, 4, 5, 6.
Additionally you want to make sure these over-revs didn't recently occur which means the tell tail signs of damage have not had the chance to be exposed.

In your case, it looks like you have a SUPER low number of over-revs in the LOWEST rev-range, plus it all occurred a LONG TIME ago. This generally indicates the engine was NOT abused.
Prior to purchase it is recommended to perform a:
+ PPI
+ Leak-Down-Test
+ Paint-Meter-Test

To rule out that certain items weren't overlooked.

 

if thats it, don't give it another thought

 

I don't know where the rev limiter is set up on this engine but to hit 4-6 you would probably need to accidentally downshift in to 2nd gear when you were aiming for 4th and were already at high revs. Generally it's not possible to go past the rev limiter any other way. You can't get there because the injectors discontinue feeding in fuel.

The rev limiter on all cars that I have seen is set at a number that is 100% safe for the engine. IN fact the common procedure when getting on the dyno, is to run the engine to the rev limiter for every single pull. This is common motorcycles as well as cars.

 

I haven't .. negotiating now

 

Yup

 

Sorry to bring back this old thread. I was wondering about the over rev limiter in the 997.2 GT3 RS. If you’re doing toe to heel and or rev matching, does the rev limiter still function for the throttle blip if you hit the throttle while in neutral with the clutch engaged? Not the kind of thing I want to figure out by testing it out on my vehicle obviously...

Thanks!

 

You'll experience ignition cut (limiter), not an “operator” induced over rev condition while in gear deaccelerating.

 

I'm sorry. I'm not sure I understand what you mean with that answer. Will the limiter or ignition cut be in effect if you blip in neutral with clutch engaged between gear shifts? Sorry if I'm not quite catching your meaning. Or does limiter not work with clutch engaged at all?