Hi all,

Considering a 997S X51 at the moment. Have asked for a log of the DME, can someone confirm for me the following:

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

..and that ignitions in 4, 5, 6 is the area of concern?

What is acceptable? I imagine any ignitions in 8400+ is starting to get serious? The rev limit is increased on X51 correct, but to what?

Thanks!

 

I could be wrong but I do not believe the rev limiter on a X51 equipped 3.8L engine is increased from a base 3.8L engine, which is 7,200. The GT3 engine has a rev limiter of 8,400 RPM.

 

I hope you’re wrong. The red line shown on the tachometer on my X51 C2S is the same as that of a normal 997S and when I asked at the dealership where I bought the car what red line was no one could definitively tell me what it was.

I have seen listed as part of the X51 package that stiffer exhaust valve springs are installed to help facilitate a higher rev range and higher red line. I have been led to believe that red line on my X51 is 7,500 rpm and that is what I have used for over 12,000 miles; the rev limiter kicks in somewhere just north of there and I have hit it often. I would guess (and that is just a guess) that the DME ranges for X51 have been increased to be more in line with it’s higher rev range.

 

Actually I believe the redline is increased with the X51, hence the stiffer exhaust valve spring to 7400rpm.

There is no change on the tach though...

Porsche ignores ranges 1-3 you start getting into the higher ranges they can deny warranty coverage.

Dave

 

That's what I remember hearing too.

 

Well, if it increased only 200 RPM's, I guess that small of an increase is not worth the effort/cost to change the tach.

 

Porsche probably just changed the fuel cut off range to 200-300 rpms higher...

The non P/K S develops its peak HP at 6600 rpm where the X51's peak HP is 600 rpm higher at 7200 and max torque is 900 rpm higher @ 5500 rpms on the P/K car

 

I think ranges 4, 5 & 6 would be mechanical overrevs such as missing a downshift at speed and would be very worrisome. The others would be managed by the rev limiter...and we've all hit that once or twice!