Hi everyone , anyone know if 996TT , X50 , GT2 stock ECU has a 6th gear speed limiter inside tha map ?
I have a 996 TT X50 with Cargraphic/rs tuning 542 hp kit and my top speed is about 329/331 Km/h speedo indicated at about 6950 rpm ...when i reached this speed / rpm in 6th gear i feel something like a fuel cut (or timing retarded i don't know) like a speed limiter .
Rev limiter was set by Rs tuning at 7000 rpm in this kit , so i thought it was the 7K rev limiter that limit my top speed in 6th gear.
So i asked to Rs tuning to raise rev limiter to 7500 rpm but top speed is still "limited" at 329 - 331 Km/h at 6950 rpm in 6th gear.
I ask them if there is a "top speed limiter" for 6th gear only in the ecu program kit but rs tuning answer was NOT.
So i don't know why i can't reach more that 6950 rpm in 6th gear since before with my old ecu program and 520 hp i saw 341 km/h and bouncing off 7200 rpm rev limiter in 6th gear , i don't know why now with 542 hp i can't see more that 330 Km/h and 6950 rpm in 6th gear.
Anyone have some ideas ?
Thank you very much and sorry for my bad english !

 

Just a guess here, if you do have the rev. limiter truly raised,then you dont have enough power to pull pass that at that RPMspeed because of the great force of drag.
I never heard of a cut off in 6th and especially after you had a reprogram..

 

Hi john , ok i know that if i'd have rev limiter at 8K i have not enough power to bouncing off it in 6th gear , i should have 800 - 900 whp , but what i don't know is why i can't go past 6950 rpm now with 542 bhp , since before i have see 7200 (bouncing the rev limiter ) simply whith my old remap and about 520 bhp , now with rstuning kit and 20 more bhp i can't go past 6950.
It seems that what happen at 6950 rpm in 6th gear is something like a fuel cut or timing retard and the speed not increase as it should reaching at least 7200 - 7300 rpm.

 

In other gears 1st to 5th i can reach 7400 and bouncing off in the 7500 rev limiter.
The problem is only in 6th gear and it is surely related to the speed .

 

Any ideas ?

 

i was told from rs tuning that he never raise the rev limit over 7000rpm....tyres are limited from TÜV and sometimes problems with the engine....so this rev limit tuning was done from another tuner?

do your car realy go to 7500rpm in 5th gear ? if yes it should go over 7000rpm too in 6.gear with around 542hp.....if not someting is wrong...boost leak...spark plugs/coils and on and on..but normaly nobody write a seperate speed limit prog in your ecu

 

My Protomotives tune is 7500 rpm also..
I have had my car to that in 5th also..
I usually only take it to that in first because of the gear spread, gear recovery drop.
In the other gears to 7200 rpm most of the time.

 

Hi WINNI ,NO Nobody other Tuner!.. raised rev limiter to 7500 was done directly by RsTuning after my specific request to have much usable low gears and much top end speed (Unfortunatly top speed is not increase here is the problem)..Yes They told me about the risks and that they raise to 7500 but without any warranty.
Yes i can rev my car to 7400 - 7500 in all gears 1st ,2,3,4,5th but NOT in 6th where at about 6950 rpms something wrong happens and speed NOT increase..
I'm interest in your idea about boost leak or coils problems but i ask to me why this problem appear only in 6th gear..
The engine load is not to much different from 5th gear to 6th gear but in 5th all is ok and rev to 7400-7500 , while in 6th it stops to 6950.
My boost is 1.1 bar dropping to 1.0 after 7200 rpm , i don't think a boost leak because boost stay to 1.0 -1.1 also in 6th gear when speed stops to 330 km/h /6950 rpm...the problem seems a cut of fuel or maybe ignition (like you say COILS problem) ..but why only in 6th gear and why always exactly at 330 Km/h - 6950 rpm ?

 

there is a top speed limiter map... its separate from the rpm maps...

 

Hi Markski....so this would explaine all . And how this top speed limiter map can be raised ? Rs tuning say to me there is not top speed limiter ...but they have very bad customer service expecially when they have take the money from the customer .
How can i raise this limiter ?

 

Switch tuners. We can do it. It's takes a push of a button on a keyboard.
ill give you the address map location so you can show it to them.

 

The problem is that i can't read the file that rstuning has upload on my ecu because they put a key in the ecu ...the problem is that i'm in Italy and they are in Germany 500 miles far and the don't answer to email ...so i don't know how i must do.

 

call them...
otherwise go somewhere else that deserve the business..

 

I'll do this...
Can i ask you how does this top speed limiter work ?
It cut fuel or retard timing ?

 

It's interesting how much conflicting information there is on this topic on the interweb. Most of what you find says the only top speed limiter is due to the fuel cut at 196 MPH because the engine reaches the RPM limiter and it cuts the fuel. However, there are a couple of reliable sources (including another tuner I won't name in respect for Markski posting the answer on this thread) that talk about removing the top speed limiter separately from the RPM limiter.

In either case, the limiter is achieved through fuel cut.