Questions about tuning a 2021 FX SVHO, 8000 RPM limiter

[lungs414]

Can I do a Stage 1 Plus ECU tune with all the hardware but tune it to a 8000 max rpm?

To keep the 4 year warranty.
If so any idea what I can expect?

[K447]

Can I do a Stage 1 plus with all the hardware but tune it to a 8000 max rpm? To keep the 4 year warranty. If so any idea what I can expect?

That is possible. There may be a Stage 1 Plus tune with 8000 limiter already shown in your tune list in the Riva software.

If not, you can request such a tune from Riva and it will then appear in the list.

I used a tune like that for a while. The downside was the impeller pitch becomes critical.

At WOT you want the impeller to be absorbing ALL of the engine power without allowing the engine RPM to touch 8000. That can be tricky to achieve as engine power varies with air and water temp and other factors.

If the impeller allows the engine RPM to climb high enough to activate the limiter then the ECU will oscillate between allowing full power and reducing engine power. This might induce porpoising and it will certainly reduce sustained top speeds in that condition.

[lungs414]

Thanks for the info. I am a novice in this . Can you suggest a different viable approach ? My goal is to unlock it and stay below 8000 rpm's at least it is now. I may abandon this later or next year if my desires change.

[K447]

- unlock it and stay below 8000 rpm's-

Well, what you are looking to do is having very little to zero ECU time logged into the 8000-10000 band.

Somewhere on here I have posted the CANDooPro histogram chart for my accumulated SVHO engine hours, showing accumulated time in each RPM band. Despite my now using the 8300 RPM tune there is almost no time logged over 8000.

I now suspect that 8000 is not the precise number the ECU is using to decide which 'band' to log the time into. It may be that Turing at 8100 or 8200 is still going to be logged mostly, or perhaps entirely, into the sub-8000 band. If this is the case then the 8300 tune will not result in 'warranty negating' ECU log history.

More info at these links;

http://greenhulk.net/showthread.php?t=296071&p=3155352&viewfull=1#post3155352

http://greenhulk.net/showthread.php?t=257035&p=2813776&viewfull=1#post2813776

http://greenhulk.net/showthread.php?t=295751&p=3151963&viewfull=1#post3151963

[K447]

Here are some RPM logs I posted from a year or so ago.

http://greenhulk.net/showthread.php?t=292859&p=3136994

[Hurricane1000]

I believe that the limiter on the OEM ECU on a SVHO is 8300 rpm.

The Stage 1+ runs really well....pitch the 13/18 Solas to run 85-8600 rpm for best performance.

A little more rpm, more boost = more power, speed.

IMHO

[K447]

I believe that the limiter on the OEM ECU on a SVHO is 8300 rpm. -

A totally stock SVHO factory ECU tune limits somewhere around 7700 RPM, is my understanding. Something well under 8000.

The Riva Stage 1 (ish) tunes often have a limit of 8300.

[Green Hulk]

A totally stock SVHO factory ECU tune limits somewhere around 7700 RPM, is my understanding. Something well under 8000.

The Riva Stage 1 (ish) tunes often have a limit of 8300.

This is correct!