Volvo 2.3 Turbo - Won't Rev past 5250rpm

[chrisscott]

Hi, I wonder if any one can help/advise...

We race a car with a 2.3 Volvo turbo engine, for over a year now we have been plauged by an issue where ther car won't rev past 5250rpm, the engine just acts like there is a rev limit there.

We've changed sensors, injectors, heads, cams etc etc - we lost a whole year to this issue and still can't cure it.

We're now wondering if it could be a fault with the map somewhere (although I can't see anything obvious)

1) If anyone fancies a look at the map, I would appreciate it (an expert eye may see something we've missed)

2) The only odd thing that seems to happen, when looking at the software is it insists there is traction control turned on, but as you can see from screen shot, it isn't - could this be a potential issue?

[stevieturbo]

do you have a datalog of it happening ?

The map seems pretty basic with most stuff turned off. Does diagnostic screen report any errors when this occurs ?

Log a sensible amount, current map has very little. Log crank/cam errors, AFR's etc etc

In fact, if it is an easily repeatable fault, just log everything to get a bigger picture ( even if some seem pointless )

And is this at all boost levels ? under load or no load ? How repeatable is it ? Only when moving ? every gear ? etc etc

[chrisscott]

Hi, thanks for the reply.

So the good news is the problem is absolutly repeatable, it happens all the time, it'll do it when under load on track and also when sitting still just revving up. It is always exactly 5250rpm (hence why we wondered if it was map related).

Hoping to get back on it on wednesday so will get some data logging info then and get it uploaded here.

Thanks

[stevieturbo]

Seems odd, nothing sticks out that I could see.

A log will tell more, just make sure to log everything.

[David Ferguson]

I notice the Turbo Target Pressure table is all zeros, and the Turbo Over Pressure is set to 285 kPa. Any chance you are getting to 285 kPA at 5250 RPM? The help for Turbo Over Pressure, indicates it cuts are fuel & spark if this value is achieved. Sounds like an Overboost rev-limiter to me.

[katana]

I notice the Turbo Target Pressure table is all zeros, and the Turbo Over Pressure is set to 285 kPa. Any chance you are getting to 285 kPA at 5250 RPM? The help for Turbo Over Pressure, indicates it cuts are fuel & spark if this value is achieved. Sounds like an Overboost rev-limiter to me.

Unlikely to make that much boost 'standing still'! The Actual rev limits seem to be turned off so maybe there is some sort of conflict but I couldn't see anywhere that would mark such a defined point !

[chrisscott]

I notice the Turbo Target Pressure table is all zeros, and the Turbo Over Pressure is set to 285 kPa. Any chance you are getting to 285 kPA at 5250 RPM? The help for Turbo Over Pressure, indicates it cuts are fuel & spark if this value is achieved. Sounds like an Overboost rev-limiter to me.

Thanks for the input, I've nothing to lose trying it - i'll add it to the list for Wednesday...it is certainly a possibility.

It's a long story, but all thse issues coinsided with a lot of engine upgrades over the winter of 2021 - so a change of turbo/boost controller may well have contributed.

[David Ferguson]

Ok, what if the calibration for the pressure sensor is incorrect (say a 1 bar sensor was fitted where it is calibrated for a 3 bar sensor), then it would indicate too high causing an overboost condition,and rev-limiting.

[stevieturbo]

overboost is extremely unlikely to occur at exact same rpm every time. Not plausible.

[aleksanderk]

How is your crank trigger set up? Original on top of the bell housing?