I hope someone can answer this as I did a search but couldnt find an answer.
Car is a cossie 4x4 with brandnew T34.55 turbo running and MSD 380 bhp setup for siemens 55's. At the road boost pressure peaking at 32psi holding 26 psi (high setting) and 18psi (low setting). Car pulls like a train.
Now yesterday I have been to a Dyno an the result (flywheel power) are:
high boost 300bhp at 26psi and
low boost 218bhp at 18 psi.
So I am very dissapointed to say at the least.
Have to say this: I have mounted an air temp prob before and after the intercooler to check. The car was running at least 20min at idle because of strapping down issues. Intake temp after intercooler were rising to 63.5 degrees Celsius. I also heard the coolings fans for the radiator go on.
Run was taken with this temp and didnt go down. Boost was also decreasing rapidly after peak so not holding it. Now I think these very low figures are pure due to the very high intake temperatur.
At which temperatur does the ECU retard the ignition? And does it also reduces the boost pressure out of savetiness?
Again at the road I do not have these issues and inlet temps stays under boosting around 20-25 degrees (ambience temp being around 13 degrees celsius)
Hope someone can tell.
Ask whoever mapped it what sort of timing compensations are applied.
And it almost reads as if the dyno had no cooling fans ? If the dyno has adequate cooling fans, air temps should have fallen very quickly once it was on. If it doesnt have adequate cooling fans, you should never have been on it in the first place.
And boost control sounds very erratic. Surely a spike to 32psi then steady at 26psi cannot be deemed normal ?
As for boost reductions as a safety strategy, again you'd need to ask whoever mapped it.
Everyone will apply different things under different conditions. But 60degC+ is certainly not good under any circumstances.
What sort of temp probes were they and what sort of response time do they have ?
But as others have said, why on earth would it ever be idling for 20 mins ? Although IMO it shouldnt pose a real issue if there is adequate airflow on offer.
Not a huge pile different than queuing in the fire up lane at a drag strip where heat soak always happens and you race straight after.