Hot/cold Boost Pressure Difference

[Peppy_t92]

Exactly what ratter said... The desired boost table is RPM vs Intake Valve Temp

[Vrdesign]

Thanks for the reply, what sort of compensation would you guys generally work with? Does a 3 psi swing over a 15 deg temp change sound normal?

17 psi @ 15 deg, 14 psi @ 30 deg

[Peppy_t92]

I would be very interested to see Ratters answer to that one mate..

When I set them I generally leave it the same when cold and at running temperature, then taper it down at the higher temperatures... What you have to remember is your IAT will be higher then ambient temp with a lot of different factors playing a part, like boost level, intercooler efficiency, airbox etc.. for a 30* ambient day your intake temps will be up in the 40*-50+* where as on a cool night with 15* ambient temps IAT could be as low as 20-30*.... Also timing maps change with IAT and ECT, this could effect boost aswell... I like closed loop, but I have seen a lot of reputable shops using open loop

[ratter]

if tuned in closed loop, you can adjust boost to what ever number mechanically possible at any rpm and any IAT temp setting, why you would I have no idea, but yes you can control different boost at different temps, but if tuned in open loop the boost will change according to gear used, IAT, turbo housing temp, timing changes etc

[IH8TOADS]

Yeah it's completely normal as a lot (not all) will use the same open loop wastegate duty cycle for all IAT. Ideally you would pull a bit of duty cycle for the colder temps to maintain a consistent boost pressure....if when you force open loop.

Some just run an external / aftermarket boost controller and have a cold temp boost curve that you can enter at the touch of a button.