Dual Stage Boost Controllers & Ecu Mapping

[Shoujiki]

Hey guys,

Had this in my head for a while and was mentioned to me yesterday again.

I've got a Blitz Profec 2 Spec B controller in my car, has the "lo" and "hi" setting.

Now let's say, with any controller, you tuned the engine and maps to 10psi. Car drives great, good power, economy etc.

Now what happens when you drop the controller to a lower setting, say.. 7-8psi? Does this mean the ECU reads the lower pressure and doesn't "use all of it's map"? Is the boost sensor a "multiplier" of sorts? Or will the car run rich as and foul plugs etc because the ECU is tuned for a higher boost pressure?

Thanks!

[Adriano]

Should be tuned for all load points, but that depends on the tuner, what ecu.

[GTSBoy]

Um.....which part of Air Flow Meter is causing you trouble?

[Shoujiki]

Air Flow Meter?

[DVS JEZ]

The black part

[Shoujiki]

I know what the afm is. Theres nothing wrong with my engine im just asking out of curiosity to learn how the mapping works.

[Rolls]

Hey guys,

Had this in my head for a while and was mentioned to me yesterday again.

I've got a Blitz Profec 2 Spec B controller in my car, has the "lo" and "hi" setting.

Now let's say, with any controller, you tuned the engine and maps to 10psi. Car drives great, good power, economy etc.

Now what happens when you drop the controller to a lower setting, say.. 7-8psi? Does this mean the ECU reads the lower pressure and doesn't "use all of it's map"? Is the boost sensor a "multiplier" of sorts? Or will the car run rich as and foul plugs etc because the ECU is tuned for a higher boost pressure?

Thanks!

Yes it uses lower load cells of the map when driving. If your tuner is a muppet he would have tuned in 4th only and never changed the load, so you will need a retune now. If he was a decent tuner he would have adjusted the load so it should be bang on.

[GTSBoy]

Tuning isn't done like a power pull you know.

[Shoujiki]

Thanks Rolls for your input. Appreciated.

[Rolls]

Tuning isn't done like a power pull you know.

Exactly which is why it isn't an issue.

[GTSBoy]

<br />I know what the afm is. Theres nothing wrong with my engine im just asking out of curiosity to learn how the mapping works.<br />

<br /><br /><br />

Yes, that's the point. The load is measured by the AFM, so the boost level is almost completely irrelevant. Turning the boost from high to low is equivalent to not opening the throttle as far.

/rocket science.

[Shoujiki]

Thanks.

[Rolls]

End of the day the tune is only as good as the tuner, who knows he could have put too much timing and not accounted for hot weather and it might ping its tits off even on low boost.

[Shoujiki]

Yup yup, makes sense. Good to learn about all this stuff, thanks guys.