Xede as Boost Control

[Crusher_13]

A quick question.

My car was on the dyno over the past 2 days getting tuned and is having issues controlling boost.

I have the Xede fitted but boost is still spiking and the tuner can not get it under control. This is the second tuner that has struggled with boost spike / cut on my car.

Should I be looking at a boost controller? What should we be checking to correct this issue?
Thanks.

[LittleredMPS]

I had an xede on my last mps too mate.

As far as I know, there is no way to stop that boost spike, I take it you mean the one around 2500-3500rpm.

Just about every dyno I have seen of an mps has a boost spike.

[MattMPS3]

More than likely spiking due to your ETS TMIC, they are a bugger for spiking, do you have an aftermarket TIP as well, if so I imagine this would also contribute to the issue, anyway a boost controller will probably do less than you can using the Xede software, what sort of spikes are you seeing?

[Crusher_13]

I didn't ask what it was getting too. But I would assume out above 22psi.

It is more a fact that the boost is unstable. It doesn't hit 18 psi and stay there. It will get to 18 then slowly creep to 19 then spike or drop off.

My car has always had issues with boost spike / cut. Having it with the ETS is nothing new. It had a partial tune done in February and hit 225kw with the ETS and CES SRI but now it is down to 211kw with boost issues.

[MattMPS3]

As discussed previously, spike and creep are 2 different animals, a 22 psi spike isnt the end of the world, the boost creep you are experiencing is most likely attributed to your divorced DP.

[Crusher_13]

Understood, but it is boost cutting and I want it solved rather than ignoring it and hoping it goes away.

Obviously I am also trying to save some money by getting an Xede based fix instead of having too buy and fit a boost controller.

[MattMPS3]

Boost cutting with the Xede in place, that sounds odd, usually the Xede can be tuned to fool the ECU's boost ceiling, what sort of scenario is inducing these cuts, is it high revs / boost, or quick acceleration from the lower rev range.

[Crusher_13]

I don't have the graph on me but I believe the cut comes in below 4000rpm.

If you look at my old graph boost is at 18psi from about 4260rpm now it is up to 18psi from around 3000rpm (from memory, it may not be that fast but it is real fast)



It may be the CPE engine mount but the wheels are spinning in 3rd again at about 80km/h

[ChipTorque]

The factory MPS boost spikes slightly due to the boost coming on quickly, it boosts at a rate relative to expected torque. I don't think this is the issue you are describing. We would require to see your vehicle's current boost graph to provide assistance.

Leah @ CT

[MattMPS3]

You might be experiencing a fuel cut, not a boost cut as such, maybe your tuner should try and dial a bit of boost out down low to avoid this, although if your on 100% wastegate duty cycle and still having boost control issues, you may need to look at other alternatives, a boost controller wont do any more than the Xede in these terms.
My understanding is that the Xede can scale the boost cut higher than your peak boost and the wastegate solenoid adjustment controls the boost, fuelling is then adjusted to suit the new boost profile.