Big spec XU10J2TE flat spot at 5300

[Hedgetrimmer 0]

I took the car to the dyno today after sorting out a small boost leak.  The car is a forged 2.0 8v bored out to 2.1 with 275 cam (unknown) Garrett gtx2860r second generation, VEMS ECU, Bosch 465cc green giants, DP Engineering down pipe and 1.9 inlet.

 

The dyno guy was impressed with the 252bhp but said there is a lot more to come if the flat spot is sorted.  He is not a VEMS expert so could not map the car.  Any ideas what could cause such a wierd flat spot?  Also the torque curve is not as flat as a normal 8v.

[Hedgetrimmer 0]

Car is running an MI16 gearbox and it was driven in 4th on the dyno.

[welshpug 1,621]

do you have a boost curve recording?

[Hedgetrimmer 0]

Unfortunately it was just a power run so the dyno guy wasnt connected to the ECU.  The DYNO guy did mention boost may be an issue.

[welshpug 1,621]

dont need to connect to the ecu, just tee off the map line, also afr curve would help.

 

do you have a boost gauge?

[opticaltrigger 52]

Whats happening at 5860 though?... Shame there's no data log,

As Mei has said above, boost jumps to mind, but if it's a boost cut,,, then why... Need more data really. 

 

All the best,

O.T.

 

[Hedgetrimmer 0]

I am not running a boost gauge as I wanted the car to look standard inside but I think I will fit one.  I was concerned that the cam might be the issue but I think I need to get it back on the dyno with the ECU connected up so that we can monitor everything.  There is someone local to me who is very good at mapping and he often hires the dyno I was using today.  It might be that the ECU is not controlling the wastegate properly.

[Hedgetrimmer 0]

Cheers for your thoughts guys

[opticaltrigger 52]

19 minutes ago, Hedgetrimmer said:

It might be that the ECU is not controlling the wastegate properly

I reckon that it probably is,,.

But yes, a full data log will tell all. When you see the waste gate duty cycle log then you will see what the ecu is telling it to do, particularly interesting at 5860...

Also, i'm not fully aware of your setup but if there's knock control or EGT control in place then that's a good place to look.

 

But regardless, I'm really interested Carl, so if you do get chance to do another dyno pull with a full data log please get back and let us know the results.

 

All the best,

O.T.

 

Edited November 30, 2019 by opticaltrigger

[Hedgetrimmer 0]

I don't know the spec of the 275 cam that's in the car so I am thinking of fitting a Catcam 4900360 turbo spec cam to make sure I don't have overlap issues- the turbo is relatively small and was struggling to spool up at the bottom end.  I don't think the cam will sort the top end issue but I would prefer to get everything sorted together and not waste time on the dyno.  I might swap to Bosch Blue 550cc so that I can increase the boost to 1.4 and not worry about fueling.