DDRH inconsistent power ....

[shane1]

Hi Guys Im in the middle of tuning a V6 s/c vx that i have tuned previously a few times. The owner has changed from auto to manual and i have altered the tune to accept it. That parts all good no fault codes everything works. Ive had to change the tune a little as it had to much timing at 2000 odd rpm as the auto never let the engine get there but now it does.The issue im having is wild swings in power on the dyno one pull will be 180rwkw next will be 140kw its intercooled and the iat doesnt vary ,the thing is picking up heaps of knock retard but its actually not knocking(listening with knock headphones ) The pcm is pulling up to 13 degrees spark ,im not even commanding that much.With the auto it was consistant so im wondering whether the changing of the code has put a funky number in the spark table or something like that.Ive swapped the knock sensors .found the heat shield near the starter loose (thought the rattle may have done it but no).It runs a flat 11.5 at wot .Any ideas?

[The1]

Got any logs?

From what you have said the fueling is ok, then looking at the bin tune the spark first, dont run split tables. Otherwise the adaptive spark system will run you up the wall which it is by the sounds of it. You would want less than 8deg at wot, depending on intercooling.

[VX L67 Getrag]

Yeah I had the same issue on my L67 with manual conversion!

Simple fix disable the knock with coolant enable temp, but to do it properly need to set-up the noise factor for knock sensitivity!

Cheers VX L67 Getrag

[shane1]

Yes ideally you would adjust the noise filter same as an ls1 but in the a5K xdf there is no knock adjustments at all. I know i can fix it by bumping the low octane spark table up but thats not the way i want to do it,im wondering if the manual trans is noisy knock wise as the car didnt do it with the auto?

[shane1]

where did you get the knock disable temps from or are you using a different xdf?

[The1]

well knock sensors are there for a reason, leaving the spark tables interpolated will net less power and be inconsistent. Id rather tune it properly, Each to his own.

edit: I have some time, ill have a look at the xdf.

[VL400]

The A5K XDF has lots of knock sensor stuff, was updated a few weeks back Look for ESC or Knock Retard.

[The1]

haha, so it was

[shane1]

doh just found the update ill let you know how it goes ...

[shane1]

Ok so ive turned off butrst knock and spark knock adjusted the spaerk tales a few degrees and 180rwkw every time , but the question is how to get it to retain some amount of spark flexibility in case of a a bad tank of fuel..........?I still think some form of knock filtering so it only picks up real knock would be the go but how to do it?