Power loss at 6250rpm for no obviously reason!!!

[rally1]

Hi there Guys, I have a 2003 VY Holden that I have fitted a 232 232deg .600 .600 cam, double valve springs, 80mm throttle body over the radiator intake, headers and mafless tune, the first problem was the new Capa OTRCAI was not up to the job at WOT the map was around 88-92, once I removed the filter it was back up to 100 so a better intake is on the cards.
My main problem is that when on the dyno ever time it reaches 6250rpm there is a massive loss in power that then picks back up just before the limiter at 6650rpm, at the same time as the power loss (spot on 6250rpm) the knock sensors pick up and set knock retard to around 1.5 deg this happens regardless of timing I have tried anywhere from 12 to 28 deg (locked timing) and there is absolutely no knock at all until exactly 6250rpm ever time which makes me think its false knock, I have also tried any where from 11.25 to 13.1 a/f ratio with no change in the dip in power and the knock still kicks in at 6250 ( the injector duty does not go over 88%). The VE map is dialled in burst knock of ect ect. I’m staring to think it may be mechanical such as valve train float that is then setting off the knock sensors, has any one seen this problem before as im really starting to pull my hair out.
Thanks in advance for any help on this matter.

[The Alchemist]

push rod deflection on the cards at that lift.
Could have told you about the OTRCAI they are ok to a point but pull a vacuum at higher HP numbers.

Mike

[SSbaby]

Have you tried flashing in an older (proven) tune to see if the results are the same?

[rally1]

Hi there Guys,
Yes I have tried a few different tunes with no change at all, I have also ordered new push rods knowing that they are the weak link in this set up but was unsure if that was the problem due to the fact that power comes back up just before redline, I really don’t know to much about push rod defection and how bad the effects can be but would assume that it would get worse with higher revs is this not the case?
This is the first time I have used the capa OTRCAI on a big cam engine and the filter they ship with it is not up to the job (a blue filter) I have never had a problem with OTRCAI that use K&N filters so will go back to them, with no filter the power went up buy 10rwkw at 2000rpm all the way through to 26rwkw at 6000rpm!! Thanks for taking the time to look over my question guys its much appreciated as I need all the help I can get on this one..

[SSbaby]

Maybe post a scan up?

[rally1]

I will try and do that soon, in saying that the saved files I have only have limited pids as I was trying to check as many as I could and I only saved a few, the customer is from out of town and will not be back till Saturday when I can save some decent logs. Thanks.

[rally1]

You will see I have a dead B2 O2 sensor, that fault only appeared half way through testing and I rest the fuel trims before every run to ensure it was not effecting the fuel mixture. This test was done yesterday being Sunday so I was not ably to get a new sensor.

[rally1]

Hi again, could I have weak spark as it starts to fail just as it is reaching peak cylinder pressure, Has anyone had a similar problem with spark on LS1 engines??

[joecar]

What wires are you using...?

[The Alchemist]

peak cylinder pressure would be be at peak torque around 4500 +/- 500rpm.
This is where spark issues would usually show up.
Unlikely to be your problem...

Mike

Hi again, could I have weak spark as it starts to fail just as it is reaching peak cylinder pressure, Has anyone had a similar problem with spark on LS1 engines??