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The reason its bleeding off is because the gas coming out of the wastegate is a bit much for size of the hole its coming out of. If you want to run higher boost i would port out the wastegate hole and get a bigger flap put on. That way your boost will be more stable.

But thats for a later time, im sure you want to enjoy it for a while before pulling the turbo out again.

Its actually the opposite.

You will get spiking/climbing if the int gate hole is not big enough to pass the exhaust gas at a given PSI, not boost bleed off.

Bleed off is due to the wastegate flap opening too much/too soon etc.

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Its actually the opposite.

You will get spiking/climbing if the int gate hole is not big enough to pass the exhaust gas at a given PSI, not boost bleed off.

Bleed off is due to the wastegate flap opening too much/too soon etc.

Yes Ash what you said is true, but i believe it is spiking and bleeding down to the set boost level of 16psi.

Thats what i got from his post anyway.

One thing that I don't think was mentioned here was that (I think) the hand controller will store the Peak value. This may have been due to a noise the knock sensor picked up or it could be acutal knock. The format of the knock values on the datalogit can be changed to show avg knock etc. On the datalogit you can also check the number of readings taken to achieve the avg value. If there was only 1 reading to get the 100 value it could probably be ignored. I am not 100% sure of this but that's want I think after reading some info on this.

Edited by Fry_33
One thing that I don't think was mentioned here was that (I think) the hand controller will store the Peak value. This may have been due to a noise the knock sensor picked up or it could be acutal knock. The format of the knock values on the datalogit can be changed to show avg knock etc. On the datalogit you can also check the number of readings taken to achieve the avg value. If there was only 1 reading to get the 100 value it could probably be ignored. I am not 100% sure of this but that's want I think after reading some info on this.

The H/C does store the peak value which is very important.. If it reads high its detonating.

'Noise' just doesn't happen out of the blue. Problem cars always read high; some read high ONLY on start up and then fine there after.

I always completely ignore the datalogit's knock values as it always damn misses knock that the h/c pics up and well before I can hear it. Always use knock cans and the h/c datalogit is great but do ignore its knock readings.

Never really had any issues up top with knock when coming off a dyno its ALWAYS at the lower rev's lugging it up a hill and coming on to boost. Or grabbing third at 60km/h and lugging it away.

Easy fix. Grab fifth on the dyno and pull it through its mid range.

Interesting posts.. Im getting the waste gate fixed monday if Anthony can fix me up..

Ive come to two guess-timates..

1) Ive got a forged rebuilt engine - Fat chance..

2) The wastegate is causing the knock as it tries to hold close, as it only knocks after 4grand and when I launch it very hard.

Now Ive got no idea if the second is at all plausable but ive had the engine going bonnet up and hit just about everything I can find.. Clueless.

Now Id tend to believe the tuner over any of you however Id firstly like to ask how you know this you tune too?

My car is fine crusing and I even went Nasho last night with 29 knock not really hammering though.. But today I registered 72 cant hear a damn thing. WTF IS IT?!

Should I take it to another tuner?

Edited by DECIM8

are ou letting it really warm up before giving it a thrash? i noticed with my mates car even though hes been driving it for a bit, its not fully warm and reads quite high knock, forged internals wont help either, as they have a tendancy to *knock* when cold, however havent seen how this effects knock sensors directly, anyone know?

*not pre-ignition or detonation, more ratling around in the cylender*

What does having a forged motor have to do with knock?

A properly assembled forged motor should knock no more than any other.

I never saw more than 20 on my H/C on startup/drive/load/whatever with forged pistsons etc etc.

Im with Paul.

And for the record, 72 really isnt audible in that you wont hear that in the car, no chance.

Interesting posts.. Im getting the waste gate fixed monday if Anthony can fix me up..

Ive come to two guess-timates..

1) Ive got a forged rebuilt engine - Fat chance..

2) The wastegate is causing the knock as it tries to hold close, as it only knocks after 4grand and when I launch it very hard.

Now Ive got no idea if the second is at all plausable but ive had the engine going bonnet up and hit just about everything I can find.. Clueless.

Now Id tend to believe the tuner over any of you however Id firstly like to ask how you know this you tune too?

My car is fine crusing and I even went Nasho last night with 29 knock not really hammering though.. But today I registered 72 cant hear a damn thing. WTF IS IT?!

Should I take it to another tuner?

Forged here.. Mine slaps on cold start slightly... No increase in knock.

Nothing to do with the wastegate...

Its knocking as its detonating. Its knocking when you launch it hard because you are loading it greater than the dyno is able to do so. As a result it knocks.

The tune is not conservative enough for road conditions.

Strange as he seems to think its very very very safe and its now running 261.5.. Really nothing but still.

So no one really backed up there claims with Yes Im a tuner..

Should I be taking it to another tuner?

Knock is any metallic sound so It could be a million things.. FYI I got 125 knock so that would be audiable.. They even increased the timing stupidly and datalogit recorded 90 knock when they could just hear it..

From what I understand the hand controller is wrong.

Edited by DECIM8

Also Paul mentioned before that the PFC and Datalogit fight for bandwidth.. This is incorrect the PowerFC is diabled at hand controller when Datalogit is on.. The functions and data going to the controller are frozen..

I suggested your suggestion and it was proved to be wrong, thanks for the info though.

My problem is Datalogit results 18knock

Hand controller = 100 knock..

How can there be so much difference when it comes out of the same damn sensors?

Edited by DECIM8

yes im a tuner

yes you need to take out some timing

yes its knocking

yes its detonating

the PFC FAQ covers how to debug knocking the common causes along with how to troubleshoot it and fix it yourself

using the hand controller

Also Paul mentioned before that the PFC and Datalogit fight for bandwidth.. This is incorrect the PowerFC is diabled at hand controller when Datalogit is on.. The functions and data going to the controller are frozen..

the hand controller freezes because it does get enough clock cycles on the bus that the hand controller and datalogit use

like i said, ive said it before and others have to, dont use both, use one or the other. even if the PFC hand controller looks frozen its still fighting for updates on the bus

and datalogit is doing the same thing, so you are likely to loose samples when logging and driving around. if you are knock logging, unplug the hand controller

apexi never designed to it be a multi device BUS, it was always intended as a single device bus point to point

datalogit added in the extra hand controller port for convienice reasons only, they should make the box disable the hand controller port when the logging function is active to ensure consistent results

but its probably not something they could code/build, its probably a limitation of the PFC bus

Right.. Well he didnt want a peice of it ..

Would there be longterm implications to my controller because it was run in this dual setup? I.E high readings.. I.E Invisable knock?

Edited by DECIM8
What does having a forged motor have to do with knock?

A properly assembled forged motor should knock no more than any other.

I never saw more than 20 on my H/C on startup/drive/load/whatever with forged pistsons etc etc.

Im with Paul.

And for the record, 72 really isnt audible in that you wont hear that in the car, no chance.

i was reffering to piston slap when motor isnt up to temp. i thought the piston bouncing around the bore may cause a higher knock reading, as i've seen a few motors that knock heaps when they arent up to tmep, although it may be something with correction values in the mapping, i'm not sure, hence i asked

Seems your right Paul.. I apoligise for listening to the tuner..

as he said everyone makes mistakes..

.

Seems ive fixed it .. Disconnected commander > Started car> Reved+ idle>Shut down!! > Reconnect

I think the main issue was not running side by side but leaving the car running while the datalogit was disconnect + commander and reconnecting without turning off engine..

Edited by DECIM8

Its fixed... Well I think 2nd and 3rd gear to 7g I record Max 20 knock.. 4th might be a different story but its pretty obvious ill only reach that on track.

Will have to see when it starts to heat up a little.

And I think you were right. Thanks!

Edited by DECIM8

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