95 replies to this topic

[chris_uk]

this is a blue injector map i found.. no idea whose lol 

[2-20]

Wiseco pistons CR is given for a 1 mm thick gasket. What thickness is your head gasket ?
With a head skim ( how much ?) And an oversized bore you continue to increase your CR.
Do you have any idea about your compression ratio ?

[Fordy]

This is where the knock is happening.

 

Your fuel is only at 90% on 2 of the 19 knock spikes from your log.
The rest is way below. So injector size is better for future usage, it does not seem to be the root cause.
 

Either this is false knock, or when looking at how early in rpm (2600-4400) it happens, but on impressive boost (0.5 to 0.8 bar) your system is not happy with to much pressure.

 

If it is false knock, one of the Dutch conversions used a very very thin gasket on his knock sensor to overcome that.
Not sure of this could be an option. Let's park that as plan C for now, and give some other time to go over your logfile.

 

Thanks for that Stefan.

 

Just to add to those points, what I have noticed when carrying out all of these logging sessions is that if I have a large change in load above 4,000 rpm then I barely see any knock retard. However, anything under 4,000 rpm I get up to 8 degrees of knock retard. The worst scenario is sticking it in 5th at low revs and then mashing the accelerator.

[Fordy]

Having looked at this. Fuel learn then Ignition learn. You'd be surprised that lowering ignition by a few degrees sometimes less prevents lots more knock being created.

I've tried lowering the ignition and running another ignition learn and it wants to remove a similar amount again. In some cases moving the ignition to after TDC.

[Johnboyhgt]

Bigger pulley time then.

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[Fordy]

Most has been said but I echo up the injectors, I maxed out blue vxr ones at 250+bhp. Even after cleaning and flow testing to make sure they were right.

The bigger ones than that are cheap enough.

 

Bigger pulley, a 3 or 3.1 is good enough for over 300. Again cheap fix.

 

Bigger TB, again cheap fix.

 

Cams and porting would be the other things but the cost goes up.

 

I'd change those first things though and see what happens before trying to fix something that may be a result of one of those.

 

I agree that a bigger pulley will help things. I have a ZZP hub fitted at the moment, has anyone got a spare 3" or 3.1" that they would like to sell?

[Fordy]

Wiseco pistons CR is given for a 1 mm thick gasket. What thickness is your head gasket ?
With a head skim ( how much ?) And an oversized bore you continue to increase your CR.
Do you have any idea about your compression ratio ?

 

If the pistons CR take into account a 1mm gasket, if they are oversized pistons does the pistons CR take into account the overbore?

 

My gasket thickness 0.5mm

 

Head skim was about 0.254mm

 

Depending on the answer to the question above I estimate that the CR is somewhere between 9.2 and 9.5:1

[Johnboyhgt]

Try the FB group for the pulley.

 

[Fordy]

Try the FB group for the pulley.

 

3.1" pulley sourced thank you

[2-20]

With a 0.5 mm gasket the Wiseco will give a compression ratio of 9.4.
With your head skim, you have another .25 cr so 9.65.
And with the 0.5mm oversize it's about .1 CR added. So around 9.75 CR

[Fordy]

When carrying out an ignition learn session for each cell it records:

1) No. of Measurements

2) Ignition Advance

3) Knock Retard

 

What is the ignition advance measurement actually telling me? I cant find the correlation

[TFD]

No idea about the SC setup (Im running a 2.2 turbo), but your knock area seems to run quite some timing with a 9.8/1 CR and at torque peak area. Your timingscale also hardly changes with more boost at the same rpm.

Did you try to just retard timing in that whole area with at least 3 degrees and work your way up again? Seems to be real knock.

Timing learning session is not for the wot boosted area if Im correct. You actually need to know what you're doing in that area.

Injectors go ballistic at +85% DC. Dont run more to keep things in control.

I run a tiny thin paper gasket to reduce phantom knock. Will take a look at it at the weekend.
Phatom knock are the spikes as said earlier. Build up tables of knock is serious.

Good luck

[Fordy]

I have a bit of an update.

 

Due to all the advice provided in this thread ive managed to start to reduce the KR spikes that I am getting.

 

I manged to achieve this by carrying out a knock retard session, process the measurements, another knock retard session and so on. This has firstly proven that it was knock being detected and secondly that the engine setup isnt quite right.

 

I am planning to fit a 3.1" pulley tomorrow once I collect a longer belt and carry out some ignition learning. Would it be best to use the process measurement feature of the learning session or just use the retard values measured and make manual changes based on the values?

 

Is there an acceptable KR value when tuning the ignition advance? I noticed that when i carried out the consecutive knock retard sessions that some cells were lowered but the knock retard detected in that cell stayed at a similar value on the next session i.e lowering the ignition advance any further did not help.

 

Many Thanks,

 

Shaun

[Johnboyhgt]

Glad you're getting to grips with the set up.
Any knock at or below 1 degree is considered acceptable.

Personally I'd carry out a fuel learn and then knock learn in your case. After that then fine tune manually to seek power.



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[Fordy]

Glad you're getting to grips with the set up.
Any knock at or below 1 degree is considered acceptable.

Personally I'd carry out a fuel learn and then knock learn in your case. After that then fine tune manually to seek power.



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Cheers John.

 

Rather than carrying out 2 different learning sessions, can the measured knock retard during the fuel learning session be used?

 

Also, when carrying out the ignition learn session what is the ignition advance value that is measured?

[Johnboyhgt]

Yes you can do both together but I prefer not to. My personal reasoning for this is that the measurement is being produced with the fueling at the wrong fuel mixture.

When fuel learn takes place it's at 14.7:1 when you run on the map you will run richer than that under boost.

The measurement you see is number of measurements and degrees retardation reduced to less than one degree knock.

The only problem with knock learning is that it's a bit of a blunt instrument and it only takes away, doesn't add.

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[Johnboyhgt]

Ps have you downloaded the manual ?

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[Fordy]

Yes you can do both together but I prefer not to. My personal reasoning for this is that the measurement is being produced with the fueling at the wrong fuel mixture.

When fuel learn takes place it's at 14.7:1 when you run on the map you will run richer than that under boost.

The measurement you see is number of measurements and degrees retardation reduced to less than one degree knock.

The only problem with knock learning is that it's a bit of a blunt instrument and it only takes away, doesn't add.

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Yeah I forgot that it switches to closed loop during fuel learning.

 

There is a third measurement that I see, Ignition advance. So for the cell at 10kPa and 2400rpm I have 152 measurements, ignition advance of 10 and knock retard of 0.

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[Johnboyhgt]

If you consult the ignition map that should if I remember correctly correlate to what you actually have there. Ie using all 10 degrees available.

Though I might be rusty on this point.

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[Fordy]

I cant see the correlation. If its not important then I will just ignore it.

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