Ignition Timing Tuning

tasroadster · Postby **tasroadster** » Sun Jun 25, 2006 10:04 am

How do the professional tuner's adjust the timing for max power.

Obviously with a programable ECU + dyno.

What is the proceedure they use when doing this ...... safely ?

A nock sensor ?

Thanks for your help.
Regards.

Sean · Postby **Sean** » Sun Jun 25, 2006 3:44 pm

tasroadster wrote:How do the professional tuner's adjust the timing for max power.

Obviously with a programable ECU + dyno.

What is the proceedure they use when doing this ...... safely ?

A nock sensor ?

Thanks for your help.
Regards.

We tune my car with an AFR meter and an ultrasonic ear. (a headset that connects to the engine to detect freqency at which know occurs) A lesser or backyeard tuner may only listen for know by ear.

In VERY basic terms, we usually tune it a bit on the rich side and keep advancing timing at the load point we are tuning until we reach maximum power without knock, then we ago about pulling out fuel until we are happy with the AFR (and EGT under boost).

As Steve and Drift fury have said before, there are usually more gains in ignition timing then leaning it out.

THE REAL BORIS wrote:Have you seen the stock SE on a dyno re A/F ratio?

It's extremely lean, until by 3000 rpm it has enriched to 13:1 & by the time you see 4,500 rpm it is off the scale (and remains off) somewhere less than 10:1!!!

This lean state at lower RPM may be due to to aid in off boost response, then it goes rich to aid turbo spool as it comes into boost and stays rich to maintain safety.

The Pupat · Postby **The Pupat** » Mon Jun 26, 2006 11:55 am

Warpspeed wrote:By far the best method is to monitor the combustion pressure on an oscilloscope. You can watch the rate of pressure rise become very steep and become ragged long before there is a shock wave generated that you can actually hear as detonation.

How are you hooking the oscilloscope up?

Incredibly useful tool especially for diagonising ECU problems, now if only I could find a cheapie that was actually good.

Sean · Postby **Sean** » Mon Jun 26, 2006 7:29 pm

Warpspeed wrote:Sean is spot on, obviously a very experienced engine tuner.

Not quite

Just spent too much time with guys who know what they're doing, I remeber what I can and do some very basic tunign myself, but always get the pro's to get it spot on

The Pupat · Postby **The Pupat** » Tue Jun 27, 2006 2:09 am

Warpspeed wrote:
The Pupat wrote:How are you hooking the oscilloscope up?

You need far more than just an oscilloscope. One of these special spark plugs with a built in pressure transducer is what you need:

http://www.kistler.com/do.productfinder ... am=1xxx.-2

Plus a suitable charge amplifier. Then you can watch where peak pressure is with respect to TDC, and also the rate and consistency of pressure rise is a very good indication of combustion stability.

************
edit.

Damn. For some reason that link does not work, but it looks perfectly o/k to me. Go to Kistler.com and look for "product finder engines". Then select, "sensors engine monitoring". You will find a whole range of products made for measuring cylinder combustion pressures.

They have an Australian agent in Melbourne.

I didn't think the oscilloscope would just magically measure the cylinder pressure. ;)

Anyway Jesus that's cool, don't reckon any of that would come cheap though.

ampz · Postby **ampz** » Tue Jun 27, 2006 4:40 pm

Wow!!!

To all of the above...
It takes things to a completely different level than what my backyard can achieve :lol:

tasroadster · Postby **tasroadster** » Tue Jun 27, 2006 9:36 pm

I must admit I have been really enjoying the info that this post has generated........ and thanks to thoses who have provided that info.....

Thanks

The Pupat · Postby **The Pupat** » Fri Jun 30, 2006 2:14 pm

Steve 818 wrote:The NAs also have a little known knock sensor that is on the car from the factory.

While reading the big forum I came across an engine tuner who uses the oil pressure guage on the NAs to see if there is any knock in the engine. Basically the guage starts to bounce at the first signs of knock and goes nuts when the knock is audible.

I did some experiments with my car and I can verify that it's true. I advanced the timing on my car at 60 kPa and 1500 rpm and when the knock was audible the gauge went nuts as it is supposed to, and as I reduced the timing the reaction on the gauge slowly went away.

I'm not saying that this is a plausible way to tune the ignition, but it is nice to know that there is something on the NAs that will detect knock and provided you have your hand controller/laptop handy, you can do something about it.

And it don't cost nuthin!!!

No wonder the oil pump sh!t themselves when pushing big power.