Tuning Guru's: timing when street tuning?
 

Hey guys,
This is something that has puzzled me thus far. When street tuning, how on earth do you know when you have optimum timing advance dialled in? I mean, with fuel its easy enough, you have a wideband O2 to show you exactly what you need to know. But what about timing?

From my limited understand it seems that on a dyno, the way to adjust timing is to look at torque curves; optimal timing will be achieved when you have found the most torque, and moving timing either side will reduce torque output. How would you know where this point is on the street, when all you have is a wideband, possibly an EGT and your bum in the drivers seat?

Cheers :)

Re:Tuning Guru's: timing when street tuning?
 

Advance the ---- out of it till it knocks!!!!!! :P

Re:Tuning Guru's: timing when street tuning?
 

Re:Tuning Guru's: timing when street tuning?
 

Those are very conservative settings. Honestly with an HMT kit, and no dyno, I would focus strictly on your A/F ratio leaving your timing for the dyno.

Re:Tuning Guru's: timing when street tuning?
 

I know EF9, if been getting flammed recently for not basing fact behind my responses..... :-\

He doesnt really say how much hes boosting but i bet its 8 psi and i bet a good number would be .7-.8(thats even conservative)

Re:Tuning Guru's: timing when street tuning?
 

yeh i have read the wiki, and seen that the consensus seems to be 0.75-1 degree retard per pound of boost to be conservative. Was just wondering how good tuners can tune the car on the street only and still end up with timing curves that are pretty much spot on optimal.

TurboEF9 that is what i was planning on doing. Setting retard to about 0.75/pound and just getting the AFR spot on using a wideband. I'll be boosting 10psi on an F22B1 engine using a GT28 turbo

Thanks for the responses so far guys :)

Re:Tuning Guru's: timing when street tuning?
 

A turbo guru will use a combination of a aftermarket knock sensor and EGTs to effectively tune ignition.

On a dyno...its relatively easy. First it has to be asteady state dyno and be able to hold load settings. Start the car, bring it to the load point you want to tune, advance the timing until knock(or most power without any knock) and retard a touch back for safety. How far back you bring the timing is your "buffer" zone.

On the street, a person with a little experience should be able to watch the EGT guage react. But EGTs are pretty tricky...you can advance until EGTs skyrocket, advance a little more and then they start to come down(which shouldnt make sense). Its hard for me to explain only reading and learning about it. I wouldnt recommend street tuning ignition, but it can be done.

Check out http://www.efi101.com/forum for some more tuning info...

Re:Tuning Guru's: timing when street tuning?
 

One word: Experience

Re:Tuning Guru's: timing when street tuning?
 

I've tuned a number of cars on the street. Stick them on a dyno and after 2 hours from a different turbo they were making less than 1% more power.

Finding MBT you just need a good set of headphones hooked up to the knock sensor (audio amp obviously). You can hear the combustion events. You can hear when they're over advancing and you can hear when they start to ping. If you still keep on it or keep advancing the timing you can hear the detonation too.

So basically you find the point where you can hear the teltale signs of pinging and knock it back about 2 degrees. This will also change your AFRs so you have to adjust a little of each as you go.

-Michael

Re:Tuning Guru's: timing when street tuning?
 

timing adjustments shouldnt change AFRs enough to really be concerned...

in your experience, if they do change. they tend to go leaner as power increases, correct? thats what i would ASSume...

Re:Tuning Guru's: timing when street tuning?
 

you would be surprised at how much of a difference on AFRs your timing can make. Don't underestimate this.

You really need accurate datalogging of RPM/MAP/wideband AFR/EGT. If you can know all of those variables at once, you can accurately tune the vehicle. Tall order...

Re:Tuning Guru's: timing when street tuning?
 

Exactly. As "pro TurboEDIT" as we all know I am, I don't believe any od the DIY tuning solutions give us the ability to tune ignition.

Hackish: Can you throw a little mini-how to, or point me in the direction of trying that out? Sounds like an interesting idea. I would like to try this out.

Re:Tuning Guru's: timing when street tuning?
 

DIY Detonation Stethoscope
http://www.autospeed.com/cms/article.html?&A=0353

on ebay, search for "spy ear". you can get them for about 7 dollars shipped.

Re:Tuning Guru's: timing when street tuning?
 

That stethoscope is definitely a good idea but wouldn't the voltage from the knock sensor tell you the same thing or is that detonation to faint for the knock sensor?

Does Turboedit display/monitor knock voltage? I'm new to the complete stand alone systems so I'm trying to learn how to not kill my Civic. My friend is in the Navy so he let me borrow his EMS for a long while so I'm trying to learn how to use it, my eyes are bleeding from reading all the PDF files and all.

P.S. Mad props on Turboedit, that is truely badass

Re:Tuning Guru's: timing when street tuning?
 

No. The advanced feature codebase of TurboEDIT is PM6 based, so, no knock sensor.

Re:Tuning Guru's: timing when street tuning?
 

But on the EMS could I use the knock sensor voltage to tune my ignition maps or is there a better way? (besides a dyno)

Re:Tuning Guru's: timing when street tuning?
 

...if there were a knock sensor to use, I imagine you could use EMS.

As for another method, there have been several listed here above in this thread.

Re:Tuning Guru's: timing when street tuning?
 

I didn't know there wasn't a knock sensor, the EMS is for a p28. I read about the stethoscope and I really would like to try it but I didn't know if it would be more accurate to use the voltage

Re:Tuning Guru's: timing when street tuning?
 

knock sensor voltage is snake oil. False security.

Not a simple explanation, but...

Knock sensors are essentially a microphone.
Microphones produce voltage in response to a pressure wave.
We call repeated pressure waves "sound." The amount of force the pressure wave carries normally registers to our hearing as "volume." The number of pressure waves / second that register normally registers to us as "pitch."
Changes in RPM generally create a change in "pitch." Knocking is a very loud event, and generaly produces a change in "volume." Also, knock occurs at a different time than most engine noise, so it disturbs the rhythm of the motor.
Voltage coming out of a knock sensor is NOT directly proportional to either "volume" or "pitch" but rather a combination of the two.
The reason that monitoring only sensor voltage is somewhat oversimplified and an overall poor knock detection strategy is that it is a very coarse measurement in the sense that individual ignition events are not being analyzed as much as the overall engine noise - voltage is more of an average of the noise*frequency in a period of time than anything else. At higher RPMs, knock sensor voltage will increase due to engine noise causing the difference between ambient noise threshold and a knock event to be small enough that subtle preignition events are missed.
Measuring the knock sensor voltage will detect extreme detonation events, as the spike produced by a LOUD ping will register clearly on the voltage output. Measuring the knock sensor voltage will not detect more subtle preignition events as they get mixed in with ambient engine noise too much. Knock sensor voltage is much more useful and relaible for LOW RPM knock detection than high RPM.

Knock detection is an area of current research in the engineering community. Current advanced approaches generally use DSPs coupled to the ECU to do spectrum analysis of the noise coming out of a knock sensor, focusing on the compression stroke for each cylinder so that as much engine noise can be ignored totaly solely based on the time at which it occurs. Ion sensing systems, genetic algorthims and non-Fourier transform DSP solutions have much promise.

I don't know how the J+S Safeguard devices work, but I imagine that they are somewhat more advanced than a simple voltage threshold / analog filter design.

Re:Tuning Guru's: timing when street tuning?
 

Thanks for the information that does clear up alot of questions I had. The stethoscope idea seems to be a good one and it seems like it would be worth the $15.00 investment

Re:Tuning Guru's: timing when street tuning?
 

a worthwhile add-on to the stethoscope is a bandpass filter to eliminate a lot of the engine noise. search around, should be able to find <$20 plans.

Re:Tuning Guru's: timing when street tuning?
 

hey, that bandpass filter might not be a bad idea.

detonation resonant frequency = 900 / pi x cylinder radius

that info was taken from the below link.
http://www.autospeed.com/cms/article.html?&A=0348

Re:Tuning Guru's: timing when street tuning?
 

That link is gold! I'm in australia so i know exactly what i need to get now...even have a staff discount at that place ;D

Great info guys, it is much appreciated :)