Tuning Guru's: timing when street tuning?

[poid]

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

[crxfreak88]

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

[miss-piggy]

http://www.nitroburn.com/pgmfiwiki/index.php/EcuTuning

[TurboEF9]

Originally Posted by bigwig

http://www.nitroburn.com/pgmfiwiki/index.php/EcuTuning

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.

[miss-piggy]

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)

[poid]

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

[Chris Harris]

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...

[TurboEF9]

Originally Posted by poid

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.

One word: Experience

[hackish]

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

[Chris Harris]

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...