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

DIRep972

iTrader: (1)

you do look at the torque curves on the dyno, but the point where you get the most torque is not exactly the point of optimal ignition advance for the engine.. When you add too much advance you can still continue to make more power but you will start to get diminishing returns.. If you advance it far enough to where you get negative returns you have gone way way way too far.. There is really no good way to tune timing on the street. I guess you could use a G-sensor, a knock sensor, and have a very good eye for diagnosing spark plugs!

Johnyquest

what a lot of people do is advance to the point of audible knock then backoff. Not the best, but hey.... we're street tuning...

poid

aha, thanks for clearing up the dyno bit.

So basically for street tuning just use conservative timing to be safe if you arent getting to a dyno to tune it?

I sure dont wanna advance it till audible knock occurs, i think that's a little too risky for me. Would rather be missing a few hp than risk the engine

Mase

i use the "set it and forget it" method

i dont like messing w/ timing much on the street. so i set it at a known safe level, and leave it.

danl

You always tune ignition timing to the knock threshold. Don't be fooled, your ear can't hear knock inside the car. Well it can, but your hearing the kind of knock that, under prolonged exposure breaks sh**. You really need some sort of knock sensing device or a microfone mounted behind the block.

On pump gas I like to tune hondas to 15 degrees at 4000 rpm's and adding timing in equal amounts to 20-22 degrees by 6500-7000rpm's and holding their if the engine runs higher. On race gas i'd add 2-3 degrees and feel safe, you could most definatley add more timing, but I typically like taking out more fuel because cars seem to recover better after a shift that way for me (not everyone) and pick up on the last 1/8 of the track.

danl

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mase &raquo;</TD></TR><TR><TD CLASS="quote">i use the "set it and forget it" method

i dont like messing w/ timing much on the street. so i set it at a known safe level, and leave it. </TD></TR></TABLE>


Yeah, thats a good way to go. Pushing timing into preignition territory breaks stuff FAST.

Bailhatch

Any examples on the internet of using a mic to hear knock audibly inside the car? I'de like to read more about this concept.
Seems like you might be able to make a pretty useful tuning tool if you found some inexpensive microphone and a either use you car stereo or a separate speaker and amp.

DIRep972

iTrader: (1)

hehe, you can use a stethoscope.. but you gotta know what to listen for.. most people don't.

Bailhatch

I know what it sounds like in the car. there must be a lot of background noise huh? Do you think this could be a good tool for street tuning if you could figure out what to listen for?

DIRep972

iTrader: (1)

Ive never done it, but ive seen it done... but you have to think about all the noise going on inside an engine anyways even without detonation.. you will be able to hear that w/ the stethoscope and then you gotta factor out all those noises to hear detonation.. I dunno, sounds hard to me!

Jockobo

doesnt timing and egts corelate?

Silverbeast

More so the timing and a/f together directly make increases and decrases in EGTs.

But, yes too much timing can definatley raise EGT temps.

The set and forget method was used on my car and it seems to work just fine

Mase

too little timing raises EGT's as well