Bird333

I always hear this term "conservative tune". What does this mean compared to a normal tune (give some numbers here)? Also, don't necessarily limit your answers to boost columns either.

Thanks!

Drkaccrd

Boost wise a really conservative a/f ratio would be around 11.5 depending more so in the area you live in temperature wise

adseguy

Has to do with ignition timing. If you are on the dyno you will notice that at some point when increasing the timing you won't have anymore or very very little gains from increasing tiing. This point is called MBT, above that doesn't yield much if any power and below that is more conservative this doesn't mean AT ALL that your engine "lasts longer" it just means that if you get a little bit worse gas in the tank, or it's a very hot day (IAT's are high) or something of that matter, the timing will be conservative enough to where you will be back at MBT or right below detonation.

Now some might say that AFR's under 12.0 is conservative, but I disagree. Under 12.0 does nothing to be "safer" as all it is doing it controlling the flame speed and a little bit of "cooling" (not much if you read up on specific heat). It's nice to be under 12.0 if an injector is a little dirty so that when some of the cylinders fire at 11.5 AFR and the "lean one" fires at 12.7 or something you won't detonate and the average at the 02 sensor will be 11.7 or something, but you shouldn't have an injector be dirty .

Basically take out more timing and make a little less power so it's safer for the average driver. Hope that helps

adseguy

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Drkaccrd &raquo;</TD></TR><TR><TD CLASS="quote">Boost wise a really conservative a/f ratio would be around 11.5 depending more so in the area you live in temperature wise</TD></TR></TABLE>

Again, AFR's arn't as much of a factor as ignition timing. The reason why lower AFR's work is because it decreases the flame speed thus in a way retarding the timing...but why don't you do that in the timing portion and just save gas

That's why people are sometimes called "AFR tuners" because all they care about is the AFR and throw in some shitty timing values

Muckman

iTrader: (2)

It seems to me that "conservative tune" means ideal tune to me. If you go too "conservative" on the ignition timing you can damage things too. And by this Im refering to EGT.

Jockobo

other than a injector being dirty wouldnt the air fuel in each cylinder vary because of intake manifold design?

sohc_turd

I think a/f is just as important as ignition.

Say you run 11.5 a/f, which has a slower flame than say... 12.5 a/f, you still have to tune ignition to relative to a/f for decent power.

plus... faster flame requires relatively less timing than slower flame.

I'm no tuner pro but thats just what ive observed.

seen4ever

also depends on the region you live in, for example, i live in KY, if I tune a car to 11.5:1 a/f in boost, it will be 12.5:1 or leaner during the winter. due to the massive temperature differences. I personally would never tune a car to an a/f of 12:1 without a very reliable IAT correction factor, which most factory ecu based programs don't have thus yet.

sohc_turd

Most recent rom editors ARE gonna have ECU and IAT modifiers that work quite well.

I live in the northwest, and although i don't drive my car in the dead of winter, in the late fall and early spring the morning to afternoon temps can change drasticly. I use Crome, its a pita to tune ECT/IATs but its a nice feature.

adseguy

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sohc_turd &raquo;</TD></TR><TR><TD CLASS="quote">I think a/f is just as important as ignition.

Say you run 11.5 a/f, which has a slower flame than say... 12.5 a/f, you still have to tune ignition to relative to a/f for decent power.

plus... faster flame requires relatively less timing than slower flame.

I'm no tuner pro but thats just what ive observed.</TD></TR></TABLE>

Then keep the fuel at 12.0. The only variable then is the ignition timing.
I live in Missouri right now and temp change are drastic too, but I have noticed that my scalars for temp changes are pretty damn accurate and that's with open loop. In closed loop it's a no brainer for partial throttle. In WOT it's just fine.

sohc_turd

right... i was just trying to add to what you where saying. I don't think most people understand the relationship between ignition/fuel.