Why retard your ignition while boosting?

What advanatges do you gain when retarding your ignition timeing?

Is there a point to where you can't retard your timeing anymore or can you pretty much just retard it silly?

Any pros/cons in retarding your timeing?

Whats the best ignition system available for our cars?

tia

Retarding the timing will preven spark knock, but it will also make you slower. If you want to go faster you want to advance timing, but be careful too much advance you will get spark knock.

Our engine advances timing quite a bit. I've heard anywhere from 20-45 degrees. That does result in quicker air/fuel combustion, but when you are boosting, there's a lot more air going in to the combustion chambers (especially at higher boost, 15 or more psi). When the ecu "sees" a greater MAP, it's going to advance timing even more, but that increases the possibility of knock (detonation--which is when the combustion of air/fuel occurs too soon--before TDC). Retarding timing will delay or pull back timing, in % of degrees, to minimize or prevent detonation. And, of course, when you "pull back" timing, you are also loosing a bit of acceleration speed. It's better be safe than sorry. With my Crane Retard module set at the first mark, I could feel that slight "delay" in acceleration. I haven't data logged my car yet, so I don't have any real numbers to show you yet.

>Our engine advances timing quite a bit. I've heard anywhere
>from 20-45 degrees.

Did you hear that on this board?

I've seen it on my data logger. I have about 21deg advance at 15psi and WOT. I will be data logging on wednesday at the track for 20psi and race gas. It will probably need some retarding at 20psi

fly1 - I just reread the post and I thought that you wrote something different. :-)

Yep, I remember having read on this forum by a few people who have datalogged their cars that, that's those are just some numbers they've seen. I believe it will vary from car to car, though.

Kon Chittavong
HRC: Stage IV | http://laoracer.homestead.com/mainpage.html

how does stage 4 feel? Is it silly? Do you get that special feeling in your pee pee when you floor it?

Stage IV is awesome when I punch it. I could break loose in 2nd or 3rd gear on dry pavement! I'm always afraid my axle will break or something. I don't know; I get this inner grin whenever I'm on the road, as if I'm not easily intimidated by any domestic muscle car anymore.

Kon Chittavong
Boosted by HRC: Stage IV | http://laoracer.homestead.com/mainpage.html

I know what you mean... exactly. It's like, the road is a playground now. How soon do you get full boost? Does it stay there through the tach?

daren

Nothing on the road scares me except me. There are, very certainly, faster cars out there. I'm the only one that scares me ;-)

You want to retard timng while boosting because this ECU is tuned to make good power NA - it increases advance at a rate that will cause knock to a high HP, FI car. When this ECU gets knock, it pulls timing WAY back - around 14* at WOT. if you take a few degrees out before it reaches that knock-causing peak, or take a degree or two up top where you might be knocking just from the high boost and advance, you'll end up making more power overfall by being able to maintain a steady smooth timing advance over your whole powerband without knock induced dropouts in your timing curve.

What is the best way to know where to start retarding the timing. Should I start at 15psi(non-absolute pressure)and retard it one degree for every psi of boost? I have the AEM FIC so it reads in absolute pressure so Ill adjust it as needed. Just wondering wheres the best place to start on these engines. Also im running 8:1 wisco pistons and eagle rods so can I safely push over 20psi?

Retarding ignition is one of those things that really is easiest to tune on a dyno, because it will be different with every setup. I think most people will agree that with a smaller turbo like the 16G, our stock ignition map is fine up to around 15psi, so you would want to start retarding spark after that point. With a larger turbo that flows more air, you are gonna want to start retarding earlier.

On forged 8.8's you should be able to handle well over 20psi, but it all depends on tune. Try to book some time at a local dyno so you can do some real tuning.

On the FIC they have a easy setup that you input the max RPM and your max PSIA and it will add a safe 1 degree retard to every pound of boost load pressure. Thats a little to conservative in my opinion for these engines. Thats why im asking I have mine right now at .5 deg retard per psia and I think I could go lower.

IIRC, James would start to retard timing 1 degree for every psi above 10. This was on 8.8 comp and 91 octane. I don't pull any timing up to 15 psi, and it seems to be working fine for me.

Originally posted by TeamJC
What is the best way to know where to start retarding the timing. Should I start at 15psi(non-absolute pressure)and retard it one degree for every psi of boost? I have the AEM FIC so it reads in absolute pressure so Ill adjust it as needed. Just wondering wheres the best place to start on these engines. Also im running 8:1 wisco pistons and eagle rods so can I safely push over 20psi?

Det cans, reading plugs, dyno.

Here is a good thread I read not too long ago:

http://forums.neons.org/viewtopic.php?f=18&t=346494&p=2967114&hilit=fic+turbo#p2967114