ClubSiRacer

I wondered if anyone else would care to share their total ignition advance/retard numbers under boost? (The numbers that you would get when you datalog your car at the drag strip for example.) Right now at 8psi @ 6700rpm my total advance (distrubitor is set right at 16°) its right at 23.5° advance and drops from there to 20.5° at 8500rpm @ 14.5psi and pretty much levels off from there. (Actualy its at 20.5° as early as 7800rpm @ 11.5psi)

To me it just seems like too little advance to make the best power, but I dont have a pyrometer (EGT for folks who dont know what a pyrometer is) and the wideband O2 readings really dont fluxuate that much changing the advance.

Sonny

Here's my old high speed ignition map.



There is definitely a point of diminishing returns as far as ignition advance. If I put the total advance above about 26.5 degrees, I started to lose power. I was making 8-9 psi with this setup.

Your numbers sound pretty close for a 91 octane pump gas boosted engine.

Sonny

boosted hybrid

0.5 degree per pound of boost. You are running pretty much 15psi, so your ignition advance should be around 24.5 degrees total advanced. This is assuming you are on pump gas. Every engine responds differently, but the .5 degree retard per pound of boost is conservative for ignition maps. I have tuned engines that made more power with more ignition advance, and other engines that started losing power even at the .5 degrees retard theory. The ONLY way to tune ignition maps is on the dyno. Your ignition numbers are pretty conservative. You could make some more power, and still be conservative if you bring up your ignition maps a bit.

SlowTeg

I gotta question then for the tuners out there.. What would you guys say is a safe boost level for a STOCK gsr block, no thicker headgasket, on pump gas daily. 9 psi or is much as 10 psi even safe? On a 57 trim .63 exh housing. Going from a built block to a stock block makes me worry. I'm running a pretty conservative .5 degree retard/psi so timing should be good, it's just that the block I have has some miles on it. Going from 1 bar to 7psi daily really blows and I see people makin power on stock blocks so I'm considering turning it up a little till I can get another block built..

Also directed towards Sonny.. Maybe it's just me but isn't that timing a little high? Was it a stock block? I see that the b16 maps run more timing than a gsrs but it seems that you're pulling very little timing under boost..?

-Mike

Honda4CX-T

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted hybrid &raquo;</TD></TR><TR><TD CLASS="quote">0.5 degree per pound of boost. You are running pretty much 15psi, so your ignition advance should be around 24.5 degrees total advanced. This is assuming you are on pump gas. Every engine responds differently, but the .5 degree retard per pound of boost is conservative for ignition maps.</TD></TR></TABLE>

So what you are saying even if with a "SMC" program and they call for your 16-BTDC to be set as 8-BTDC.

So, in reality I should advance ? I'm currently running stock 6.5psi from wastegate.

and if I do, how are you figuiring your .5-Deg. per pound of Boost ?

boosted hybrid

There is a difference between static and dynamic timing. Your static timing is your base timing at the distributer. You can alter this, but you want to keep it at the stock setting which is either 14 or 16 degrees depending on the engine. Your dynamic timing is something that you cannot change unless you have a standalone, or a ignition tuning device. The dynamic timing is what you alter with the .5 degree per pound of boost theory. 32 degrees total advance is what the total ecu runs the engines at. You are taking .5 degrees retard per pound of boost subtracted from the dynamic timing, or total advance.

SlowTeg

Ok I don't quite understand what you're trying to say but I''ll give it a shot..

You retarded your timing to 8 deg after getting an SMC? That's pulling way too much timing for only 7 psi. I remember back in the day many many yrs ago when we set a friend's timing to 8 deg static it was so slow. Try setting the dist to 13-14 deg at least. That's pretty safe. .5 deg/psi is just a figure that alot of people use. It pulls a good amount of timing so it's pretty safe.

-Mike

boosted hybrid

Altering your distributor static timing is not a good idea. Your loose all your lower end power, then are safe on the upper end. Its a way to be safe, but you need a standalone to make the best of your ignition maps and overall driveability of the engine.

I really have no idea what you should set your base timing at. I have always messed with standalones, and never tried to alter the base timing in effort to retard the timing in the upper rpm. I am not sure how accurate it would be if you pulled out the timing from the distributor.

ClubSiRacer

Ahh, thanks much folks... I guess I need to hit the dyno again and tweak these cam gears and retune the ignition and fuel maps again now that I have some nifty new GSR cams in the car.

DIRep972

iTrader: (1)

I run 23-24 degrees ignition values @ 5000rpm + and 13lbs of boost on my LS. 9.2:1 compression motor on pump gas. havn't really tried to make more power w/ ignition advance and I don't plan too.

Honda4CX-T

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted hybrid &raquo;</TD></TR><TR><TD CLASS="quote">There is a difference between static and dynamic timing. Your static timing is your base timing at the distributer. You can alter this, but you want to keep it at the stock setting which is either 14 or 16 degrees depending on the engine. Your dynamic timing is something that you cannot change unless you have a standalone, or a ignition tuning device. The dynamic timing is what you alter with the .5 degree per pound of boost theory. 32 degrees total advance is what the total ecu runs the engines at. You are taking .5 degrees retard per pound of boost subtracted from the dynamic timing, or total advance.</TD></TR></TABLE>

This is what I did. Maybe the instructions "OWNED" me.

I had engine running at stock 16-BTDC (Using Timing Gun w/Advance to check lines on crank) considered Static timing correct. The I adjusted the timing via the T-Gun to around 8-BTDC.

If I was to mess with the "Dynamic" (Coming from a Chevelle muscle car owner), wouldn't I just unhook a major vaccum source with the engine running, then correct it with the Dist. loosened (Fwd/Rev).

ClubSiRacer

Huh, go figure... I just double checked my ignition timing at the distrubitor since the car was feeling sluggish and by mistake i had it retarded an extra 5° more than it was expecting. I fixed that and it seems to rev a lot smoother and quicker now.

Now to get the new cams retuned for a/f and bump up the timing where its lagging.