Does it involve any Fords? :D

:gitrdun:

My honest opinion --- that's what your DYNO operator should have been helping you with....


A guess on timing is a motor that's going to have problems.

There is no guessing here on timing. We already tuned for timing on the dyno. And you know his rep. He isn't a schlep. (Hey that rhymes)

This is just for the start up and low rpm retard. I am not putting in MORE timing. We are already running at least 2 degrees less advance than what we tested fine on the dyno, but since power difference was less than 1% 30* is where it stays. Add to that E85 has much better anti-detonation characteristics than gas and we are in a pretty conservative safe zone, all things considered.

I already discussed with Mike that I was going to put some retard in down low with my programmable box and he agreed it was a good idea.

That being said, some smarter guys than me on Corner Carvers encouraged me to increase the timing from 0 to about 800 rpm and then have a constant retard surrounding my idle rpm (300 rpm on each side of it -- target idle is approx 1100) and then at 1400 rpm start pulling out the retard (advancing more) in a linear fashion up to 3000 rpm. Again, smarter guys than me! Here is where I am out now. They encouraged me to add a MAP sensor if I really start driving this on the street a lot but only time will tell how much that is.

http://i236.photobucket.com/albums/f...ps747646c3.jpg

In drag racing with a timing lockout ----- we put a coil interrupter (Susie can probably explain the whole interruptus thing to you) so you could spin the motor --- no timing in --- lift off the switch and let it fire. That, of course, is just for a start sequence.


The motor in the Mustang has a normal timing curve and idles about 1200 but doesn't "like" anything but "punch it I know the road!".... so I have no clue about street driving your monster race car -- 'cause I just wouldn't do it. :>)

The reason I said your dyno operator should have worked with you on the timing is because THAT IS THE PLACE TO DO THOSE THINGS.... he is able to put a load on the motor -- run it at an rpm -- watch all the parameters of importance.... and dial it right in. Including fueling.

I know that the TOTAL timing was set at the dyno --- but the curve is every bit as important.

That's now how Mike rolls with his dyno. He gets it running good and safe and then says tune it in the car. Many people tune on a dyno but not Mike. He says too many conditions (loads, etc) change from dyno to car so it's a wasted strain on the dyno.

This is just getting a base curve to start out.

Plenty of people (like you in your tracky car) just run a locked out full advance setup just fine. We ran it on my last motor and it was great for 2 years.

MSD probably had not invented the programmable 6AL-2 box back when you were dealing with your coilus interruptus. :action-smiley-027:

Are you kidding! MSD didn't even exist back then!!!



HAHAHAHAHA


We're talking 1970 here! My guess is --- YOU didn't even exist then!




EEEEEEEEHHHHHHHHHHAAAAAAAAAA

The Digital 6 has a 20 deg retard for starting so no worries about cranking. The Dinosaur method GW mentions if for motors back in the day of the FE.:lol:

I have to look at the MSD instructions so I don't know if the 20 is subtracted from the rpm at cranking or total timing. I say leave 20 in it below idle, or 10 out if you want to look at it that way. As people have told you this stabilizes idle by quickly building some torque if the motor falls below the desired rpm range bouncing it back into that range.

You have an efficient combustion chamber and high compression so flame travel across the piston shouldn't be an issue as evidenced by only needing 30 deg of total timing. I don't think you need a bunch of timing down low like some of us with archaic combustion chambers.


For your idle rpm start conservative at 20 out and leave the linear curve you have from there to 4000 for starters. I don't know enough about your SB2.2 but I would think you don't need to be all in as early as 3000 because of your compression and cyl head efficiency.

Once it runs in the car. You can add timing in at idle with the car running and get a feel for how much timing it likes at idle by listening to the motor. The idle quality will get better as you move timing up and then start to get choppy when you get to much timing because the cyl pressure peaking too early will be fighting the piston traveling up the bore. I would do this little exercise with the idle set a little on the low side since it will make the changes in idle more obvious.

Keep in mind this is all based on a proper AF ratio. You are running fat which requires a little more timing that if you were dead on. If you optimize your jetting you will have to go back and tweak the timing again. Your chassis dyno told you a peak all in timing #. Some old school ear tuning can get you pretty close on what the motor wants at idle. From there you can get pretty close on when to bring it in. JMHO


Your car is relatively light and your gearing and tire diameter are helping to minimize the load on the motor. That along with the preigniton resistance of E85 reduces a lot of concerns of hurting your motor with to much timing.

But as mentioned you don't need a bunch of timing to ensure peak pressure is reached early enough so I wouldn't get to aggressive with the timing without running it on a chassis dyno.

When the motor is running in the car you can dial in the carb and ignition on the chassis dyno and that will tell you how much timing you really need.

Where is Ron in Nor CA? He has a "developed" SB2.2:headscratch: He'll probably call BS on my advice.:underchair:

:cheers:


http://i372.photobucket.com/albums/o...g/26260053.jpg

The Digital 6 (6520) does have the start retard built in. The programmable 6AL-2 (6530) does not. You program it exactly how you want it. I have the 6AL-2 and I think you do too? :computer:

http://www.msdignition.com/forum/showthread.php?t=14791

Ron in Norcal has a developed motor yes... but it's a 23 degree not SB2.2. His developed SB2.2 would probably make 100 more hp than mine. :sieg:

Not a bad photo there, Mr Forvette. :mock:

So how'd that trip go? :stirthepot:

I've seen better:mock:

:cheers:



http://i291.photobucket.com/albums/l...ps7c5dfee7.jpg