Megasquirt tune for 3.5.

[parrisw]

Anyone have a good starting timing curve for my car? It's a 81 TR8 with 4.0 heads, 3.9 intake, Isky 270, LS Coils, full sequential fuel and ignition.

[Moderator]

This should get you running:
Bonnie1_2014-12-16_09.07.32.msq

Hardware details and jpg versions of my fuel & ignition maps may be found here:
http://www.britishv8.org/MG/CurtisJacobson.htm

[parrisw]

Hi. Thank you. I guess that's a complete tune?  I looked at you're timing table jpg, looks like 20 degrees advance at idle?  How come so much?   What kind of iac are you using?  I'm using a GM 4 wire stepper.

Thanks.

Will

[Moderator]

Think of it as 11 degrees of initial advance plus 8 degrees of vacuum advance for a total of 19 degrees of idle advance at ~800rpm.

For IAC, I'm using a GM 4-wire stepper motor mounted on a Chevy Blazer V6 throttle body. The same throttle body was used on many different models.

[parrisw]

So I got it running on your tune. Runs better, but it seems doggy?  looking at the advance curve, why is it what looks like at WOT your timing is conservitive at 25deg adv? at around 80-100kpa?  The AFR's seem to be fairly good, it ran rich at first, I ran autotune, and it sorted that a abit.  WOT seems to be around 12.5, I'm thinking it shoud be 13.5.   But it just seems like a dog, part throtthe where the timing hits around 34 seems better?

[Moderator]

Our engines may "want" different tunes for any number of reasons (e.g. different cams, exhaust systems, how we're doing baro correction, fuel pressure differences, etc., etc., etc.) My ignition tuning probably is a bit conservative. One of these days I'll get on a dyno and further refine the WOT. That's not something I want to push too far on instinct.

Make sure to turn "Accel-pump AE" on for actual driving but off whenever you're running autotune. (You'll probably also want to turn the overrun fuel cut feature off when running autotune.)  

The top couple rows of the tables, where afrload is 90% or higher, don't really amount to much since your normally aspirated engine probably won't pull an afrload higher than ~85%.

Now that you're up and running, I'd encourage you to post a log and a tune file on the msextra message board (perhaps <a href="http://www.msextra.com/forums/viewforum.php?f=134">here</a>). Lots of knowledge there, but not so many people with specific experience with the little aluminum V8.  

And you're going to post a couple engine bay photos here soon, aren't you?

[parrisw]

your timing curve starts dropping timing at 55kpa, and gets very consertive.  I think that's where its dogging out.  I can post pics for sure, or you can go here and see everything I've done.  http://www.tr-8.ca/?page_id=190

[parrisw]

Ok here are a couple of pics.  Have still not build a air intake. I know my bad, shouldn't even be tuning without it.

I'll take a more up to date pic tomorrow.