Need help building my A/F and Spark Tables

[2VNTG68S]

Hey guys,

Hoping I can get another set of eyes on my FAST A/F targets and Spark table

Relevant specs (let me know if I missed anyting):

445 stroker (built by Barry at Survival)
(ported) Edelbrock Performer RPM top end
Fast XFI Sportsman EFI system
Fast Dual Sync Distributor
Cam specs: only known to Barry
Dyno'd at 495 hp and 541 ft. lbs.
TKO 600 with .64 OD
9" with 3.70's

I know cam specs are important but guessing that a ~500 hp 445 stroker would have a reasonably narrow range for A/F and spark?

Also, I know V/E table is critical but I will tune (and/or let the ECU tune) the base V/E tables to minimize O2 correction factors but need the right A/F targets to start with.

Attached are the current spark and A/F tables.  The top of the tables were tuned by Barry during the dyno pulls so I think those are pretty close.  Looking more at the cruise ranges and spark table transitions.

Definitely an EFI newbie so look forward to any guidance you guys can provide!

Thank guys!

[stangbuilder]

So how does it run?  Post a running log on it is a auto or stick car?  Been tuning a 477in deal with the sportsman ecu..

[2VNTG68S]

Runs pretty good.  I haven't been pushing it much though.

I'll run a log tomorrow and post it.

Its a stick car (TKO 600 5 speed).

What I'm trying to figure out is how fast my timing curve should be at different loads and RPM's, and what the appropriate A/F ratios are for different conditions.  So its not that its not running well (it is) but I'm not sure if there is some more optimization I can do to increase mileage and responsiveness under all driving conditions.   

[jayb]

On the timing, think about how a distributor works.  The vacuum advance of a distributor will kick in at cruising speeds to increase advance by quite a bit; 50 degrees total advance is not uncommon.  This would be around 2500 RPM and relatively high vacuum, so maybe 40 kPa and below on your map.  You are already up at 38-41 degrees in that area, so you might get the car running down the road in that area of the map and try increasing those numbers.  More will be better for mileage, but you don't want to hear pinging under acceleration from cruise.

You really have to just drive the car while monitoring the lap top to figure some of this stuff out.

[2VNTG68S]

Thanks Jay!  Definitely will help to see where it is on the graph while driving and play around in real-time - I'll give that a shot. 

Any thoughts on the A/F numbers? I feel like I could lean it out a bit at low loads and idle, but not sure how to tell if I'm going the right direction or not...

WOT Barry set on the dyno and it was rock solid so I won't mess with that - its more around the transitions and cruise / idle I want to optimize.

Attached the latest set of Spark and A/F tables after some playing around

[Autoholic]

I was looking at your AFR table yesterday and I was going to type that at cruising (low load and low RPM) I think you should be running more towards lean, not rich. A lambda value greater than 1 is rather common for low load an low RPM cruising.

[stangbuilder]

your v/e table might not be that far off...In your program you have some what fast calls AE tables they make a big time changes TPS rate of change makes the biggest..dont mess with the MAP rate of change...The best way to do a stick car is to do 3rd gear runs in 500 rpm sets...your sets will evolve as you learn....turn learn off.. The real and best way to do a tune on this deal is take your car have a tech set your targets on the chassis dyno real time .Once you have your target numbers you can street tune it  I can tell you this on my set up...FEs like fuel BIG TIME..When you have your car tuned on a chassis dyno it really takes all the quess work out of it

              Tim

[2VNTG68S]

Playing around today and she gave me a little "rattle" when I dropped the hammer in 3rd gear at 2500.  So the spark advance must be too fast?

Confusing because I don't have any more spark in it than Barry did when he ran it on the dyno.  So must be something else, which raises a couple of questions:

1. how much does temp affect it?  I have a 195F thermostat in it now.  Should I back that off to a 180?  (I thought EFI wanted to run hot typically)
2. Air temp was really high (for Toronto in Sept - it was in the 90's with high humidity)
3. A/F ratio.  Does a leaner mixture promote more detonation at a given spark level?  If I fatten the mixture would it be a little happier?

Thanks in advance guys - steep learning curve over here!

[jayb]

Were you datalogging when that happened?  If so, figure out where you were on the MAP and RPM scales and pull some timing out.  You can also richen the mixture there, richer A/F will have less of a tendency to detonate.

EFI does not want to run hot typically, but a 195 thermostat shouldn't be an issue.