IIRC, Louie said it wasn't worth much going over ~13.25, or below 12.??.

For my S3 chips, I try to keep a 12.8 or lower average, because overall AFR varies by engine/fuel/air/MAF temp, and there are no knock sensors.
12.8 was usually pretty stable most of the time for keeping knock free.

For my S4, I'm going for an average of 13-ish, minus.


At the highest rpms, if you are way rich, you are losing power because fuel is displacing air.
It can knock when it is too rich, too, limiting the amount of possible advance.

When I put in the clutch to shift at redline - throttle full open with No-Lift-Shift - when the injectors cut out, MAF units spike by 5 or more, which, I think, shows how much air is being traded for fuel.

 

I targetted 12.5 to keep the knocks at bay. Some of this I put down to our fuel. I now have some STP anti knock additive so that may help and hopefully my breather project will help stop ingesting octane killing dino oil.

I suspect an optimal setup will be around 13:1 so we look forward to seeing your results as they progress.

Regards

Fred

 

Then one day, long after it seems like you are living the movie Groundhog Day, you look down at the log screen, and it looks like, this...


There is more EZ tuning in here.
At the top end, when the fueling is stable enough to support it, there needs to be more ignition advance to use up the mixture.
This smooths the AFR out, but more importantly, makes more power.


Black line, rpm, doesn't taper off very much at the top end any longer = more HP.
Red line, injector duty, will usually kinda match dyno HP plot at this point.
Blue line (shift light) shows when the 2nd WOT map kicks in.

3rd gear, S4 manual, on road

 

So..Porken, how close are we to an S4 auto chip set?

 

For the V0.5 chipset (mostly LH tuning, no extra fancy EZK reprogramming), I can add a touch more WOT fuel overall for an auto version.

 

So that would be for an 87s4 auto? If so do want!! Just say when my friend.

 

More better.


Updates
- RMB
- S300s S4 LH-24, V0.5
- Limited tuning of EZ w/minor code changes


SAE (STD)

Blue: Stock
Grn: X-pipe, airpump del, minor LH tune, stock EZ
Red: X-pipe, RMB, airpump del, extensive LH tuning, some EZ tuning

 

Well, Mr., you'd feel that kick in the pants.

 

Ok so where do I send the funds??

 

He is going for 310/320

 

You can see the airbox limiting air flow around the plateau at 4000 rpm and the sharp drop after 6000.
Taking the lid off raises the MAF voltage quite a bit in some areas.

Taking the lid off along with high definition EZ tuning should get it close to 310/320 SAE.
(Already there, UNCorrected @ 56F, with the lid off - 311/324)

Going through the the EZ code will take a little while, though.

Fortunately, there is less EZ code vs. the LH which means lots of room for new maps for fine ignition tuning.

 

There are other things you can do physically. Not everyone will wish to and thats fine. Greg has done alot of work on the S4 intake.

 

There has been talk about an enhanced intake system, I think Roger sells it.

Do you think it will work well with the tuning you are doing now, and address the air box lid issue?

 

I'm sure the S4 intake could use gasket matching at the heads, for a start.
I'd like to bolt on a set of plenum spacers and check the MAF voltages, too.


Anything should be better than the stock airbox.
The design of the top is mainly for noise reduction.
For my '86.5 black car, I made just an open frame to replace the top.
It didn't have a problem with underhood air temps, but I removed the firewall seal.


Not a perfect example as the engine was at different temperatures, but this shows the difference without the airbox top.
It did not make a huge difference in peak numbers - but it was not tuned for the increase in airflow.
An untuned increase/change may actually lower peak numbers...

You don't normally see the third power hump because of the airflow restriction.
(And that area was not previously tuneable to any great extent.)

Proper ignition advance will raise the MAF airflow voltages too, as ideal timing will allow the cylinders to pull more air.



Side note - the S4 is much more sensitive to temperature than my S3s.
My S3s will make the same graph over, and over, and over again.
True, though, that I spent years refining the S3 chips to be reactive to air and coolant temps.

 

Ken,

Impressive results although not sure I understand what the 3 curves are other than stock, interim and latest results.

With respect to the plenum spacers it seems to be contested point- I fitted them and felt the top end breathed a bit better and I am not inclined to remove them.

I have long believed the airbox is a compromised. When I had the K&N filter element fitted I noticed that the matrix had a circular dark stain above the MAF aperture that suggested to me that the plenum was not working and most of the air was going where it really wanted to go. Whether that happens with a stock filter element all I can say is I have not seen a clear stain on the paper element.

Quite some years ago I modifed a spare air box cover and cut some horizontal slats on the back side and removed the firewall seal. there was a theory that there is higher pressure at the base of the windshield favoring some cold air flow into the motor- true or not I felt it worked OK until I lost the damm thing in a house move.

I now have Roger's EIS system fitted and generally I like it and I get the impression it really does hlp the motor breath a little easier although I would like to be able to measure the inlet air temp as it enters the MAF to see if there is a measureable increase at all with all that aluminium/SS surface area [very hot over here in summer].

Keep up the good work

Fred