PorKen

I added some descriptions to the post, above.

I've been meaning to ask Roger if he has some prototypes or something laying around.
I'm just a poor S3 refugee...I can't afford these S4 luxuries.


If the MAF voltage goes up, then they can be tuned for more power.
Many times, if airflow is improved, ignition timing and fuel need to be reduced for max power.
It may need a new row/column for changing fueling at a particular maf/rpm.
EG. a spike in MAF volts will make it super rich at high rpms.


I really need to break open the EZ code to make more RPM divisions.
The stock map is too coarse to be able to really make any more power.
It may only need some retard at one particular rpm, but you have to take out 1000 rpm to get at it.

PorKen

The lid off dyno run may have been an outlier.

I can't seem to replicate it with an open frame top I made today?

Logging shows the same MAF voltages as if the lid were there.


Unlike the S3, where MAF voltages log higher over the whole rpm range without it.
S3s have the smaller intake tubes, though.

BC

Smaller?

PorKen

85-86 air intake tubes (and the corresponding inlets into the airbox) are much smaller in diameter than all other years.


Too bad the open top doesn't appear to flow any better.
(Better said, perhaps, good that the stock top works well.)

I may keep it for the simplicity.

FredR

Ken,

It would be interesting to know what happens if you can lift the filter to create more volume under the filter element. I suspect this is too close to the MAF aperture to allow the plenum to work correctly thus why the EIS has some potential as this restriction to air flow is eliminated.

Regards

Fred

PorKen

One problem may be the flat bottom of the S4 airbox.

On thing Louie tried was forming a bellmouth around the opening, similar to what is found in the S2/S3 airbox.


From what I have recorded, the stock S4 box flows about as well as a S3 with the lid off, 'topping' out at roughly 415 MAF units (@50F/10C).



I am really tempted to dial in some cam retard to try to push the second torque peak closer to 5000 rpm, which would ease the HP into the 310 range.
It may just lower the dynamic compression and make it lose power, though.

I should wait until I am able to pump up that area with ignition timing. Work, work work.

PorKen

"I don't feel tardy."

I think I have the right combination for a worthwhile S4 tune.

-3° cam retard (-5/-3 cold)
24# injectors
91+ octane

Drives really nice. I'm starting to like my S4.
Fueling is more stable, knocks are infrequent.

Looks like it will be raining this week - will have to wait for the dyno (rainy days = poor dyno results).


Note the combination above will probably work OK with stock chips.
The LH will compensate for cruise/idle and stock WOT is usually lean on S4.
Retarding the cams effectively 'leans' out the fueling calculation, raising the RPM point at which MAF airflow happens.

PorKen

Even though the early S4s have lower compression pistons, the 'tight' 106° LSA cams require Super.
The closeness of the intake and exhaust openings really packs air in, but only in a narrow range.
In this case, the goal seems to have been a big first torque peak, not HP. (For automatics?)
The later S4s with higher compression pistons must be really knock happy.


By retarding the cams a touch, the intake valve stays open a bit longer.
The tight LSA means they don't lose compression/power like a S3 (or GT) does.
Some compression loss may be good, reducing the knock potential allowing for more ignition advance.

Over -3° only flattened out the airflow past 6000, with progressively worse airflow around 3000.


AFAIK, 106 could be a high performance, 'peaky' cam, but duration is much less than a S3/GT so there is no overlap.
Reducing the base circle (increasing duration and lift) might make them a decent cam?

ptuomov

Why not retard the cams even more?

PorKen

I tried up to -6°.


Even with a PKrank and all the PK32V'r tools, it's a backbreaking job!

Hilton

Good news for S4 owners

Interesting - I assume you mean "usually rich".

I haven't done any serious logging on my '89 5-speed yet against its stock maps, but it does run insanely rich under WOT (non-cat car) even with the idle mixture adjusted to factory spec and with a brand-new MAF from JDS. I always assumed it was contingency for MAF aging, but it might well be more fuel for the knocks.

My 87 is my DD commuter at present, although I'm thinking once my timing belt is due for a retension (its been 800 miles so far on the new belt) I'll have a bash at the -3° cam retard. I might as well get it ready for your chips

PorKen

Rich on the top end, but lean up to 4-5K.

IIRC, JDS calibrates his rebuilds a little rich for aging.

Another reason it can be silly rich is weather related, I think.
Air temp, humidity, pressure, adds or subtracts from the MAF signal, and the LH just blindly follows.
Gearing will change the calculation too. Numerically lower gears will usually end up being richer.
A torque converter constantly changes the gearing, but there is no auto/manual coding for the LH.
Weight is a factor. Lighter weight 'leans' out the calculation.


For WOT, you have to pick a weather condition, be it DIN, STD or SAE, plus some, and hope it covers most operating environments.
I have not figured out the coolant temp scaling as yet. When I do, I'm thinking of adding an air temp sensor in-line to help correct WOT fueling.

Rob Edwards

Ken, FWIW I have been playing with the JDS AlphaN setup on my GTS for the past couple of weeks, and installed the requisite air temp sensor in the airbox (pic below). Stock S4 intake tubes and airbox.

On a 70 degree day (yesterday) I am seeing air intake temps between 32oC (after a few miles cruising at 75 mph) and as high as 60oC. (Sitting in a parking lot idling for 5 minutes, with the hood closed). Lots of heat between the headers radiating up and sucking air off the top of the radiator...

NB: No idea whether the sensor is perfectly accurate since I don't know how to calibrate it, but it reads about ambient when the car is cold.

Do you happen to have any more of those rubber radiator heatshields made up? I could make one but no point in reinventing your wheel. Perhaps a package deal with a PKRank when they're available?

MjRocket

Do you have a pic of the rubber radiator heat shield your speaking of?

Thanks

MJ

PorKen

Updates
-92 octane
-cams -3° retard (crank°, -5°|-3° cold 32V'r)
-retuning of LH and EZ for retard, higher octane


Observations
-Can't run 89 octane
-S4 cams need some retard (≤4°)
-best to be in the low 12s for AFR


STD 314/317

002 - completely stock, 89 octane
006 - 24#, Ott X, -cat, LH tweaked for 24#, stock EZ, 89 octane
020 - 24#, Ott X, -cat, RMB, -3° cam, LH/EZ tuned for retard, 92 octane