Tony

Somewhat long winded but i want to explain what the images are...

The images below are screen shots from the sharkunter data logging feature.
In addition to the regular parameters it can monitor I also added “boost” via the auxiliary 5v inputs. Very easy to do.
Below are boost, igntion advance, kock count and RPM


Anyway, I set out to do some WOT tuning last week after reaching the limits of autotuning the car at “normal” speeds during everyday driving. I use a stretch of road NW of vegas that leads up to the ski resort. Its long, straight and upslopes nicely. The slope keeps the speed in check somewhat and helps load up the engine. All the runs were done from a standing stop to basically the limits of 4th gear where the car really wasn’t accelerating anymore due ot the incline and/or I was running out of “good” road....and *****!! Anywhere from 140 to 170mph. I went through the gears manually and had the autotune set up to do WOT only as I had cruise and idle pretty much nailed.

The differences in the car since I did this last time are not that much. Mainly the fueling system. I no longer have the BEGI fuel pressure regulator. With the shark tuner I was able to get a a perfect idle with my 42lb injectors and stock fuel pressure. At WOT with the 044 fuel pump I was getting more than adequate fuel delivery. My fuel pressure at idle is 57ish…and under boost it hits appx 63-65psi due to the fact that im using my original RRregulator I bought from DR years ago. It simply adds 5psi pressure at 0”vac. Its meant for a NA car but works fine on mine.

The EZK igniton side I had 3 option I wanted to run and is basically what this thread is about.
1)stock s4 chip
2) an s4 chip I burned last spring with reduced timing….and
3) a GT Sharktuned chip running on a car with a similar set up. Yes I loaded a GT chip in my automatic S4. Ran great really.

I started with the my modified s4 chip as I new that these were working fine over the last year and through the heat of the summer here in vegas. With that chip I made all my WOT fueling runs and got them squared away without having to worry too much about knock count. After that I had time to play with the other chips.

Now this is where having John Speakes PEMs (flash tune Sharktuner Chips) is a treat. After autotuning my fuel maps I simply pulled over and pulled up the EZK file I wanted and loaded it. No more disconnecting the battery…opening the brains up…pulling the chips out etc etc. There is one connection to the car and it was left intact for the entire tuning and it takes 5 secs to remove. Simply remove the carpet cover around the brains mounting areas and remove the connection from the diagnostics port.

Nice thing about this section of road is that I could do VERY repeatable runs as you can see from the RPM charts. Minus some wheel spin on launch here and there, for comparisons sake they are the same.

The green charts are my Sharktuned EZK chip on a TwinScrew boosted S4.….the BLUE is a STOCK S4 normilayy aspirated EZK chip….the red is the Shartuned GT EZK chip on a TwinScrew boosted GT.

With the aid of photoshop I over laid the runs for each parameter on top of each other for comparison.

Just thought Id share and show whats going on under boost in my car with various igntion timing…..and same fueling over the course of 3 almost identical runs.

I still want to tweek a few things and smooth the fuel maps out before I to hit the dyno again.

The time is displayed along the bottom and as you can see all the runs are very much identical(see the RPM chart). You can compare an area of time on one run with another.

Conclusion...Stock S4 maps in a SC application need some timing pulled. Perhaps a "DUH" but heres some proof. I can use some of the "pulled" timing from the GT chip in my current car in a few of the upper RPM ranges.(see knock count 30-45sec range)

Comments and input always appreciated.

AO

Cool stuff. I need to do this too.

Tony

I like this kind of stuff, but to be honest the biggest PITA is determining what all this stuff is telling you, what it means, then figuring out what you should do with it. Hence, i share it...

All i have to say is that with my foot to floor in my car for 55 secs on LEVEL ground i eat up road and the speedometer VERY quickly. These runs were UP hill

AO

Should have hooked up the G-Tech for ****s and giggles.

Jim Morton

Tony:

Great post and good coincidental timing.

Last Friday, I was helping another Rennlister tune a boosted Shark and given the stock EZK maps, we focused on ignition timing based on the observed effects of knock retard and where knocks were occuring.

I ended up making up a relative mechanical advance looking ignition curve (think old school distriubutor) as I think a lot of the varience in the stock maps surround tuning the transients of the intake manifold, something not as significant on the boosted engine.

In smoothing out the ignition curve through the midrange, we pleasantly picked up the torque values and reduced knocks. I hope to work this concept further over a few more dyno sessions.

T_MaX

Thanks for the share!

How did your car idle with the GT progam?

Cheers, T__MaX

Porsche Car Underground

Tony

It actually started and idled fine...but i could tell it was not quite the same. Id have to load the chips again and just do an idle comparison so to speak. I wasnt really concerned with idle when doing this. I guess i could just print out the GT map and alter MY map on the fly as it idles. Great tool!


from what i can see , i should be able to add some timing back in on my chip. While the S4 timing did produce a couple of knocks it really was not that many in the first 10-12 secs when comparing all the timing i had pulled on my chip in the same area. The car felt noticeable quicker off the line initially with the stock S4 timing. So stock S4 at the bottom...and the Sharktuned GT chip at the top! Hmmmm

Bill Ball

Tony:

To really have fun with the ignition timing, baring use of a dyno, you need to have someone in the passenger seat tweaking the timing to find the edge where it starts to knock at various stable loads and speeds on that long grade. Once you have good power and a minimum of knocks you can drop the knock recovery time.

I like Jim's idea of smoothing out the timing table numbers.

T_MaX

I am hoping one day someone will come up with a set of chips for an na S4 w/auto trans and GT cams.

worf928

Have you tried the bin files I sent you yet?

Louie928

Tony,
You can log ignition retard for each cylinder. That tells more of the story than knock count. If you get just one retard event for a cyl, it's ok. If you get successive retards that get more and more retard up to the max, then it is time to pull some timing at that RPM and load. You can reduce the recovery time to something like one second so you can see these retards stacking up in a narrow RPM range. Probably not explained very well, but it's easier to see whats happening on the log chart than explain it. I find that the rule of thumb 1 degree retard for each lb of boost isn't far off.

John Speake

Tony
Have you disconnected the WOT switch feed to the EZK ? The advantage of doing this is so your igntion mapping is then load and rpm based, but you know that already.....

Certainly log knock retard each cylinder (K1.......K8 on the ST menu) this tells you much more about what is going on.

AO