DAP@EPL

As many of you know, my car is in the process of being tuned by Tony@EPL (with excellent results, I might add).

We had the boost and fueling down well but were not entirely happy with the 100-110% injector duty cycles at the top end. AFR was in the high 11s so it wasn't leaning out but the lack of any safety margin was something that gave us pause.

So we opted to try out some of the Siemens Deka Mototron 60lb/hr injectors like Mike2kS4 is running in his car. However, we chose to stick with the stock 4bar fuel pressure regulator, giving the injectors an effective flow rate of 70 lb/hr (728 cc/min)!!!

I'm happy to report that Tony was able to tune the injectors to idle and run stock smooth with perfect fuel trims despite their enormous flow rate (over twice that of the stock injectors).

These injectors run extremely well in the S4 (better than the greentops, IMO), though I don't think they are a good option without custom tuning. For a homebrew setup, you wouldn't be able to pull enough fuel with Lemmiwinks and would have to resort to fuel pressure below 3bar to maintain adequate fuel trims. I've experimented with low fuel pressures when I first started homebrew tuning before Lemmiwinks was freely available (yes, that's how long I've been tweaking) and wasn't pleased with the starting and idling issues that the low fuel pressures caused.

Anyway, enough narrative, on to the pictures and data...
Mototrons vs. Greentops:
<img src="http://www.pramanik.net/AW/EPL/injector1.jpg">

<img src="http://www.pramanik.net/AW/EPL/injector2.jpg">

Injector duty comparison:
<img src="http://www.pramanik.net/AW/EPL/duty.GIF">

Plenty of overhead/safety margin with that setup.

<a href="https://forums.audiworld.com/s4/msgs/2299820.phtml">performance videos</a>

-Dave Pramanik

DAP@EPL

Mark P, Ron_C, Ron's cousin and myself were hanging out on Saturday so we decided to do a quick comparison of my car vs. Mark's.

Its been a while since we did our last comparison and both of our cars have undergone significant software changes (Mark was in the early stages of beta testing the new APR software and I was running a MUCH earlier beta version of software from Tony@EPL).

The relevant data:
Both cars are Stage 3 S4s with a driver and a passenger. Mark P's is an Avant so it has a slight weight penalty there but he was running lighter 17" OZ Chrono Evolution wheels while I was running stock wheels and snow tires.

Here is the video (much thanks to Ron_C for recording and compiling them).

<a href="http://www.pramanik.net/AW/EPL/EPLvAPR_GearTitles.wmv">WMV format (higher quality and smaller file)</a>

<a href="http://www.pramanik.net/AW/EPL/EPLvAPR_GearTitles.mpeg">Same video but in MPG format (larger file and lower quality)</a> for those that complain about WMV formats

-Dave Pramanik

Captain Matt, I be

what did the comparison show? I dont like watching movies at work

DAP@EPL

Its just a video of two cars, nothing work offensive.

-Dave Pramanik

ModifiedA4

obviously you are running a higher flow version, but perhaps the spray pattern...etc is the same as the oem verions which is why they work well. the "greentop" solution looks like a kludge...they arent the same injector style as oem.

DAP@EPL

But I agree that the Siemens Deka injectors do likely have a spray pattern that is much more suited for the multivalve intake head design of the S4 than the greentops.

-Dave Pramanik

DAP@EPL

However, a quick look at ETKA shows Siemens as the OEM injector mfr. Good call.

ModifiedA4

<ul><li><a href="https://forums.audiworld.com/s4/msgs/2277928.phtml">the oem injectors might be fat, but i think that is all they share in common with the bosch greentops</a></li></ul>

box_of_partS4

I've been in Mark's car, and it's fast...

Is it me or did you have a huge grin on your face while driving? =)

ModifiedA4

by injector "type" above, i specifically mean spray pattern, spray angle and oriface style....not necessarily manufacturer.