dbgeek

Has been posted in the MS section for a while, but I thought I would share here as well:

Well, after 9 months of procrastinating, I went to the dyno to tune the car. The results were pretty good considering this engine made 160 at the crank stock: 183.5 hp, 138.8 tq (dynojet).

For reference, it made 169 hp, 137 tq on the stock ECU on a dyno dynamics a long time ago with 6* of advance dialed in on the CAS.

Relevant mods include removed air pump, 5/6 ports, sleeves, actuators. Cold intake, header, exhaust, no cat. MS1 v2.2, error*s daughter board.

Blue = VDI in high RPM mode
Red = VDI in low RPM mode

As you can see, VDI in low RPM mode went lean and STILL made more torque <5k rpms than high rpm mode. If I can get the VDI working again (electric air pump), then I can add fuel there to bring the torque up, restoring the midrange. The weirdness at 4300ish is the injector staging - which I moved down to 2500 rpms to be a non-factor (after I got home from the dyno). We developed a good fuel map (thought their A/F meter was wacky - the LC-1 on the car was reading better), then tweaked spark to find what the car liked. We went through 25 runs to do so, including testing the stock air filter, no air filter, and leading/trailing split changes. I'm going to look for a filter with more area and less restriction - there were gains all over with no filter at all. It was really cool, but I went there on a budget so I had to stop at 2 hours.

It liked more advance (28 ish) and less fuel (13.5) below 6k, and less advance (26) and more fuel (12.8) above 6k.

arghx

iTrader: (3)

Impressive. I can definitely tell you have an s5 motor. I made 172rwhp @ 7000 and 129rwtq @ 6000 with s4 manifolds and rotors a couple years ago. That was using an SAFC and an advanced CAS.

the VDI and auxilary ports are such a pain in the *** to keep working on these cars after so many years. My s4 didn't have VDI but I used an electric setup. the sleeves would still stick though.

question: what size exhaust are you running? I had the RB header with a test pipe and 2.5" turbo catback.

dbgeek

RB header, test pipe, and Borla cat-back. I HAD an 80mm single, but it was waaaay to loud. I've been told by fellow track rats that my car sounds good on-track, and I don't go deaf with the Borlas.

A friend and I had a conversation about actuating the VDI. I am going to use the stock solenoid and a vacuum actuator (junkyard part). The megasquirt operated everything well, but the 5/6 ports were needing cleaning once a year or so. If I retain the stock solenoid and fab a mount for the actuator, it will be almost pain-free. Interestingly, I think a distributor vacuum actuator will work. I need a stroke of about an inch, and it doesn't take a whole lot of force to move.