Using factory injection computer on a modified 3.6

EarlySport · 08-21-2007, 07:45 PM

Hey guys,

I'm starting to collect some parts for a 3.6 build-up. I'm going to 3.8 pistons and cylinders (11.5:1), and will run a reasonably aggressive cam ( DC62 or more ). I'm looking for an idle at 1000-1200rpm and good power from 4-7k. I was hoping to avoid porting heads or any other changes. I'll run 1-5/8 or 1-3/4" headers with a mufflers.

I intend to fabricate an individual throttle system using the largest motorcycle throttles I can find ( 45mm ).

I then have a couple of questions;

Has anyone used a device like a HKS VPC to eliminate the airflow meter and run the factory computer with manifold pressure sensing? Or, is it possible to remap the factory computer to run on Throttle position?

Has anyone had good experiences with remapping the factory 3.6 motronic computer? While I can go to an aftermarket computer I'd like to retain the factory one if possible.

What is the horsepower limit of factory 1992 3.6 injectors?

I'm hoping to make 330 horsepower or more from this combination. Realistic?

Thanks,

petevb · 08-21-2007, 08:45 PM

Sounds like an interesting build. I like the idea of MAP if you can get that working...

I can't help you with some of your questions, but:
Which year motor/ brain do you have? In the US some years can be reprogrammed/ chipped, others not. I guess Austrailia probably uses "euro" brains, which in the >96 units are easier to reprogram, but in the US the '95 993 or earlier brains are the ones to have, or swap to euro. Of course not everyone can program one, and what you're talking about sounds pretty extensive, so...

My '95 was remapped to a 7500 rpm redline, changed for a different cam, varioram, etc, so a fair bit can be done, but I suspect most will tell you to use motec, dta or similar- it took a day on the dyno just to raise my rev limit that high, as I guess the tuner ran into an unexpected issue above 7k.

If you get it tuned correctly and have the correct length intake runners I'd say 330 sounds conservative depending on octane. I've got bigger valves but a milder cam, less displacement and a VRam manifold, and I'm making those numbers. I'd be betting on 350 +/- 10 for your combo, but it's so dependent on tuning, runner lengths, etc that I'm just guessing...