mercury ECU program upgrade
 

I'm looking to re-bulid my 502MPI's into a mid'ly cammed, stroked 540's. I own a 370SS Formula and I'm looking for more mid-range torque motors to pick up my cruise speed. Does anybody have a good knowledgeable ECU programer that can tweak my computers to handle the changes they would need. My stock ECU'S have already been fattened up, raised rev limiter and had all the EPA regs taken out of them by Arizona speed when I put Stainless Marine Exhaust on my stock 502's. It took Arizona a couple of try's to get my computers right. So I don't really want to use them again plus I recently read all the negative threads about that place .It sounds like they don't know what the "F" their doing out there anymore !! Who out there knows a "REALLY GOOD" computer guy that can handle my project needs ??

From what I've read, Mark at Precision Marine does very good work on retuning ECM's.

That being said, I don't think your current EFI will flow enough.

Mark at Precision was good to me when we built 540's out of my 500EFI's.
Your 502 intake's won't flow enough air to make full use of all those C.I. (my 500 intakes don't either). We did make 700/TQ full dressed on the dyno though!!!! Which brings me to my next recommendation.....don't send anyone your computers.... send them the ENTIRE ENGINE to be tuned!!!!

Eric Betty at EB Marine in Nashville reprogrammed my ECU's on my 500 efi's after the upgrades in the boat.

I've got a great engine builder already (Tony,CMS Racing, in MD) and we were planning on running the motors on the dyno. As far as the the EFI system.I was told if I mill and extrude honed the intake manifold runners to shorten the length they would give me enough airflow ? Can anybody confirm that ??

I checked on the extrude honing. Will cost you roughly 500.00 per motor/manifold and will only remove 40-50 thousands of material. That is not enough for a significant change in flow. Cutting the runners shorter might help. I am going to try that this winter and see.

I would recommend just going 30 over to 509 CI and just call Bob Madera and have custom cams made specific to your appl.

Bob is the best when it comes to the valve train of a motor. Call him at 585-654-8583

Smitty

I also agree with Griff. Mark at Precision is the best out there that I know of.

http://pmefi.com/
504.469.7463

Don't even think about going elsewhere.

Can a 502 mpi system support a 540 cu in engine,yes and no. Yes you can make decent power with the correct mods,it just won't be quite as much as if every thing was absolutely ideal. I built a 540 with a handported mpi intake with the runners cut down and a bored out throttle body,it made 657 hp at 5400/665 ft lbs of tq. The compression was only 8.3-1 and cam was a big hyd roller blower cam,with a little more compression and a little different cam the same set-up should make a little better tq and maybe a little less hp. Smitty

Call Tyler Crockett 810-531-1809. He is the man.