Dragracer_Art

I'm trying to make some minor cheap upgrades to my 2007 Chap 256ssx.

It currently has ECM# 3885461, which is correct for the 380hp 8.1, Gi-H package.

I managed to find a complete wiring harness and ECM from a VP 8.1 GXi which is supposed to be a 420hp combo and compatible with Raylar kits. This ECM is number 3883664 and I *believe* is from 2005.
I also have a few new 420hp HO camshafts under my workbench... so that is a cheap option as well.


I'm curious what issues I may encounter and if this 3883664 ECM will plug into my existing 2007 harness, or if I will need to swap the entire mess. I dont know what years the 3883664 ECM was used and if it's compatible with my 2007 drive by wire throttle. I have no problem swapping to a cable throttle if thats the only issue... but it would be eff'n wonderful if it would just plug and play.

I spent $500 for this used harness and ECM so I dont want to just jam connectors together and brick the ECM.

Thanks in advance !

TomZ

Reach out to John Mosetti (BUP) at Boats Unlimited - he's in the Houston area. He's really good with the factory ECM thing. Not sure about Volvo specific, but I know that he is able to repair the GM ECM at the board level. Worth a shot.
https://www.boatunlimited.com/

Griff

What exactly are you trying to achieve??

techman

Sounds like he's turning a 8.1 GI into a 8.1 GXi with a cam and ECM change.

Be warned that GXi ECM tune is one of the worst running and bad behavior inducing software programs ever. I don't know what they were thinking when they programed it. During the time they were for sale, the dealer I worked with actually wouldn't order the GXi's because they were just awful and the Gi's were fine.

Another reason the Merc 496's were better IMHO. Smooth......

cheech

Where you been Griff?

I just cant leave anything alone !!!

PSI 8.8 liter / 550ci ???

Dragracer_Art

Mo powa

Keith Atlanta

Whats Larrys take on this? I know Ray wasnt big on them at all... I know its money, but its money well spent. In a HP application, like what you are going after I dont know if its worth messing with the volvo ECU.

Dragracer_Art

Per email from Larry Hofer, the GXi ECM works well with his 525 and 600hp kits.

I do have a local guy that swears he can hack the ECM... but I havent connected with him yet on this.

I'd like to try running one of these 8.8's on a test stand using the VP ECM if possible... just to experiment and play around with tune/software before it gets anywhere near the boat.

Problem is, much of this depends on this garage im trying to build and it's already a month behind schedule.
I cut a check for $44,500 back in December and all I have to show for it is a big hole in the yard. I may own a Kubota skidloader too if they dont soon get back out here for it.

Dragracer_Art

Just sent him a message.

Thanks!

Dragracer_Art

Im trying to keep it simple and avoid running aftermarket engine management if possible...

Larry Hofer says the GXi ECM is the way to go with his 525/600hp kits... so I assumed it wasnt too horribly bad.