5.0 EFI Upgrade to 5.7 or 6.2?

[WillyBWright]

I have a customer that neglected to winterize his boat, so now I get to do a Long Block. It's a 1995 5.0L Throttle Body EFI. As long as I'm at it, I thought to make some of the sting out of this major expense that this could be an opportunity to upgrade to a larger motor, say a 5.7 or 6.2. I have two questions for the experts.<br /><br />1) Would I just have to change the MEFI3 ECM to a 5.7 ECM? Or is there more? They're rather expensive. Does anybody reprogram MEFI3 ECMs?<br /><br />2) Could I put in a 6.2 Long Block? This would require reprogramming the MEFI3 since I think only the 5.0s and 5.7s had MEFI3's. The 6.2s I've seen in the parts books use MEFI1s or 2s. Or are there MEFI3 ECMs available for 6.2s?<br /><br />The boat and drive would handle the extra ponies, so that's not a concern.

 

[Bondo]

Re: 5.0 EFI Upgrade to 5.7 or 6.2?

Arizona Speed & Marine, in Lake Havasu Az. is the Only place I've ever seen that reprograms ECMs for Merc.s.............<br />I think they have a web site.....<br />If Not,<br />Go over to hotboats.com forums,+ ask around........<br />Someone there can No Doubt Help you out.........

 

[anesthes]

Re: 5.0 EFI Upgrade to 5.7 or 6.2?

You need to change the PROM inside the ECM to a 5.7 calibration. <br /><br />You could also get an adjustable FPR and run the boat WOT and adjust it until its just right.<br /><br />If you were local i'd do the prom for you, but your not. <br /><br />-- Joe

 

[Bondo]

Re: 5.0 EFI Upgrade to 5.7 or 6.2?

anesthes,<br />What's an adjustable FPR ??????<br />Can you build a Complete Fuel,+ Timing Map with it ????????<br /><br />Sorry to Hi-jack your thread Willy.....

 

[anesthes]

Re: 5.0 EFI Upgrade to 5.7 or 6.2?

Originally posted by Bondo:<br /> anesthes,<br />What's an adjustable FPR ??????<br />Can you build a Complete Fuel,+ Timing Map with it ????????<br /><br />Sorry to Hi-jack your thread Willy.....

Adjustable Fuel pressure regulator. No you can't change the timing map, though its prolly not that far different from the 305 - 350.<br /><br />Most of the changes would be in the lower VE areas. Prolly a little more initial spark on the 305 to fight bog, etc. <br /><br />-- Joe

 

[Bondo]

Re: 5.0 EFI Upgrade to 5.7 or 6.2?

Cool..........<br />Neat Trick to Fool the 'puter.......

 

[anesthes]

Re: 5.0 EFI Upgrade to 5.7 or 6.2?

Your not really tricking the computer. Its gonna adjust the fuel mixture to achieve the right AFR anyway, but by increasing the rail pressure you'll be able to do it without much correction.<br /><br /><br />-- Joe

 

[WillyBWright]

Re: 5.0 EFI Upgrade to 5.7 or 6.2?

Waiting to see if the customer is interested, but thanks for all the good ideas.