500 EFI Upgrade
 

Who can reprogram the ECU on these motors? If you did it did it help any? I know about AS&M.

Has anyone turned this motor into a 540 and used the ECU with reprogramming? Did it need new injectors?

Has anyone purchased the mono blade throttle body from AS&M? What where the results?

Any help appreciated.

Re: 500 EFI Upgrade
 

Lister, I put the AS&M throttle body, kit with the reprogramd ECU. I gained one to two mph. 288 Sunsation. It really helped with the transom soot.

I'm selling my boat, and would part with this kit if you want to swap Computers?

Re: 500 EFI Upgrade
 

I think the guys at Boostpower USA sell a similar kit. There have an article from a mag on their website. They say they have performed this on 150+ engines so far.

From what I hear the kit includes:

Mono blade throttle, intake manifold spacers, modify intake at throttle body, reprogram ECU for improved airflow, add more advance, and increase rev limit to 5800.

Re: 500 EFI Upgrade
 

Jeff,

I may want to do that. I need to think ablut it a little more.

I went to Boostpowers web page and saw the 65HP article gain. I will call them today to see what they have to say. That seems like too much for what they did.

Any other replies?

Thanks Linnie

Re: 500 EFI Upgrade
 

I talk to them when the article came out. First of all it took them like three days of calling to get some one to talk too, and the price at that time was out to lunch. But that was two years ago now. I forget, did they dino test it.
If I remember, they wanted you to install a crossover too.

Lister, what ever the cost is from AS&M I will sell mine for half price, you pick up the shipping. Keep in mind, my computer shows 268 hours!

Re: 500 EFI Upgrade
 

Ask to look at the dyno sheets. Probably nearly the same curve until 5800 rpm where there is 65 more HP than stock because the stock curve is falling off.

Re: 500 EFI Upgrade
 

Cobra Marty is right on. Check the dyno sheets. They say 65hp and another 25hp if you install the crossover instead of the reciculating pump. That's 590hp out of a 500. But you are spinning 5800rpm now, ouch. Merc builds them the way they do for a reason. To provide safety margin.

Re: 500 EFI Upgrade
 

65 hp My a**. It is more like 25 hp max increase. The hp 500 pretty much stops making power around 5200rpms.

Re: 500 EFI Upgrade
 

What corrected hp are you using on your dyno?

Re: 500 EFI Upgrade
 

call mark at PRECISION 504 469 7463 he can give you the advice you are looking for. e