niceguy

So I've read a couple of threads on this subject and several people seem to be torn.

But if one person decided to change FROM the efi to a blower with carbs.... what all would need to be changed?

I realize that person would have to measure the hatch and make any clearance issues. But what about wiring and linkage, fuel pumps, etc?

Young Performance

It is actually an easy swap from efi to carb. Don't know why you want to get rid of the efi. You can have a blower and still retain the efi. Anyway, I need to know a little more info, to determine what has to be changed. What engine do you currently have and what do you want to go to? What type of blower? How much power do you want? etc.
Eddie.

niceguy

Thanks Eddie. I am just trying to decide what I want to do and want to know my options. I appreciate you taking your time to help. I am currently looking to buy and just trying to see what my options would be.

Young Performance

No problem. Like I said, if you give me a particular engine that you want to modify, then I can tell you exactly what needs to be changed. Give me a shout if you need any help, Eddie.

pkspx

What engine is it? My boat came factory with the an 454EFI MPI. I had mine converted because the ecm would not except the mods. However today, there are options to solve that. I know when it was done the intake manifold came off had to add in a stock Merc HP 500 fuel pump, merc HP 500 harness bracket, new MSD ignition system and of course a Holly carb. I have the original invoice and I know there were a few little parts as with any major project.

niceguy

Well I asked this because I found some 250 blowers with carbs and everything for a pretty good deal. The motors in question are 502efi's. The Prochargers for these things would be close to 9.5k. I could get the blowers and carbs for half that. SO it got me to thinking.... and I thought who better to bounce ideas off than you guys!!!

Remember I dont have anything yet.... I just want to make sure I do the right thing the first time out. I am old school carb guy, so tuning and rebuilding, etc is second nature for me. But the Prochargers are suppossed to be a bolt on deal with no computer mods and they DO have intercoolers.

Trying to decide if I am just being cheap or if I should do what I am familiar with?

Young Performance

If you happen to go the Procharger route, you will need to reprogram the ecm. I realize they say you don't need to, but if you want the thing to be reliable and not soot the transom and foul plugs everytime out, then the ecm needs to be touched up some. Just keep that in mind if you go that route. The 250 blower would be a pretty simple deal to do. I take it they don't have intercoolers. You could always add them later, but you would have to keep the boost down low until you did.
Eddie

Airpacker

I am currently doing a 500efi with a roots blower. I just purchased two holley throttle bodies and spacer plates( which is where the injectors will be mounted) so the fuel will enter above the blower.

Bigger injectors,fuel pump, filter,cooler and custom fuel rails and lines. It will be reprogrammed on the dyno.

Result should be a 800hp, easy starting, idling and clean running fuel injected motor with the benefit of knock protection. Why go carb when FI is so much nicer?

niceguy

Eddie,
Right on.... I thought you would have to reprogram the ecu. Just another strike against the efi in my book. What are the chances of actually getting them right the first time??

EFI is great for fuel economy and idle on cars. As for power, carbs will make the same power at WOT but will always be easier to work on IMO.

Man I love the compact package of the prochargers and the intercoolers, but the ease of tuning and such is a big plus for the 250 blowers. Now the downside to the 250 is two-fold
1. No intercoolers and 2. Clearance under the hatch.

ZXXX Donzi

The ECM can be reprogrammed by guys like Eddie. I have had it done and the end result was very turn key. My boat actually ran better than stock when I had a Procharger and reprogrammed ECU.

I got it all set up, sent off my ECU on Monday, got it back on Friday and put it in that afternoon.