502 Efi
 

I'm looking at a boat with twin 502 EFI's. Can you add more power to these engines or is it best to leave them along?

:rolleyes: :rolleyes: ...better know what your get'n into...if ya want to mod them out??....then go with carbs....actually go bid on boat on ebay with 500+hp's:D

http://cgi.ebay.com/ebaymotors/ws/eB...ADME:B:LC:MT:1

I personally think there the best for adding a Procharger or whipple too. They have very good internals such as forged J&E pistons Steel cranks ect... and to top it off they have a low compresion ratio of 8.75:1, which is what you want for super charging. The only week part is the cheap head gaskets. but thats an easy fix to have a reliable engine. I have over 190 procharged hrs. on mine running at 5-6 lbs of boost.
Have fun

in a single or twin application...the weight of the boat does matter! what prop???

In a 31' Warlock SXT cat. Twins with 30p Bravo 1 props. I installed Whipples on carbed 454 mags. I understand the EFI's are harder to do. I just wanted to be sure the 502 EFI's could take more HP. If I do get this boat, it will be some time before I could afford more HP.

Thanks Roger:D

hummm,,, cats, big props, and bravos=big budget!...i guess if your in smaller lakes it would not be as bad:rolleyes:

OK Audacity
What do want to say. I know you are selling a Active Thunder and they are great in the rough stuff but your Active Thunder will not run 95 MPH with the same power. To get that kind of speed out of a Active Thunder you would probabley need 525SC's or better. The HP 500's won't make it. I'm sure you know better than me what you would need to make a Active Thunder run 95. If I put Whipples on the 502's, I think 115 MPH or 120 MPH may be reached. What would you need to make your Active Thunder run 115 MPH?
Yes, the Active Thunder will handle 4'+ waves better than the cat but if its that rough come over to my place and we can party on the dock.:cool:

don't get me wrong i LOVE cats...6 months ago i had plans myself of buying one....but a cat w/o #6's or better was not a parameter. i'm about reliability and go'n boating every weekend.

I'm runnig a 502 mag efi with a stage 1 Procharger and Stainless Marine exhaust. It makes aprox 620hp with 5 lbs of boost and has been very reliable. Had a little problem with vapor lock in very hot weather, 98 deg plus range other than that no problems. If you exceed 5lbs you should consider head work.

I saw the boat this weekend and the motors are 502 Mag MPI's. Is that the same as 502 EFI's?

Joey, I see what you mean. If I add as much power as Mate 229 has it will probably distroy the Bravo 1 drives. Domino effect.

Mate 229, what drive do you have?

well the 500 efi's are 502 ci...just 500 hp not the 415 like the mag....the 500 engine are the way to go!....hard to beat them for reliability!

Those Motors are fine Quiet storm. Some people call them EFI's but there MPI's. The internals are the same as the 500, but with a different exhaust, cam and Intake.The 500 Leaves you with 470 HP. rather than 415.
have fun

415 is at the crank as is the 500....and the internals are different!!!!!

Not looking for an argument Audacity, But I have the Mercury Mercruiser book in front of me and the 415 is PROP SHAFT HP!!!!
The 500 is 470 Propshaft HP;) here's the link502 mag MPI spec

here's the 500
500 efi specs
I also agree that the internals are a little different, but they both use good internals:cool:
Happy boating

you are 110% correct...thanks for making me re-think that!

I've done that more than once or twice:p :p
I usually blame it on my typing fingers.:D

Thanks for the input guys. From all of this I think I would not be going wrong with this boat. The 502 mags could take more HP and I would use Whipples to get it. The 500 EFI is a stronger motor but the boat that I'm interested in doesn't have them. So, someday when I can afford more HP, I will be confident that I can add it without loosing reliability. Also, if I add more HP to the motors I should look at strenghtening or replacing the drives.

Hey Joey,
Why don't you sell that Active Thunder and buy my Supercharged Checkmate. :D I'm ready to make a deal.

ok,,,lets talk.

I have almost 100 hours on a Whipplecharged stock 502 Mag MPI in a 2000 Velocity 280 ... it works beautifully. I turn a Bravo 1 30". I also have the larger 2100cfm throttlebody from Whipple. I have had no engine or outdrive problems. It's a stock Bravo 1 outdrive except for a drive shower (Gaffrig Innercooler).

I noticed the cat already had 30" Bravos ... you may need to go to 1.36 which will put more stress on the outdrives. 34"s would be tough to turn and inefficient.

Good luck

wilerty

I needed to hear that someone had good experience with Whipples on the 502 MAG MPI's. They are great on my 454 MAG's but they have 750 Holleys. I wasn't sure how well the Whipples worked with MPI's.

I hope to take a ride in this boat tomarrow and I just might find that 95 MPH is fast enough:D or untill I get passed:eek: Then I would go with the Whipples.:cool: