Similarities/differences between 525EFI and 700SCi?
 

Except for the obvious, the 700 being supercharged, how much other technical differences are there between these two engines?

The 700SCi spec´s

http://i418.photobucket.com/albums/p...ble/700SCi.jpg

The 525EFI spec´s

http://i418.photobucket.com/albums/p...ble/525EFI.jpg

Obviously they are both 502 cui, the bore and stroke are the same... but are they using the same block and crank?

The compression ratio is naturally lower on the supercharged engine... (other pistons? rods? thicker gasket?)

The 700´ is using Sequential Fuel Injection versus the MPI fuel system for the EFI...

So, all in all... Has the 700´ "beefier" internal components, such as rods and pistons, other?

Other differences?

Two last questions;

Does anyone know the displacement of the supercharger itself on the 700´?

Does Mercury manufacture their own superchargers? ...or do they buy them OEM from someone else, such as Whipple or Eaton?

One reason for why I wonder this?

-How much different would a "Whippled" 525 behave compared to a standard 700SCi?
-Same size... roughly the same power...
-How much stronger "entrails" comes with the standard 700SCi? ... compared to a bolt on blower kit from Whipple for the 525?

Same internals on both motors.
Different cams.
Different pistons.
Same heads.
3.3 l supercharger on the 600sci and 700sci.

A 3.3 Whipple kit on a 525 makes around 800hp due mostly to the higher compression of the 525, and the more radical cam in the 525.

Hope this helps,
Chris

Cheaper to whipple the 525 EFI and lots more HP in the end.

Thanks for your helpful replys. Is the 3,3 L supercharger used on the 700SCi actually also the same as the Whipple bolt-on kit?

The 700sci supercharger is an exact copy of the Whipple 3.3 supercharger. Dustin did the R&D for these motors.

Chris

This is very interesting!

Many boats found in the classifieds comes with relatively fresh 525EFI:s... Very few comes with the 700SCi... To import one of these boats and then upgrade with the Whipple 3,3L bolt-on kit sounds like a very interesting way to go, if the 525EFI and 700SCi are so similar engines internally. In Europe we run with slightly higher octane, that maybe can compensate some of problems with maybe too high compression with the "whippled" 525???

Still; the compression in the 525EFI is relatively modest at 8,75:1

In my opinion.. being that I have a 600sci.. I think that the 525 with a whipple is a better package than the 700sci. The low 7.5 compression (on the 700sci) makes it more difficult to make power. 8.75 compression is just about perfect for a supercharged motor.

Chris

I agree, I was also told the same thing when i was pricing out A/T's before i found the one I have, I was told to order the 525 boat and then put the money into upgrade down the road versus the 700 package due to cost and performance. If you put the $ difference into the 525 you will have a far superior motor package.

After the whipple update, is there a need for running the engine on the dyno? ...just to make sure it is not running lean, or otherwise missbehaves? ...on the other hand, can the injection (and other related parameters) be fine-tuned under any circumstances, or is it "factory presets" from Whipple only, with no possibility for fine tuning?