DMOORE

With an intercooler 6psi should be ok. Just watch the timing and REALLY read the plugs.



Darrell.

blue thunder

I didn't build the engines with blowers in mind. Just kicking around what I might do at this time to get a little more top end pop, without teardown again. Unfortunately, I am a forced induction novice. So, I have many rather basic questions, heres a couple more:

What would it take to add an innercooled setup to a merc blower off 525sc?

Without intercooling, which I presume is cooling the intake air charge, how much hp could one expect with 3-4psi? How much more with 6psi?

Thanks for the feedback guys.

BT

Griff

Adding the chiller is relatively simple. Just needs to be bolted between the intake and SC. Next, you have to feed it some water. You can do this in many ways. Easiest way without adding a new hull pick up is to use a 2 stage sea pump. Then you just have mount a dump tube for the water to exit.
I would GUESS about a 75hp gain with 3-4# and maybe up to 140hp with 6# through a chiller.

StraightJacket

I would say only 3-4 lbs with your set up, the cam sounds ok. If you can run a chiller do so, the 177 blowers make alot off heat when you run the smaller pulley

rdoactive

No offence blue thunder, but:
9.5:1 CR, a supercharger, and "a forced induction novice" usually results in melted pistons.
Do a lot of research, check to see if your cooling (oil & water) are sufficient, fuel system, ignition is tuned for your setup, etc.

DMOORE

There was just a guy in the general section selling some Merc 420 set ups. With the 420's you can build the same boost at a much lower temp than the 177's. They had the carbs and all.


Darrell.

blue thunder

Believe me I considered this rdoactive, no offense at all taken. I do build my own engines and have blown plenty so if I do it again, oh well. That seems to be how I learn. I do run closed cooling which I am slightly concerned with. Typically no tstats though and water temps of about 125F, oil about 200f unless running hard, then 230f. I feel ok about my base engines.

Anyway, the 525sc blowers in the classifieds evidently sold whilst I was learning from you guys.... so, anyone know of where another set could be had? I really want to step up to this level of engine tuning/building. NA has become boring.

As always, thanks to all for your inputs.

BT

Old Navy

I have a 525sc in a single engined boat. If you "want to step up to the plate" get real blowers. The 177's just dont give you that much more power nfor the money- BUT mine is extremely reliable.(SO FAR)

blue thunder

Old Navy, with my already high 9.5:1 comp ratio would a better blower make any difference? Other than the intercooler part anyway. I think I am forced to keep boost low anyway, no?

blue thunder

Couple more questions guys if you are still out there. When installing the 525sc induction on a mark IV setup:

Will the distributor just drop in where it was?

Looks like I need to change something with the tstat housing?

How about the v-belts? Still run them to steering, circ pump and sea pump or do you have to do something else?

BT