Chris Sunkin

On what-to-do while you're in there, I'd throw a new set of valve springs in.

Pick your blower/intercooler/etc., then have a cam ground by Clay Smith or rmbuilder to match your combination exactly.

Probably the best bang for the buck is the chiller on your existing setup. The Whipple is nice but $$$.

Steve Zuckerman

They definitely tweak the fuel curve and get rid of that annoying high rev on warm start. Also, no more black transom. Merc has these motors set up really fat. My kit also came with a low temp thermostat (a good idea with iron heads and more boost to prevent detonation), 3.5" blower pulley, and MSD 6M spark box. The rev limit on mine was 5600. A friend's is @ 5700, or our tachs may be off a little.
There is some HP to found on a SC motor (particularly the low compression 575) just by spinning it and the blower faster (more boost with more RPM = more HP).
As mentioned earlier, run the FelPros or Cometics, and check the heads (valves, seats, springs, retainers, surface) while you have them off.
Steve

Steve Zuckerman

After adding the Whipple to my 575, it was definitely much stronger, and picked up acelleration and 3 MPH, even though I lost 2PSI boost (was 6, then 4). I figured at that point we were on to something. I trien the 3.25", picked up 1 more MPH and showed 5PSI. I put the 3" on and got back to 6PSI intercooled, and a gained a total of 5 MPH from the previous non-intercooled 6PSI 3.5" set up. This was in cold weather when the intercooler was at it's most efficient, but my boat was much more consistent than it had been in the past, even in warm weather and water.
Here's a pic.
Steve

ciaoderhead

Any recommendations on springs?? Use stock Merc?

Chris Sunkin

All a Merc spring will accomplish is a faster lightening of your wallet. Any good spring will work.

I have read comments recently about some ultra-high-end springs and their unsuitability for use at extended low-RPM. Don't know why but they're rumored to have failed in these situations. Unless you're running .700+ and big RPM, there's no advantage anyway. The secret is getting them in at the proper installed height/seat pressure.

Quaid24

Hey guys, I have really enjoyed reading your post. I hadn't visited OSO in a while, but w/ the season approaching I figured I get back in the game.

Here's my experience w/ 575's: I have a pair in my 35' Lightening w/ Super Chiller's & aluminum Merlin’s. 1st of all I was new to blower motors, so I can tell you to go thru the blowers every 150hrs. Positively no more than 200 hrs unless you want to ruin one like I did! Secondly, watch the head gaskets. This is all stuff you have covered but I ruined a motor at 281 hrs because of a gasket failure.

Here's my question for you: Now that I have added the Super Chiller's, when the motor is cold and I am idling out of my marina (this takes 4-5 minutes), both motors load up real bad. I'm assuming this has to do with fuel puddle'ing on the top of the intake. When I go to take off I get BLACK smoke out of the exhaust and it takes a second to clean up. I have to change spark plugs with every oil change now (25 hrs).

I’m thinking the Whipple’s might have been a better choice. I didn’t want to flip the coin for them but considering it is a fully integrated intercooler and intake, it might flow smoother, instead of just dropping the fuel on top of the intake.

Any thoughts/suggestions??

ciaoderhead

Quaid,

2-things come to mind. Did you have the ECM remapped? Whipple leans out the mixture. From what I have read Merc programmed them on the rich side to be conservative.

Are you pumping water through the chillers at idle or do they pick up the water under way through pickups? If you pump water through the chillers it will cool the intake too much at idle and run rich.

Good luck and let us know what you find out.

Woody

Quaid24

Woody,

My ECM's are not reprogrammed but yes, I did use pick ups.

So Merc has the motors fat at idle? I could see them being fat at WOT but why would they make it fat at idle? Before I added the Super Chiller's it never, ever did anything like this before. I would change my plugs once a season (100 hrs).

Should I also swap to an MSD ignition system as well?

Who should I use to reprogram the ECM's? Teague sold me all of my parts and never mentioned reprogramming the ECM's.

ciaoderhead

Good question. Not sure if it's only and WOT or throughout. ASM, (Arizona Speed and Marine) would be a good one to ask. What does Teague say?

Quaid24

I haven't mentioned it to Teague yet. It's something I just dealt with last summer and kinda forgot about it over the winter. I'll give him a call today.