More Power

[MtSkier]

Hello, I just bought a new SD ProStar 197. I live in Montana and Ski a lake at 6000' elevation. The Boat runs great but is lacking HP at this altitude. Has anyone had any experiance or know of anyone who has done any performance work on the MCX motor?

Any help will be much appreciated..

MtSkier

[G-man]

There is a current post about a boat on Lake Tahoe with the same problem, Search for it if you can. A different prop will be the answer but I don't remember which prop. I would hope your dealer could tell you.

[Andyg]

What year is it? If you want to spend the cash there are a couple of things you can do. Get the new exhaust risers, I think $1400 for a set. Add a set of 1.6 roller rockers. They run about $300, but you do need to make some room in the heads for the extra travel of the pushrods. I wouldn't suggest doing this one unless you have experience with engine overhauling.

[east tx skier]

If it's a new SD 197, he ought to already have the nifty new risers.

[John B]

The lake that I'm on is 6750.
I have a 4 blade 13-13 and I just the right amount of power.
The motor is a LT1. I ski no footing,not sure how it would do for footing. I am missing some of my pony's. My top end is 40 mph.

[Thrall]

I'm w/ John B on this one. I have a 190, LT-1, std 13x13 OJ, and I can tell a difference here in NM, at 5kft, but not much. I've lost 2-3mph on top end and the boat doesn't feel quite as quick out of the hole, but it still does fine. On ACME's site, my 190 gets dropped 1" in pitch for high altitude.
Someone else in another thread has talked about reccomendations to drop his 'slot like 4" in pitch to compensate for altitude. That seems really excessive.

[MtSkier]

Andyg, that is exactly what I'm looking for! Where can I buy the exhaust riser?? What shop do you know of that has experience with tournament boat engine mods? I would like to talk to them. I have done quite a bit of Hot rod work on cars so I know enough to be dangerous.
My boat is a 2004 SD 197, with a MCX 350HP. I will tell you its a long ways from 350HP, I'm going to pull the motor this winter and dyno it. We will see for sure what its making before I start working it over.

"We need more power captain"

[alpace]

Just bought an 06 x30 with 5.7 350 hp. Dog at altitude of 6600 ft. Dealer is sending someone up to reprop...again. original spec at sea level is 13.7*19.5. Tried 13.7 by 17.5 for Tahoe, but was terrible. Tahoe locals say 13.7*15.5 4 blade will do the trick....we'll see. Wont know until next weekend. Will keep you posted.

[MtSkier]

AlPace, Please keep me posted on the prop you end up with. I just orderd a new prop and I'm sure its the wrong one, so I need to send it back to get the right one.

thanks

[Andyg]

Andyg, that is exactly what I'm looking for! Where can I buy the exhaust riser?? What shop do you know of that has experience with tournament boat engine mods? I would like to talk to them. I have done quite a bit of Hot rod work on cars so I know enough to be dangerous.
My boat is a 2004 SD 197, with a MCX 350HP. I will tell you its a long ways from 350HP, I'm going to pull the motor this winter and dyno it. We will see for sure what its making before I start working it over.

"We need more power captain"


I am not positive when they went to the new riser, but I think your boat actually already has it. The new risers look like more like a set of headers would look like for a car. The older style riser is very square while the new one is very rounded.

The only person that I know of that has done the roller rockers is MYMC. I will probably be doing it this winter to my 2003 MCX, along with the new risers.

I would talk to a local race shop and see what they can do. You may want to wait until your warranty is up though. You go into your motor and you can kiss that warranty goodbye. Remember because this is not a closed loop system (no O2 sensor) the amount of work you can do to the motor is limited by the fuel/ignition program currently in the ECM. I don't know that it is possible to reprogram the ECM for the changes you would make, but I am sure it would need to be done on a dyno at the least.

[Workin' 4 Toys]

Your dealer should be able to get you the new risers, I think they can get them in polished stainless or aluminum if I recall correctly. Look at the MC site and at the bottom where it has "add bling to your MC".

Otherwise if your really into mods, how about a paxton?

I have a MCX myself, and I have no complaints about the power, but I am not in your high alt. catagory. However I wouldn't think it would matter much with the EFI, but it apparently does.

[COSkier]

MtSkier,
I'll quit lurking and log in. Maybe this will help. I have a '03 PS197 with an LQ9 here in Colorado. I ski at about 6000' in elevation also. I changed my 13x14 4 blade SS OJ Legend out with a 13x12 ACME (#843). It works awesome. I picked up about 600 rpm at WOT and the holeshot is unbelievable.
My friend runs the same diameter-pitch non-splined ACME prop on his LXi Bu 340 monsoon, it works great also.

[6ballsisall]

MTSkier, what did you decide on doing? Seems like a prop would be the best way to start. You loose 6-8% power for every 1k feet in altitude so you are right, you aren't pulling 350hp. I used to live near COskier until 2 years ago, I was blown away the difference in performance as compared to no altitude. Your 350hp engine is probably in the neighborhood of 275-290hp. You could always bolt up a set of turbos or a supercharger and feed that air pump some more air :D

[JimN]

Workin' 4 Toys- the EFI does a better job of delivering the right amount of fuel, but when there's less air, it has to give it less of that, too. Vicious cycle, I'd say. Or a cruel hoax- "it's beautiful here, but nothing has any power".

Re: the Paxton- the motor would need a different MAP sensor for this(two atmosphere) and a completely different program for the ECM. It definitely could be done(actually some development boats have been tested with blowers), but at what cost?

[6ballsisall]

Workin' 4 Toys- the EFI does a better job of delivering the right amount of fuel, but when there's less air, it has to give it less of that, too. Vicious cycle, I'd say. Or a cruel hoax- "it's beautiful here, but nothing has any power".

Re: the Paxton- the motor would need a different MAP sensor for this(two atmosphere) and a completely different program for the ECM. It definitely could be done(actually some development boats have been tested with blowers), but at what cost?

You said it Jim! There's a fitting saying here:

"Speed costs money, how fast can you afford to go?"

[MtSkier]

Yep, Ive been looking into all of the power adders.
As for the performance difference, its actually 3% per 1k feet in altitude.
What/Who I need to find is a dealer or performance shop that has experience in supercharging one of these systems. I used to work for a dyno company so I know many of the contacts for the manufactures of turbos and superchargers but would love to get as much info from someone who has already done one so I can avoid any and all un forseen pit falls.
I will keep all of you posted on my progress.
I will supercharge this motor this winter!
It should be a fun project.

:cool:

[Lake_Tippy_Skier]

i think that these guys have done a supercharged mc a few years back. they do the engine testing for mc along with r&d

http://www.precisionautomotive.net/

[JimN]

MtSkier- You may want to consider buying a motor to play with instead of voiding the warranty on your original one. Besides, you can always take it out when you sell or trade the boat.

Yes, they have installed blowers and various other sick devices on boat motors, not to mention training MC techs.

[6ballsisall]

MTskier, you might try contacting Jim @ Baws for more info. I seem to remember they had a 197 (used) for sale that was yellow some time back that had the LQ9 and was supercharged. He might be able to give you some insight into how that all worked out.