Nauti By Nature

do you think XR sport master -2 's would give same type results?

Marginmn

iTrader: (1)

I haven't tried -2 sportmasters but I would sure like to. I have talked to some race teams about the -2 sportmasters, and they say that while they are not as fast in a straight line as the -2 imco's, overall their boat handles better with them on, especially in the turns. The longer skeg on sportmasters has more bite in the water so it gives you better control, but at the cost of a little speed.

I was running standard length sportmasters, and I have no doubt that -2's sportmasters would have run faster - just not quite as fast as the imco's.
If you are running XR's and thinking about switching to -2 sportmasters, how much they help you will depend on how fast you are running. They are more hydrodynamic than the XR's but you won't see that benefit kick in unless your boat is running over 90 mph.

If anyone has an extra set they would like to get rid of I'd be interested in them. I have a set of standard length sportmasters as well if anyone is interested in them.

Ran-Dom 32

I tested a set of the -2 Sportmaster Lowers and seen 4-5 mph gain. I hoping to see a bit more using the imco or bravo shop lowers. My X Dim on my '99 is 16 3/4 which is basically 2" lower than the newer 35 X 's out there.

RaggedEdge

This has admittedly been beaten to death, but is scattered all over this site. Personally I have thought of starting a thread to attempt to gather all the info on this "Shortie" topic into a single thread. I think we all could benefit .

I have a 99 35 Lightning, stock 500 carb's, complete rebuilds last summer after being bitten by the Crane valve spring bug, runs 82-83 mph with stock 26 4b Hydros or 28 Lab Bravos. I am seriously interested in getting some more performance/speed from this package, but resisted the temptation to tweak the engines during rebuild because last ride was a drive crushing nightmare. Ran upper 90's but ate Bravos on a way to often regular basis.

Sooooo Here's the deal !!!!! We are all looking to improve the performance of our boats. We all know that a standard Bravo drive has it's limits. We all know more power means more speed, but also means more stress on that drive which leads to it's failure and big dollars to fix something that will simply fail again.

Sooooo Let's share what we know. Straight foreward info, real experiences, what your buddy saw for results with "Shorties", and see if we can gather all this info into one thread. Then we can make intelligent decisions, spend our money wisely, and all end up running faster!!!!!

Here's what I know:
Two close friends both running late 90's single step 35 Fountains gained 6 MPH by changing to -2" Imco lower's. Both these boats were in the high 90's and are now over 100 MPH. One, MV35 was at 104 after the change to the -2" Imco lowers, no other changes, a 6 MPH gain from the standard length Bravo lowers. Then cut the difuser off the Maximus 5 blades he was running and ran 109.9.

Newer 35 Executioners run an "X" dimension that is 2" higher than Fountain used in the late 90's. These boats with 496 Mag HO's will run close to 80 MPH. I have run next to several and have been more than impressed with the way this set up runs. These two hulls, my 99 Lightning and the new Executioners, are the same and therefore the plain and simple fact is that the higher "X" makes up for a lot of the horsepower difference.

The current owner of my last boat changed to Imco's, same "X" and gained 5-6 MPH. No doubt just the more hydrodynamic design of the lower. Also claims the boat is more stable at speed than before.

Sooooo Let's get this going!!!! Shorties vs Regular. Imco's vs Merc Sportmasters. Speed vs Handling. Real info. Real experiences. In the end we all stand to gain.

BTW Robert, no prob with valve spring deal, I love the boat. Just one of these Hi Po deals.

Marginmn

iTrader: (1)

Great Post Ragged Edge.

To bring you up to date on my project, I had put a set of 525's in a 2000 38 Fountain Fever (I bought it with no power or drives). The boat came with the factory X dimension of around 16 1/2 . When the riggers installed the 525's last summer I had them raise it an inch to around 17 1/2.

The boat ran 81's tops running standard length Sportmaster lowers and 30 bravo one's. At the end of the season I finally put on a set of -2 polished Imco shorties and 32 bravo ones and on my first trip out with no chop the boat ran 86+ and was solid as a rock. I had high water pressure issues though.

During the off-season I was kicking around the idea of putting blowers on my 525's but thought better of it because of reliability fears with both the engines and the XR drives. I then ran into a good deal on a set of new takeout 625 Ilmors and decided to put them in the boat.

At the request of Ilmor the boat is being rigged at a racing shop outside of Cleveland. Today the riggers sat one of the Ilmors down in the boat and the drive shaft is off by about an inch, so they are going to have to rise my drives up by 1 to 1 1/2" in order to get things to line up. Because of that, and due to the fact the Ilmors are going to weigh around 600+ lbs lighter than my 525s, they were going to have to install spacers in my drives to get them back down to where they were with the 525's. So I thought about that for a while and after talking to a few people I have decided to put a set of Imco Stand off Boxes on the back end. This will have the effect of lowering the drives the required 1 1/2 lower in the water, adding some of the weight to the back end, and as an added benefit, the Imco boxes have a soft coupler that (say the experts) cushions the connection between the drives and the engines. I have been told by those who have tried it that it really prolongs the life of the drives in higher HP applications. I don't expect to gain any speed from the boxes, but some have said that their boats seem to take the rough water better after installing boxes. Since you have to pull the engines in order to install them, I figure now is the time to do it. Also, I have been told that installing spacers can reduce the life of drives. So doing something that increases drive life seems like the better move to me. Plus they look cool

I don't know about 38's, but the few 35's that Fountain put out with extension boxes ran around 85 with 500's - about 4 - 5 mph faster than their counterparts without them.

I'll let you know how they work out.

P.S. I"ll have a nice set of 525 efi's going up for sale as soon as the Ilmors are a go in the boat. Let me know if anyone is interested. One has just 38ish hours on it, and the other around 90 with fresh valve springs put in before it went into the Fountain - so just 38 hrs with the new springs. I'm looking to get around $33,500 for the pair.

RaggedEdge

Back to the top!

jryan26

What are your X-diminsions? The X on my 35 is 16 3/8 per the performance report. What is the X on the new executioners? What props are they running to hit 80? I have 14.5x28 4 blades. Hp500s 84.5 radar on the report.

RaggedEdge

Hey Marginmn/Robert -

I followed the deal on your boat and BYW I like that paint job! ;0. Want a pair of fresh 500's in trade on those 525's?? LOL!! I'll give you a call on the phone some day. We should BS and catch up.

I'm really hoping that we can get all of this shortie information gathered up where we call all maybe learn something from this.

Say hi to the Mrs. from the both of us.

Peter

Marginmn

iTrader: (1)

I talked to the factory today and they said the new 35's and 38's are running as much as 19 to 19 1/2.

jryan26

Damn. Do they make a -3 shorty??!