KAAMA

iTrader: (1)

I really appreciate the responses and willingness to help from you guys----thanks! I'll be leaving for the shop in a couple hours and see if we can do comp test. One of the other things you guys need to keep in mind that I had mentioned earlier is that there is A LOT of BLACK, THICK, SOOTY, RICH exhuast carbon coming from my engine. I had this engine on two different dyno's and one set of headers had larger (2 1/8") primaries tubes on it. I used a Crane Hi6-M ignition box. The second dyno had 1 7/8" primary tubes. Remember, I could be wrong, but I think the exhaust is overscavening the cylinders and pulling raw fuel and I think it's because of too much overlap on the original cam 244*/244* on 112* lobes. It's an Ultradyne cam which usually have aggresive profiles. The advertised duration on this cam is a 296*/296*. BTW, I DO have a Desk Top Dyno and it is close to my actuall and REAL dyno numbers and have been playing with cam specs---more as a reference kind of thing---pretty interesting! The cams I am using now are a Crower hyd roller with a 236*/244* duration @ .050 on 114* lobes and advertised duration of 300*/307*. The guy I spoke to at Crower said that this cam is a "smooth" running cam and is easier going on hydraulic roller lifters. I take it he meant that the ramp speeds on this cam of their's is not as radical as the Ultradyne's. The thing that throws me off is the comparison of the Ultradyne's advertised numbers (296*/296*) compared to the Crower's advertised numbers of 300*/307*----that's that part that I am having a hard time understanding! If the Ultradyne is a more radical/aggresive grind then why are the advertised numbers lower?----ramp speeds??? Jump in, I want to know! And thanks again guys!

WETTE VETTE

The ultradyne starts to open the valve slightly later, but then opens it faster than the Crower. That is the explanation of the Ultradyne being a more radical cam. For more comparisons it is also good to look at dur @ .100 and .200 lift. Below .050 lift there really isn't anything happening and the lift rate is a major key in determining how hard on parts a cam is and how much HP can be made.

KAAMA

iTrader: (1)

We're not able to do a comp test yet today, but we will. Well, the headers, bell housings, couplers and "Drive Savers" are all bolted up to the engines now. We keep having to do little modifications that slow us down. Anyway, the engines are now ready to install and that will happen on Teusday evening. The wire harness/bracket need a few wire mods. We should be making noise by Thursday---I hope!

WETTE VETTE

Maybe you will have it ready for the water in time for the Hardy Party? Hopefully there is a good turn out and not a lot of Barney Fifes.

KAAMA

iTrader: (1)

Oh hey dude, IF everything is running smoothly, I am DEFINATELY going to be at that HOT BOAT weekend up at Hardy Dam for sure! Just don't you worry about it---ol' KAAMA is gonna be there! Just listen for that sweet rumble-----or HOWL of my Stellings-----depends if I'm idling around or on plane. You coming up for it?

Tinkerer

I plan on being there. I plan on pulling the motors out this fall and fixing the leaking tiller arm seals, sand blasting the drives from the transom back and painting them with IMRON, going through the motors to freshen them up and do some more TINKERING. I am planing on installing big hyd. roller cams at the very least . I plan on using a rev kit with the cam since this seams to make the lifters last longer.

KAAMA

iTrader: (1)

Hey Steve, glad to see you'll be there----it was a good time up there last year eh?

Crazyhorse

KAAMA, compression test coming soon? It'll be interesting to see what the numbers are. I'm still thinking I'd like to see SuperV turning around 5300 rpm instead of the higher numbers he can reach right now. Besides, he'd have a higher cruise speed than he has now. It was good to hear that his drive looked like brand new inside. Over the years he's run the boat pretty hard and he's always been able to turn around 5600 with it.

WETTE VETTE

I am planning on going to Hardy and look forward to meeting some OSO dudes and seeing their boats run. I plan on taking it easy on the WETTE VETTE the next couple of weeks so she should still be in one piece and in working order. I think we will have a convoy of 4 or 5 boats from LaPorte. Hopefully my buddy will have his Obsession 234 running strong after some hull repairs. This 23 footer has an 860 HP 540 blower motor and did 99 MPH earlier this year on radar. While he was getting the hull fixed he added a short bravo which I think will really help. We have 1 22 Velocity and a 24' Check coming along that are still stock, but not for long. Which day is better on this weekend? Hopefully the weather is good (75 and dry = heavy HP ). Sounds fun!!!

Nordicflame

iTrader: (4)

Hey Kamma,
I don’t know if this info would be of any help to you but I thought I’d throw it out there anyway. Can’t have too much info I suppose. The first variable is that I run at 4000-6000 feet of altitude and built the motor with that in mind (i.e. smaller cam, oval ports, compression etc..). It is a 540 c.i. with an Ultradyne HR 232/240 114 .600/.600 straight up. The heads are fully ported and polished Edelbrock (Chapman Racing) ovals and my compression is 9.3:1. Fuel management is handled via a Holley MPI system. Boat idles very smooth at 750 rpm.
You would think that this would be a 5000 rpm motor Read on……
These are real on the water GPS results with Bravo 1 props in back to back test:
Boat is a 4800 lb. 28 foot single engine stepped hull with raised X dimension.
At 4250 feet elevation I can turn a 28 4600 and 64.6; I turn a lab 26 5100 and 67.7 and I can turn a stock 24 5500 and 69.8.
At 1250 feet elevation I can turn the 28 5200 and 73.1 and the lab 26 5600 and 74.3 and obviously I didn’t try the 24.
If peak speed is function of peak hp then it seems that even this smaller cam likes the higher rpms. The prop feels very torque loaded with the 28 and then everything seems to free up with rpm. Hydromotive told me that you want to be at least 1250 rpms higher than the peak torque so that you unload the torque on the prop to achieve optimum speed. Seems to be true I suppose.
I’m not sure how, but this must tie into the dyno vs. the “in the boat” comparison somewhere.

Sorry to change the subject but I was just curious about an earlier statement in this thread about turning a Bravo over 5000 being detrimental to its health; from a mechanical view, I would think that you’d much rather spin a Bravo 5500 that isn’t loaded up vs. 5000 under massive amounts of torque load. To a point, gears and bearings are impervious to rpm; throw side load and stress on them and you start having problems.
I will be adding a M3 ProCharger over the winter and I think I still want to turn 5300-5500 for this reason.
Any thoughts on this?
Dave