What's the difference?
What does a billet top cap do? How about water pick-up standard or low?
thanks
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What's the difference?
What does a billet top cap do? How about water pick-up standard or low?
thanks
TheGreyGoose:
What's the difference?
What does a billet top cap do? How about water pick-up standard or low?
thanks Grey,
I had 1.36 gears on my Eliminator 300 Eagle, but it depends on your application. Those gears were a tad steep for my application, but the dealer bought it that way in case the purchaser wanted to put a cool charger, procharger or other blower on the engines.
Horsepower, speed prop pitch, Engine RPM are all factors in the equation. If you plan a high horsepower engine(s), you may want to go with the steeper gears so that you can still prop the boat for the horsepower to keep it within engine RPM limits. I am not sure but I seem to think that the steepest pitch prop available (production) from Mercruy is either 34 or 36". If your engine can turn these props at a higher RPM than your engine should turn, you should use steeper gears.
This link may help you see all of the variables and play with them interactively:
Prop Calculator
As far as the Billet top cap, the top cap is one of the weak points in the drive. But one of many. If you plan to put tons of torque and HP through the drive, you need a fully upgraded drive which would include a reinforced top cap.
The low water pickup relates to the X dimension of the drive. If the drive is set aggressively high, when you trim the drive the water intakes come out of the water. This is not a good thing for the powerplant, hence the introduction of the low water pickup.
If you are able to you, you want to stick with 1.5 gears. It's when you start comming up on 32" of prop pitch that you should look at 1.36 gears.
Some people say that a billet top cap is needed to help control the thrust from the gears. I don't know if that's true or not, but I run a stock one on my drive with no problems.
Only go to the low water pickup if you have a high x-dim. There is proably a merc bulletin out there to help you determine when to use it. If you don't need the low pickup, you really don't want one. If you ever ground the boat the pickup will suck bottom and fill your block, exhaust and coolers. Not fun. There is now a drive out that combines the low water and strut pickup. I've heard that on some applications, the strut can suck air causing cooling problems. That proably only happens on applications that should only have the low water pickup.
My CV23 had a twin turbo set up when I bought it. The previous owner installed an alpha with 1.36 gearing. Had a piston melt down last summer. This summer I ran a slightly modified 350 without the turbos. I dont plan on using the turbos on this boat anymore? Are the 1.36 gears with my current engine a good thing or bad. Is it overkill on reliability of the outdrive or is it killing my performance potential? I am running a 21" prop and only getting around 4500 rpm out of it!
Thanks
Originally posted by dorC
If you are able to you, you want to stick with 1.5 gears. It's when you start comming up on 32" of prop pitch that you should look at 1.36 gears.