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just saying hi
what size stock prop comes on a 1998 z202. i have a 17p now on a 5.7 250hp it runs about 48 mph good but i want to go faster
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Re: just saying hi
Welcome aboard Todd. Try moving up to a 19" pitch. To get more accurate we need to know your RPM's at WOT as well as your top speed and exactly what prop you have now (make/SS or aluminum/size).
Have a look under our "Prop Talk" threads, particularly this one as it involves a Z200 with a 5.7L. Likely the 19" was the standard prop. I would think that the 17" would have your WOT rpms well over 5000 which isn't good for the engine wear. |
Re: just saying hi
Ahoy and welcome to the forum Todd!
Mikey's right, how much faster will depend on what RPMs you're are running right now at WOT so get back to him with this info and he'll get you that extra speed :wink_thumbup: Just remember, faster top speed normally equals a slower take off and vise-a-versa. WetWilly |
Re: just saying hi
right now WOT is at 4500, 48mph maybe my tack off but it reading 4500 with a 17p prop. i'm going back out sunday hopefully. i just got boat so far we love it? THANKS AGAIN
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Re: just saying hi
Hi Todd, well it looks like you're in the ballpark as far as RPM which is weird considering you're running a 17P prop. I'm with Mikey on this one, I would have though you'd be in the 5K range too.
The book says you should be between 4400 to 4800 RPM so unless your Tach is way off or the speedometer is reading too low, a change in prop pitch isn't going to help you. If you can, check the speed with a GPS to confirm how fast you're really going and see if you can find a hand held Tach like the ones for tuning up your car to verify your RPMs. Another thing, I assume your 5.7 is carbed from the 250hp you stated and if that's the case, then it's just possible that it's near it's limit in HP and torque. If this is true, you're going to have to have to figure how to bump up both the HP and torque to gain that speed your looking for. There are some other things you can do to squeezing out a few extra MPH. Try waxing the lower hull to reduce water friction unless of course you've got bottom paint and check the prop's and outdrive's condition, dings and dents rob speed and try lightening the load, remove any excess weight from your Mariah. Well that's about it for me, WetWilly |
Re: just saying hi
i had a gps on the boat speedo is right on, not sure on the tach. do u thought a 19p prop would do ok? ya the hull is clean & prop looking good, 48mph is fast but i thought i cound get a little more speed.
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Re: just saying hi
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Re: just saying hi
Hi Todd, one possible answer to the pitch mystery is the gear ratio in your outdrive. We tend to forget that not all of us are running the same ratios making a difference in the prop pitch we each can use. The brochure shows speeds of up to 57mph but that may be the high performance 5.7 (350 MPI motor) doing the work and since it pumps out 300hp it can swing a bigger pitch. See if you can verify the tach and we'll go from there. WetWilly Dang, Mikey beat me to the reply :tongue_2:... he's right, see if you can "barrow" another prop and see how it works. |
Re: just saying hi
i well look at the back of the tach, we're putting it in the water tomorrow. thanks again
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Re: just saying hi
where can i find the ratio to the outdrive
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Re: just saying hi
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Drive Unit Gear Ratio Identification All Bravo drive unit gear ratios are identified on each drive in two places: A) The first place to look is on the decal on the port side of the drive housing. It will have a number such as (1.50R) and then the seal number. B) The second place to look will be on the universal joint splined yoke. It will be identified with a letter such as (F). This method is explained in the following chart and is true for new or un-tampered with drive units. A drive unit could have had the gear ratio changed for high altitude, which would void out any application of the following chart. The gear ratio then would have to be determined by counting the teeth on the drive gear and the driven gear in the drive shaft housing and using the following chart for reference. Bravo Three U-JOINT IDENTIFICATION: RATIO U-JOINT SHAFT MARKING 2.43:1 N 2.20:1 K 2.00:1 B 1.81:1 G 1.65:1 C 1.50:1 F 1.36:1 P NUMBER OF TEETH PER GEAR - DRIVE SHAFT HOUSING: RATIO – DRIVE / DRIVEN 2.43:1 - 23 / 30 2.20:1 - 23 / 30 2.00:1 - 27 / 32 1.81:1 – 27 / 29 1.65:1 – 27 / 32 1.50:1 – 27 / 32 1.36:1 – 27 / 29 Here's the info on Alpha outdrives which is similar if not the same method as the Bravo: |
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