Turning Point Mach 4 SS propeller

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Turning Point Mach 4 SS propeller

Postby black4vcobra » Fri May 11, 2018 8:19 am

Just wanted to give everyone a heads up that I got my boat out on the water (97 2100 LSR w/5.7) with a 21p, 4 blade, stainless Turning Point propeller. The difference between that prop and the 3 blade, 23p aluminum prop is night and day. The holeshot is better and I gained 6 mph on the top end. I guess that shows how much aluminum deflects under load. Anyway, I highly recommend the Turning Point 4 blade props but make sure to choose the right one for your application.

Amazon link for the prop but bear in mind the title is wrong, it is in fact right rotation prop and that can be easily verified through Turning Point -

https://www.amazon.com/gp/product/B00TU ... UTF8&psc=1
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Re: Turning Point Mach 4 SS propeller

Postby gofast24 » Fri May 11, 2018 10:33 am

Main question is what was the engines WOT RPM with original aluminum prop vs new SS prop? You may have been over propped with the 23P aluminum 3 blade and now with the 21" P 4 blade you may have gained a few hundred RPM on the engine increasing the HP at the higher RPM. No, aluminum normally doesn't bend on on any propeller unless you hit something? Can you imagine a aluminum part continually flexing it would break in a few thousand cycles.
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2001 Regal 4160
Twin VP 8.1GSiI V Drive Inboards
Lake Lanier, GA
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Re: Turning Point Mach 4 SS propeller

Postby black4vcobra » Mon May 14, 2018 8:34 am

gofast24 wrote:Main question is what was the engines WOT RPM with original aluminum prop vs new SS prop? You may have been over propped with the 23P aluminum 3 blade and now with the 21" P 4 blade you may have gained a few hundred RPM on the engine increasing the HP at the higher RPM. No, aluminum normally doesn't bend on on any propeller unless you hit something? Can you imagine a aluminum part continually flexing it would break in a few thousand cycles.


With the 23p aluminum the tach read 4800 rpm at the boats top speed. Now, I saw about 4500-4600 rpm with the 21p 4 blade prop. The rpm range for the 2 barrel 5.7 is 4200-4600.

So a few hundred less rpm and I gained 6 mph so it's pretty clear that the SS prop is a much better prop than the aluminum.

Some people do feel that aluminum deflects under load, I guess you can't really see it happening in the water though!

http://petersmarine.blogspot.com/2009/0 ... minum.html
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Re: Turning Point Mach 4 SS propeller

Postby gofast24 » Mon May 14, 2018 10:56 am

The new SS prop may be "cupped" which will increase its efficiency and you are still in the manufactures recommended RPM band width so HP most likely the approximately same from 4800 to the 4500/4600 you are currently running at. Guess you should be happy the new SS prop is better than the old aluminum 3 blade! Also, the 4 blade shoud give you better hole shots than a 3 blade non cupped aluminum prop.
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2001 Regal 4160
Twin VP 8.1GSiI V Drive Inboards
Lake Lanier, GA
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