looking for more speed

[Steve P]

I have a PT sport20 (one of the first ones) with a CMB RSV7 with a Andy Brown pipe( I think see pic purple pipe) at 8 1/4". At the moment I have a sightly backcut x440 on it (it would not pull it before backcut). By looking at the plug and the amount of fuel I am using I an sure I am on the rich side but the last couple of adjustments leaner did not give me any more speed.

I am sure there is prop work the can be done to get more speed but and other ideas are welcome also. (pipe lenght?) I have resticted water to the head but I can still hold my hand on it when it comes in.

Thanks in advance.

 

[Steve P]

Looks like picture did not attatch.

http://www.intlwaters.com/index.php?showtopic=53017&hl=pipe

I guess I an doing some thing wrong. purple pipe on this topic.

 

[SayMikey]

Steve too much prop x442 or x642

 

[TimothyJones]

I'm sure Phil T can help you he had his 20 running very well.

 

[wayne middlemiss]

push your pipe in to the 8'' mark for more rpm , restrict the water flow a little to get more heat in the engine.

 

[Steve P]

Steve too much prop x442 or x642

Mike X440 is smaller than a X442 right ?

I was thinking less prop too, as it is RPMs are dropping off a little in the conners also. what about an M series prop?

Wayne, I was thinking about shortening the pipe some more but was worried I would just need to go smaller on prop if I do. I was planning to restrict water some more next time I run.

I seem to remember a topic on head temp, were some one was saying that you and get stickers that change color to indicate temp. any one remeber were to get those?

 

[FloridaScaleBoater]

Steve too much prop x442 or x642

Mike X440 is smaller than a X442 right

You are correct, X442 is larger/more pitch than a X440

I would look at a X437 or X537 (same diameter as X437 W/ 10% more pitch)

I was thinking less prop too, as it is RPMs are dropping off a little in the conners also. what about an M series prop?

Less prop, or LONGER on the pipe, or you could be just to the lean side of the needle adjustment.

What pipe are you running? What is your head clearance set at? What fuel, what %?

Wayne, I was thinking about shortening the pipe some more but was worried I would just need to go smaller on prop if I do. I was planning to restrict water some more next time I run.

I seem to remember a topic on head temp, were some one was saying that you and get stickers that change color to indicate temp. any one remeber were to get those?

 

[Steve P]

Rick,

I am not sure about the head clearance. I guess I need to measure it. Kenny set it for me the same as what they were running on Chuckies sport 20 when I bought it from him. He might have told me but I do not remember. I looked back through my PMs and he said they were running a 437/3. I guess I will try that next.

 

[Roxyflash]

It could be the pipe try and find a original Andy Brown nitro 21 pipe

 

[RobertWurster]

put an 3280 pipe on it.my nova 5 p pulls a 442 no prob.

 

[shoboat]

Steve,

M-440 with reduced trailing edge cup and shorten your pipe.

How much Nitro are you running?

Thanks,

Mark

 

[Steve P]

Mark,

60%

Do you have a S/B M440 on hand.

Steve,

M-440 with reduced trailing edge cup and shorten your pipe.

How much Nitro are you running?

Thanks,

Mark

 

[Steve P]

Seem a lot of poeple run this pipe I might have to try it anyone have one?

put an 3280 pipe on it.my nova 5 p pulls a 442 no prob.

 

[RobertWurster]

Search in the manufacture for sell I thinck its on page 2 por the pipe .or got nitro .com http://shop.gotnitroonline.com/searchquick-submit.sc;jsessionid=8F4F090A7C8B287B2332643E6795D569.qscstrfrnt04?keywords=ops