8 petal Polaris reed intakes

ja-moo · Post by **ja-moo** » Mon Jun 29, 2009 11:10 am

Suzukidave wrote:John , if someone were to send you a GT750 block would you care to take a look at it to see what input you might have or you could come up with to improve its performance ?

Hey Dave, I actually tried to get a 750 block for years, to look at. I wanted to see if I could do a reed valve conversion on them.

I'm no "super tuner", but I would like to see one "live"......

Suzukidave · Post by **Suzukidave** » Mon Jun 29, 2009 11:22 am

tz375 · Post by **tz375** » Mon Jun 29, 2009 12:55 pm

Dave,

When I get some time and a new monitor, I'll check out the large versus small reed block and see what MOTA tells us.

JA-Moo,
I think that all depends on blowdown timing and exhaust effects. I'll try to get back to the PC with all my simulation software and check out the pressure waves in the transfers. I'll get back to you on that.

I also started to measure transfer port areas at teh crankcase and those GT750 ports are larger than they look and with a slight tweak my be better than straitening the block. A bigger problem between left and center is the lack of space which leads to very skinny ports without sufficient curvature.

So I may have to work out a better exhaust configuration within the twisted block.

ja-moo · Post by **ja-moo** » Mon Jun 29, 2009 2:12 pm

I just wrote a huge reed valve response to the "bigger is better" train of thought. But it got "lost".

So you guys got lucky you didn't have to read a bunch of my babble.....

So the condensed version.......

Here is a pic of 4 reed blocks. Most would think the 16 petal is a huge improvment over my Stage 2, because of the size.

One thing that needs to be looked at is there are 2 equally important parts you have to look at, area and flow velocity. It basically breaks down into compromising one for the other. With a "V" block set-up you get great area at the expense of velocity.

Air/air fuel does not like any obstructions. Even with a 4 petal setup, the sides are closed off, and there are 3 sealing bars right in the flow path. (with the Radd valve you have 14 sealing bars in the path)

It's a "stretch", but I describe this as liken to a wire airaiter (SP) in a faucet. The have basically the same area, but the velocity is greatly reduced by the turbulance caused by the wire obstructions.

So the reduced velocity requires more area.

With my set-up, the area is compromised, but, when the reeds are open there is absolutely no restriction to the mixture flow.

How well does it work?, How about 83 rwhp (approx 95-97 at the crank) from a stage 2 500 Kaw triple. With enough torque to do a 4th gear start!

http://www.youtube.com/watch?v=Ns5bwbGcsZE

The point is, "bigger" is not always better.....

ja-moo · Post by **ja-moo** » Mon Jun 29, 2009 2:14 pm

tz375 wrote:Dave,

When I get some time and a new monitor, I'll check out the large versus small reed block and see what MOTA tells us.

JA-Moo,
I think that all depends on blowdown timing and exhaust effects. I'll try to get back to the PC with all my simulation software and check out the pressure waves in the transfers. I'll get back to you on that.

That info came straight from "Wobbly".........

tz375 · Post by **tz375** » Mon Jun 29, 2009 2:29 pm

Err, who is "wobbly"?

ja-moo · Post by **ja-moo** » Mon Jun 29, 2009 2:42 pm

tz375 wrote:Err, who is "wobbly"?

Probably one of the top 10 2 stroke tuners in the world.....

http://www.twostrokeshop.com/

ja-moo · Post by **ja-moo** » Mon Jun 29, 2009 3:53 pm

Hay Sukidave, do you have the large version of your Avatar up somewhere?

Suzukidave · Post by **Suzukidave** » Mon Jun 29, 2009 4:09 pm

I made the avatar from this article http://draken.gotdns.com/Suzukidave/tr750/

ja-moo · Post by **ja-moo** » Mon Jun 29, 2009 4:51 pm

Thanks Dave, got some readin to do.......