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-   -   Modifing Stock Rotors---high Compression (https://www.rx7club.com/rotary-car-performance-77/modifing-stock-rotors-high-compression-563146/)

rx7vadim 07-27-06 03:19 PM

Modifing Stock Rotors---high Compression
 
I Think This Idea Will Work.. Rotors Are Made Of Iron Stell I Believe. Why Not Take 1/8 In Plates And Weld Them In To Rotor Grove.

It Will Make Them Slight Heavier But Hp Gain Will Be Much Greater..

Im Sure It Will Be Possible To Get 13:1 Ratio, Thats Close To 30-40 Hp Gain..

jgrewe 07-27-06 03:33 PM

I've always wondered about something like that. But the increase in power you project is a little optimistic. On a piston engine you get 3-4% increase for every point increase in compression(just an old rule of thumb don't ask for dyno sheets) If it worked it would probably be in the 12-15hp range. If you are fighting for every HP fitting in a rule structure it would be worth a try.

rx7vadim 07-27-06 04:24 PM

4% Is 6 Hp,, Then 4 Point Increase 9.4:1 To 13.4:1 =24hp

Hades12 07-27-06 09:42 PM

this has been discussed before, but it may have been on the other forum.

samperry007 07-28-06 11:26 AM


Originally Posted by Hades12
this has been discussed before, but it may have been on the other forum.

I would like to read up on this. On what forum was it, if you remember?

rotarygod 07-28-06 11:47 AM


Originally Posted by rx7vadim
4% Is 6 Hp,, Then 4 Point Increase 9.4:1 To 13.4:1 =24hp

There is a chart floating around the internet somewhere that shows where Mazda ran tests on different compression ratios and found that the power difference between 9:1 and 11:1 is almost identical but it falls off below and above that point. Of course that was on gasoline too and not other fuels. The problem being the sahpe of the dish in the rotor face not having enough room for air to get through efficiently enough. Remember on piston engines air doesn't move around the engine and doesn't have to worry about this happening. For the most part it stays in one place. I remember a conversation I had with Eamon Hurley several years back about raising compression. He said he tried it by welding up the faces and then milling them back to where he wanted them. He said he didn't find any more power arfter about 10:1 compression. The only functional way to increase the dynamic compression ratio (what actucally does the work) is to use forced induction. The static compression ratio is going to be limited to around 10:1 or so max.

drago86 07-28-06 02:18 PM

Yes above 11:1 compression ratio and the trochoid begins to split the comustion chamber in two leading to a horrible burn.

GoodfellaFD3S 07-28-06 09:25 PM


Originally Posted by samperry007
I would like to read up on this. On what forum was it, if you remember?

He's probably talking about www.nopistons.com


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