NoPistons -Mazda Rx7 & Rx8 Rotary Forum

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Srce 05-18-2004 02:47 PM

That thing will be a monster when in a car.

Jeff20B 05-18-2004 03:13 PM

Thanks for the great feedback everyone. https://www.nopistons.com/forums/pub...#>/biggrin.png



It'll rev a tad slower in a car because there was no clutch or pressure plate during the test. You can hear the starter engaging the flywheel which doesn't normally 'ding' with a clutch and p plate (I think). It'll also have to be a lot quieter. It'll still have the distinctive 20B exhaust note of course. I won't rest until it's quiet AND sounds good.



I have a couple ideas to try to get a reliable idle.



For more info about the 20B, Craig's page is currently up. http://cp_www.tripod.com/rotary/pg20.htm

Fd3BOOST 05-18-2004 08:53 PM

I dunno man, engien sounds great, really great actually. Maybe a vac leak. What are you using for iginition? Sounds like its not firing properly. But man does that make me want a 20b.



https://www.nopistons.com/forums/pub...1047683894.gif

Jeff20B 05-18-2004 09:08 PM

I think it's just a bad AF mixture due to a vacuum leak and fuel pooling in the UIM. I've listened to the clips several times and when it revs up, it sounds really good. It just seems to stumble greatly at low RPM and won't idle. It could be a timing problem, maybe. It's probably that big upper manifold that's allowing fuel to pool inside. If that's true, it'll never idle well.



I'm trying to come up with alternatives. The fuel pump and lines are set up for a carb, so I'd rather not rip it all out for FI.



I can think of a radical way to keep fuel from pooling inside the UIM. What if I chopped the LIM and welded the UIM to it rotated 90 degrees so the ports are straight up? I could set a Holley or Edelbrock carb right on it. The secondary 'siamese ports' are roughly the same size as typical carb barrels. The single primary port could be widened to accept the primaries of the carb. The runners would be shorter too.



I don't know if there would be enough hood clearance with this idea.

j9fd3s 05-18-2004 10:25 PM

i like it! it revs like pauls when he took the turbo off.



you're running too much cranking timing. set it to 5btdc. sounds rich down low too, but its hard to tell

j9fd3s 05-18-2004 10:28 PM

ok i just heard #2 i gotta uncork mine! yours sounds so mean!

ColinRX7 05-18-2004 10:38 PM

Sounds badass. I love the 20B sound. NICE WORK! https://www.nopistons.com/forums/pub...#>/biggrin.png

Jeff20B 05-19-2004 02:43 AM

Thanks guys. I'll change the timing a little and try again after I've figured out a better intake system.



I think I set the timing to TDC static as best as I could with the remarked FC pulley. Which direction should I go? A little less advance?



I'm not too worried about the slow starter. It was pulled from a parts car. I have two others within easy reach to try next time.

Jeff20B 05-19-2004 02:58 AM

Oh, ok. I'll mod the intake some more and advance the timing a little.

Srce 05-19-2004 03:14 AM

Is the plan still to get this thing into an FC, or has that plan changed?



BTW, how long have you been at this project and was the engine ever in a car or have you just begun to build it?


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