Grose jets / float level

I just got my rebuilt carb back from Yaw, and I want to install Grose jets. Does any one know if I should set the float level the same as with the standard carb jets...ie: just a bit below half way in the window...???

FYI, I understand you don't want to use gross jets for mazda rotary engines. I have heard this several times from people more knowlegable than me. The guy that built my carb (in 1996) and its never been rebuilt and I've only changed jets twice said don't use gross jets. I've never had any type of carb problem (that's the kiss of death). http://Forums.ImprovedTouring.com/it/eek.gif

Just my .02. Maybe others have a different point of view. http://Forums.ImprovedTouring.com/it/smile.gif

Not to be a smart arse, but shouldn't you be asking Paul Yaw about this? He says on his website to call him about tuning questions once you've purchased a carb from him. I'd go directly to the source.

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Scott
It's not what you build... it's how you build it
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PFM Racing

Hey guys,

Thanks so far.

As to the first point, I used Grose jets all last season, and found they help with fuel starvation in corners...just that I didn't set it up myself last year.

As to the second point, I have already tried to contact Paul, but he is so busy, he doesn't get around to his e-mail often, and rarely if ever answers the phone. I think he is actually out of town.

I also bought grose jets a couple of seasons ago thinking I needed them to fix what I thought was fuel starvation problems in corners. Found out what I thought was Fuel Starvation was actually too high fuel pressure setting on the Regulator. The Grose jets are still in my tool box.

My 2 cents.

FWIW - Amen, to the fuel pressure question. If you go to mazspeed.com there is a wealth of knowledge re: Yaw carbs, fuel pressure, gross jets, etc. My understanding is with a Yaw carb you need to be between 2 and 2.5 lbs pressure. Also, I understand that Paul Yaw has a special fuel pressure guage that i accurate at those low pressures. I do know if you have too much fuel pressure you will have problems.

Drive well.

Yaw is very much against Grose Jets. In fact, the carb that I sent him had them already installed. He said to throw them away.

I have just spoken with Paul, and you guys seem to be on the right track. I'm going to go back to the stock needles, but have the grose jets set up with a seperate set of floats,as spares, and see what happens on the track. If I have fuel problems, I can switch to the Grose jets in a few minutes.

I have grose jets.........

Want 'em???

Every so often (like when I pull up to tech) the ignition gets left on, but the car isn't running, and someone says, "Whats that puddle under your engine?" To which I reply, "Just some gas....anyone got a hammer??" (just kidding on the hammer part!)

My problem is that they just don't seat effectively. And this is with the low pressure high volume pump as recomended by everybody.



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Jake Gulick
ITA 57 RX-7

your problem may be the one I had in cornering that turned out to be the stock plastic back flow valve in the fuel line, some call it a rollover valve but whatever you do take it out and throw it away.
after removing it my fuel starvation problems went away.

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Daryl Brightwell
ITA Mazda #77
SFR, NORPAC
CSCC, SOPAC

Ok..I'll go to the opposite end of the spectrum....My engine builder (Stan, SDJ) swears by 'em.

I ran a set at Road Atlanta (wrong size) the March 31st Pro-IT and was running a little lean but I never really had a problem with the jets (other then the wrong size). I swapped them out to pump more fuel in but will probably get the chance to run them again (density altitude permitting). When I do I'll drop you a note back on them.

Best regards...

Frank
#67 IT-7
www.balz.myip.org

So what's with Paul Yaw? I have heard all kinds of good things about him and his carbs, and his website is great with lots of info, but I need a carb and have been sending him e-mails all week and haven't gotten any response. The bad part is I really need to get the car running correctly for races on the 27th-28th week-end, and I am running out of time. His website doesn't list a phone number, so I really have no alternative to his e-mail. Any suggestions?

Thanks - Rick

Rick, try Paul at 1-520-670-0110.

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Have Fun

David Dewhurst
CenDiv Milwaukee Region Spec-7 #14

How come all you spec rx7 guys have Paul's phone number? Nevermind.....

Do ya think I could do a 4:88 if it was used appropriately ? http://Forums.ImprovedTouring.com/it/wink.gif