Myron 3 660

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Myron 3 660

Postby Manups14004 » Sun Jun 12, 2016 8:33 am

Is it possible to get in accurate cylinder head temp. I have to keep leaning out to get cylinder temp up and now car has a bog at the hit.
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Re: Myron 3 660

Postby WILD BILL » Sun Jun 12, 2016 8:46 am

Welcome to the POOL. smiley-wave

What numbers are you getting and what are you going after. CHT numbers posted by other memebers should be used as a guide not a rule. EGT's are a better indictaion of how rich or lean the mix is but stil will vary some for every one.

If you had it running good and clean and it was consitent and perdictable I would go back to that jetting and then note what the temps were and use those for your "good temp" numbers.

FWIW, I would let my old 3x3 leave at 130 and it ran flawlessly every time.

More info about what your running would help as well.
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Re: Myron 3 660

Postby Manups14004 » Sun Jun 12, 2016 9:01 am

Egts were around 625 with the 55 piolt, when we went back to the 52 piolt it was like 725 on the starting line. Motor is 3.5 ZR4. Car runs consistent either way just has a hesitation at the hit of the throttle. Mostly just affects reaction time.
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Re: Myron 3 660

Postby WILD BILL » Sun Jun 12, 2016 9:22 am

What were the CHT's with the 55?

Do you have an air bleed in the Pilot side?

Is the air screw cut or is it stock?
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Re: Myron 3 660

Postby Manups14004 » Sun Jun 12, 2016 9:54 am

Mixture screw is cut off. 1.1 air bleed.with 55 in could only get to 128 degrees. And it was 90 degrees outside side.
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Re: Myron 3 660

Postby WILD BILL » Sun Jun 12, 2016 10:33 am

Sounds like a Craws prepped carb. Had the same thing with Kailin's carb.

Get an uncut air screw (blossom has them) and ditch the air bleed. Leave the hole open.You can try staring out with the 55 pilot but I like a little larger so it will really richen it up when I close off the screw. I have a 57 pilot in both of mine.

Once you have the carb set up this way, you can really fine tune your mix and get your head temps where they want to be for the best performance. A little turn of the screw will make a difference you can wath. The CHT doesn't climb immediately but you can tell from the RPM if you went leaner or richer. The RPM will raise when leaned out and fall when richens. (you may need to adjust the idle screw doing this) Also, (at least on mine) I can see and almost immediate change in EGTS even if I turn the screw in so slightly it doesn't affect RPM. Turn the screw out until I see about a 10-20 number rise in EGT's and shortly after that I see the CHT start to come up. Turn it in about the same and then wait for it to fall.

Once you play with it a little you'll start to get the hang of what it takes to control both temps to get it right where the motor wants it.

It's more about where you motor wants to be then what the numbers are. That said, both my motors are ZR 4's One a 3 1/2 the other a 3 3/4. oth seem to have the same happy range. Starts at about 150 and really comes alive the closer it gets to 165. Much above that (say 170-175) and they risk popping at the hit and not running where they should. So I shoot for around 150-155 when they take the pre stage bulb so even if they sit for a minute they won't get much above 160 ish. Also, my girls know this and know the longer they are sitting there the hotter the motor is getting and the chances are they will go faster then anticipated and have to drive it a little more than norm.

Again, these are my numbers so the same may not hold true for you but it should give you an idea of what I'm doing and how I'm doing it. It's up to you to find what works best for you setup and driver. smiley-lol
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Re: Myron 3 660

Postby Manups14004 » Sun Jun 12, 2016 11:09 am

Thank you . I will try that.how far out with mixture screw to start?
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Re: Myron 3 660

Postby WILD BILL » Sun Jun 12, 2016 11:26 am

Try 1 to 1 1/4 turns off the seat.

That should get the motor running untill you can start playing with it.

I stopped trying to keep track of where the screw ends up and just adjust as needed to get my temps where I want them.
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Re: Myron 3 660

Postby Manups14004 » Sun Jun 12, 2016 11:50 am

Thanks
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