Proform 850 dialing it in closer

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It’s good grabbing a few carb tuning tidbits/nuggets on this thread gleaned from other forums.:thumbsup:

This was one of those nuggets for me:
Halfway measures don't work in a situation like this. When there is too much air introduced, its no longer an 'emulsion'. It doesn't act like a lower density liquid, it acts like a fluid with big air pockets and randomly spurts out fuel in different amounts and densities. And how does it flow - laminar or turbulent? Its a mess.
Way back in the beginning Tuner quotes Klaus about "two phase" liquids. The emulsion has to be a mix of fuel with tiny air bubbles for it to act as a lower density liquid.
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I have a new carb I put together a few years ago, but have yet to try it on anything.
I may mess with the emulsion a bit before running it.

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I agree PRH. I’ve learned a bunch from this thread and the links Mattax has posted. Thanks to all. Keep at it.
 
factory installed
f
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crude measuring tool to show fuel level.
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Had a hard time moving that factory plug to the bottom hole. but i did and added one more.
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Sweet! I have to tap the rest of my emulsion holes. Also doing the carb body so I can put in transfer slot restricters, going to go from .094 to .081 to see if I can lean out cruise.
 
I need to go take it out for a quick 2nt gear full stomp.............not sure i dare.........will see how i feel tomorrow.
If it was licences and had muffler on it. It would be a hole lot easier.......

Sure is nice to have a garage with some elbow room around the car.

Last race of the season this week end.
 
Cudafever said:
I need to go take it out for a quick 2nt gear full stomp.............not sure i dare.........will see how i feel tomorrow.
If it was licences and had muffler on it. It would be a hole lot easier.......

Sure is nice to have a garage with some elbow room around the car.

Last race of the season this week end.
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You’re going to make us wait till tomorrow for results? Come on man!!!
:lol:
 
Swap plates with your truck and run it, aren’t you in the middle of nowhere?
 
well 2nt gear stomp into 3d didn't quit spinning until 3d
saw tooth is still there..........but seam like a flatter air fuel ratio????????????????
091521 plug 2 and 4 hole in fuel well on front and rear carb.JPG
 
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I like the way it was flatter in High Gear.
Had to go make this stomp to see if it was going to lean out enough that i need to jet it back up............Don't think so..........
will have to wait until the race this weekend to know of sure.
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Bringing jets and air bleed kit just in case.
It sounded clean and smooth.........but i didn't hit 6000 rpm in either gear.
 
Cudafever said:
I like the way it was flatter in High Gear.
Had to go make this stomp to see if it was going to lean out enough that i need to jet it back up............Don't think so..........
will have to wait until the race this weekend to know of sure.
View attachment 1715791250

Bringing jets and air bleed kit just in case.
It sounded clean and smooth.........but i didn't hit 6000 rpm in either gear.
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I agree. AFR now looks to be staying flatter under increasing load.
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Change both metering blocks or just primary?
 
Now that it is flatter and staying in the 12-1 area, were before it was from high 13-8 to 11s. It made it hard to decide if i needed more or less fuel.
thinking of adding 2 jet size all the way around. To get it in the 11-1 ratio.
 
The curve looks like it’s “trending” lean to me through the run. That says to me that jetting is close and maybe an air bleed change to flatten it a little. Do you really want to be down in the 11:1 afr range? It’ll likely make best power up at 12.5:1 or so.
 
But is that AFR reflecting coming off pump shot and idle circuits?
Is the load, or lack of, while spinning tires affecting the combustion? yes. Is that in turn effecting the leftover oxygen or felecting an actual change in AFR?
That's hard to know about the early part of the first gear.

IDK. Guess I'd go 1 jet size all the way around, or maybe two jet sizes if just doing one end.
I mean there's nothing to suggest the overall mixture is far off is there?
 
To add to this. First gear was light throttle, enough to get it out on the road. 2nt was full throttle but spinning. 3d gear was hooked and loaded. But caught up to the car in front of me and had to lift.
 
I can’t remember, have you tried disconnecting the secondaries and dialing in on just the primaries?
 
Thanks. That was quite a while ago and you’ve made a decent amount of changes since. Have you thought about trying it again?

I’m probably going to do it this weekend after I get the T-slot restricters out in, unless I see a big change in the right direction on the maiden voyage.
 
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