Biochem

If I lower the psi to 3psi, it still runs rich, but will go progressively leaner if I stomp on the gas as the rpms rise. But then it will go rich again (according to the A/F gauge) when it shifts or I let off again. Lowering my float level doesn't (so far) seem to have an effect on it either...

How can I lean it out?

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

Jester

If it's rich down low but leans out as rpm's rise, that means your primary side is too rich, and your secondaries are too lean.

Rejet both accordingly.


For the 30 gagilionth time...lowering the the FP will NOT change the A/F unless you were flooding it out before

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"American made baby. 100% American iron. The muscle among the masses. My hero. Yep, you can take your ergonomically designed, space age, computer controlled, 4 door, cup holding map lighted split double wishbone split fold down retractable cargo covered moon roof piece of transportation and keep it. For I have felt the thunder. And I know the difference!"
JSP Motorsports
ICON Motorsports

Biochem

Well Jester, I think I was flooding it out before at 6-7psi... I think maybe 4-5 is about right. I have gone down in jet size from 72 now to 68s... I have 66s in my tool box. I have plans on switching to a secondary metering block too...

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

Apeiron

Did you try setting the float level at 6-7 psi?

82camaro

Too bad everybody didn't learn about carbs before fuel injection came along, being able to lean/richen the mix using fuel pressure. As long as you get enough fuel to keep the fuel bowls from getting empty and the needle and seat can handle what ever pressure you may have, fuel pressure won't make any difference. Not trying to flame anybody, I've just seen alot of posts since I've been on this board about trying to richen/lean a carb using fuel pressure. I'm done venting now.

It should go rich when it shifts or you let off the throttle, the fuel doesn't stop flowing immediately when the engine needs less fuel. The carb takes a little bit to react to the change in fuel requirements.




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350 with stealth intake, holley carb, 470 lift cam. 700r4 with .5 boost valve, vette servo, tci lock-up kit, B&M megashifter. Richmond 3.73 gears, powertrax locker, timkin bearings, synthetic lube. Custom 3 inch single into 2 2.5 pipes. 1 1/2 drop springs, 1 5/16 solid front sway bar, 1 inch rear bar, custom subframe connectors, custom LCA relocation brackets. Kobel ground FX, currant red metallic paint. Lots of other stuff...
82camaro

Biochem

No flame taken...

It does go lean as I floor it when the psi is only at 3psi... due to an empty bowl I'll bet. I'm going to try lowering the float level quite a bit next time to see how that does... then raise it until it's normal (if it works). If not, then I'll go in and install the #66 jets and see if that does anything. It's not rich at part throttle or cruise only... but typically all throughout the rpms.

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

five7kid

iTrader: (14)

The proper way to tune a Holley is with the float levels set so the fuel is at the bottom of or just dribbles out of the site plug holes. Don't bother trying to change the mixture by changing the float level. Set it and jet it. You may also need to change the power valve.

Get the secondary metering block ASAP. Get a full set of jets while you're at it (66's-99's IIRC for about $35).

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 2.93 limited slip. 2-1/2" cat-back, ZZ3 intake, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 CC system w/'87 LB9 block, ZZ3 cam, ported World 305 heads, Hooker 2055 headers, 3" Catco cat & 3" catback, restalled TC, Spohn SFCs).
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