Holley TB secondary linkage change. Affect tune

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Holley TB secondary linkage change. Affect tune

Postby Mr DOHC » Mon Nov 28, 2022 8:18 pm

Tuning question. I’m running a Holley 4150 throttle body on a dual plane manifold, and it came with the progressive linkages installed. The car is tuned, if I move to the 1:1 linkage, will that require a tune change?

I don’t think it will because, for example, in the VE map it’ll move from 1600rpm and 60VE to say 1600 and 80, because the increased air will just move it up the VE map won’t it.
And that area is tuned so no issue?

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Re: Holley TB secondary linkage change. Affect tune

Postby immortality » Mon Nov 28, 2022 9:00 pm

Will probably make the throttle very touchy and a pain to drive.

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Re: Holley TB secondary linkage change. Affect tune

Postby Mr DOHC » Mon Nov 28, 2022 9:10 pm

Yeah the kit gives you all 3 options.
The TBs come with progressive, then you can buy super progressive and 1:1

I can try all 3 and see what I like best

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Re: Holley TB secondary linkage change. Affect tune

Postby VK_3800 » Tue Nov 29, 2022 3:50 am

If you're referring to what Holley calls a progressive linkage, I think that just delays opening the secondaries?

Mine has that and I've still been chasing more progression on the primary opening (before the secondary even starts) to reduce the touchy throttle, hate to think how it would behave if all four opened at the same time.
Image

The tune can be affected as the TPS reading is linear but obviously you're changing the actual rate of opening area. Generally not too big a deal though.

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Re: Holley TB secondary linkage change. Affect tune

Postby vlad01 » Tue Nov 29, 2022 1:38 pm

VE and all that won't be affected but depending if it's bad enough, you may have to adjust the AE multiplier table to account for the initial air in rush lean out/burst knock. Larger throttles/more linear needs more AE typically. Even if you get a lean spike on the WB, if it doesn't stumble or have burst knock then you can leave it as is, if it does, then increase the AE for the corresponding RPM range.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.

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Re: Holley TB secondary linkage change. Affect tune

Postby Mr DOHC » Fri Dec 23, 2022 10:02 am

quick update. the 1:1 was not good for my engine. way too much air too early. probably slowed down the air flow.
super progressive was no better or worse, just pointless.

Tune seemed to be unaffected.

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