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Question for H/C A4s with vacuum modulation?

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Old Jul 19, 2005 | 08:24 PM
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1ORANGEWS6's Avatar
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Default Question for H/C A4s with vacuum modulation?

Will a cam affect your vaccum modulation set up? I have a vaccum modulated tranny and my tranny doesn't seem to shift the same after the H/C install. Also What size vaccum line should I use, the one that came with my kit is a clear plastic line with a spring in it and I don't like it.
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Old Jul 19, 2005 | 11:47 PM
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Should shift later and harder if vacuum is depressed by
the cam. Used to be you'd see short runs of vacuum
hose and the main run from manifold to biscuit was
bent hard line. Cut the flare ends off brake line, or
get something close from an aftermarket stainless
tubing place (I see them in the back of some mags
but forget the names).
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Old Jul 19, 2005 | 11:53 PM
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I've noticed h/c low vaccume at idle will make a vaccume modulated trans engage reverse and drive a lot harder, also shifting while coasting will be harsh.
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Old Jul 20, 2005 | 06:59 AM
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Would a vacuum canister or some sort of booster work to help this problem?
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Old Jul 20, 2005 | 09:13 AM
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Originally Posted by 1ORANGEWS6
Would a vacuum canister or some sort of booster work to help this problem?
If it does, it'll do it by obscuring the true vacuum level,
which is probably not a good thing. Is the modulator at
all adjustable?

If it's shifting too harshly at low pedal you must need
a bigger converter
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Old Jul 21, 2005 | 07:00 AM
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If you are using the Trans-Go Performance Shift kit along with the modulator, then make sure you not using any spacers in the 2nd gear accumulator, this will make part throttle shifts even firmer that it needs to be. I do not add any spacers to the vast majority of my performance build ups, not necessary.
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Old Jul 21, 2005 | 08:06 AM
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Not to sound stupid but I don't know the inter workings of the tranny. Is the 2nd gear accumulator in the shift kit? Is it something that I can get to without messing anything up in the process? The car shifted pretty hard before the H/C install. Dana will the cam mess with the modulator?
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