vacuum advance
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Bimmer *****
Joined: Jun 2002
Posts: 2,199
Likes: 1
From: Plano, TX
vacuum advance
i don't have it hooked up on my FB... while i know i don't have my timing set exactly right, i got it closer now than i did yesterday, but i still get a little breakup around 6000 rpm... is the vacuum advance necissary? i need to get my motor back to TDC and get the pulley put on right and time it first, but just wondering about this...
Vac advance is only there for 1000-2000 rpms basically. The mechanical advance (AKA centrifugal) takes over after that and is good until 4000 rpms. This is what other people have explained to me and this is apparently why setting the timing at full advance (4K) is necessary.
Joined: May 2002
Posts: 5,972
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From: Ottawa, Soviet Canuckistan
You can disconnect your vac advance while you set timing. (Someone please correct me if I'm wrong).
If you're following the timing instructions in the Heynes or Factory Workshop manual then it assumes you have it.... but if you disable your vac advance and set your timing at a low enough RPM that your centrifugal advance isn't kicking in, you can be sure that you're setting your timing at wherever you want it.
Vac advance isn't necessary, but it helps for things like gas mileage. My car is so bad on gas as it is that I can use any help I can get.
Do you have a rat's nest? I've got mine done directly as per Rx7Carl and Pratch's instructions. Works fine for me. On the flip side, my friend Taylor (WankelingBeer in the Canadian seciton) has no vac advance and his runs fine. Just burns more gas. Cap the vac source at the manifold, leave the vac diaphragms open to air.
Jon
If you're following the timing instructions in the Heynes or Factory Workshop manual then it assumes you have it.... but if you disable your vac advance and set your timing at a low enough RPM that your centrifugal advance isn't kicking in, you can be sure that you're setting your timing at wherever you want it.
Vac advance isn't necessary, but it helps for things like gas mileage. My car is so bad on gas as it is that I can use any help I can get.
Do you have a rat's nest? I've got mine done directly as per Rx7Carl and Pratch's instructions. Works fine for me. On the flip side, my friend Taylor (WankelingBeer in the Canadian seciton) has no vac advance and his runs fine. Just burns more gas. Cap the vac source at the manifold, leave the vac diaphragms open to air.
Jon
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Bimmer *****
Joined: Jun 2002
Posts: 2,199
Likes: 1
From: Plano, TX
i'm running a holley... no rats nest for me... i do notice i'm running stupidly rich tho lol... i'm gonna get a fuel pressure regulator, tho i'm not sure what psi i should run at... if that doesn't fix it i'll go with a jet kit....
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Thread Starter
Bimmer *****
Joined: Jun 2002
Posts: 2,199
Likes: 1
From: Plano, TX
i think i'm beating the fuel pump... but i got it dialed in a little bit better now, idles at 1.5k, doesn't run as rich at idle, and seems to have more constant power... gonna get a new fuel pump friday
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