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Discussion Starter · #1 ·
Hi friends.
I set up weber dcoe 40 earlier without vacuum port in my gtv 78 2.0
I have 2 distributers.
1. 045 bosch centrifugal +ignitior
2. 018 bosch +module +vacuum advance (alfa75?)
Which one is best?
Did the 018 have mechanical advance in addition to vacuum Advance?
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But Mad North-Northwest
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The 018 has ~28 degrees of mechanical advance and ~15 degrees of vacuum advance (at crank). The spec static advance is 7 degrees, which gets you to 35 degrees total advance at 5000 RPM.

If your Alfetta has the intake manifold vacuum port off of runner #1 you can use that as the vacuum source for the advance, otherwise it's more of a challenge to use vacuum advance with Webers. The vacuum advance isn't required but it's a nice way to get a bit better fuel economy and part-throttle performance.

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But Mad North-Northwest
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These aren't my data but someone posted them to the BB, and it's got the 045 advance curve.

If I'm reading that right, 32 degrees max mechanical advance at 4200 RPM, with 4 degrees static, for a total of 36. Advance comes on a lot faster so at 1000 RPM typical Weber idle it's running at 14 degrees total advance. Again, not my data, so I can't vouch for accuracy.

This seems to be a more aggressive curve but I have no personal experience with the 045.

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Discussion Starter · #4 ·
Its great information.
Thank you all.
I install both dizzys and feel difference .
The 045 have aggressive mid range rpm throttle respond.
The 018 have fell like good respond of throttle
In all rpm but 045 more aggressive in 2000-3500 rpm. Another scale of curve 018 feel beter then 045.
Can't decide which one best.
The 018 i connect to cyl1#manifold with shutter valve (ot carbs nipple )
But i feel that its no true.
In idle i have a lot of advance.
Because all this issue i have ask about option of 018 advance without vacuum advance.
How much advance i loose is i disconnect the vacuum advance ?!
 

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But Mad North-Northwest
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The 018 i connect to cyl1#manifold with shutter valve (ot carbs nipple )
But i feel that its no true.
In idle i have a lot of advance.
Because all this issue i have ask about option of 018 advance without vacuum advance.
How much advance i loose is i disconnect the vacuum advance ?!
That is normal. At idle you want to set the static advance with the vacuum line disconnected. Then when you plug in the vacuum line the advance will go up (because there's vacuum at idle, and that advances the distributor.) That's the way it's supposed to work.

When you're accelerating there will be little vacuum in the line, so the distributor won't vacuum advance, you'll just get the mechanical advance. At idle and cruise you get the additional vacuum advance.

I use a 123 distributor with a custom mechanical advance curve, but the vacuum advance curve I'm using is from the 018. There's a video in the post below that shows distributor status during a drive. You can see at idle it's at about 21 degrees advance (mechanical + static + vacuum).

 
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