ThermoQuad vacuum advance port

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Professor Fate

Professor Fate

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Question for the ThermoQuad guys:
I've got a 9087S (ELB carb) that I stripped down to add a vacuum advance port to.
Then I noticed that the ECS port (vacuum cannister purge) has metered ports in almost the same location as the advance port would be, the only difference is that the ECS draws from both primaries and the advance port only draws from the driver's side primary.
Is there any drawback to using the ECS port for a vacuum advance signal other than using a reducer to get from 1/4" hose to 5/32" hose?
This would save me the time and possible screw ups of installing the normal advance fitting and transfer slot.
And for the inevitable guys who are going to say "just run manifold vacuum", that ain't happening- so save your breath.
 
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Since you are wanting to add PVA, I am assuming that the carb is not being used on the original ELB engine. Throttle opening v load will probably be slightly different.
So I see no problem using the ECS port for PVA. Good to see you using the TQ.
If you are building a performance engine [ cam that has reduced idle vacuum ], I would urge you to at least consider MVA. There is a simple, 5 min test, that will show you the benefit. Simply warm up the engine, engine idling, rotate dist slowly advancing the timing. If RPM increases, MVA will be a benefit, no downside, & behaves the same as PVA at cruise.
 
Professor Fate said:
Question for the ThermoQuad guys:
I've got a 9087S (ELB carb) that I stripped down to add a vacuum advance port to.
Then I noticed that the ECS port (vacuum cannister purge) has metered ports in almost the same location as the advance port would be, the only difference is that the ECS draws from both primaries and the advance port only draws from the driver's side primary.
Is there any drawback to using the ECS port for a vacuum advance signal other than using a reducer to get from 1/4" hose to 5/32" hose?
Click to expand...
Interesting. I've seen the purge and distributor using the same port on the AMC motorcraft 2 bbls.
 
Just run manifold vacuum to the distributor. So simple.
 
Mattax said:
Interesting. I've seen the purge and distributor using the same port on the AMC motorcraft 2 bbls.
Click to expand...
My other non-ELB TQs with an advance port have a transfer slot about 1/16x1/8 or so in the driver's side primary, the ECS has 1/16 ports in each primary, I figure the vacuum signal should be approximately the same...
 
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