Vacuum advance tap into booster line?

[Duke Mk1a]

Hello all. What you do guys think about me taping into the vacuum line to the booster for my distributor vacuum advance?

My new carb does not have any vacuum fittings. Need all the help with MPGs I can get.

 

[wag123]

The vacuum that controls distributor advance is not the same as manifold vacuum. It is venturi vacuum, unlike manifold vacuum it increases with RPMs. Air flow through the carburetor venturis draw a vacuum based upon air flow (a fundamental principle of how carburetors work). That is why the distributor advance vacuum port is located on the carburetor and not on the manifold. Many high-end electronic ignition systems control the advance electronically. If your ignition is not capable of this, you will have to do it all by mechanical means with the weights and springs inside the distributor.

 

[66TigerMK1A]

Hello all. What you do guys think about me taping into the vacuum line to the booster for my distributor vacuum advance?

My new carb does not have any vacuum fittings. Need all the help with MPGs I can get.

Geez,Duke... you mean you want mid/lo 11's AND MPG ??!! lol!

What kind of mileage have you been getting??

My setup runs about 2200 rpm @ 60 mph with 400 hp and I get 21 mpg highway ( mech. adv. dizzy )

MY Dodge Ram 1500 Hemi only gets about 17 mpg

Jim
B382000446

 

[Erich]

Yes you can use manifold vacuum for your vacuum advance. The booster line is as good a source as any on the car.

Ported vacuum advance was created as a way to begin crude emissions control. It is in no way superior to using manifold vacuum for spark advance.

 

[Duke Mk1a]

Thanks guys,

Jim - got ~17 MPG last summer running 75 MPH (3400 rpm).

With my tires (22.7") and my 3.07 rear and a 1:1 4th, 2200 rpm is 48 mph.

 

[66TigerMK1A]

Thanks guys,

Jim - got ~17 MPG last summer running 75 MPH (3400 rpm).

With my tires (22.7") and my 3.07 rear and a 1:1 4th, 2200 rpm is 48 mph.

Ya... I used to run 3750 rpm @ 75 mph ...

That's why I have a 5 spd now... 2750 rpm @ 75 mph with the same 3.54 rear ! ( .73 o.d. )

I know of someone in the process of having a Keisler 5 spd installed... Could be in you future??

Jim
B382000446

 

[michael-king]

Thanks guys,

Jim - got ~17 MPG last summer running 75 MPH (3400 rpm).

With my tires (22.7") and my 3.07 rear and a 1:1 4th, 2200 rpm is 48 mph.

Duke i'd say 17mpg sitting on a constant 3400 rpm is not that bad.. i assume you have the secondaries open which is what's killing you. I found that once i get over 110kph (68ish MPH) my fuel consumption goes to hell... so either slow down.. disconnect secondaries on long runs.. or.. 5 speed it.

 

[Duke Mk1a]

i assume you have the secondaries open which is what's killing you.

Primaries are barely open. For the secondaries to be even cracked open, I would be very quickly heading to redline.

It's the rpm that is killing me as it does not take much more than 40 HP to keep the car at 75 MPH.

5 speed defiantly in future.

 

[cobrakidz]

I know Modern Driveline makes 5 speed kits for Mustangs---does anyone make one for the Tigers?

 

[Erich]

http://www.tigerengineering.net/

 

[chirodoc]

VACUUM ADVANCE

wHAT KIND OF CAM SPECS ARE YOU RUNNING (OVERLAP & DURATION) AND STILL RUNNING A VACUUM ADVANCE DISTRIBUTOR? YEARS AGO I TRIED RUNNING A FORD MUSCLE PARTS LEMANS CAM WITH A VACUUM ADVANCE DISTRIBUTOR, BUT THE IDLE TIMING AT IDLE WENT NUTS.

 

[Duke Mk1a]

Trick Flow Stage 2 Hydraulic Roller Cam
Specs - (Duration at .050 Int - 224 Exh – 232 with Intake lift at .542 and exhaust at .563 with a 1.6 rocker, 112 overlap)

Vacuum advance is 10 degrees. Static timing 12 degrees, mechanical 19 degrees = 31 total.

You always disconnect the distributor vacuum advance when setting static timing.

 

[BernieZ]

Keisler 5 Speed

Keep us posted on the Keisler 5 speed.

Thanks

Bernie