I recently found out I have mechanical secondaries on my 465 holley. From my understanding this means that I can chomp it almost all threw the rev range and it will stand up. Whats the point of having vaccum secondaries if mechanical are so good?

cheers,
hebdog.

 

It's NOT what that means at all!

Mechanical secondaries give the driver the full control over the opening of the secondary barrels. The driver, especially where rotories are concidered, needs to demonstrate some FINESS while driving to learn the subtleties of his carb/engine combo.

YOU WILL NEVER MAKE AN NA ROTARY BEHAVE LIKE A HIGH-TORQUE-LOW END V8!!!

Read "Driving With a Modified Carburetor" on my website.
Just click on my sig picture, and then click on the next one.

 

It's cause it's got like no rotating mass, right?

 

No, it's just the nature of rotary engines. They make their power up high.
But many people falsely believe they can make a rotary behave like a torquey engine by putting on a mechanical four barrel.
-It's just not so.

Mechanical secondaries will win you a race compared to the same carb with vacuum sec.s, but ONLY if you know how to drive it!

Stomping the **** outta her will definitely LOSE you the race.

-Ya know, this holds true even for other engines. It's just more clearly illustrated on a "high-rpm power" engine like ours.

 

Let's see if I understood the info in your write-up (by stating it in Jon-simple terms)

With mech secs, you have to control the rate at which you put the pedal down because if you do it too fast, it'll choke the engine in a sense.. However, once you learn how fast you can open up without getting ahead of the engine's ability to catch up, you can have better response time than the vacuum secs. AND, the vaccum secs don't open fully like the mech ones can.

Did I get that right? Do I get a cookie?

Jon

 

sounds about right. *hands viper a cookie*

 

Jon, I told ya you should write all my website stuff!

 

Damn Sterling... I've heard about your carbs... but DAMN! That's nice looking...

Might just have to get one for the Wife's 85 S...

 

ok well its good to know I have the right setup.

 

so then whats the benefit of vacuum??

 

What's the benifit of an automatic tranny?

Any idiot can drive it?

It's a matter of automation, and it ensures consistancy at the sacrafice of control. It's a more fuel efficient carb, because it will behave consistantly under the same load every time, only delivering "just enough" fuel for the load. It's harder for a person to mimic that consistancy, even with alot of practice.
This consistancy also supports the MPG sticker put on the car.
Convert to mechanical secondaries and you MIGHT get the same high MPG, but not if you drive it for performance.

There really is nothing wrong with having vac. sec.s! But they have to be set up for performance.
The stock Nikki isn't.

I'm working on a vac. sec. operated Sterling Carb. It will have a completely tuneable secondary circuit.
Tests pending, it may actually replace my standard mec. sec.s.

A retro kit will be made available for every Sterling Carb owner at a reduced price.

 

hmm.... interesting....

I like my mech secondaries, though... I think I'll keep them.