Secondaries

[austindavis1993]

So i was experimenting yesterday with my 93 mtx. I wanted to see how my car would run with secondaries open all the time, surprisingly it runs really well like that. If i kept it permanent would there be any fall backs and would it hurt my mpg. Thoughts/opinions?

 

[LOUDSHO92]

It will be really slow on take off. The secondaries are needed to keep the bottom end.

 

[SHOspazz92]

It will be really slow on take off. The secondaries are needed to keep the bottom end.

I honestly don't believe that this would be the case. I'm not saying it is better to leave them unplugged, but it doesn't make THAT big of a difference. I drove around in my 89 for months with the secondaries stuck open due to a leaky vacuum line. I finally noticed, replaced the line and you know what? The difference was hardly noticeable. Just like it is hardly noticeable when you lower the point that the secondaries open Via a tune.

With that being said, just plug them back in.

-Sam

 

[rubydist]

remember this graph?

with the secondaries open, everything left of 4000 rpm drops about 40 lb-ft. That is definitely noticeable! (Generally, the butt dyno will notice anything more than about 15 lb-ft, in my experience.)

 

[austindavis1993]

Yeah i decided to keep my secondaries hooked up, it does sound way cooler and throatier with them open all the time no doubt, but its just not practical.

 

[SHOspazz92]

remember this graph?

with the secondaries open, everything left of 4000 rpm drops about 40 lb-ft. That is definitely noticeable! (Generally, the butt dyno will notice anything more than about 15 lb-ft, in my experience.)

Is that an actual dyno plot? Sure doesn't look like one. But if it is....I sure never noticed a difference that significant. But if that's the actual case then so be it!

 

[rubydist]

that is the Ford marketing published chart from back in the day. actual dyno plots show the dual torque peaks just like that one; if the secondaries are always open, the first peak disappears, and if the secondaries never open, the second peak disappears.

 

[RonPorter]

I had them quit working on one of my Gen 2s. Car was an absolute dog below 4K. This was a basically stock car.

 

[MR-R1CHTER]

Where is this plug for the secondaries anyway?

 

[yamahaSHO]

Without secondaries closing on my boosted car, I had bogging power until the secondaries would normally open. At that point, the wheels would spin.

 

[rubydist]

Where is this plug for the secondaries anyway?

on the firewall side of the intake manifold, you will see a small vacuum canister (about 2" diameter, 2" long) that is connected via vacuum tube to the intake butterfly actuators and to a control valve. the control valve has an electrical connector on it. if you disconnect the electrical connection to that control valve, the secondaries stay open all the time. leaving them open all the time is a bad idea, for all the reasons discussed above.

 

[MR-R1CHTER]

on the firewall side of the intake manifold, you will see a small vacuum canister (about 2" diameter, 2" long) that is connected via vacuum tube to the intake butterfly actuators and to a control valve. the control valve has an electrical connector on it. if you disconnect the electrical connection to that control valve, the secondaries stay open all the time. leaving them open all the time is a bad idea, for all the reasons discussed above.

Thanks! Was always curious how people simply "unplug" their secondaries