FE428, cable throttle linkage, brackets springs etc

[patrickt]

Originally Posted by Luke427

Patrick, nice! I had a similar air filter on the 750 cfm and I plan to use a pair of smaller ones on the 8 barrel....

You know, since installing that X-Treme filter, and then having to recalibrate my vacuum secondaries opening, I've run across several threads, elsewhere, where the poster writes "I installed the X-Treme filter and my engine runs slower than it did before -- this thing is crap." Just remember, if you increase the volume of the air coming down through the filter, the velocity will be reduced and you'll have to change the spring in your vacuum secondary canister (or they won't open right). Once you do that, the easier breathing that the X-Treme filter (or something similar) affords really makes a difference (both at slow speeds and high).

[Detroit Bill]

It is aluminum. It mounts on two studs.



Good luck!

[davids2toys]

Mine is similar but my springs go to different locations. I was told somewhere a lighter spring should go to the carb linkage to avoid damage, and a heavier one to another linkage location other than the carb.
No issues

[undy]

Originally Posted by patrickt

You know, since installing that X-Treme filter, and then having to recalibrate my vacuum secondaries opening, I've run across several threads, elsewhere, where the poster writes "I installed the X-Treme filter and my engine runs slower than it did before -- this thing is crap." Just remember, if you increase the volume of the air coming down through the filter, the velocity will be reduced and you'll have to change the spring in your vacuum secondary canister (or they won't open right). Once you do that, the easier breathing that the X-Treme filter (or something similar) affords really makes a difference (both at slow speeds and high).

Also, the air coming in from the top and the air coming in from the sides collides and creates turbulence, impeding flow. I've heard the reports of HP loss many times before.

[patrickt]

Originally Posted by undy

Also, the air coming in from the top and the air coming in from the sides collides and creates turbulence, impeding flow. I've heard the reports of HP loss many times before.

The real problem with the "internet reports" is that they are coming from guys, the majority of whom, really have no idea how to do anything other than just change the air cleaner. Without changing the vac spring, my switch to the X-treme filter had the effect of pulling my four barrel carb off and replacing it with a two barrel. My secondaries would not open with the same spring that had opened them (a little bit) just going to the grocery store. (That's really no exaggeration.) Of course, replacing the vac spring, with a correct one, made all the difference and the overall improvement, at both low speeds and high speeds, was significant. The increase in air flow from my original S&H air cleaner was really quite noticeable.

[davids2toys]

Originally Posted by undy

Also, the air coming in from the top and the air coming in from the sides collides and creates turbulence, impeding flow. I've heard the reports of HP loss many times before.

Along with my air breathing top, I am running the K&N stubstack and have a Holley 750 with mechanical secondary's. Can't say that I notice any difference with our without the stubstack.
Patrick, what are your thoughts for mechanicals vs. your vacuum in this situation?

[patrickt]

Originally Posted by davids2toys

Patrick, what are your thoughts for mechanicals vs. your vacuum in this situation?

The goal of secondaries, be they mechanically operated or vacuum operated, is to provide just the right amount of increased air/fuel at just the right time when the engine is calling for that increase. If you have your mechanicals, or your vacuum, adjusted perfectly, then it doesn't really matter which one you have. Your car will run as perfectly as possible for the condition that you adjusted them for. It's very easy to mis-adjust mechanicals and very easy to mis-adjust vacuum secondaries. If your secondaries don't open when they're needed, you're robbing your engine of performance. If they open too soon, then you get a bog. If they open "unsmoothly," then you get unsmooth performance. In a light weight, powerful car, like a Cobra, the last thing you want is an unexpected blast of power, maybe after a subtle bog. It makes the car more dangerous to drive.

The physical act of adjusting mechanical secondaries is easier than adjusting vacuum secondaries, because you don't have to take the canister apart and pull the spring out. With mechanicals, you can do your adjusting by the side of the road, as you're testing your acceleration and, most importantly, testing the smoothness. I know Holley has a "quick change" kit for their vacuum secondary spring, but I've never used it, and I have my doubts that it's that "quick." Personally, I always drop little springs, and I always rip holes in diaphragms. That's why I bought the Quick Fuel adjustable vacuum canister for my Holley:



It makes adjusting the opening of the vacuum secondaries as simple as turning a screw. If you can just avoid dropping the screwdriver, you'll be fine.

My personal opinion is that a "perfectly adjusted" vacuum secondary will be preferable to a mechanical secondary, especially in a light car like the Cobra. It will give the engine all the fuel/air it can handle, and it will do it nice and smoothly, so you don't get any unexpected surprises. Here, all I do is turn the screw, circled in yellow, and I can control how quickly (too much creates a bog) the secondaries open, or how slowly (too little and I'm leaving power on the table) they open. It does not take long to find the spot that is "just right." Anyone can do it, even RodKnock.