Fixed position idler?

[bill Dedman]

I have an S-Trim V1 blow-through, carbureted system that I am installing on my Dodge 360 Magnum engine in an early (1972) Plymouth Valiant. Nobody makes a kit for these, so I am trying to make my own, so to speak.

I was wondering if it's okay to run a static (fixed-position) idler instead of a spring-loaded idler. I really can't figure out a practical way to position (and mount) a spring-loaded idler in this system, so I have mounted a "fixed position" idler pulley close to the top pulley, so that it acts as a belt adjuster and also increases belt wrap around the top pulley.

Is this unusual, or even workable, not having a spring-loaded idler pulley setup? I am using a 6-rib Polycog serpentine belt, and will only be looking for 5-6 pounds of boost, max.

I have no clue as to how tight to make the belt. It doesn't drive anything but the blower.

Any information or advice would be much appreciated.

Thanks in advance.

Bill

[tstang]

the fox body s trims only come with a manual set idler as well. So I cant see why that set up in the pic wouldnt work for the blower drive. Good Luck Nice to see people get creative. I assume they dont sell a kit for that year car?

[bill Dedman]

Thanks for the information. Maybe it'll work okay after all.

No, I could have used a Dakota kit, but that kit places the blower pretty much on top of the engine, and my car doesn't have hood clearance for a setup like that.... so, I had to put the battery in the trunk and mount the blower where the battery used to be located. By doing so, I won't have to modify my hood in any way; everything fits without a scoop.

[root]

Yep do not fear the static tensioner, most kits these days use them.

Ian

[bill Dedman]

Thanks for that information. I will do my best to make this work, but I am not sure about how much belt tension might be required, nor how to measure it.

My gut feeling just says "TIGHT," but I don't want to destroy my front main bearing, or the bearings in this new Vortech head unit. As you can see in the picture, I have lots of belt-wrap at the blower pulley, and a little over 180 degrees at the 7" crank pulley, bearing in mind that this 6-rib serpentine belt only drives the blower; nothing else. I don't see this combination making more than 5 or 6 pounds of boost, so maybe I won't need a HUGE amount of tension.

Any ideas?

Thanks for any information on this.

Bill