I heard a couple guys run manual only tensioners, and heard a couple of other guys swear it won't last for more than a couple of weeks. Who's right?

 

Spring loaded tensioner works better because the belt elongate ever so slightly at high RPM

 

I've temporarily removed my automatic tensioner and made the blower head a manual adjustment. I've run this for about 150 miles without a problem so far.

I did this because I bought a Dayco 870K6R belt, which at first tight, stretched beyond the automatic adjuster range. So I made the blower head manually adjustable by pivoting on the drivers' side idler, and slotted the passenger side idler bolt hole in the mounting bracket. I'll put the automatic adjuster back in tomorrow when I (hopefully) receive the 3" Reichard Racing 6-rib pulley. The manually adjustable blower head will help me keep the automatic adjuster in the center of the range.


[Modified by blu00rdstr, 4:09 PM 5/18/2004]

 

Just periodically check your bel tension with a manual tensioner and you'll be fine...

 

Seems to be a lot of opinions on this one, I thought the manual tensioner was the way to go till I put it on a Dyno and watched my boost drop off after 4.8 lbs.
Changed back to the stock spring loaded tensioner and now boost is over 7lbs
Going back to the dyno this afternoon
I t seems the real culprit is irregularties in the belt, kinda like the belt in tires there is a real stiff spot where the belt is joined and the manual tensioner cannot compensate for it.

 

I tried a 870r6 belt and for some reason it's about 2" too long on my setup. I'm running the MMS bracket with a 3.85" blower pulley. Are you getting "full boost" with your manual setup?

 

wow! What length belt, pulley, and bracket are you running?

 

If you are running a MMS bracket, you should run a manual tensioner... and even then you will be lucky if you dont get any slippage. If you run the A&A bracket with the single tensioner pulley and an 8 rib, then you wont need one.

Too bad you were not reading along one year ago as we talked about all this stuff in great detail back then.

VR

 

Sorry, I didn't have a kit back then so didn't pay much attention, and for some reason there isn't much in the search about manual tensioners. Anyway I want to maximize my 6 rib setup. If Opticz06 can make 7_whatever hp with a 6-rib and the stock ATI bracket it seems we should be able to have no slip in our 500_whatever hp applications.

My spring loaded setup "seems" to be working fine @ 9psi (3.85" pulley), but I like the idea of more belt wrap (since I'm planning on a 3.5" pulley in a few weeks). Anyway I guess I'll just do it and let you all know how it works for me.

If anyone knows exactly what length belt I need I'd appreciate it, 870K6 was about 2 inches too long.

 

Are you making normal boost with the setup? I really like the MMS kit but the downside is it's a pita to take apart. I'm trying to avoid having to remove the headunit, so my plan is to tension it on the alternator side. Actually before deciding to go manual I tried your method and I have to give you props for a neat idea. If someone made a "cleaner" tensioner that bolted up that way I'd be all over it.

 

I'm making around 6-7psi and 5psi (3rd gear) on the dyno. With a new guitar-string tight belt I hit 8psi. This is with a 3.5" slotted pulley.

I tried a 3" slotted pulley today with a new shorter belt, and I'm getting less boost (4psi) due to slippage, but it's setup as a manual tensioner. I'll wait for it to stretch and add the automatic tensioner. I have a Reichard 3" pulley coming in tomorrow. The 3" pulley I tried today was a cancelled order from ATI that they let me keep.


[Modified by blu00rdstr, 4:09 PM 5/18/2004]

 

I was running a Gates 60868 belt with the stock ATI bracket with about 70% belt wrap on a 3.6" blower pulley.
The manual tensioner was on the alt side and was a slide type that used the top bolt of the alt. to lock it down to the slide.
I had about 150 miles on the belt before we put on the dyno and you could hear it slipping and smell the burnt rubber.
We tightened it with a 2 foot long bar and the belt was tighter then a drum head, next run it started slipping at about the same spot.

Yesterday I went back to the dyno with the stock tensioner and the same blower pulley but added a second 3" idler pulley so now the lower idler and the one next to the rt frame rail are 3" dia idlers.
It made 9lbs boost at 6300 rpm with no hint of slippage and the belt was a Goodyear Gatorback 4060967.
This is with twin intercoolers and the stock rad location and the stock ATI intake on the rear of the rad with a P1SC head unit and Kook's headers and 3" high flow cats and exhaust pipes.

Based on this experment on 1 I would conclude that one of the most important factors is, the abilty of the stock tensioner to compensate for the irregularties of the belt and the load of the belt on the pulley.
Kind of like driving a car with wide tires in the snow and then switching to narrower tires and getting better traction.