2.93 upper belt tension

[lunadiver]

Hey guys, I just put a billetflow 2.93 upper along with the 4 piece idler and I installed the 75.55" belt that billetflow had in their chart. My issue is the tensioner is about a 1/4" to 1/2" past the tension marks I was curios if this was normal.
Thanks

 

[Steve Cea]

That's not terrible but you really want that belt tight as possible , I run a 3 inch pulley on my Whipple with the added metco pulley assortment and the smallest belt I can get on is 70 inch !! But my belt slip is basically zero !!! See if you can drop a size , maybe a 74 ? Or less not real familiar with the setup you have so I'm guessing a bit

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[lunadiver]

Thanks for the response! Im sorry I left it out but the tensioner is on the over tighten side of the marker. I don't think I can get a smaller belt it took two of us to get this belt on! But if it's normal then I'll leave it be!

 

[Bdubbs]

The best way to get a tighter belt on is this. First take the auxiliary idler pulley off the bracket. Next put the belt on. Lastly, take tension off the belt with a breaker bar. With tension off the belt, push the auxiliary idler pulley into place. Now release tension and tighten pulley down.

Also make sure when running a super tight belt to notch the stop off of the tensioner. A flat head screwdriver and a hammer will work.

 

[P49Y-CY]

I disagree with post #2 - you do NOT want your belt "as tight as possible". The indicator should be as close to the middle as possible. There are threads on this board discussing how the force increases exponentially once you go past the center mark of the tensioner.

I have two cars similar to the op - upper only cars, billetflow 4-piece, stock lower. One has the 2.80 (2.76) and the other has the 2.93.

With the 2.80, I kept the stock belt and the mark sits right in the middle. This combo has worked perfectly for 80 thousand miles - the car has 120k total and is still on the original alternator (might be a record lol).

But, same as the op, my car with the 2.93 needed a belt. I think they sent me the wrong one (I didn't notice) and it was a very tight fit. The indicator was just off the scale at the top of the range. With this setup I fried the alternator in less than 10k miles, and the car only had 20k total when it failed! Since correcting it, I have had no problems, and the car now has 50k.

 

[lunadiver]

That made life so much easier thanks! Alright I went out there today and pulled a 100mm aux idler off and the belt tension goes right in the middle of the marks. So should I go up to a 76" belt?

 

[BLOWN9646]

I think you misread what bdubbs was saying. You just want to remove the aux idler, in order to slide it back on with the belt on, and in place. Just makes it easier getting the belt on by removing the pulley first.

 

[lunadiver]

Yeah I put the aux idler back on with the belt. I was just saying that when it was removed the the tensioner marks were right in the middle where they should be. I didn't know if I should get a larger belt or just leave it be since it's the belt that is recommended on billetflows chart.

 

[BLOWN9646]

When what was removed? If it's right in the middle of indicator, it's good

 

[lunadiver]

When I removed the auxiliary idler the tensioner went to the middle.

 

[01yellercobra]

I'd get a longer belt so you can keep the aux idler and put the tensioner in the correct place. I'm not a fan of overly tight belts. I've seen what they can do to main bearings.

 

[KLLR SNK]

Ford engineers put an indicator on the tensioner for a reason so that is my target when selecting the proper belt length.

 

[Bdubbs]

I now run a thump tensioner, no notch marks to go by anymore.

 

[roy_1031]

Following notch marks and recommended tension and belt length charts and what not, all that goes out the window when you start chasing big boost and power and you start running into belt slip issues. I run as tight as possible and it still slips! Next step is to have slots cut into the TVS pulley and get it coated along with getting the crank pulley coated. (Carbinite texture coated)


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[big dad]

I disagree with post #2 - you do NOT want your belt "as tight as possible". The indicator should be as close to the middle as possible. There are threads on this board discussing how the force increases exponentially once you go past the center mark of the tensioner.

I have two cars similar to the op - upper only cars, billetflow 4-piece, stock lower. One has the 2.80 (2.76) and the other has the 2.93.

With the 2.80, I kept the stock belt and the mark sits right in the middle. This combo has worked perfectly for 80 thousand miles - the car has 120k total and is still on the original alternator (might be a record lol).

But, same as the op, my car with the 2.93 needed a belt. I think they sent me the wrong one (I didn't notice) and it was a very tight fit. The indicator was just off the scale at the top of the range. With this setup I fried the alternator in less than 10k miles, and the car only had 20k total when it failed! Since correcting it, I have had no problems, and the car now has 50k.

That is spot on advise. There is such a thing as to much tightness. Install a belt that has the tensioner marks as close to the middle as possible, then tweak the throttle while observing what the tensioner does, it will go up to tighten the belt even tighter, and that is precisely how it should work. When the tensioner is so tight that it can't move any tighter you're gonna get belt slip. That might sound counter intuitive but that's how it works.

I've read more than one thread about belt slip and they all share the same thing, too much static initial tension, and the fix was to let the tensioner do its' job. The important thing is to get enough of the belt to wrap around the blower pulley so there is more surface contact.

 

[Bdubbs]

Following notch marks and recommended tension and belt length charts and what not, all that goes out the window when you start chasing big boost and power and you start running into belt slip issues. I run as tight as possible and it still slips! Next step is to have slots cut into the TVS pulley and get it coated along with getting the crank pulley coated. (Carbinite texture coated)


Sent from my iPhone using Tapatalk

Yeah I have the coating on my 2.6 pulley, but want to add the cut slots.