Pulley/Belt questions

1012 Views 5 Replies 3 Participants Last post by SofaKingSlow, 3 mo ago

Infvmous

Discussion Starter · 3 mo ago

Hi, new V owner as of a few weeks ago. I bought a Hennessey HPE 650, 2012 V.

Late last week the lower idler pulley shredded the Supercharger belt. I haven’t been able to source one out for pick up, so I have 2 separately ordered waiting for the new one. I’m curious on the relocation bracket set up. I didn’t get the Hennessey receipts from the previous owner, nor does Hennessey have records from 2012. I know for a fact they changed up the pulleys but to what? I’m not sure.

All I know is the belt on there now (just replaced with the heavy duty version) is the Gates K080685 HD, and the lower idler pulley is the 50mm (apparently Metro from the research I’ve done on here) and that’s what I’ve reordered and spent hours looking through this past weekend. I’m curious though if the LPE (I believe) relocation bracket allows me to use the stock (more readily available) lower idler pulley, and not have to bother with anything else, or tune it. I’m still new to the performance side of cars as this is my first nice car.

So my questions are, if I buy the relocation bracket and a stock 70mm idler pulley, will I need to do anything extra? The second question is to ask if there’s an easy way to find the measurements of the pulleys I have currently so I can know and understand what my current setup is. I have tools readily available to me but I’m not sure which tools I might need if they’re special.

Sorry if I sound stupid, but I haven’t really had time to look into all this as I’ve been away from home all weekend and then work needs me today and the rest of the week instead of the usually 4x10 hrs.

Any help or advice is super appreciated. I’m at work now so I’ll try to check in on this thread later when I get the chance. Again, thanks all!

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Karch

· #2 · 3 mo ago

You can either check the diameter with something like calipers or other measuring device, or wrap something around it (string or measuring tape like that used to measure a waist) and divide by pi.

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Infvmous

Discussion Starter · #3 · 3 mo ago

Karch said:
You can either check the diameter with something like calipers or other measuring device, or wrap something around it (string or measuring tape like that used to measure a waist) and divide by pi.

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So then the 9.55 or whatever it comes out to be is the outer diameter right? Those numbers I get would then be my setup and I could use the chart from another thread to find out other info right?

Thank you

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Karch

· #4 · 3 mo ago

Yes, it’s pretty simple, don’t overthink it.

And the 50mm idler pulleys have been problematic for years. Relocation bracket and stock idler pulley is preferred.

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Infvmous

Discussion Starter · #5 · 3 mo ago

Karch said:
Yes, it’s pretty simple, don’t overthink it.

And the 50mm idler pulleys have been problematic for years. Relocation bracket and stock idler pulley is preferred.

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I think I’m going to go with that, then just gotta figure out which belt to get, unless this one would still work. Also which relocation bracket brand would you suggest? I’ve heard some of them require even more replacing parts and such. I’d rather be able to get one piece, a new pulley and get back to driving it.

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SofaKingSlow

· #6 · 3 mo ago

Infvmous said:
Gates K080685 HD

Your belt has 08 ribs and is 068.5 inches in belt length, not unlike your 36-inch waist jeans.
Lingenfelter has compiled a chart showing charger speeds achieved with various upper and lower pulley combos and belt sizes required. The majority of the data assumes stock idlers, except as noted.
Long post shortened: A larger idler will require a longer belt. I just can't tell you how much longer you'll need. Just ensure the belt places the tensioner within the operating range indicator on the tensioner housing.
Along with the LPE bracket, I have 9.77 lower, 3.05 upper 100 and 90mm idlers and I THINK I have a 72.5-inch belt. If you quote me, be warned you may be quoting inaccurate info.

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