What belt do I need?

[ZL W0N]

As soon as I get a balancer, I'm going to be installing a Metco 2.5 upper w/ 100mm idler, and a Lingenfelter 8.66 lower. What belt size do I need?

Also, if anyone has a balancer for sale, please let me know! I'll take ATI or Lingenfelter.

[nighttowl]

See attached.

[ZL1 TIBS]

Looking at this chart, I have a question. The chart shows an 8.66" crank pulley as being 11% overdrive, and I just bought and installed an ATI PULLEY 916106 - SUPERCHARGER - 8.86 - 8 GRV - CADILLAC 10% OD from Brian Tooley. This is an 8.86" pulley and it is advertised as 10% when according to the chart it would be about 13%-14%. What is different here? Also when I do the circumference calculations, the 8.86" pulley comes out at 13.5% overdrive. Does the CTS-V have a different crank pulley OD stock?

[Travis104]

There is another chart from ligenfelter that I used and got a belt that was too short. I will have a brand new gates hd green belt for sale if anyone is interested. K080675HD 67.5 inch

[ZL1 TIBS]

After doing a little more research I believe Brian Tooley has a misprint and it should be 8.66" Diameter.
For Travis if you were doing just the 8.66" pulley, the right belt is the 68" from Gates K080680HD

[Travis104]

I was doing an 18% lower, thanks though.

[ZL W0N]

Originally Posted by nighttowl

See attached.

8.66, 2.5, and 100mm does not show a belt...I've seen this chart many times, that's why I'm asking. It's not listed on here.

[cal45]

Originally Posted by ZL W0N

8.66, 2.5, and 100mm does not show a belt...I've seen this chart many times, that's why I'm asking. It's not listed on here.

I have the Lingenfelter 2.55 upper and the ATI 8.66 lower w/a 67" belt.
Why are you adding the 100mm idler over the stock 90mm?


See mods in my sig

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[ZL W0N]

Originally Posted by cal45

I have the Lingenfelter 2.55 upper and the ATI 8.66 lower w/a 67" belt.
Why are you adding the 100mm idler over the stock 90mm?


See mods in my sig

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I bought the 2.5 brand new from a guy on here and he gave me a new 100mm idler as well. Should I not be installing it? I was under the impression it would give me more wrap around the smaller upper pulley.

[cal45]

Originally Posted by ZL W0N

I bought the 2.5 brand new from a guy on here and he gave me a new 100mm idler as well. Should I not be installing it? I was under the impression it would give me more wrap around the smaller upper pulley.

Well, it wasn't suggested by my installer/tuner (who knows a lot more about it than I do) and judging from my car's performance, I didn't need it.
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[ZL W0N]

Originally Posted by cal45

Well, it wasn't suggested by my installer/tuner (who knows a lot more about it than I do) and judging from my car's performance, I didn't need it.
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Oh ok. I just figured that's what you had to do when getting a smaller pulley. That or the relocation bracket. I see you still have the stock HX. No overheating issues with the added boost?

[cal45]

Originally Posted by ZL W0N

Oh ok. I just figured that's what you had to do when getting a smaller pulley. That or the relocation bracket. I see you still have the stock HX. No overheating issues with the added boost?

No over heating issues as I do not track the car - it's my DD, so I am not flooring it every where I go.
I may add the Rotofab coolant reservoir in the future.

The relocation bracket will be needed if you decide to go larger on the crank pulley than the 10% (8.66) for belt clearance.

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[ZL W0N]

Originally Posted by cal45

No over heating issues as I do not track the car - it's my DD, so I am not flooring it every where I go.
I may add the Rotofab coolant reservoir in the future.

The relocation bracket will be needed if you decide to go larger on the crank pulley than the 10% (8.66) for belt clearance.

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I may take it to the strip and a roll racing event as well, but I definitely don't track it very often. I guess I should be ok.