2.6" Upper Pulley and Lower 10% OVerdrive ATI Pulley

[CaliGT500524]

Hi all,

I've been contemplating for a while now whether to install an ATI 10% lower overdrive pulley. I am running a 2.6" upper pulley now and wanted to get some insight into the pros and cons of having both pulleys.

I understand blower efficiency and added heat creation, but I dont formally track the car, I mostly cruise around and get on it every now and again, etc. Will I run into any issues with the 10% pulley that would detract from the street ability of the car? I really dont want to upgrade my cooling system and figured the 10% wouldn't require that like say a 15% or bigger would. I may also be looking into porting the stock blower, as I dont see myself going down the path of supercharger swapping.

Also, would I need a new belt for the combo of upper and lower pulley, or will the stock belt work out just fine?

Looking forward to some insight!

 

[einehund]

I've got the 2.6 upper and a 10% lower. Had them both on for 3 or 4 years now with no issues. I still have the stock heat exchanger, which I know is causing me heat soak issues, but I just haven't swapped it out yet. The heat soak is only noticeable when I'm drag racing and don't give the car time to cool down between runs. On the street, I haven't noticed anything too much, maybe a little down on power in stop and go, but other than that, nothing really.

As for belt size, I ordered a Gates green belt from Van @ Revan Racing in the size he recommended for the pulley combo. I forgot the length, but it wasn't stock. After a couple of years, I noticed belt slip; however I attribute this to the 100 or so dragstrip passes and not the fault of the belt for daily driving. I added a 90mm idler and that solved the belt slip issue for a time, and then it returned. I then added an Aux Idler set up (from Evolution I think, I don't remember) which solved the belt issue for a time. The belt slip issue has returned, but only at above 5k RPM in 4th or 5th gears, so I am pretty sure my tensioner spring is wearing out. All of these issues I attribute to hard driving and not the 2.6 upper and 10% lower. I would do an upper and lower again in a heartbeat.

 

[Mbiro594]

How much will the lower add on average? I have a 2.6 with a 90 mm idler


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[einehund]

I don't know for sure. I haven't bothered to log it. I know it pegs the stock gauge, which isn't the greatest as that is an inferred PSI and not an actual reading. I put down 536 hp and 566 tq corrected SAE on a mustang Dyno. Not sure how accurate that actual correction is as it was done in Denver (actual altitude was 5600', DA at the time was 6400').

 

[sleek98]

10%/2.6 is just slightly more rpm than a 2.4 with a stock lower. The ati 10% and a 2.6 upper has a step up of 3.0. A 2.4 and a stock lower has a step up of 2.96.

 

[snakepit3]

I have the 2.6 upper with the Innovator West 10% I pick up 3 lbs. of boost.