SC Pulley Help

[BSouders80]

I have the Livernois 6.6L, running Whipple with 2.75" pulley. Crank pulley is ATI 12% OD. 8 rib setup

There has been a problem with this setup. With a quick hit of the acceleration, it's about 50/50 on if the SC belt will fly off.

Livernois says that the problem is caused by OD crank pulley causing a bad angle of the belt.

Livernois has a fix for this. Basically their fix is switch back to OE ATI crank pulley, crank seal kit, 125.3" 8 rib belt, and one SC idler pulley.

My beef with this - - I'd lose boost/power. Livernois says the power decrease is not noticeable. I spent big $$ to be able to run E85 and have as much boost as I could to optimize the power.

I bought the livernois kit and have it sittingng here in my office. They sent 3 of the 125.3" belts. That's odd. Unless they think there's a reason I'd need 3 belts.......

Griptech has a wide range of whipple pullies. I am currently on 2.75". The sizes offered are 2.75", 2.70", 2.625", 2.60", 2.55" and 2.50"

I'm having an A-Pilloar 3 pod gauge setup. Should be done tomorrow. I have boost gauge, trans temp and AFR gauges.

My plan is to make some pulls after the gauges are installed and see exactly where I'm at on boost. Then have the Livernois kit installed.

Here is where I need help. What size pulley should I start with? I've tried calculators and not really landed on a sure decision. The pulley is right around $180/EA. I was about to buy the 2.60", but thought I would get some input on here.

TIA

Brian

 

[MTF]

Have you tried a laser and tried to hit the first rib on all pulleys to see what is out of alignment?

You must be at crazy boost levels with your setup, nice.
I had the OEM crank pulley and 3.375 SC pulley and I was doing 10.5 to 11 lbs. of boost.

 

[BSouders80]

I have talked with another guy who has the same setup from Livernois (minus E85 mods). He went back and forth with Livernois, sent his truck to them more than once. Livernois said it had to be an alignment issue with him. Livernois confirmed no alignment issue with pullies and he also had it checked on his own. Livernois came up with the belt angle caused by the OD pulley is what the problem was. Livernois put this package together for him and he's had good luck. Said his belt has only flew off once related to some "dumb" driving on his part. He also said the power loss isn't noticeable.

I'm not okay with losing boost. I paid for IDX 1300 injectors and a fuel pump to flow that E85. I don't want to lose potential.

 

[BSouders80]

Any guesses on what the boost is at? I say 18 PSI. Should get the truck back tomorrow with gauges installed. I got the 1" shorter belt as compared to what Livernois sent. Odd that they sent 3 belts. Also talked with Andrew and swapped some pictures. The GT500 lipped pulley is what I'm missing. I'm hoping that Linverois just forgot to put it in the kit vs thinking I don't need it now. I'll report back tomorrow.

 

[New recaros]

Your belt is stretching more the tensioner can compensate for. The shorter belt should help, increasing tensioner tension and stroke is needed,

 

[MTF]

The lipped pullies would solve the problem in my opinion. I hope their fix for now, works!!!

Going shorter with the belt would put the tensioner in a position that would not be optimal for belt stretch.
I tried the stronger spring "Thumper" tensioner, and it ate through two alternators in a month, not good.
It's expensive to replace the alternator due to having to remove the supercharger each time.

 

[New recaros]

If the stronger spring is wiping out the alternator bearings then an additional idler may need added to take the load. I also just saw that most belts are stretchy by design but some, like the Bondo brand is belted with fibers to limit stretch. This alone might fix the issue.
This is a design problem that they cut corners on to save money. Belt stretching should have been kept at factory levels or additional idlers and tensioner added to account for the belt stretching from increased load.

 

[MTF]

The 6.2L was never designed to be Supercharged, so no room for extra pulleys.
and unfortunately, Gates is the only brand that makes the two sizes we can use.

Gates now lists a new one for forced air induction could be worth a shot.

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[BSouders80]

I got my truck back today with the gauges in the A-Pillar. The most boost that I could catch was around 16 PSI. I also added wide band AFR. It does pretty good keeping it around 14.8 which is really close to a 1.0 lambda. I was a little surprised of how often the truck is running at vacuum vs boost. When I first got the truck back with the 6.6, when you get on it above half throttle, it sounded like an old 4 barrel carb opening up. What's really going on there is when the boost hits. I was expecting closer to the 18 PSI. A little disappointed there. Just for chits and giggles, what's the higher boosted guys running? Turbo? SC?