03-02-2019, 04:50 PM | #1 |
Drives: 2011 l99 Join Date: Aug 2012
Location: Ames, Iowa
Posts: 305
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Pulleys
I have a 2011 SS that was a L99, converted to a LS3 when we installed a BTR stage cam. Before this work, it would boost up to 11-12 psi. I'm running a Kennebell 2.8. Now I'm down to about 3 psi. I understand why I'm down but what would be a good choice for a pulley size to get me back to 10 or so psi? I'm thinking stock is a 4" pulley.
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03-02-2019, 05:06 PM | #2 |
Drives: 2011 Camaro 2Ss M6 Join Date: Dec 2011
Location: Southern California
Posts: 4,013
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Stock bottom end? I would suggest against 12psi long term..
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03-02-2019, 08:19 PM | #3 |
Drives: 14 and 15 SS's Join Date: Feb 2018
Location: Minneapolis, Minnesota
Posts: 387
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What caused the drop in boost? The cam didn't cause that much of a drop (11 to 3psi)...
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03-03-2019, 10:26 AM | #4 |
Drives: 2011 l99 Join Date: Aug 2012
Location: Ames, Iowa
Posts: 305
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Oh yeah it did. The L99 cam is a weiner of a cam. The cam in there now is flowing big time. Beed to spin the blower (positive displacement) a little harder! Maybe not 10 psi, maybe 6-7?
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03-03-2019, 03:41 PM | #5 |
Drives: 14 and 15 SS's Join Date: Feb 2018
Location: Minneapolis, Minnesota
Posts: 387
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Well with a btr stage 3pd torque cam, a real ls3, stock 7.5" balancer and a 4" pulley I was seeing about 6.5psi out of a Whipple 2.9. I saw 8-9 on a 3.75 and 10.5 on a 3.5". All also with longtube headers, no cats and full exhaust.
If you are legitimately only seeing 3psi now I think something else is wrong.
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03-03-2019, 04:23 PM | #6 |
Drives: 2011 l99 Join Date: Aug 2012
Location: Ames, Iowa
Posts: 305
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Well a little bit smaller supercharger and maybe i'm wrong on total boost. Things are happening fast in my car so maybe it's above 3 psi. Maybe i need to talk to KB.
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03-04-2019, 12:14 AM | #7 |
Drives: 14 and 15 SS's Join Date: Feb 2018
Location: Minneapolis, Minnesota
Posts: 387
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Maybe you need some facts. Talking to KB isn't a bad idea but some facts will be needed for them or anyone to help you.
First you say the car was previously making 11psi. Then 6-7 Next you claim it is only making 3 psi, now it might be more but you don't know. Do you have anyway to monitor what is happening? Do you have anyway to log l What do you want? Buy a smaller pulley, make some more boost. I recommend a 2.75" upper and get a 8+" harmonic balancer
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03-04-2019, 05:31 PM | #8 |
Drives: 2011 l99 Join Date: Aug 2012
Location: Ames, Iowa
Posts: 305
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Easy there big dog! You do alot of boosted runs in the winter? I havent driven this thing since last October. And then not a whole lot. Just day dreaming about a winter from hell project.
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03-04-2019, 07:28 PM | #9 |
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Cornfield, I have a Whipple, and Whipple says that for every 1/8" of pulley change is worth about 1 psi of boost (+/-).
For what it's worth, with ported heads, mild blower cam, stock damper, and a 3.625" pulley, I made ~10psi. |
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