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Most boost on a stock bottom end?

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Old 11-24-2015, 06:22 PM
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Default Most boost on a stock bottom end?

What's the most boost you've run or know of anyone running on a SBE without pushing water or blowing **** up. I thought I recalled stock48 running 25 psi thru his LQ4. Be curious if anyone knows how much boost he was running when he ran the 9 sec pass on the stock lq4 since he doesn't post here much anymore. Isn't dbrods pushing 30 psi thru a stock 5.3?

Would there be any benefit to me re-torquing my head bolts from 80 lb/ft to 90 lb/ft?
Old 11-24-2015, 08:59 PM
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I worry about mine at 15 psi mainly due to the blowers load on the crank. With a turbo it's a bit different.

Good topic for discussion though.
Old 11-25-2015, 01:36 AM
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40 psi
Old 11-25-2015, 07:33 AM
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28psi most i saw
E85
Head studs at 95ftlbs
Ls9 gaskets
Twin 7665
Old 11-25-2015, 08:31 AM
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Boost really isn't the problem, its cylinder pressure. Around 1000 (give or take) at the wheel you still start to lift the heads on a typical 4bolt studded setup no matter the boost.
Old 11-25-2015, 08:37 AM
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I was making over 1000 rwhp on 23 psi and 20* timing, never pushed a drop of coolant...made 1053 rwhp thru a Th400


4" strokes are more prone to lifting heads then stock stroke with 4 bolt heads cause of the cylinder pressure peaking

a setup like I ran or even Dbrods ran makes power later in rpms which helps keeps the heads from lifting


even at 28psi I didnt push any coolant, DBrods bent rods around 30 psi but when he was 28 psi it lived

I started at 16* when I was at 28psi, typical tune up for 2 seasons was 25 psi and 20* 11.4-11.6 afr on e85 Br7ef plugs
Old 11-25-2015, 08:39 AM
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also have to take into account 28 psi from 1 combo wont be the same as another combo

when stock48 went from his one 76mm to his other 76mm the car required much more fuel at same boost level cause of volume of air
Old 11-25-2015, 10:12 AM
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Originally Posted by Atomic
Boost really isn't the problem, its cylinder pressure.
This.
Old 11-25-2015, 11:14 AM
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Originally Posted by George C....
I was making over 1000 rwhp on 23 psi and 20* timing, never pushed a drop of coolant...made 1053 rwhp thru a Th400


4" strokes are more prone to lifting heads then stock stroke with 4 bolt heads cause of the cylinder pressure peaking

a setup like I ran or even Dbrods ran makes power later in rpms which helps keeps the heads from lifting


even at 28psi I didnt push any coolant, DBrods bent rods around 30 psi but when he was 28 psi it lived

I started at 16* when I was at 28psi, typical tune up for 2 seasons was 25 psi and 20* 11.4-11.6 afr on e85 Br7ef plugs
What was the motor's compression?
Old 11-25-2015, 12:01 PM
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9.5 whatever a 09 LY6 is


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