Benifits of changing from 48mm to 52mm TB on 383 LT1

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10-23-2009, 04:16 PM

#21

bjankuski

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Quote:

Originally Posted by 93 ragtop

Are you sure? I would think peak cfm would be at peak rpm.

Peak HP is pretty close to peak airflow. After peak HP is reached the VE of the engine is dropping so fast that the airflow is actually reduced as the engine speed picks up. Each engine is a different but that is a general rule.

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10-23-2009, 04:34 PM

#22

5abivt

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Quote:

Originally Posted by bjankuski

At peak torque the engine has the highest VE but not the highest CFM readings. The highest CFM reading will occur at or near peak HP.

You are right I should have said it is most efficient and 'uses' the most air at peak Torque.

Something to consider, Didn't the ls2/3 and ls7 go slightly larger with their throttle bodies vs an ls1?

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10-23-2009, 08:29 PM

#23

pelensky

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The intake manifold was already ported and it is 52mm. If I can find a dyno in my area, I think I'll Try the 52mm and see what happens.

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10-23-2009, 08:35 PM

#24

rickneworleansla

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Quote:

Originally Posted by pelensky

The intake manifold was already ported and it is 52mm. If I can find a dyno in my area, I think I'll Try the 52mm and see what happens.

Usually porters will open it up to 58mm since the stock intake is already 52mm. Did they enlarger the runners to the gasket?

Last edited by rickneworleansla; 10-24-2009 at 10:32 AM.

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10-23-2009, 08:50 PM

#25

5abivt

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Quote:

Originally Posted by pelensky

The intake manifold was already ported and it is 52mm. If I can find a dyno in my area, I think I'll Try the 52mm and see what happens.

try to keep the variables in check as much as you can. Take the tools with you and do a run with the car as it is then swap it. let it cool and do one with the bigger tb.

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