Begi Intake Manifold
10-27-2008, 12:26 PM
#61
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The design was solely to get shorter runners, which should in turn bump the torque curve up in the RPMs, as they should be less restrictive to airflow (which is what I'm trying to eliminate). Hopefully I'll see benefits throughout the entire rpm band like Paul saw with BEGi's cast manifold. The plenum being 4x12" or so should have about 2400cc of volume, or 1.5X the displacement of the motor, so I should never be starved for air, is the supossed to be the ideal size for a FI motor.
The 45*bends in my design were utilized to keep the centerline of the TB only about .5-1" lower than stock and to keep the plenum in a close-to-stock location, so I should still have access to the oil filter and not run into clearance issues. This would also require less fab work on my part to install it.
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10-27-2008, 02:18 PM
#62
By math do you mean looking at a lot of pictures and copying what Honda guys do?
The design was solely to get shorter runners, which should in turn bump the torque curve up in the RPMs, as they should be less restrictive to airflow (which is what I'm trying to eliminate). Hopefully I'll see benefits throughout the entire rpm band like Paul saw with BEGi's cast manifold. The plenum being 4x12" or so should have about 2400cc of volume, or 1.5X the displacement of the motor, so I should never be starved for air, is the supossed to be the ideal size for a FI motor.
The 45*bends in my design were utilized to keep the centerline of the TB only about .5-1" lower than stock and to keep the plenum in a close-to-stock location, so I should still have access to the oil filter and not run into clearance issues. This would also require less fab work on my part to install it.
The design was solely to get shorter runners, which should in turn bump the torque curve up in the RPMs, as they should be less restrictive to airflow (which is what I'm trying to eliminate). Hopefully I'll see benefits throughout the entire rpm band like Paul saw with BEGi's cast manifold. The plenum being 4x12" or so should have about 2400cc of volume, or 1.5X the displacement of the motor, so I should never be starved for air, is the supossed to be the ideal size for a FI motor.
The 45*bends in my design were utilized to keep the centerline of the TB only about .5-1" lower than stock and to keep the plenum in a close-to-stock location, so I should still have access to the oil filter and not run into clearance issues. This would also require less fab work on my part to install it.
i was just curious, i really don't know much about it other than short runners are generally better for improved high rpm flow and long runners are better for velocity at low rpms. But for practical reasons i guess it would be reasonably safe to say something designed for a b16 honda turbo application might work well for us too.
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10-27-2008, 08:34 PM
#63
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This is what I understood as well, where did we fall off the path?
That turbo rabbit mani is nice; I've seen a few reports that airflow is indeed restricted on the 1st and 2nd cylinders (IE where the mani tapers down).
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10-30-2008, 04:09 PM
#69
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Ohh someone tell me the theory of the swage (sp?) on the runners.
Looks very pretty, nice job BEGI!
Sell your dealers the components seperately/unassembled for dirt cheap please. hehe
Looks very pretty, nice job BEGI!
Sell your dealers the components seperately/unassembled for dirt cheap please. hehe
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10-30-2008, 05:21 PM
#72
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promotes flow. The swage creates a region of low pressure...this also increases the velocity of the air. See Bernoulli's principle.
Usually you see the runners slowly taper in size. I'm assuming BEGi's design was used to match the ports when you squashed X size pipe at the flange, but to have a larger radius for the air to enter at the plenum. Something to that matter.
Usually you see the runners slowly taper in size. I'm assuming BEGi's design was used to match the ports when you squashed X size pipe at the flange, but to have a larger radius for the air to enter at the plenum. Something to that matter.
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10-31-2008, 01:55 PM
#80
You all need to get a flow bench, put these manifolds on a head, and test. Just randomly building designs that Corky "thinks" are good without any empirical data is just ridiculous. It must be nice to have all that time to waste building parts.
Don't get me wrong, I love that you all are trying to get out a part that I know is needed greatly for our little cars in a performance application. However, building one off manifolds by hand without knowing anything about how they will perform is a huge waste of time. You need to take that young man that you have there, have him learn how to use solid works or any other nice CAD suite, and perform some computer flow analysis on your designs before you waste time fabricating manifolds.
Sure you might find a design that performs better than the stock manifold by randomly welding together parts. I don't think that will be very hard. The fact is that you will not know how much better it is, or if you could have made something even better than that for the same price.
Don't get me wrong, I love that you all are trying to get out a part that I know is needed greatly for our little cars in a performance application. However, building one off manifolds by hand without knowing anything about how they will perform is a huge waste of time. You need to take that young man that you have there, have him learn how to use solid works or any other nice CAD suite, and perform some computer flow analysis on your designs before you waste time fabricating manifolds.
Sure you might find a design that performs better than the stock manifold by randomly welding together parts. I don't think that will be very hard. The fact is that you will not know how much better it is, or if you could have made something even better than that for the same price.
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