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Thread: intake pipe sizes

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Posts: 1-6 of 6
2010-09-01 20:00:08
#1
intake pipe sizes
. I honestly don't understand how using intake piping greater than the size of the throttle body can flow more air. can someone explain this to me somehow.
I noticed on this particular air intake built by password Jdm that it uses a combination of large and small sections.

http://passwordjdm.com/PasswordJDM-Dry-Carbon-Fiber-PowerChamber-Intake-EG-92-95-EK-96-00-Civic-P2591C429.aspx
2010-09-01 20:11:30
#2
The idea is that you can pass more air through a 1" length section of pipe with a 3" diameter than a mile long section of pipe 3" in diameter. Same reason every racing series that uses a restrictor will have huge pipes before and after the restrictor. Also a ram air effect can be taken advantage of.

Would you rather drink a milk shake through a short straw, or a straw miles long?
2010-09-01 20:14:16
#3
Originally Posted by BenFenner
The idea is that you can pass more air through a 1" length section of pipe with a 3" diameter than a mile long section of pipe 3" in diameter. Same reason every racing series that uses a restrictor will have huge pipes before and after the restrictor. Also a ram air effect can be taken advantage of.

Would you rather drink a milk shake through a short straw, or a straw miles long?


it would melt by then....lol
2010-09-01 20:16:50
#4
I recently changed MAF's. That was a big restriction that exists in the car to begin with.

My air would flow filter>piping (at 3 inches) down to the MAF (at 2 inches) than open back up to 3 inches where it goes to the throttle body which is 50mm or two inches (I think that is what it is stock).

Immediate difference felt , throttle response went way up and mid range came back some. I do not see any difference at 4500 and up.

I have a naturally aspirated engine and I noticed a difference. If you have any breathing mods on your car, I think you should toss the stock MAF. But that would require you to stick to one ECU (unless you do all that fun tuning stuff with chips and burners and stuff). I use JWT so I got mine reprogrammed for a 95-99 Maxima MAF.

I have cams and a 2.5" exhaust so maybe that is why I noticed such a difference? But still, I see t25 setups running the stock MAF with large intake piping like mine.
2010-09-01 23:59:15
#5
Pipes of larger diameter have a reduced friction factor compared to pipes of smaller diameter. By opening up the intake pipe before the TB, you increase volumetric efficiency by decreasing the amount of flow resistance prior to the TB. While you still have a bottleneck, you have effectively reduced the length of (and thus the friction created by) the bottleneck, which used to be the whole length of the pipe. This is what Ben was saying.
2010-09-02 10:51:05
#6
Originally Posted by BenFenner


Would you rather drink a milk shake through a short straw, or a straw miles long?




I can has milkshake? ComPLETLY O.T but has anyone tried that strawberry shake from Chic-Fil-A. It's delish!

That is all.
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