tianporn

Hi, I've searched but no definate answers. My engine is a JDM B16a with ported and polished head, thinner head gasket, intake and exhaust modded only.

I've recently bought a short ram intake pipe that goes from 3" where it connects to the pod filter into 5" and then back to 3" right before where it goes into the throttle body. The guy at the shop ws explaining me the theory of "dead air" created as the diameter changes from 3" to 5". I went about and bought the pipe. Now my friend's been telling me it's too big and I should just get a straight 3" short ram intake pipe.

Now im confused. Should I stick to the 5" or change to the 3"?

Thanks for the input.

skrewdriver88

Go with the straight 3 inch pipe.

darkcvc

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tianporn &raquo;</TD></TR><TR><TD CLASS="quote">Should I stick to the 5" or change to the 3"?

Thanks for the input.</TD></TR></TABLE>

unless you are making crazy amounts of horsepower, it doesnt ******* matter that much at all

Deemeetree

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by skrewdriver88 &raquo;</TD></TR><TR><TD CLASS="quote">Go with the straight 3 inch pipe.</TD></TR></TABLE>

The Mista Mike

There's a thing called dead air that happens when pipes curve. At any point where an intake makes some sort of turn, the air heads straight to the top of the pipe and the bottom half is virtually useless. If the 5"-3" conversion occurs on a bend, the intake fabricators know what they're doing and you should go with that, but if the conversion doesn't happen on a bend it's just going to create a stubborn bottleneck that will do nothing but rob you of air.

There's also an air flow theory that exists about headers (anti-reversion) that the intake makers could be trying to employ here but that's pretty much useless when it jumps around 2". Plus, without some sort of ram flow you cannot achieve the vacuum that anti-reversion needs to function properly.

tianporn

So the general consensus tells me to change to 3"?

BlueTeg

iTrader: (2)

It depends on what size TB you use.

All these people just make blind recommendations on the tube size without any regard to engine package.

ARIZONA

I concur... stick with a diameter equal or close to your TB

The Mista Mike

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tianporn &raquo;</TD></TR><TR><TD CLASS="quote">My engine is a JDM B16a with ported and polished head, thinner head gasket, intake and exhaust modded only.</TD></TR></TABLE>

Agreed on the engine package, but without any MAJOR modifications, it won't make any difference with any greater than 3". My point with the dead air would be applicable with a 5" bend, but other than that, it would be dumb to run anything bigger than what your throttle body can handle.

Remember, a chain is only as strong as its weakest link, so without a bigger throttle body, anything larger than about 3" is just going to create a useless and flow-damaging bottleneck.