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3" or 4" cai

 
Old 01-13-2012, 02:57 PM
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Been slacking I finished the intake but need a 4" coupler so its just a short ram till I get one.

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Old 01-13-2012, 05:23 PM
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Old 01-13-2012, 09:28 PM
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i hope that's a joke, intakes are not tricky, but slapping on a 4" intake to a oem honda penlum/tb you will drop massive horsepower, the penlum needs to be opened up first, including the runners, or get an aftermarket intake..

then you can play with 3.5-4" intakes,
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Old 01-14-2012, 06:04 AM
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Have you tested this on the dyno? I have and it does not drop any power. It picks up power every time. I have tested it 100 times.

You are right they are not tricky... the bigger and longer you can make it the better.
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Old 01-14-2012, 12:11 PM
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Originally Posted by wadzii View Post
the bigger and longer you can make it the better.

thats what she said

joking aside I dont see how the width would help 3" will flow more then enough the length just tunes where the resonance hump in the tq curve will happen
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Old 01-14-2012, 12:24 PM
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Originally Posted by speedjunky01 View Post
Originally Posted by wadzii' timestamp='1326553454' post='21316666
the bigger and longer you can make it the better.

thats what she said

joking aside I dont see how the width would help 3" will flow more then enough the length just tunes where the resonance hump in the tq curve will happen

No it doesnt and no it doesnt.

The length just makes the airflow smoother, Nothing at all to do with any hump in the tq. If you get a "hump" that just means the intake is costing you power where there is no hump. The idea is for NO "hump", which really isnt a hump.. .but a dip. Also a longer intake will smooth out the power and provide very good gains out past the power peak.

The last car I put on the dyno for an intake test only picked up about 10hp peak going from a short 3 inch intake to a very long 4 inch intake. Power peaked at 8600 rpms. The real story was at lower rpms where it picked up about 15 tq and way out at 9500 rpms where it picked up 20hp. That effectively extended the usable power by 1000 rpms vs the short intake and on the low end made the car drivable a gear higher than before. At the track the car picked up a 1/2 second due to the added power and ability to shift at 9800 instead of 8800. That car was a 2 liter 4 cylinder making 250 to the tires.

You wont see any gains going bigger than 3inch making under about 180ish to the tires, more importantly is you wont see any losses if its "too big"

3 inch intakes really start to be a bottleneck at about 205-210 to the tires, and again.. if you go "too big" you wont see any difference in power.

remember when everyone used to say 3 inch exhaust was too big, etc... in 2 years the conversation will be "remember when everyone said a 3 inch intake was good enough?"
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Old 01-14-2012, 12:31 PM
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pic of said dyno plots?

and if the resonance isnt what changes the powerband why did manufactures spend millions developing variable length intake manifolds?
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Old 01-14-2012, 06:47 PM
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Originally Posted by speedjunky01 View Post
pic of said dyno plots?

and if the resonance isnt what changes the powerband why did manufactures spend millions developing variable length intake manifolds?
lol intakes and intake manifolds are completely different animals. Intake use resonance, intake manifolds have pulses you need to time right.
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Old 01-14-2012, 07:41 PM
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Originally Posted by ApWhat View Post
i hope that's a joke, intakes are not tricky, but slapping on a 4" intake to a oem honda penlum/tb you will drop massive horsepower, the penlum needs to be opened up first, including the runners, or get an aftermarket intake..

then you can play with 3.5-4" intakes,

Wheres your facts? Proof? You have none Im sure, since anything in front of the throttle body is a restriction. Yes having a bigger tb and better flowing intake mani will allow you to really use the larger diameter intake to its full extent.

I will produce dyne results once I finish building my exhaust and get a few little items on the car.
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Old 01-15-2012, 06:22 AM
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Originally Posted by H22toF20 View Post
Originally Posted by speedjunky01' timestamp='1326576673' post='21317379
pic of said dyno plots?

and if the resonance isnt what changes the powerband why did manufactures spend millions developing variable length intake manifolds?
lol intakes and intake manifolds are completely different animals. Intake use resonance, intake manifolds have pulses you need to time right.
resonance is pulse timing

as the valve shuts it pushes a wave out the runner those waves bounce around the IM and come out of the TB. the length of the runner is tuned for a certain resonance so that the 1st wave travels back down the runner as the valve opens the 2nd time causing a higher velocity and making a bit more power.

the intake pipe length works the same way the waves join and travel out of the TB, depending on the length a sweet spot will be hit where the wave travels back at a higher velocity at a certain rpm band. this is why a really well tuned NA car can at times run even at slight positive pressure and why honda runs the stock maps on every honda out to 0.33" of positive pressure in the stock ECU's
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