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-   -   Matching intake ports heads/intake (http://www.hotrodders.com/forum/matching-intake-ports-heads-intake-122087.html)

dpjmw 08-13-2007 08:15 AM

Matching intake ports heads/intake
 
I ordred a summit brand intake manifold for my street rod build. I notice that the intake runner openings that match up to the intake runners on the heads are not square with each other and they are a little smaller than those on the heads.



Is this a big deal or is that how they make them?



Thanks,

XNTRCI-T 08-13-2007 09:09 AM

It's not unusual for ports not to match perfectly. It's not a big deal unless you're trying squeeze every possible horsepower out of your motor. Some folks actually think the mismatch helps with fuel-air mixture by creating turbulence in the intake port at the expense of some flow. Probably OK for a street motor.

Jmark 08-13-2007 09:28 AM

I have read more then once that smaller intake to larger head is ok, but not the other way around. Sounds like you're good to go.

53_belair 08-13-2007 10:15 AM

Quote:

Originally Posted by Jmark
I have read more then once that smaller intake to larger head is ok, but not the other way around. Sounds like you're good to go.

I have read the same thing, something about velocity. You will be fine on a street motor as others have mentioned, if you really want to port match the two, it is really easy with a few hours of work.

oldbogie 08-13-2007 10:53 AM

Quote:

Originally Posted by dpjmw
I ordred a summit brand intake manifold for my street rod build. I notice that the intake runner openings that match up to the intake runners on the heads are not square with each other and they are a little smaller than those on the heads.

Is this a big deal ? or ? is that how they make them?



Thanks,

Unless you're a competitive racer needing every conceivable horsepower, this is fine. It's better to have the manifold a bit smaller than the ports such that the port never presents a 90 degree wall to the oncoming flow. The other direction where the manifold walls present a 90 degree surface to any reversion flow coming back up the port is beneficial to reducing this reverse pumping into the plenum and backward thru the carb where it causes stand-off.

Bogie

techinspector1 08-13-2007 07:21 PM

If you study fluid dynamics, you'll learn that it doesn't amount to a fart in a whirlwind anyway. Most of the flow goes down the middle of the port. There is a dead space at the surface of the port walls, like the flow in a river. Goes real fast down the middle of the channel, little or no flow at the bank.

dpjmw 08-13-2007 07:29 PM

Thanks for the replys
 
Thanks for all the replies. As usual, I was overthinking the whole damn thing. I'm going with it, thanks for the advise.


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