intake manifold porting

how important is it to port the intake manifold and what advantages are there? Would the operating rpm range change?

Larry if I may offer my opinion, porting or flowing an intake manifold is a "must" if one expects their engine's intake track to perform at it's potential. I too believe the process offers equal opportunity (aids) in each cylinder's power production. Like we attempt to equal all other areas of the engine, combustion chamber volume, compression ratio and how it's produced, cylinder head individual runner performance, the intake runners and volume (per application) are in need of equal performance to offer each cylinder it best opportunity to produce the most power achievable. I don't think one should hope to change an engine's operating speed through the intake manifold only, it's simply a sum of parts willing to work together that reaches a goal to each application.

Just my two cents,
Dave.

LivermoreDave wrote:Larry if I may offer my opinion, porting or flowing an intake manifold is a "must" if one expects their engine's intake track to perform at it's potential. I too believe the process offers equal opportunity (aids) in each cylinder's power production. Like we attempt to equal all other areas of the engine, combustion chamber volume, compression ratio and how it's produced, cylinder head individual runner performance, the intake runners and volume (per application) are in need of equal performance to offer each cylinder it best opportunity to produce the most power achievable. I don't think one should hope to change an engine's operating speed through the intake manifold only, it's simply a sum of parts willing to work together that reaches a goal to each application.

Just my two cents,
Dave.

thanks dave I am wondering how much I am leaving on the table with an unported vic sr on my small block. The heads I am very pleased with. Now if I can find some one in Ontario that can do a great job. Maybe charlie would like to play with some small block stuff

porting the intake is very inportant,just as the HEADS

BOSS 429 wrote:porting the intake is very inportant,just as the intake

I think he meant heads.....

yellowhorse7 wrote:

BOSS 429 wrote:porting the intake is very inportant,just as the intake

I think he meant heads.....

FIXED

Larry Williams wrote:
I am wondering how much I am leaving on the table with an unported vic sr on my small block.

Larry a SBF of with a displacement of 306 cubic inches that we worked on at the shop seem to like a bit less plenum. The intake was a Wiend hi-rise single plane of sorts. After blending and attempting to size the runners consistently, the plenum area seemed big, relative to the application. I simply removed some volume from the plenum offering a higher plenum floor or a better entry to each port floor. Maybe raising the velocity a bit or simply removed some turbulence. It seemed to offer better drive-ability although with applications that operate from start to finish at WOT, it may not be a concern.

Dave.

Thanks Dave. My small block is now a 438 cuin. The heads flow 324 on the intake. I use a vic sr for an intake. as a 393 cuin it made 688 hp on a dyno @ 7100 rpm's. I have used the same upper motor and cam etc for the 438. I am wanting to pick up a but more rpm's and horse power. Do you think porting the intake will give that to me?

Larry Williams wrote:how important is it to port the intake manifold and what advantages are there? Would the operating rpm range change?

Ported wrong ... not a good thing.
Correct porting COULD change the engine operating range a lot but, usually it just extends it a little, (if any), with power improvements in that engine's present range.

Larry your stuff is far, far ahead of mine! If my thinking is not flawed I would think the intake's runners should flow close to the cylinder head's intake runners. Not offering a restriction of sorts. Charlie or Randy can offer some percentages which the two should flow of one another. It just seems appropriate for producing maximum power the intake manifold's performance should enhance the cylinder head's ability to produce power not restrict it! I suppose the only way to decide would do the A-B-A test! Otherwise make the adjustment before hand.

Dave.

rmcomprandy wrote:
Correct porting COULD change the engine operating range a lot (!) but, usually it just extends it a little,(!) (if any) (?), with power improvements in that engine's present range.

Randy you smokin weed?... ...

Dave.

LivermoreDave wrote:

rmcomprandy wrote:
Correct porting COULD change the engine operating range a lot (!) but, usually it just extends it a little,(!) (if any) (?), with power improvements in that engine's present range.

Randy you smokin weed?... ...

Dave.

Porting does not change the legnth of the runners, thats where most of the tuning is for RPM (Not all but most.) Volumn also has something to do with it, but typical your not increasing the size of the runners that much.