[Elkyman]

I wish Chad and all involved in the EMC this first off. Now, down to buisss

I have seen many of the intakes and heads you guys work your magic on and I give Kudo's to all of you, but one question I have is this, is there any difference in flow or fuel Suspension from the way the grinding & sanding directions are??? I see some ports where the sanding lines go horizontal vs a vertical port design!!!! then I see some that try to go parallel with the port or runner.

I know it is hard to get sanding or grinding directions to be in the same flow direction as the fuel/air suspension flows, but is there any difference that someone has noticed or is this one of them "Top Secret" thingy's?????

Seems to me that if the flow of suspension of fuel/air is moving soo fast, why would it want to hang around on the walls, floor, ceiling and so on??? other then natural forces working here!!!
Wouldn't a specific flow be better if the port grinding/sanding was going in the same direction other words??? Just an observation I have had.

 

[Enigma]

A lot of it depends on what happens right from the start of the fuel path. Aka: the booster. A poorly atomized fuel will benefit (to some degree or other) from a very course pattern perpendicular to the flow path. Aka: across the port, or up&down on the walls. Doing this allows fuel rivulets to be sheared into smaller molecules which "should" then be lifted back into suspension. This also helps with wall wetting. If the port has very high velocity and/or the boosters atomize the fuel very well, it's of less consequence in which direction and/or how fine the finish is. To an extent. Separation also has an effect on a porters choice of finish and direction, as you can manipulate the boundary layer this way. My question is: how many of you guys (Curtis, Scott, Chad, Eric, and others) have every experimented with different finishes throughout the port? IE: a finer finish on inside walls to help flow "stick", across from a more course finish on the outside wall for more shear action, or a very fine finish just ahead of (and ON) the SSR to help make the turn? Any of you guys with a bench ever experiment with this?

 

[Elkyman]

Mmmmmmmmm, Johnny 5 loves inpuuuuuuuuuuuutt
Great Info enigma, thanks for posting this. Always need to learn something new every day....

 

[CFMCNC]

My question is: how many of you guys (Curtis, Scott, Chad, Eric, and others) have every experimented with different finishes throughout the port? IE: a finer finish on inside walls to help flow "stick", across from a more course finish on the outside wall for more shear action, or a very fine finish just ahead of (and ON) the SSR to help make the turn? Any of you guys with a bench ever experiment with this?

Have fooled with this a lot over the years..one wall different finish from the other wall...slicked-up SSR and so on . Can get an idea on the bench...but really need to observe fuel A&B and BSFC on the dyno as well as take carb off once its run a while to see staining in the plenum & runners to see whats happening. Used to do the poor mans wet-flow as well on the bench..dykem and mineral spirits in a spray bottle! I know, I know...probably not safe .

There is something in finishes...but this is the stuff that is painstakingly small gains and I don't think I'd share most of it . Then again...most of the guys here already know! Cheers , Johnny

 

[Enigma]

Have fooled with this a lot over the years..one wall different finish from the other wall...slicked-up SSR and so on . Can get an idea on the bench...but really need to observe fuel A&B and BSFC on the dyno as well as take carb off once its run a while to see staining in the plenum & runners to see whats happening. Used to do the poor mans wet-flow as well on the bench..dykem and mineral spirits in a spray bottle! I know, I know...probably not safe .

There is something in finishes...but this is the stuff that is painstakingly small gains and I don't think I'd share most of it . Then again...most of the guys here already know! Cheers , Johnny

I've gone through many a bottle of windex just checking wetting patterns. I agree that any power gains/losses would be very small. Mostly I'm curious as to how different finishes along the path would affect distribution and EGT's. Well, that and I've always been curious about SSR finish. In my (to quote Scott) "be the air" moments, it seems that smoothing the finish and collapsing the boundary layer right at the turn would improve flow a little at the back side of the valve. Which would then improve mixture motion in the chamber due to the squish pad. Who knows.

 

[Lobes]

...I'm still trying to find the best radius for the air speed...

 

[Enigma]

...I'm still trying to find the best radius for the air speed...

I know that surface finish is trivial. But I don't have the time or resources to experiment with port development and such, like most of you guys do. So I wind up sitting around just thinking about stuff all day. Putting theory to application would be much more exciting.

 

[john marcella]

...I'm still trying to find the best radius for the air speed...

Compound and varying radially depending on angle change kinda sorta maybe

 

[john marcella]

For the OP,

I personally am only really concerned about finish right at or local to the entrance to a runner. And the plenum floor in a cast 1 carb manifold.

 

[Lobes]

Compound and varying radially depending on angle change kinda sorta maybe

Yep, multidimensional splines everywhere accompanied with high quality surfaces for the transitions...it's enough to keep one busy; that's for sure!

 

[Bad78Cutlass]

For the OP,

I personally am only really concerned about finish right at or local to the entrance to a runner. And the plenum floor in a cast 1 carb manifold.

John, what finish do you prefer on the plenum floor? I have a Bowtie intake on my SBC, I'm looking to do a few small touches to over the Winter.