Intake Manifolds

Is there a benefit to using a 24 grit aluminum blast instead of an 80 grit? I want to bring my manifold to work and put it in our blast cabinet but we use 24 grit instead of the 80 that was suggested. Thoughts anyone?

Thanks...

P.S. I am talking abour for the inside of the manifold, not the outside.....

I wouldn't....24 is extra course for fast removal of material and 80 is medium grit(same grit as used for skateboard grip tape)

IMO you'd be making a lot of extra work for yourself,you'd have to work your way back up to 80grit and you don't want to remove material from the manifold ,just rough up the surface some...if 80 grit is what's recommended to get the proper surface finish,I'd start and finish with it and call it good

Good advice there...some things are best left to the Pro's...If you used the 24 grit you'd definitely reshape the manifold...and most likely not for the better...I've seen guys make expensive paperweights messing around with stuff and wind up hogging them out bigger than they're supposed to be....

What makes you think that we are using such pressure that we would accomplish reshaping the manifold? We also have materials that I can put onto the manifold that would stand up to the aluminum oxide blast that is a protective barrier in key areas.

I thought you said you were puttin it in a blaster and 24 grit would take a good bite,then you'd have to work your way down to the deepest bite with 60 then 80,so I figure you'd be opening it up a bit starting with a course grit,doesn't take much to change airflow and velocity...I'd let the head porter do it,and get another one to practice on if you wanna try it yourself...JMHO...

I spoke to an engine builder friend of mine here just 5 minutes ago and he said that the 24 grit wouldn't really warp the manifold but it would however cause too deep of pockets and could actually trap the fuel in the pockets therefore taking away the turbulence that is needed for air/fuel mix and suspension. Which was the answer that I was after. ( Benefit or No Benefit). Of course he mentioned that it is beneficial that the intake port on the head should be done as well.

Yep,you'd have to get rid of the deep scratches from the 24 grit...bigger ain't always better,you'd have to go over it again and again to get it to an 80...you just want to get rid of any casting ridges and rough it up a little

He didn't mention anything about going in a stepped process but I can see that if one were to do that the stepped process would be the way to go. It sure would take a long time though. Switching the grit blast out over and over. LOL. Frankie never steers me wrong and I trust what he says. My thought process was that if texturing improves turbulence, why not try and get a rough as possible surface without damaging the intake or losing the benefit that the purpose of texturing provides. I think that I may practice on my old intake manifold just to give it a whirl. One never learns how do do something if he just listens and doesn't try it....

JB...HRK is giving good advice...Ya give that stuff to Kirby or Paul or your head guy and let them do their thing....lotta math learning that chit and these guys put the years in...

If you aren't doing the heads...why ya wanna fck with the manifold???They go together...:drunk:

Where do get that the heads aren't being done?????

the whole "rough up the intake track for atomization" thing has been turned around with in the last 10 years or so,wet flow benches have shown the air/fuel mixture actully runs about .050 over the sides of the ports,so the roughing dosnt do ****,while not wanting the ports mirror polished,you want the smooth (spend more time on port conture instead of port surface)

Well,there ya go,shape is more important than surface texture...

Kirby what grit do you use when porting a manifold??

I use 80G,then finish with SCOTCHBRITE buffs.

the other VERY important thing is the valve job itself,a crappy valve job can ruin a decently set of ported heads,thats why we use a SERDI 100 for all our seat work,$45K,but worth thr coin if your putting out race quality headwork.so between conturing the right parts of the ports & good seat work will make the difference,not how rough the port/manifold walls are

Lucifer, I hope that you weren't thinking that I wasn't going to port match the intake to the port? :roflmao: I know that I specifically said that I was in my build thread. When I dropped my intake off to my indy I told him that I wanted the intake port matched and textured. (Both intake port and intake). That was a week ago already...