[Land-speed] Intake Manifold Question(s)

[Dave Dahlgren]

36 to no finer than 60 grit is just fine.
You will be hard pressed to build a 200 cu in plenum...
10 X 5 X 4 =200 and will not reach the end runners very well.
----- Original Message ----- 
From: "Larry Mayfield" <drmayf at mayfco.com>
To: <land-speed at autox.team.net>
Sent: Sunday, June 05, 2011 11:48 AM
Subject: [Land-speed] Intake Manifold Question(s)


> Ok, those of you who consider me a crank can hit delete now, lol....
> 
> I am making or revising an old manifold for use on the Sunbeam. I notice 
> that the runners are pretty dog gone rough and I want to do port 
> matching and polishing.  My questions have to do with the smoothness of 
> the air flow in the runners.  This is an EFI manifold so it is what I 
> would call dry. No fuel in the manifold. So do I want a really smooth 
> runner wall or rough? If smooth just how smooth? Should I have it 
> extrude honed for smoothness and removal of any small turbulence 
> generators? If really smooth would coating the runner walls with glyptol 
> be a good thing? That stuff drys to a hard finish and is pretty slippery 
> and dang near impervious to oils and anything else.
> 
> The manifold will be a short runner box with a plenum about 2/3 size of 
> the engine displacement (an old rule of thumb I once heard and maybe be 
> invalid) for use with my HP72 turbo(s).
> 
> Thoughts, comments, ideas? I'll listen to them all....
> 
> Just going to try and increase the Sunbeams speed over the old first 
> Sunbeam top speed.  Class record speeds are way beyond my capabilities 
> and pockets, lol...
> 
> --