S12 Technical Areas => Engine Tech => ENGINE (OEM): CA18ET Tech => Topic started by: deucekazoo on 08:37:04 AM / 08-Jan-19

Title: manifold spacing
Post by: deucekazoo on 08:37:04 AM / 08-Jan-19
Hey guys, need a little help.
Can someone that has access to the manifold or the head measure the distance between the two ports. Maybe from port 2 edge to port 3 edge. I just need a rough reference, well the more accurate the better until I have a chance to pull my car out of storage. Even measuring the mounting holes would work. I just need to know how far the two flanges are from each other.
I have a crazy idea of making my own top mount header and just need this to get stuff going.
Thanks for the help.
Title: Re: manifold spacing
Post by: JonB on 11:35:12 AM / 08-Jan-19
Maybe someone with a manifold off will chime in. I just put a tape to the junk motor I have here.

4 and 13/16 is the centerline distance between the inner most manifold studs on the head. Meaning the two studs closest togther on different flanges are 4.8125 apart.

The pacesetter had meh results on tge NA. The primary size and length are related to turbo effeciency, overlap, valve size, duration, etc... what are you scheming?

Title: Re: manifold spacing
Post by: deucekazoo on 01:35:08 PM / 08-Jan-19
Thanks for that info.
The turbo I have now is leaking oil and I can't even get to the oil line to see if it is leaking or it its the turbo itself. So I found pictures of the top mount turbo manifold and I am going to try to create one. I bought a stainless flange for the turbo and I bought some 1/2" thick 304 stainless plate to make my own flanges bolting to the head. I am going to try to model up the routing using 3D software of the tubes to see what will be needed to TIG this up. I am going to try to keep this common to use with a mandrel bent U that I will buy from eBay. I am also going to try to keep the tubes the same length. For now I just needed to see how far the flanges are apart so I can start the modeling process. I will get more accurate once I can get to my engine and see how all this fits up. First step is to see how the routing will look and what angles I need to cut up the mandrel bent U. This will also tell me how many U pieces I will need to buy to make this.
Thanks again,
Title: Re: manifold spacing
Post by: JonB on 02:18:10 PM / 08-Jan-19
I think heavy wall, typically cast is the the pipe used. Not sure that common exhaust wall will survive.

Id assume pulse seperation and shortness of length are more significant than primary equal lengths. Unless its a super effiecient high flow system, i dont think theres any overlap scavenging.

I think stainless has some issues with milling. Ive cut it before using both carbide and hss,  but i have yet to attempt a flange. I ordered a 5 flute end mill to make flanges out of stainless stock i have, but havent attempted yet. I also had brackets laser cut, and they supplied the steel - youd have to ask to see whats possible at what cost. Not sure they can throw a small piece of stainless on there - maybe

Keep us informed
Title: Re: manifold spacing
Post by: deucekazoo on 08:14:29 AM / 09-Jan-19
I was and still am worried about the size of the tubing. I found some 14 gauge SS and hope its thick enough not to crack. I will also probably add some other support to make sure it survives.

I still want to make them as close to the same length as possible. I did read that once you have a turbo on the exhaust all the exhaust theory goes out the window. You want to go as big as possible on the piping.

As of right now I was planning on cutting the flanges out by hand. I do have a band saw for the outside which should not be an issue but the inside will take a little while. I will follow the profile of the gasket to make the flange. I think a small run like this for a shop would be too expensive, but I could always ask and see what it would be. Right now it's just a crazy idea in my head for a project for this car. If it does not work out at least I will have more practice in TIG welding.

Thanks for the input and I will keep you guys posted.
Title: Re: manifold spacing
Post by: JonB on 10:24:58 AM / 09-Jan-19
I think a mask when you weld that; hexavalent chromium?