i don't even know why this keeps going and going, if he's going to modify the turbo backplate there is no gasket there or anywhere, nor does there need to be.

 

Well hold on there Ben. I had a pretty nasty exhaust leak from that exact spot. While there shouldn't be the need for one there, sometimes they do get warped and will leak.

That's how I ended up losing my S5 turbine housing and manifold. I took it to a machine shop and was quoted about $100 to get the surfaces machined. When I went to get it back, they changed it on me to nearly triple. I told them to get bent, and that they could keep the damn thing if it was going to cost that much. I only paid like $15 for all 3 pieces in the first place.

Anyways, before all that happened, I did try making a copper gasket, I tried a bead-rolled steel gasket, I tried generic exhaust gasket material, and I'll tell you that nothing works. The only other option available is to either get the surfaces machined down, or just weld the damn things together.

 

Thanks for the offer. I'm actually still thinking about making the gasket for this downpipe project I am doing. It will no longer be using the 3 bolt flange If it doesn't go through, I'll def hit you up! That is a good price

My engine-manifold and manifold- turbo gaskets seem pretty good.

I will be milling the flange before I weld on it, but I don't think I would be able to mill it after the welding because I won't have a good way to clamp it down.

 

i'd have to say it's extremely uncommon to have that plate warp.

and if the machine shop quoted you $100 for the job and didn't revise it and ask you for additional then they have no legal right to hold your part hostage or demand a penny more than that. in fact $100 is steep, it should be about $40-50. if they're charging $300 they shouldn't be in business, even if it happened to be something strange like a seized stud that needed to be addressed.

 

That is what I was thinking. I was going to reuse the stock plate to do my custom downpipe, but the thing is .5" cast iron! Cutting on that would be a huge pain. Well, .5" 304 isn't much better either. After cutting and welding I'm pretty sure any of these pieces will get warped after the work is done. I'm going to try to think of a way to machine it after I have the pipes welded to the flange.

 

Yes peoples, this is one of those things where I might have too much time on my hands and the outcome may not be worth it. But I am going with a BNR turbo, stage 3 or 4 and I'm scared of boost creep. I already lost one engine to it. I'm hoping allowing the wastegate flapper to fully open with a smoother flow will keep problems like that happening. Thanks for the great input guys

 

cast iron is actually quite easy to cut and drill, regardless of it's 300,000psi tensile strength.

drill pilot holes where you want the hole, in a circular pattern, if you do it right you can do this without having to cut between the pilot holes to remove the plug. once the pilots are all drilled, cut between the holes to remove the plug. once the plug is removed then you can clean up the opening with a dremel or an actual die grinder(i only use dremels for small intricate work, but some people don't have the luxury of full shop equipment).

or if you don't want to do the above at all, make a template for the area you want cut and find a water jet/plasma jet facility. they can cut it for you in about 30 minutes.

 

Hmmm, I've never looked around for a place with a water jet nearby. I will do a quick search!

Ever tig welded cast iron to 304 ss? I've never done it. I was thinking about falling back onto using my stock cast iron plate if things don't go well with the flange. I was really debating on just using mild steel or ss, after thinking about the trouble i'm going through I ordered ss. If I would have used my stock cast piece I would have just bought mild steel and just mig welded everything, which would have worked just fine.

I would start a new thread with my progress, but this is going to be a long project because I still need to send my turbo out to bnr, get my car driving on the road so I can bring it to the shop to mock everything up. I'm taking pictures so I can at least post the progress weeks from finishing. In the meantime I am making the flange and gathering ideas.

After the input from you guys, I have been thinking about how I can chuck it up on a mil after welding to surface the flange. Debating on surfacing the turbo side too. No gasket like factory

 

i haven't used SS on cast iron but virtually anything will stick to it with enough heat during welding. normally a nickel rod is best for welding on cast iron but not even really necessary, especially since this area will be seeing a lot of heat where the nickel may degrade.