Turbine housing - how to set a V-Band flange onto it?
 

Hello,

I just bought a new turbo and I can't figure out how to set a V-Band flange onto it.

Is it only press fit? Is there any weld required? I tried to search, without any success.

https://cimg8.ibsrv.net/gimg/www.rx7...ffe706e1cc.jpg

Yes, it needs to be welded on

Hmmm, not good. Cast iron isn't the easiest to weld...

from the cjmotors.com.au website:

"Product Notes:
In standard form, these turbine housings do not come with a V-Band Flange connection for the turbine outlet (Image 1). To make fitment universal throughout the T04Z/GTW36/GTW38 range, we press fit, and weld a sleeve into the back of the turbine housing, to allow for a standard Garrett 3" V-Band assembly for the dump pipe (Image 3). The Turbine Housing price includes the sleeve, the pressing and welding of the sleeve, and the housing itself. The opposing dump pipe flange and clamp are sold separately."


Turbine housings can be welded. but it needs to be done correctly. Proper filler and technique are critcal to a lasting weld.
I'd suggest talking first to the vendor to see what they have to say.

Thats why when you are buying the turbo, you can chose v band option. Maybe you can return it and get the one with v band. :dunno:

The type of connection that turbo is set-up for is "slip joint" connection.

Common on old diesel stuff and some oldschool JDM turbo kits had it too (cause commercial diesels are where big turbos used to come from).

Downpipes connection would look like this.

https://cimg5.ibsrv.net/gimg/www.rx7...9eaf1061aa.jpg

If you have v-band welded on the correct way is to preheat the cast iron and the v-band on a gas burner till its just dull red and then TIG weld it with Nickel filler rod to the Stainless v-band.

Its toasty welding over the hot turbine housing!

Its pretty common for people to just fit the v-band up and TIG weld it on. Its also common for the v-bands to crack off the turbo housing when done this way.

Wow, it's pretty clear. Couldn't ask for more, now I understand. I will simply return that turbo, didn't seem authentic anyway (with proofs). Subject closed, I do not want to get involved with those messy mods.

Thanks a lot guys. Once again, you quickly helped me!

[QUOTE] we press fit, and weld a sleeve into the back of the turbine housing, to allow for a standard Garrett 3" V-Band assembly for the dump pipe [/QUOTE]

In my opinion thats a lot of work to *almost* do it right.
I would rather they machine and press a v-band adapter in and then pin it in 3 locations with stainless or even inconel roll pins in blind hole.

actually I read from a number of welders who’ve done it successfully is not to preheat. They instead use 309 or 312 wire and only weld 1/2” - 1”, then let it cool, rinse and repeat until completed. I believe they called it cold-weld method. Drags it out, but they said no cracks or failures.
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Short stitches on opposing sides till its welded all around is how I do post turbine exhaust v-bands to avoid warpage and leaks.

Ofc cast iron can be sucessfully welded cold without cracking during the welding process, it just wont stand up to actual racing without cracking.

The preheat and braze weld with Nickel rod provides a gradient of ductile material between the cast iron exhaust housing and the stainless v-band while relieving stresses in the materials.

I forgot to add, you actually peen the exhaust housing with a hammer around the weld as it cools to help align molecular structure.

Its a big deal for a racer, not so much a welder.

Honda engined Indy teams struggled with weld failures on their EFR 9180 stainless exhaust housing to stainless "Y".

And that was just piston engine egts with cast stainless to cast stainless welding.

Well I thought it was just a street car. I also wouldn’t expect the stress imparted from the downpipe to be that great. It’s not really comparable to an Indy car, but ok.

You may be right that cold welding is adequate for this application. :dunno:

And if a forum user tries either welding method and experiences a failure, they can try the other method now that we have described them and provided our reasoning for their efficacy.

It's interesting how the discussion of welding procedure has progressed. If you were to post this topic on a welding forum, It would have played out much the same. Except there would have been some more "colorful" language.

When I first saw the picture of this turbine housing, I couldn't wrap my head around the reasoning behind the design.

After BLUE TII posted the picture of the actual application, it makes sense.

A properly fitted sleeve of an appropriate material that has a higher thermal expansion rate, would expand when heated and tighten itself up. really, it wouldn't need to be welded.

Though, in this application where the temperatures are more extreme,and there are housings available with an appropriate flange machined into the housing, it seems like an an unnecessary complication that could fail.

Sorry if it came across like I was challenging anyone on it, but that wasn’t the case any more than to carry on over it.

I don’t see it as any issue if done properly by someone who knows what they’re doing, but don’t feel any need to get into why that is starting from 45 years ago. Hope it works out.

Robust discussion is good for us all.
Where would we be if we all just toed the line?

This robust discussion is the reason why I sent the turbo back for a refund!

I dont mind if my posts are challenged.

Often leads to an interesting discussion and sometimes enlightens me- though Im pretty hard headed. :suspect:

Often see cast manifold cracks tig brazed with aluminum bronze filler...wonder if that would be a suitable process? ...alumumium bronze has a higher melt point then silicon bronze

It wasn’t a challenge, just a different experience and perspective. That said, going in a different direction likely makes the most sense. It wasn’t clear to me that it could be sent back.
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