Hi all!!! I need to install an external wastegate to my car but I don't like to use s/s exhaust manifold because it is not durable. I need to keep my standard 4wd cast one but I'd like to know which is the best and most durable way to weld a pipe (and also what kind of material for the pipe) on the manifold? Also what would be best; MIG, TIG or ARC? Also is it better to weld it preheated or cold? Cheers!!!

 

Welding to cast is never a good idea really. It will need to be pre heated, and welded in very small sections at a time. Chances are though on a manifold egtting so hot it will just crack anyway later on.

 

I get your point... I saw it somewhere by the way but if not durable then not good for me... That's the reason that I dont like to use s/s manifold...

 

If the SS manifold is good qauilty and braced then it shouldn't be a problem. If you do have to weld cast I'd probably ARC weld it with a nickel rod on a low heat setting, but still not ideal.

 

ok thanks!

 

Why not use a CAST rod to weld cast, no reason you can't, this is how I modded my front pulley when welding a steel trigger wheel onto it.
That said the heat will affect it, not likely in long term to last unless you use a LUMIWELD rod, the stuff is simply amazing, don't even need a welding set!!, just the rod and a heat source, eg blowtorch will do it, works on pretty much all metals.
tabetha

 

why do you need an external wastegate? surely if you are on a standard manifold an internally gated turbo will be fine.

 

or just go 2wd manifold and get a a trouser part off reyland already done to accept a external wastegate

 

does reyland not sell the convertion for this?

 

that would deffo be the best option imo

 

I'm just doing this at the moment. I don't have room for a 2wd manifold and need to do the wastegate piping myself. I'm going to mill a hole in the right place at the angle i need and then insert a mild steel tube. I'll tack it in place with a mig and mild steel wire and then take it to a welding shop who specialise in cast iron and get them to do it. From what I've read it needs pre heating and then cooling very slowly to stop it cracking. Mild steel should flex enough in use to stop it cracking, stainless would most likely crack. As the whole lot will be going to Zircotec it should be nice and rust proof when its ceramic coated.

 

The turbocharger internal one is unable to cope above 5500 rpm, the boost just rises as the revs rise and with w/g fully open! I'm on a stroker kit also...

I might think about that but space is a bit restricted...

That thing with the mild steel tube sounds good! The tube will flex and with good preheating and ideal cooling for anealing it should be fine...
The only problem is who on earth can do it here properly?

 

Sorry but you are such a cock. Have you ever used a lumiweld rod?

I guess not or you would know they are for welding aluminium (hence the name) and not cast steel / iron alloys.

Not to mention the fact that they are shite.

I can't stand people who give out advice on something they have no idea about.

 

Now my wastegate has turned up and I can see what angle I need the pipe inserting at, I'm having a problem getting the hole machined. None of the machine shops round here have a 45mm slot drill (unsurprisingly), cnc time is expensive and will take ages as no-one has any spare capacity.

For the cost of the machining I could buy a slot drill and have access to several different mills. At this rate I could just buy a cheap stainless manifold!

 

Why do you need a 45mm slot drill? Just use whatever size smaller than 45mm is available and machine the hole to size.

Absolutely every machine shop is going to have a 10mm or 20mm slot drill knocking about.

 

Ignore the quality of the welding, there aren't any leaks.