Custom fitting wastegate to cast manifold

[guzzla]

A couple of years ago I got a good deal on a Safari cast turbo manifold to suit my 1FZFE. But, now,I have the opportunity to get a really good deal on an externally gated Garrett turbo. (instead of internally as originally planned)

Because the manifold has no provision for a wastegate, and if I get the turbo I will need one, I need to figure out a way to fit one without getting another manifold.

So the question is, is there any reason why I can't have a 38mm hole cut into the manifold (there's enough room and thickness close to where the turbo bolts to the manifold) and have an adapter welded in to fit the wastegate to?

I'm not sure if the Safari manifold is cast iron or cast steel. If it is cast iron, I've read that steel can be successfully welded to it using nickel rods/wire and soft peening the welds to relieve stress. Anyone with experience on this subject is much appreciated.

I really would like to find a way to make this work because as far as I know, this is the only well made low mount manifold around - it just needs a minor tweak to be perfect.

 

[landtank]

Both Safari and AVO use internal gated turbos and I thought it was do to the fact that the steering wheel, brakes and clutch assemblies are on the exhaust side of the motor.

I'd make real sure none of those items will interfear with your plans before cutting up that manifold.

 

[guzzla]

Yeah, Rick, that was one of the first things I checked - the turbo will fit fine down low as is, and if it's possible to modify the manifold to fit the wastegate straight off the side of the manifold, it'd be above the turbo (mostly over the exhaust housing) and well clear of any obstructions.

I will most likely have a new AC line made up that runs from the firewall along the steering input shaft as that has always looked messy and could be better routed anyway.

The $64,000 question is, 'IF' it'd be OK to mod the manifold to fit the wastegate???

 

[landtank]

I'd take the manifold down to a welder and get his opinion on it. From my understanding not only does the material make up have a bearing of success but also the quality of the casting as far as contamination goes.

 

[Wheelingnoob]

I have seen people weld wastegate flanges to cast manifolds before with mixed results.

If its a good quality casting and is preheated then welded with the correct welding rod (think it needs to be high nickle) they hold up fine.

If its a poor casting (sand left from casting or pours) or not pre heated correctly then they will fail/crack off.

Another big thing (from the research I did) with welding cast is once its welded put it back in the oven you used to preheat for about 5-10min then turn to off leaving the part in there to cool slowly with the rest of the oven.

Would it be hard to get an internally gated turbine housing? Maybe easier and remove that variable from the equation of reliability.

Jeremy

 

[guzzla]

Thanks for the feedback, guys.

After talking to the owner at my local exhaust shop, who's done all of my exhaust work in the past, including welding a 2.5in MS pipe to the EOM cast iron manifold that never had any issues, we were both quietly confident of a good result.

So I took to the manifold with a 38mm hole saw and then scribed a piece of 38mm pipe (1,1/2in OD)to fit neatly inside and took it back to him for welding. I will post some pics later when I get a chance, but I picked it up this morning and he was quite happy with the result and commented that the cast quality was very good which goes a long way to ensuring a good weld. I've since tidied up the welds on the outside for aesthetic purposes and also did a bit of work on the inside with the die grinder to remove obvious sharp edges and improve airflow.

From a support point of view, I've given the thing a damn good shake without issue and by the time the other end of the wastegate is plumbed into the dump pipe, it wont be going anywhere in a hurry.

The only issue now, is to see how it performs with heat cycling and expansion and contraction. Though, the exhaust shop guy and an old bloke at the hardware store that has been welding cast for years without issues, were both confident that the steel exhaust pipe will absorb any movement before the cast does.

The engine will be on the dyno for over 2hrs early next year getting run in and tuned so we will know soon enough how everything holds out. In the meantime, based on what I've seen and been told, all should be good as gold.

 

[landtank]

Glad you got what you wanted and post up a few pics of that thing.