BC

The intake for the S3 is clearly at least a portion Magnesium - as it reacts with vinegar.

Is there ever a way to weld aluminum to this?

BC

Kiln_Red

Magnesium can be TIG'd but it is very very challenging. It would require a super good TIG welder to do it. I have an extra S3 intake if you are interested.

Ducman82

specialty TIG shops can do it. find a aircraft maintenance shop, they should be able to do it

slate blue

I don't think you can weld aluminium to magnesium, you can certainly weld it but I don't think such dissimilar materials. Why don't you JB weld those parts together? Probably best to blast both materials before glueing.

BC

I usually think of JB weld as a last ditch, the world is ending type of option. Also, I know for a fact that JB weld is taken apart by ethanol, and ethanol will be in this intake, though technically this bonding would be happening quite a bit up stream from the injector.

depami

Ok, I’ll bite. What are you concocting?

BC

I am just back to the drawing board, so to speak, for a hybrid intake using the S3 Runner pieces. It seems that through coincidence, some velocity stacks made by ross machine racing fit (nearly) perfectly onto the cast end of the S3 runners - where the rubber collar normally goes to connect the box plenum on the outer sides.





If one were to find a way to bond these velocity stacks to those existing runners, he/she could simplify and reduce the cost of "custom" intake manifold with better breathing and different throttle body placement (front facing)

It may be something that would be more work than its worth, I don't know.

polecat702

Magnesium can be welded in a purge box, it's the only safe way to prevent a fire. I prefer to use helium as a backing gas.

Why don't you take your parts to a machine shop and have them cut threads into the pieces you want to mate together?

BC

Threads. That would be an interesting idea PoleCat, thank you. The S3 castings are a bit rough and uneven though.

dr bob

If the bells already fit perfectly into the ends of the runners, not much there to thread. I'd be looking for the right adhesive solution.

Imo000

If they are upstream from the injectors, how will they be in contact with the fuel?

Speedtoys

Case venting, etc? I cant imagine anything under the throttle body is truly fuel free, ever.

Jim Morton

Given the choice of a mechanical connection (threads) or welded, I would do welds. Here's why:

I've repaired many of these Mg castings as well as welding machined bungs onto the castings, mostly breathers. As Polecat mentions, you need to purge the area of the weld with inert gas. I like to preheat the pieces to minimize embrittlement at the edge of the weld (heat effected zone), then cool the piece slowly. Somewhat "Billy-Joe-Bob" and likely "hobbiest" to many on here, you can wrap the piece in foil after welding and cool it slowly in a gas BBQ.

Biggest challenge when doing aluminum to the Mg casting is filler rod choice. Mg rod definately melds into the casting but does not typically join to the aluminum. There seems to be enough alloying elements in the P-Car Mg castings that Al rod tends to work for these sort of bung or breather connections, but getting the weld pool is tricky. Also, think clean, clean, clean as needed prep. Nothing is worse on the Mg castings then have left over oil or oil fumes get into the weld area / purge gas.

Overall, I would not expect this work to be a simply six pack job for any decent welder. If you find a good, old school TIG guy, the job should be straight forward, just time consuming. All toughness considered, I would still think the weld option cheaper and better than machined threads...

Again, simply my $0.02

BC

Thanks for your response Jim.

I have a Welding Guy that I would trust not only with Welding, but with my own life, so thats not a problem really. He is within shipping-it distance, so thats good. I didn't even know it was possible, and as can be seen, many will say that its not. I didn't want to put the onus on him to do something thats possible, but very very difficult.

If I could use an epoxy, then that is okay too, but its obviously subject to different failures than welding.

One other challenge is that the two rear runners on the driver's side are very (very) close together if you think about it. That limits some of my "Just stick the stacks on the end" but its not that large of a problem.

I am trying to use one throttle body (two would just be more expensive and create complexity) and then into a Y which branches to each side. It seems easier than going down the custom flange path, which I already have and have the design, etc - but trying to keep this more simple.

BC

Depending on how this all works, there may be ethanol in the runners upstream of the injectors themselves.