Turbo temps?

magicmike · Post by **magicmike** » Fri Jul 11, 2003 12:56 pm

On my quest for turbo inlet piping I modified a copper pipe using some solder. I know the melting point is very low for solder, but I did not think it would be a problem on the air intake side of the turbo. Does anyone see a problem with heat melting away my solder???

Mike

scottzg · Post by **scottzg** » Fri Jul 11, 2003 7:51 pm

solder is wimpy stuff, it softens up at about 500 degrees
i would worry about vibration/heat working together, it doesnt stick that well either

ciper · Post by **ciper** » Fri Jul 11, 2003 8:21 pm

Ive seen turbos glow before. I wouldnt worry so much while you drive because incoming air would cool it. But as soon as you stop the heat starts to soak into the entire turbo and would probably melt the solder.

While the solder is melted you start to drive again and the vacuum sucks the solder into the engine !!!

evolutionmovement · Post by **evolutionmovement** » Fri Jul 11, 2003 11:22 pm

I agree it would be a bad idea - even that horrible lead-free solder reflows at somewhere around 230 C.

Steve.

vrg3 · Post by **vrg3** » Sat Jul 12, 2003 7:49 am

Yeah, solder won't do when you consider the heat soak like ciper said. You could probably do okay if you braze it instead.

magicmike · Post by **magicmike** » Sun Jul 13, 2003 4:59 pm

If I can get some copper wire for my welder I'll just do that. DAMN, I thought I was going to get away with the solder lol

Mike

magicmike · Post by **magicmike** » Mon Jul 14, 2003 11:55 am

ok, I looked up the melting point of copper and its 1080°C. I think I'm going to try to braze the piece instead of trying to weld since I'm a pretty shitty welder. I looked into some blazing rods that are "Silver/Copper/Phosphorous Alloy". The melting point of this wire is like 1068°C or something like that. They also had just plain silver rods but i'm not sure if it will "stick" to the copper. Does this sound right to you guys?

Mike

vrg3 · Post by **vrg3** » Tue Jul 15, 2003 3:39 am

It depends on what kind of joints you're making. Are you making butt joints (where the pipes just butt up against each other and are joined with a fillet) or do you have more surface area contact, like a socket joint?

If it's more like the former, the copper/phosphorous alloy (I guess the one you found has a little silver mixed in too -- how much silver though?) would be better suited because it builds fillets pretty well. It's also a little easier to use because it self-fluxes on copper.

If it's more like the latter, silver brazing rod would probably be best. It's just very good at bonding by filling all the little microscopic surface cracks through capillary action. It flows well which kind of prevents it building up into a fillet.

If you're careful, use plenty of flux, and heat everything thoroughly, pretty much any rod should stick to copper well. Do you have experience brazing? What kind of torch are you using? If you can get your hands on an oxyacetylene torch you'll be much happier than if you're stuck using MAPP gas. I brazed with MAPP for the first time two days ago (attaching a fitting on my brother's Supra's oil pan for a turbo installation) and it sucked since all my experience has been with acetylene.

ciper · Post by **ciper** » Tue Jul 15, 2003 3:49 am

What year supra? What engine?

vrg3 · Post by **vrg3** » Tue Jul 15, 2003 4:45 am

A Mark II. 1985, I believe. It has a JDM 6MGE in it and a W58 from a Cressida or somesuch. I don't know exactly what turbo he put on there; I presume it's a stock Supra turbo of some type, probably from a MkIII. He has a few different intercoolers that he'll pick from. I got him injectors for a MkIII turbo for his birthday and we're going to try to run it off a DIY fuel management computer (MegaSquirt).

magicmike · Post by **magicmike** » Tue Jul 15, 2003 1:37 pm

I have never tried brazing before but I'm sure I can handle it. I have mapp gas here at work so I'll be using that. The copper silver mix was like 8% silver the rest copper. I'll let you know how I make out, thanks

Mike

ciper · Post by **ciper** » Tue Jul 15, 2003 8:10 pm

vrg3: Nice. The Mk II is pretty light, how much power do you guys predict? THe W58 was also used in the NA Supra MKIII.

vrg3 · Post by **vrg3** » Tue Jul 15, 2003 8:26 pm

We don't yet know how much boost we'll run so we have no idea what power to expect. It'll kind of depend on how the intercooling turns out. Probably start up slow and then build up. Our plan is actually to build a little "boost inhibitor" device to keep the wastegate open while we tune MegaSquirt and then increase boost little by little.

We had several W58s that we chose from. We pulled one out of his other MkII parts car, he bought one out of a MkIII, I think, but then he got a good deal on one from a Cressida that had much lower mileage than the other two. It fit quite nicely except that the shifter was a little further back so we had to cut his transmission tunnel. We filled it up with Redline MT-90 and it shifts smoother than anything else I've ever driven. Only problem is that we didn't swap the brake pedal out for one from an MT when we did the 5-speed conversion, so the brake pedal and clutch pedal are about a millimeter apart.

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Turbo temps?

Turbo temps?