if it's aluminium, then maybe you used the wrong filler, I think a high silica rod is better. I'm guessing it was tig welded?

yea the throttle bodys just an xf item, na nothing fancy like aluminium or tig, was just mig welded and let sit to cool down. Im starting to think 1.6mm might be a tad thin for intake manifolds, but its already bulk heavy so i dont no, was a big leak though!!

nice and neat mig welds..that's for sure.

The size of the plenum looks too big. ever though of using some 3 or 4 inch exhaust piping for the plenum body?

Yea lots of practise using a top quality welder i guess. From what ive heard you want the plenum volume to be approx twice engine cappacity for good power, since its a two litre that means four litres, mine is approximatelly 4.5-5 L. Also this is supposed to make your bottem end tourque down a bit however, i just thought when building it that a rb30 3L turbo loves big plenums for big power and that mines similar (ohc 2valves per cyl etc) so i went for it. Then again i could have been told lies so who knows

What you could try doing is braceing it to the block from the underneith for support dupending on how far the inlet sticks out, its like with the chinese turbo manifold ppl say they crack but thats cause they dont brace them and so it heats up and the weight of the turbo causes the manifold to slowly bend and then it cracks. ok ill stop my rambling now

Could the splits be caused by a backfire

na its got a backfire valve in it and i havnt heard anything backfire. unfortunatelly there is no room for a brace, ive thought about it before. My manifold is getting machined today so hopefully ill be back boosting soon! i really need to make some tramp bars too, dirty axle tramp

Was just a thought....... my thinking was 3 welds failing simultaneously was a tad unusual

well got it machined locally for $50, threw it all back together (after repairing manifold crack) and took it for a flogging, gave it crap for over an hour and it hasnt got a single leak, im sooo happy now i can actually hear my bov and music haha. Im goin to Gtech it later today hopefully and post my time in the 1/4mile thread! For it to be accurate i need the cars total wieght in pounds, im thinking that the standard 1200 sedan is said to be 730kg, with the l20b/turbo etc and 280zx box it would be more like 800kg, then add me at 65kg and fuel, would it be fair to guesstimate 900kg? Which would be 2000 pounds!

although the welds look neat, it seems as though they didnt "bite" to the sheet metal.

could have been avoided by turning the amps up a few...