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480sx »
https://forums.nicoclub.com/480sx-u50548.html
Thu Jan 24, 2008 3:28 pm
Spent a LOT of time the last few days redoing the BD manifold. I figured out exactly why it spiked so bad, and how BD made the mistake.
There was so much excess weld on the inside of the WG dump tube from the collector, the gas was not pressurizing the WG dump. So even though the WG would open, hardly any gas would flow through it. I cant remember exactly what my friend called the effect that the excess weld had on the gas, but it was something like an air eddy.
So i hacked off the dump tube, and cleaned it back up. Got my friend to tig it back on. He told me halfway through the weld that we really should have purged the whole manifold with Argon. What your supposed to do when welding stainless is cover up all openings in your manifold and have the whole thing filled with pressurized argon. Your supposed to create a special flange that bolts onto the turbo flange, or whatever with a air fitting to connect to your pressure regulator, then to your Argon tank. The idea is to have it so that argon is constantly coming out of the area your trying to weld, and no where else. This is where Boost Designs failed. They did it the same half assed way we did it(we would have blown through many hours, and at least a tank of Argon), and didnt clean up the mess it creates after they finished welding it up.
So really, i didnt need to hack off the dump tube at all, i just needed to spend some time with a dye grinder on that area. I did, and while i was at it i smoothed out the collector and everything i could get my grinder to. Turned out really well. Didnt take to much off, but everything is smooth with a rounded edge. Im pretty sure that this will fix my boost spike issue, but we'll see. Unfortunately i didnt take any pics of the collector before and after, i got in a hurry. I still could take a pic of it now but, it would look like a.. collector..
I also took a 8 foot belt sander to the manifold to try to fix the warped flange. After i got it close to perfect(i was standing there FOREVER) i slotted the 4th and 1st runner, so the tubes would flex enough to ensure a tight seal against a copper gasket that i recently picked up.
The only thing im worried about is it cracking, but its not like i can do anything about it till it happens so.. Fingers crossed, we'll see.
I decided to put new main bearings in my donor KA, so im waiting on them to come in the mail. 50 bucks --> ACL ---> ebay ---> done.
The donor Ka is sitting on my stand waiting for me to work on it. I plan to spend the whole weekend on it. REALLY hope the bearings come tomorrow, but who knows. If they dont, everything else will be ready and the bearings will go in last.
Im also taking this time to paint my engine bay. I got stage one of the 3 stage paint from Mattos, they matched the paint code for me. Didnt bother spending another 50 bucks on a half pint of paint for the second stage of the Pearl White color, its just a freaken engine bay. I figure it will look like a mil bucks just with fresh paint that matches the exterior. The problem on that has been that its so damn cold here recently, i cant get a good day to paint. My idea was to wait for a 50 degree day, paint it, then move it into my shop where it can bake for an hour, then spray it again, bake, ect. Hopefully sunday will be a warm day and i will be able to do it then.
Im also trying to pick up a AMS manifold for Ka # 3 which will be built to the hills. For now though, i dont wana redo everything that iv already done, i want to have a drivable 240!