Got a little bit ahead of myself.

I opened up the Precision Wastegate. It is slightly oversized compared to a 38mm wastegate at 39mm. Mainly it was what AGP had in the 38mm bolt pattern that fit my manifold when I ordered my turbo.

Unfortunately it seems like the bolt hole spacing is a little off. Going to have to clearance the holes. Given how many of the holes seem off on the Treadstone manifold, I’m going to say it is probably their fault. Someone hogged out most of the holes, which I am told is a fairly common occurrence to try and fit this manifold. I had a hell of a time trying to get all the burs off since it is stainless. Turns out using a flapper wheel with 120 grit was the best way, very fast and doesn’t hurt the flange surface.


Well overall the wastegateSeems like a really solid complete unit, came with all the springs and all the gaskets and bolts. The material and machining is fairly important and a failed waste gate can cause a lot of problems so I went with name brand. Found out the waste gate I ordered comes setup to open around 15lbs of boost. Rule of thumb is you can go about twice your waste gate pressure on top of the spring. Since I have no plans on running 45lbs of boost and would most likely like to try and get the boost as low as I can to start, I decided to step down to a 10lb spring setup. Chances are with the 0.63 hotside, this small of a wastegate won’t be able to bleed enough exhaust to keep the boost pressure that low, but easier to change the spring now then later.

This is a fairly easy process to do with a vice or even a friend to hold the cap down when tightening and loosening or a couple zip ties really. If you don’t have a friend or a vice handy you can do it by hand at the risk of marring the last thread when the cap pops. The thread pitch is M5 x 0.8 on the Precision wastegate, not sure why I know that...*cough*


Time to deal with one of the real problems. Mounting the trigger wheel. Unfortunately I never heard back from my tuner, so I decided to go ahead with my old mounting method. Turns out the 1jz crank pulley has 4 holes compared to the 2jz crank pulley.


Two of them are tapped, but two of them are not and oversized for the M8 thread of the other two. Turns out that the hole is almost a perfect match for a M8x1.25 helicoil kit. Just to be safe I bought the 21/64 bit and give it a quick poke and threaded in the helicoil kit with red loctite. I had to trim two of the threads, but looks like it should work.


Then I added the trigger wheel. The studs as can be seen were ground down to just fit the slot on the trigger wheel on my old setup. This lines of the trigger wheel and keeps the studs from turning so a win win. The hole in the center had to be drilled out quite a bit to clear the crank pulley bolt. In an ideal world I would be able to drill it out enough to fit a socket on the bolt with the trigger wheel attached, but I fear as of now it would be too much material from the center and compromise the wheel.


I threw on the new timing cover, once again deeply thankful that I had the forsight to label the bolts in a ziploc bag. Then it was a simple matter of letting the car cool overnight and warming up the pulley in a heated room and it slipped right on.

Then the crank pulley bolt and finally the trigger wheel.


With that hurdle overcome, I can naturally segway into dealing with the hall effect sensor and the intake manifold.

Lessons learned:

One of the nice things about ebay parts is that it forces the manufacturer of real parts to either innovate or reduce their prices. Kind of a kick in the pants when your customer base has to consider buying one of your parts to 6 of the knockoffs.


Sometimes you can’t get in touch with people or they choose to drop communication with you. It is a bummer, but you don’t know the reason and you can either butt your head up against it, or just move on.

It seems like it takes forever to solve all the little problems as you near the end.


Money spent:

Precision 39mm Wastegate - 240

Red loctite - 7

Subtotal -247

Total spent - 27865