My gauge doesn't have a hard stop...but it does "stop" a little after 10psi.

That'* ok though...got a plan and it'll be slick once I can get moving on it.

Paul... not sure about you blowing oil out your nose... but that coating was there when you bought the car. The only things I've found to degrade the coating is either TB cleaner used without removing the TB from the SC or the meth injection. Honestly..the amount you have missing.....my money is on the injection. TB cleaner is usually a much lesser degree.

Boosty, the earlier clusters do have a hard stop on the gauge (and mine is confirmed). It'* at about 12psi. I hit it daily. Maybe if I hit it hard enough and often enough, I'll wear it off.

Greyhare and I are both injecting also. We were discussing this yesterday at work. In his VW boosted community and in all the research we've BOTH done including memberships on injection forums, we've found this to be somewhat uncommon. And cars that DON'T inject pre-rotor sometimes see this as well.

I have yet to find a documented case where injection is known to have stripped coating. The point is somewhat moot for now, as Paul is now injecting post-rotor. And again, mine may help add to the story depending on what it looks like when it comes out.

Maybe I'll pull it tonight to look.

Right..newer clusters don't have the stop. And? I think the needle will give before the pin.

Hmmm I have a spare set of bad rotor plate rotors. PM me the mix. I'd like to test the mix on the coating in a controlled experiment.

Paul bought the car new and should be able to answer if he'* ever allowed any substance besides air or meth mix down the intake. I doubt air alone removed that much coating that quickly. That leaves us with defect (I doubt) and meth mix as long as he never sprayed TB cleaner etc down it. Agreed on pulling yours for comparison. And I've pulled a few sets myself after a year, no coating loss.

The most extreme commonly used mix is 50/50 methanol and water.

Keep in mind I've had that in my injection tank all winter. 50/50 mix in a PVC (glued) tank under 60psi. Still holding 60psi. I can say without doubt the tank was unaffected by it.

Try a test. Paul and I both tested our rotors with 100% methanol on the end of the rotor where it doesn't matter much with methanol. I kept it wet with a qtip off and on over a 24 hour period and it didn't even begin to soften.

I agree with Boosty. I'm comparing the coating loss to a car that has just been waxed; Take a car flying down the freeway @ 90mph in the rain. Of course the wax is going to wear off faster if your driving your car around in the elements opposed to just doing the same in nice weather.

Bill wouldn't the speed of the water/meth hitting the rotors have more of a effect on the coating then if the water/meth was just static on a rotor for a given period of time?

The test we performed was accellerated in two ways:

Concentration doubled.
Exposure time GREATLY increased.

During operation, that methanol has already evaporated. It'* supposed to. Much of the water also. The idea is that as it evaporates, it removes heat from the air around it. The methanol is already in a gas form and most of the water by the time it hits the rotors.

Note that Paul'* was worse on one rotor than the other? I suspect a manufacturing defect. I've seen other rotors do this occasionally without ever injecting anything in them.

Again, my Gen3 will tell the story when it comes off.

I have never used any TB cleaner, or anything else for that matter.

One interesting observation when inspecting the coatingless rotor is some scuffing on the snout end of the rotor in one location about 1 square inch in size.

I suspect two possibilities. As McGrath stated, it could be velocity/pressure related.
Or it could be the sudden cooling of the injection effect on the hot rotor. Expansion/contraction hence coating delamination. :?

If you look at the edges of the coating, they are not smooth like erosion but look as if the coating simply broke away.

Paul...great thoughts...

Bill...will you be removing it tonight?

Organizing the garage to make room for the dissection.

SC is off the Zilla. No coating loss at all:







Rest of the pics are in Performance.