MyE28.com

I had the turbo car apart for some modifications to run megasquirt, which I should be getting on wednesday. I pulled the throttle body and about half of the cooled side chargepipes. I did some work on the TB and made some new piping to fit where the Split Second MAF used to. I was also lending a hand replacing valve cover gaskets on a 540i, so I was back and forth between the two vehicles. My m20 was open at the intake manifold for a few hours total.

I slapped it back together as it was getting dark and got on my way. The first thing I noticed was that it sounded different. Slightly louder, and a little rougher. I found this odd, but it wasn't alarming. The first time I opened it up, with the extra noise still present, I noticed it seemed rougher under power especially over about 5500. Just rough, like the kind of rough you can slightly feel through the chassis. It still ran great, pulled hard, but it was distinctly rough. Thats when I started to think about having the intake open, and what might have gotten in there.

Now, I haven't performed any engine integrity tests, but I plan to tomorrow. I'm really hoping some peice of metal didn't get in there, but it feels like that. I would expect a destroyed plug and a dead cylinder, but its firing on all six and it still feels alright under low loads. Its not using any coolant or oil, theres no cross contamination between the two. Its just usually so smooth, and it was all normal until it came apart. I can't imagine what the problem could be.

Look for a vacuum leak. Check your intake manifold gaskets, one may have fallen off or is askew.

Compression test came up with all six being well within 10% of 130, which is about right for an 8.5:1 super e motor at 5500 feet. All gaskets and connections were good. The only thing I actually changed was to add an open element intake air temp sensor in the throttle body, which went in the hole where the crank breather used to connect. I drilled it out and inserted the IAT sensor. It protruded a good 1/2" into the throttle body, probably an inch before the butterfly. I'm starting to think that might have had something to do with it. So I pulled it out and reinstalled it a little farther out. Hopefully it smooths things back out.

One thing I wasn't expecting to find was a crack in my turbine housing. Its a month old Garrett GT2871R. Maybe a month and a half. And its got a crack right across the wastegate flapper seating surface. Thats really great. We'll see how ATPTurbo.com handles this one. I havent found any source for single parts for GT series turbos, so I'll probably need a new turbo if they dont help me out.

turbodan wrote: One thing I wasn't expecting to find was a crack in my turbine housing. Its a month old Garrett GT2871R. Maybe a month and a half. And its got a crack right across the wastegate flapper seating surface. Thats really great. We'll see how ATPTurbo.com handles this one. I havent found any source for single parts for GT series turbos, so I'll probably need a new turbo if they dont help me out.

I've got a box full of old cracked T25s, I guess they still haven't figured it out. Tough gig, being a turbine housing.

I really expected more than six weeks from a 1300 dollar, brand new Garrett turbo. It still runs great, but its going to keep cracking with heat cycling until its through the discharge flange. I would be disappointed if it were a chinese knock off turbo, let alone a six month old Garrett. Totally weak.



It didn't photograph very clearly, but its about 2 o clock in the picture. Pretty typical for an internally gated turbo, just not a six month old one. You can still see the white paint on the turbine wheel from when it was new.

I just got an email back from ATP Turbo.com. They said they'll warranty it. I just need to send the old one in for inspection. I'm going to see if they'll ship me a new housing so I can swap it out and ship the old one back. I can't be without a car for a week or more while the turbo goes back and forth. So far so good though. They might just come through...