I need some thoughts on this issue.

info on my setup: vf39, pinks, ebay large tmic, walbro fp, accessport v2, full catless 3-inch turboback.

during a pull getting on the high way I heard a noise like a small pebble hitting the exhaust pipe and bouncing down to the end of the pipe, then immediately after that noise the car started to shudder so I let up my foot off the throttle and checked things out.

my finding:

no smoke from exhaust, no power loss until full boost at 16ish psi (when the shuddering starts), no other odd or outstanding sounds from the engine or exhaust, no change in clutch, brakes, electrical, etc. no new CEL code (other than my O2 sensor one that's been on)

looking under the hood:

some fresh-looking oil buildups from the return line near the turbo, no sounds of grinding, or anything odd from the turbo while at idle and at on-throttle.

my biggest concerns:

pistons/rings/cylinders damaged (but then there would be so kind of smoke right?)

turbo damaged (oil buildup) maybe lost a turbine blade on the hot side???

I'm stumped. the car drives and sounds fine, until i hit 16psi...Please help.

I'm going to take the turbo out this weekend for closer inspection. a part of me is really hoping that i can just swap in a dif. turbo and be back on the road. I'm just not at a point where i can easily do an engine rebuild.

 

I would just back the downpipe off the turbo and check the turbine side before you start taking everything apart.

 

hmm. good call. I will do that first. Thanks!

 

Get a real tune before it blows up.

On a side note. Was this happening before?

 

nope. it happened lastnight.

is the cobb ots really that bad? just curious. I had to use it when i was in Iowa. the lack of tuners and shops were far and few where i lived :/

 

I wouldn't waste the money on a tune if you don't think the car is healthy. Make sure to get it running right first then get tuned at snail performance

 

yeah that's kinda my thinking too. it would be nice to switch up the turbo and get a real tune but I do think that my car may not hold up to the extra abuse....I may be better off saving for a motor rebuild/swap if I can't sort out my current issue with my current funds.

 

If you have an extra wideband bung bring it over to my work in foster city and I will look down inside at the turbine with a borescope.

Otherwise just drop the downpipe and look inside. Was the vf39 cracked at the wastegate when you bought it? Maybe it cracked and you heard a micro piece of metal bouncing down and out. Or maybe your o2 sensors tip fell off......
Trying to think of anything else post turbo that could happen......so it will make a noise @ 16psi? Post a video of said noise maybe too

 

I think that may be the case. I took of the DP and here's what I found.



I know that the VF39 is prone to crack but with minor to no boost issues. This one, however, is the largest crack I've seen! I'm thinking that this maybe the root of my issue. What you do guys think?

 

hmmm pic's not working...? i'll sort this out later.

does anyone know of any good placed to rebuild my vf39? or if it is even rebuildable?

ooor does anyone have a vf39 for sale?

 

Check for a vacuum leak or boostleak

 

I thought of that at first but decided that a leak only at 16psi and up seems very unlikely with the small amount of piping that the TMIC has. so I took a chance and choose to look at the turbo.

 

so I guess i'm looking at this as my opportunity to upgrade my turbo. Are FP green 16g's not made any more? Does any shop in the bay rebuild vf39's?

 

How did the turbo look when you pulled the downpipe? Was their shaft play or damaged blades? From your description my first thought was that your engine might be pinging at high boost.

 

On my setup, my tmic hose blew off on the turbo side and I was still able to drive fine but going onto full boost it would shudder so bad felt like it was misfiring