Motion Dynamics 3" down pipe has serious issues

[tateg]

I had to replace my turbo nuts today and while I was at it I discovered that the waste gate on the MD down pipe has seized shut!

Apparently when I was having the issues a few months ago with it not holding boost the flapper was just starting to stick. It would still move so when I tested the waste gate it responded so I moved on. Several weeks ago I replaced the spring in the gillis valve with one of his higher boost springs. After this I had no issues with it holding boost; in fact I couldn't get it low enough so I chalked it up to the heavy spring and just stayed out of the high boost. What I didn't know was that the waste gate flapper had ceased to open at all. I had to soak it in WD40 to get it to open again.

The MD down pipe has a pretty substantial shaft for the flapper to rotate on and I think that with the about 3/4" long shaft it's just asking for it to seize up.

Has anyone else with this down pipe had any issues? Any suggestions on how to prevent it in the future? I attempted to saturate in in copper anti seize but it's not able to really get in between the flapper shaft and the tube.

[8T6 SVO]

You know, I had a similar type set up - not a Motion Dynamic one though, and it worked fine.

Sounds like you have carbon build up effecting the movement of the shaft arm. Is there a bushing or seal at the shaft? The location of the shaft might cause it to stick. If I remember, the shaft sits at a downward angle where rich stuff (carbon) can collect. Is you motor running too rich?

[tateg]

It was rust that caused the problem; Common rust. It's not rich anyway. I keep it a little lean when off boost for the mileage.

[8T6 SVO]

I guess they don't have that problem in Texas. What are you going to do?

[SVORob]

replacement

I found this a while ago at atpturbo.com it seems to be similar to the flapper valve spacer that is on the MD down pipe part # ATP-FLS-067

I have not seen this part in hand so I no nothing about quality
But I have ordered a bunch of stuff fron ATP and everything I have recieved is top notch with great service
Hope this helps

[indiana dave]

Same thing happened to my stock flapper. It was rusted stuck, and took lots of liquid wrench to even be a ble to move it by hand. No way the wastegate could move it.
I wouldn't say it's isolated to the Motion Dynamics one.

[tateg]

That looks very similar to what I have now but without the provision to bolt the external pipe to it.

I've gotten it freed back up now (thanks wd-40) so I'll see how long it lasts. I don't expect more than another few months after driving it home since the heat burned off the wd-40. It *will* rust again; I live in south Florida where everything rusts. Jim Whelan has asked me to send it back so that they can check it out (great service from those folks at MD) so I'll do that when it locks up again.

I have a Bobslog header with a provision for an external wastegate so I'll probably just end up going that route. I hear it's more accurate anyway for keeping boost steady. My only question is with a three inch down pipe occupying all usable space where does the two inch dump tube go in an SVO?

[SVOeric]

The ATR stainless pipe used to have this same problem, but I believe that problem was more becuase of stianless expansion, and dissimilar metals.

I have one of the first pipes from MD, and mine is still working, but it don't have a lot of miles on it. Mine is also bolted to a Bob's log.

[tateg]

I drive mine everyday now and commute from Key West to Hollywood Fl. every weekend. I'm putting LOTS of miles on the car.

Other than the wastegate it's been 100% reliable.

Now that I got the wastegate working I have an old problem returning. boost will max out at 20psi and then immediately fall to about 16psi. I can adjust it upward and both numbers will go up together. The problem is I want to run 22psi but if I do it will spike to 26 or 27 before it falls back to the 22 I want.

Anyone have any suggestions on how to fix this? Maybe it's the wastegate actuator responding too slow?

EDIT: I'm running a Gillis boostvalve with a heavy spring in it.

[SVOeric]

I think the fix will be your external wastegate... it's hard to control 22 psi with a bleed-type valve.
that actuator may be getting old too...

[8T6 SVO]

I think the fix will be your external wastegate... it's hard to control 22 psi with a bleed-type valve.
that actuator may be getting old too...

I agree..... an external wastegate works flawlessly and is VERY accurate. This would be your best solution. Return the external wastegate pipe back into the 3" down pipe. People say it should be 24" downstream from the turbo to downpipe attachment, but I've got mine a lot closer.

I positioned my wastegate under the turbo, there's really nothing under there to get in the way of the wastegate or piping. Boport decided that placement for me. You just have to make sure the turbo water line and the oil return line doesn't get blocked. This is all for a stock location header.

Here's a picture of a Rod's header were I positioned the External wastegate attachment under the turbo. I did the same exact placement with a Motion Dynamics header that's on my car now. It works way better than a internal wastegate - IMHO.

PM me if you want some other pictures - or to discuss.

8T6

[tateg]

The actuator went on at the same time as Charlie's hybrid turbo... About March or February.

The Bob's Log has the wastegate provision above the manifold so I'll have to run the dump pipe down from above. I asked Bob how he had handled it in the past and he said he's never used it, he'd only installed the port for the wastegate for others. I'm considering one of these for the dump pipe: Ebay item 380078267114. It looks like an east install and the routing should be no problem.

Want to sell your Rods header since you're not using it?

[BrianO]

have you called Motion yet and told them? if it's an issue that may come up it would be nice if to know about so they can fix it.

[8T6 SVO]

Jim Whelan has asked me to send it back so that they can check it out (great service from those folks at MD) so I'll do that when it locks up again.

Jim is a great guy - that's why he's a vender here.

[BrianO]

ah, that was burried in amognst the posts thx.. cool, he'll do you right.