I tried to order one today from ATP Turbo and they emailed back saying they were currently out of stock of the p/n listed in post 61. I'll nose around on ebay.

__________________
Jim

wastegate actuator

This is one of the styles I've come up with so far. Wonder how it is adjustable?

__________________
Jim

is based on the "Pre-Load" tension you set up the Actuator with.

http://www.youtube.com/watch?v=p12g1PpIcjE

you tube,Garrett Turbo preload tension - Google Search

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"Recently we ran into an issue on my buddy's car when trying to achieve anything over 18psi. The car has a 34mm internally-gated Frank 5 20G (60-trim Garrett compressor, TD06H turbine) and we were using a T25 actuator (the turbo had a welded flapper when I got it, be he wanted to go internal and the T25 actuator was the only one I had that would fit properly.)

Anytime we tried to boost past 18psi, the flapper would blow open. The car has an external dump for the wastegate chamber, so we could hear when the wastegate would open....no hiding that. I began shimming the gate tighter and tighter and we were getting the same results. We were down to 1/4" of arm travel, and I had the boost source going to the actuator completely disconnected- same result. I ended up getting a universal AGP actuator with a much stronger spring and an adjustable arm and manufacturing a bracket to hold the actuator head.

The first time out with the new actuator the car made 28psi....I had far too much preload on the actuator arm. Plently of tuning later, we've found a sweet spot between the actuator having enough spring strength to hold the flapper shut and just enough preload that there isn't a huge spike in boost. The boost now spikes to 23-24psi before settling at 22 and holding it rock-steady to redline.

Lesson learned: If you want to run more than 20psi and have absolutely no issues controlling boost, an external wastegate is highly recommended.


By adding more tension than necessary to the wastegate arm you're preloading the spring which is delaying the opening of the wastegate, and raising the boost level.

Adjustable wastegate arms were previously the only way raise or lower your boost level until the boost controller became a popular item. Basically if you had an 8psi actuator you could run no less than 8psi when the arm was at it's loosest setting, and the boost level would raise slightly as you'd shorten the rod.

The downfall to this method is that by preloading the spring heavily to achieve a very high boost level you're taking the responsiveness out of the actuator. Many times if you have too much preload on the actuator you'll see a slight spike in boost pressure prior to the wastegate opening before it drops and settles to the desired level.

Many of today's solid-rod actuators (like those found on the T25 and 14B/16G) cannot hold much past 18 or 20psi before they begin begin to open on their own. The only way to control this is to use washers to shim underneath the mounting tabs of the actuator and add a bit of preload to the wastegate system. Of course there are tons of variables that determine the final pressure at which a wastegate will open- wastegate hole size and flapper size being the two biggest factors.

You'd be surprised- once you reach higher boost levels, wastegate arm travel and flapper size have absolutely NOTHING to do with controlling the boost level. If the wastegate opens as much as 1/4", the boost level will be limited. For those who think bigger flappers are better at higher boost levels, take a look at a 16cm2 Holset turbine housing for a large diesel truck running 35 or 40psi....the wastegate hole itself is barely big enough to fit your pinky into, and the flapper is about the size of a nickle.


____________________________
~Justin~ Rebuilding your journal-bearing turbochargers since 2004."

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If that's a Pressure operated WG the "Rod" length would have to be cut down
to the Specs GSXR provided before Pre-load.

__________________
'84 300SD sold
124.128

What about the 603.971?

I see 12-14 psi then its gone, turn the key off and it comes back for a few miles.
Tied WG to vacuum source to hold it closed and can only get 8 psi. Odd...

Yep, pretty sure the 3.5L does the same thing... if the EDS thinks you've killed EGR, it will kill boost.



Check the fault codes from the computer. You will need a hand-held blink code reader (or SDS).



Now that is odd. Are you sure it's a full 25" vacuum source? With full vac you should see >14psi at WOT.

__________________
Check out my website photos, documents, and movies!

I too am interested in the 603.971 wastegate. Can the same part number as has been mentioned for the 602 be used on the 603? I think my understanding from reading this thread is that then603 unit is larger.

What should be used for 3.5L W140 engines?

Thanks!

__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (116k)
1991 350SD (206k)
1991 300D (228k)
2008 ML320 CDI (199k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (267k)

Past Diesels:
1983 300D (228K), 1985 300D (233K), 1993 300D 2.5T (338k), 1993 300SD (291k)

Vacuum was straight from the pump although, I did not measure it. All other vac operated devices work well.
Mity vac held the wg closed with no leaks. I did not test drive with MV.

The black thing on the right controls a flap that IIRC creates vacuum to draw effluent from the EGR valve. I don't know if the actuator pulls the flap open or pushes it closed. If/when you do the wastegate mod, you'll wedge the flap open.

Sixto
87 300D

Would that black thing or the wastegate failing explain my inability to get above 2k rpm off the line?

__________________
Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out.
Check here for compatibility, diagnostics, and availability!

(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
93 190E 3.0 235k
93 300E 195k

^ The flap stuck closed will prevent the engine from accelerating like it is supposed to.

__________________
Jim

Jim,

The flap actuated by the black actuator or the waste gate? Can I wedge the black actuator flap open?

__________________
Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out.
Check here for compatibility, diagnostics, and availability!

(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
93 190E 3.0 235k
93 300E 195k

You can but EDS might notice and cut boost. From a diagnostic standpoint, you could get better than 2000 even without the turbo so it's worth trying.

Sixto
87 300D

Try tie wrapping the flap in the intake manifold wide open. Flap actuated by black actuator.

__________________
Jim

Ok so doing that just angered the engine very much. I did more looking around and found the wastegate actuator. The vacuum hoses were pretty crappy and I couldn't get a reliable reading on the gauge either. So new hoses. And well see.

__________________
Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out.
Check here for compatibility, diagnostics, and availability!

(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
93 190E 3.0 235k
93 300E 195k

These sorts of issues are why I'm such a strong advocate for ditching as much of the nanny systems as possible. These cars are nearly all 20 years old by now and the vacuum and electrical bits have degraded to the point that they're no longer reliable. Switching to a boost activated actuator and scaling the vacuum lines back to just the bare minimum makes these cars so much more of a joy to drive and maintain. I choose turbo diesels because they're powerful, efficient and simple. Why deviate from that successful formula?