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The top teams are using drilled screws, safety wire, and a lead seal. There must be a recess deep enough in the restrictor so that several truns of the screw are required to release it from the compressor housing.

Alternately, we have also been sealing the boot to the restrictor or compressor housing with a random color of OE touch-up paint (thousands of possible colors), but I would like to see everyone eventually go to a wire seal method.

http://www.subaru-sti.co.jp/e/GRN/tec_info/img/tecinfo_3e.jpg

We do random checks for the restrictor seals at O controls, MTCs, RGCs, and services. In some cases those without the wire seal method may have to access the restrictor to have it re-checked at a service or end of the day, so having the wire seal is eventually more convenient for the competitor.
 

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It is smart to have the set screws (or at least one). It's amazing how things can work themselves loose. If you have smaller OD restrictor (one that does not have the wide bell mouth like in Mike's pix), you would not be happy to be inspected just to find that the restrictor had worked its was out of the compressor housing a ways, enough so as to not meet the requirement of having the restriction within the prescribed distance of the impeller.

Regards,
Mark B.
 

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The set screws are only to be used when a depression is drilled in to the restrictor, so the screws must turn several revolutions before the restrictor is released from the housing...per the illustration in the lower right.
 

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It may not make much difference, but with more than one set-screw, it may be wise to not install them in opposite sides of the compressor inlet. The compressor housing and restritor will see different temps, and there for different degrees of expansion, as the engine heats up, and one can imagine some stresses on both if the screws are inserted on opposite sides.

Also, use stainless steel screws (to avoid corrsion problems).

Mark B.
 

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Not trying to be contrary, but I asked Mike Harris all of these same questions last year.

If there is a screw on each side of the restrictor, then removing one of the screws could release a loose fitting restrictor, putting the screws on the same side of the restricor means that both would have to be removed before the restrictor came out, and the restictor would sure to be "surface to surface" opposite of the screws.

Proper, legal, restrictors fit so tight that they usually seize together, and won't come apart without a major application of force even after the screws have been removed.
 

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I'm sorry but looking at those pictures how does the intercooler pipe connect with that safety wire in the way??----i'm looking at the last pic in that series.


Gary Cavett
Cavett Rally Motorsports
 

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>I'm sorry but looking at those pictures how does the
>intercooler pipe connect with that safety wire in the
>way??----i'm looking at the last pic in that series.
>
>
>Gary Cavett
>Cavett Rally Motorsport

Thats an extra piece of wire long enough for the seal...It only looks like it's part of the turbo in the pic ...Thats FIA way of sealing a turbo.
 

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Hey Mike, since the RESTRICTOR is what we are concerned with being tampered with, and I guess there are those who might be slimey enough to want to chance changing the entire compressor housing, whats the deal in the piccies about wiring up the center section, and the wastegate actuator etc???

Is it required to be wired up like EVERYTHING in the piccies?
We CAN change those parts during an event, CAN'T we?

John Vanlandingham
Seattle, WA.
www.jvab.f4.ca

janvanvurpa(at)f4(dot) ca

Vive le Prole-le-ralliat!
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Rally Anarchy Rallyist BBS
- http://www.rallyanarchy.com/
 

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>The set screws are only to be used when a depression is
>drilled in to the restrictor, so the screws must turn several
>revolutions before the restrictor is released from the
>housing...per the illustration in the lower right.


Mike, how does one (you) know that the proper indention is made in the restrictor if they are supplying the turbos screwed, wired, and ready for "inspection"?

It would seem to me that an evildoer or even a common scoundrel could lock the screws in the housing short of the actual restrictor, wire the cap screws, and lock the restrictor with another (much less obvious...and much more temporary) fixation.

Want an example? PM me.
 

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>Hey Mike, since the RESTRICTOR is what we are concerned with
>being tampered with, and I guess there are those who might be
>slimey enough to want to chance changing the entire compressor
>housing, whats the deal in the piccies about wiring up the
>center section, and the wastegate actuator etc???
>
>Is it required to be wired up like EVERYTHING in the piccies?
>We CAN change those parts during an event, CAN'T we?
>
>John Vanlandingham


This sealing method is also used by the FIA for enforcement of number of spares (not an issue for us), but if the compressor housing isn't sealed to the rest of the turbo, it would be easy to remove the compressor housing / restrictor as an assembly, grind out the restrictor, and re-assemble without breaking the seal...especially on the spare turbo's I'm sealing on a workbench before the first service.

These parts can be changed, and this sealing method is not required, but it is done for your own convenience, because with this sealing method, we can quickly open the hoods and check the seals at an RGC, or MTC coming into service, or at the end of a day. Without the seals, we're going to follow the car into service and require access to the restrictor to check it.

Even with the seals, restrictors are still checked at least once per event weekend.
 

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>Mike, how does one (you) know that the proper indention is
>made in the restrictor if they are supplying the turbos
>screwed, wired, and ready for "inspection"?
>
>It would seem to me that an evildoer or even a common
>scoundrel could lock the screws in the housing short of the
>actual restrictor, wire the cap screws, and lock the
>restrictor with another (much less obvious...and much more
>temporary) fixation.
>
>Want an example? PM me.

At certain times (Pike's Peak last year was one), we have removed the turbos from the vehicles, and checked the restrictor fit and retaining method to the compressor housing. We also apply quite a bit of force to the restrictor each time before sealing, and make sure nothing wiggles.

As a former Nascar crewman, I've plenty of ideas on how to get around wire seals, bleeding air around restrictors, creative rules interpretation etc, but send me another!
 
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