external gate

[Ahapartridge]

Originally Posted by Spearmint

Take the downpipe off and have a look inside the back. The wastegate should open freely without the actuator arm on.

It does Richie, was fouling before final fitment but the divider in the turbo Elbow was 'adjusted' to eliminate that

I wonder if a dump/elbow without the separated pipes might be better, wondering if the small wastegate pipework might be causing too much of a restriction

Steves is like this


Wonder if this type would help

[MR Y]

Cheers Pete, I've emailed GCG again to see what they think

[MR Y]

And this was their reply.........

Steve

I have sold dump pipes with these turbochargers as you have pictured (split stainless pipe) without any further boost creep issues. I do know for a fact that our RB25DET high flows we do will boost creep if the car doesn't have a cat, but I can't see why a further open flow dump pipe would have a problem (such as the D2 picture you sent). Apart from trying that flying dump pipe, I cannot suggest anything else as the flapper/porting we do is as big as you can possibly go in that exhaust housing, so there is no more room for porting.


Regards,

MICHAEL RAMSAY
Internal Sales
GCG Turbochargers Australia Pty Ltd

[Ahapartridge]

So basically they have sold you a Turbo that cannot control boost and all they can say is I cannot suggest anything else, that's a bit crap isn't it?

[MR Y]

Yup! And looking at these pics I dont think theres any hope of fitting a bigger flap either






And reading back through the problems the other guys on sau had, if I've got the 38mm gate/flap then I dont think I should be having this issue??

edit: this was another reply from GCG

Steve

There are a few things you need to check in order to eliminate some possible scenarios.
*Blocked Catalytic Convertor causing excessive exhaust back pressure.
*Broken/Split Vacuum hose from actuator to pressure source.
*Too much pre-load on the actuator rod
*Actuator rod bent and possibly catching on the bottom of the cannister/bracket.

The reason I ask these questions is that we fit 38mm wastegate flappers to these turbochargers, which we also fot to XR6T turbos, and we never run into boost regulation issues. The only other thing you can do is pull the actuator off the turbo and bring it down for testing.

[MR Y]

Right, GCG have offered to send me a modified manifold with external wastegate for 700 dooollars (posted) to cure it, but after many nights of thinking about it, Im going to try the flying dump pipe first. Thinking back me and Pete had loads of trouble setting up the profec b on my standard tubby, the boost on that used to climb at high revs, I always put it down to the boost controller not being set up right but after lots of reading up and thinking, I think all my problems may lie with the split dump I have, fingers crossed it is that as thats the cheapest solution

Im sure I read that the way its piped up the wastegate gasses would struggle to meet up and exit with the exhaust gasses possibly due to no cat and the exhaust gasses exiting with less restriction, though I may have dreamt that bit


Seem to be going round in circles with this but havent drove it much, its about time I got round to sorting it