Boost Creep

[diablo]

I have just completed the installation of a 3" exhaust and big 16G with the upgraded flapper door for the internal waste gate in my 2g.

I am getting a fairly severe boost creep past 5500 rpm. Obviously my MBC is no use since my boost is going all the way to 18 - 19 psi. I have read that the External Wastegate is the way to remedy this situation.

I am trying to decide which route to go.
Should I go with replacing the o2 housing and the external wastegate mounted on it with a return dump tube to the exhaust to keep it quiet? I don't understand this setup and I would want to know if that would really work and solve this problem? if so can someone please explain it to me
or is it better to install an external wastegate on the manifold?

Thanks

 

[redwards]

to mount a wastegate on the o2 sensor housing, you need a custom fabricated o2 housing. What you do is split the two exhaust passages (the one for the WG and the one that goes over the exhaust turbine) and mount the wastegate at the end of the WG side passage (the flapper would have to be removed if the turbo were originally set up to be internally gated) and the standard side then bolts to the downpipe like a regular o2 housing.

Like so:

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Some people say it controls boost even better than a WG mounted on the manifold, but I think the main advantage is that it's a lot less eyegrabbing if you get your hood popped (because it's hidden down in the engine compartment instead of in your face).

 

[diablo]

Thanks. That was good info.
Can the internal wastgate and larger O2 housing combo handle the problem or do I have to go with the external wastegate.

I also need to know what size of wastegate to choose and what model. I prefer being able to control my boost between 10 and 20 psi.

 

[redwards]

Originally posted by diablo
Thanks. That was good info.
Can the internal wastgate and larger O2 housing combo handle the problem or do I have to go with the external wastegate.

I also need to know what size of wastegate to choose and what model. I prefer being able to control my boost between 10 and 20 psi.

Could, but most people end up going with an external setup sooner or later. Most common is the 35mm Tial, which is wonderful for your particular application. Big16g / 35mm tial is a common combo.

It's really nice to have your boost levels go to exactly where you want them and stay there. Plus, if you decide not to route the dump tube back in, you can scare a lot of people

 

[Kevin Jewer]

If you do a search on boost creep (with my name perhaps) you'll find that its not that hard to get boost under control with a 16g. It doesnt cost much if you arent afraid to do your own porting. But the external really is the way to go, so I wont talk you out of it

http://www.dsmtuners.com/forums/showthread.php?s=&threadid=55813&highlight=internal+open