You are saying that 1) a restrictive O2 housing won't create exhaust backpressure? You are also stating that 2) a restrictive wastegate won't cause backpressure? Hmmm!

What specifically about the 16G's turbine and impeller combination causes backpressure in your opinion?

Why do you say that that running less boost is the "only" way to reduce backpressure? Less boost than what?

Do you mean larger A/R turbine housing? A larger turbine wheel should also reduce exhaust backpressure, shouldn't it?

Man how can you make so many ill-founded generalizations in just two short sentences? And to think...you've logged well over 3,000 posts!

Edit: The only one of your statements that I might tend to agree with is the one about the WG having little to do with backpressure. But, even in this scenario, I only partially agree: Under certain circumstances the WG could conceivably come into play as a contributing factor in the exhaust backpressure equation. Still, you need to be more precise.

 

i think you should do it external wastegate on stock turbos can work wonders on boost taper i have done it on my old 2g dsm

 

By definition, if the WG is mounted on the turbine housing at the outlet of the wastegate bypass port, then it is still more accurately, an internal, or, integral gate. To be external, or remote, in the case of the Evo's inline four, engine configuration, then the WG would need to be flanged directly off the exhaust manifold.

 

I would have to disagree with that statement. Look at FP's turbos and the log manifold kits that buschur sells. Same concept. Either the top of the housing or on the manifold it is taking the air from the same spot.

 

Yeah, it's merely a semantic distinction on my part. I have no argument with the pictured aftermarket gate being more efficient than the stock integral 16G gate.

But, still for argument's sake, it can't be denied that the larger aftermarket gate is mounted at the outlet end of the turbine housing's bypass port although it(the integrated bypass port)may be bored out internally. We are talking about a larger diameter aftmarket gate which is still as far as I can tell sourced off the turbine housing's original bypass port which is internal to that housing. It is not a true remote WG design per se.

As far as I'm concerned it is a bit overkill. For all practical purposes, the enlarging of the turbine housing's wastegate bypass port's internal diameter along with simply fitting a larger diameter flapper valve should substantially accomplish the same exhaust gas bleed function at a sigificantly lower expense. Although admittedly it wouldn't be as elegant.

 

I will post some pics tomorrow of it so you can see.

 

Thanks buddy! Is the turbine housing's siamesed bypass port, bored out internally to become a single, larger port? I mean is the bypass port's divider wall done away with.

 

No. You will have to see it.

 

EDIT: Sorry guys for my excessively OT posts to this thread. I don`t know why one lousy can of that Belgian, 8.4% alcohol, by volume, beer, called "Navigator", always strays me off beam into such rough seas. LOL

 

3 questions-
Was this a single flapper or dual flapper housing?
Will you be recirculating or dumping to atmosphere?
What boost control method/port setup will you be using? (my .02 is that if you are using any sort of EBC method that a direct uncontrolled boost signal to the bottom of the WG and a controlled signal to the top will be best)

I look forward to the results.

 

I will post pics up later. The housing is completely different. Their is no longer a flapper in this housing. I know you normally weld it but this is a little different. The dump will be vented to atmosphere. My boost control will first start with a hallman and maybe just a wastegate for a solid 24lbs.

 

Yeah I realize that the flapper was removed but I was just trying to figure out if it started life as a single flapper or dual flapper 10.5.

The reason I asked about the boost control is because Buschur said that he lost spool with this setup. I think the reason was that he may have been running either on spring pressure or with a boost controller intercepting the signal to the bottom of the wastegate. Either way the valve can creep open.

If you have a constant pressure to the bottom and modulate the pressure at the top I would think you can get the valve to stay closed longer by keeping pressure in the top.

 

A manual boost controller might be able to pull that off. I will be testing all ways.

 

Are you going to be trying out a BCS at all? like the GM 3 port? (That's what I was going to do )

 

Man whats with the Megan o2 housings and boost creep??!! Seems like everyone has this problem. I know you can enlarge the hole but who wants to go through that??