What's with the multiple restrictive "steps" into the wastegate side??? Built in boost creep feature?



- bryan

 

Looks like a big hole bored, and the small hole bored through that is offset from the big bore. I'm guessing that big bore is necessary for clearance for the stock flapper valve to open all the way.

It'll only creep if it can't flow enough, but I'm guessing it's fine. It has a pretty nice merge with the main flow.

 

Its because in the picture they are using a 38mm external wastegate. You can use up to a 44mm wastegate, hence the size of the hole and step down for the 38mm

 

The 38mm doesn't come with V-band connectors. That's a 44mm in the picture.

 

oh ok my mistake

 

its the new tial MV-S wg, comes in vband, its the new "compact" 38mm design

 

Completely different top end/diaphram housing. It's a 44mm

Tial MVS

 

oh i didnt even bother to compare the pictures, i read somewhere that you could buy it with the new 38mm and i assumed that was it

 

Doesn't the fact that you allow the exhaust streams to mix beyond the divided section dilute the pressure wave integrity for the dual scroll turbo? I got within a few days of fabbing one of these myself before this thought stopped me dead in my tracks.

 

No I highly doubt it because the stock DP isn't divided. There is still two different channels before the turbines and that's all that matters is where they get their propulsion from, not where the leftover exhaust gas goes after it's propelled each turbine wheel. Besides, the stock turbo doesn't have divided outlets on the hotside, so it doesn't matter what's after that.

 

Let me make sure we are referring to the same thing. I am referring to the division between the BPV channels beneath the flapper. The BPV channels exit prior to reaching the volutes. If the flapper is open (or removed) and replaced with a Tial above the BPV chamber, gases will comingle before they hit the turbo.

To take it even further, since the two volutes are of different geometry, they are going to have potentially different pressures and gas velocities. Since gas follows the the path of least resistance, if the flapper is gone and the exhaust is comingling in the common chamber, it goes to reason that the pressure wave signal is going to be muddied, mitigating the pressure wave effects that benefit a twin scroll.

It's all theory, so I guess the only way to know for sure is side by side comparison.

 

Has anyone tried this DP with the stock turbo yet?*

 

Bump, also what wastegate should be used with the stock turbo on about 24-27 lbs? 44mm or 38mm?

 

I would say a 38mm would do the job. For anything higher, a 44mm.

 

Quote:

"Let me make sure we are referring to the same thing. I am referring to the division between the BPV channels beneath the flapper. The BPV channels exit prior to reaching the volutes. If the flapper is open (or removed) and replaced with a Tial above the BPV chamber, gases will comingle before they hit the turbo. To take it even further, since the two volutes are of different geometry, they are going to have potentially different pressures and gas velocities. Since gas follows the the path of least resistance, if the flapper is gone and the exhaust is comingling in the common chamber, it goes to reason that the pressure wave signal is going to be muddied, mitigating the pressure wave effects that benefit a twin scroll. It's all theory, so I guess the only way to know for sure is side by side comparison. "

This is making me have second thoughts about buying this DP, does anyone else have an opinion on this?