VTT Aluminum Outlet Testing Results!

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Captain
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Oct 24, 2016
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Tony had to drop some pistons off over with the fine gentlemen at Rebello Racing, and being as they have a flow bench... well, it just seemed like some testing was the right thing to do. We grabbed a stock outlet we had laying around, and one of the new outlets right out of the bin they get pulled from for shipping. We asked Dave if he would mind some back-to-back flow testing. The guys are Rebello Racing are awesome so they didn't hesitate to stop everything they were doing in order to indulge us.

We didn't do anything fancy, as this isn't a fancy test. We ran all tests at 28" of water, which is standard for most flow bench tests. The flow bench they use is an SF-600, which can flow up to 600 CFM. You can read specs about it to your heart's content at this site: http://www.assurich.com.my/engine-dynamometer-system-superflow-sf-600.htm

IMG_5980.jpg


We began by installing the stock outlet on the bench using a 2.5" silicone adapter and turned the machine on. Dave does A LOT of flow testing, so his guess that "Range 4" was about right was dead on. Range 4 has a maximum flow of 295 CFM at 28" of water. Results showed it flowed right at 73% (of 295 CFM), so the stock outlet flowed 215.4 CFM.

IMG_5985.jpg



With no setting changes, we pulled the stock outlet off and put on the VTT aluminum outlet. When turning the machine back on, it flowed 100% at 28" of water -out of range (high) on Range 4 and Range 5. Dave laughed and said "you maxed out my flow bench" as he rarely has to use "Range 6". Dave schooled Tony on the topic after testing and explained how if you have ranges left unused, once you hit above 75% you'll always want to go up to the next range and bring the flow percentage down into a more reasonable range for more accurate readings. Range 6 has a maximum flow of 597 CFM at 28" of water. When Dave turned the machine back on, we could see that the VTT outlet flowed 59% (of 597 CFM), so the VTT outlet flowed 352.2 CFM.

The VTT outlet flows 1.63x as much as the stock outlet. This is a significant difference.

Keep in mind this is a flow bench designed to test NA heads for flow. The CFM reading isn't representative of what it would flow under boost, the purpose of this test was to simply state, outlet A stock when put on a flow bench flows X. Outlet B VTT under the same conditions flows 63% more. This should lay to rest the doubts about performance.

Results Recap:
Stock Outlet: 215.35 CFM @ 28" water
VTT Outlet: 352.23 CFM @ 28" water
Difference: VTT outflows by ~63%

Vids:
Video #1: Stock testing
[video=youtu;V5DDjIwFB9A]


Video #2: VTT Outlet testing
[video=youtu;VA5trZCW9l0]


Video #3: Wrap up
[video=youtu;6PwqwrI6Lu4]
 

DennisKing

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The VTT outlet didn't even have the flange for the turbo on it for bank 2 turbo.
The flange itself will change flow characteristics.
Could we see data with both flanges present instead of what appears to be one flange on bank 1 and no flange on bank 2
 

aus335iguy

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It’s hard to see because its not in the shot most of the time but if its not on both pipes i think youre right. It would have a dramatic affect on the result

Edit - i zoomed in and on my screen it doesnt even look like its got flanges on either bank !
 
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NoQuarter

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Agreed. This is awesome that there are some results listed here. But the impromptu testing just invites critisim with the omission of including the actual turbo outlet size.

That said... I will probably order a set anyway because it has to better than my silicone outlets. And I am on stock turbos so getting them for looks counts as well.

Hell... If all of this was about $$ we wouldn't be doing any of it.
 
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KevinC39

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This is a vendor thread as it's created by a vendor and per the vendor rules he is welcome to do that but he would need to share those opinions in a different thread in our octagon/dispute section.

A post in violation of our Vendor rules has been moved, related discussion may continue here: https://bmw.spoolstreet.com/threads/questions-about-vtt-aluminum-outlet-testing-results.3411/

You even talked about the rule right before he broke it?
 

BQTuning

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I am contributing to the thread in support as I am a VTT customer who bought their aluminum outlet for my Z4 stock turbo project.

Edit - i zoomed in and on my screen it doesnt even look like its got flanges on either bank !

VTT sells 3 or 4 different outlet types. I think the ones tested are the hose barb type usually seen with the silicone VTT couplers.

http://performance.vargasturbo.com/bmw-products/

Aluminum%20Outlet%201-1000x1000.jpg
 

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Captain
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Hey guys, that was a GC outlet with no hoses on it. The ID of all outlets is identical, the only difference is hose barb or v-band. Dave thought that the silicone couplers being attached would give an unfair advantage due to the slight bell mouth effect, so we took the time to remove the pinch clamps/hoses. Dave estimated a 20 CFM gain if we would have left them on, and that gain would not be representative of the real world outlet flow advantage over stock. If you're unfamiliar with bell mouth flow characteristics, they essentially help shape the flow of air into the piping system in lieu of air having to cut directly across.

Chris
 

The Convert

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"The compressor housing outlet ID is actually quite small (~1") whereas the OE outlet tubing is quite a bit larger (~1.5"). BMW engineers designed a transitional adapter (which is integrated into the OE outlet assembly) to provide a "port matching taper" to transition the smaller ID (at the compressor housing outlet) to the larger ID (at the outlet tubing entrance)- to effectively increase airflow by reducing turbulence from the otherwise gaping mismatch of port sizing."

"1) Any idea the impact of the outlet assembly flow increase that can be accredited to the removal of these transitional adapters?
2) Any idea the impact of removing the OE engineered transitional adapter from this connection from a functional system/turbulence perspective?"

I "cleaned" up a response by another person to ask it in an allowable way in this thread to try to get an answer that would likely require another round of testing if you guys get the opportunity. Cool to see the results posted above. Would also be cool to see how it all works together within the system.

Thanks!
 
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foe516

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i have your silicone outlets from 2016 for 2016, i was in pre-sale, i have not had any problems besides a few times the connection to the fmic popped off, fixed with a longer metal adapter. i was worried about heat but i had enough clearance and wrapped with titanium exhaust wrap. would these be an upgrade? im doing turbos this month and considered ordering and just putting mine up for sale for 100$ for a quick sale. are these in stock?
 
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aus335iguy

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Hey guys, that was a GC outlet with no hoses on it. The ID of all outlets is identical, the only difference is hose barb or v-band. Dave thought that the silicone couplers being attached would give an unfair advantage due to the slight bell mouth effect, so we took the time to remove the pinch clamps/hoses. Dave estimated a 20 CFM gain if we would have left them on, and that gain would not be representative of the real world outlet flow advantage over stock. If you're unfamiliar with bell mouth flow characteristics, they essentially help shape the flow of air into the piping system in lieu of air having to cut directly across.

Chris
I dont think that theres anything deliberate about omitting this from your original post. But it would be nice to see all three versions compared.
 

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Captain
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i have your silicone outlets from 2016 for 2016, i was in pre-sale, i have not had any problems besides a few times the connection to the fmic popped off, fixed with a longer metal adapter. i was worried about heat but i had enough clearance and wrapped with titanium exhaust wrap. would these be an upgrade? im doing turbos this month and considered ordering and just putting mine up for sale for 100$ for a quick sale. are these in stock?

It would be an upgrade with respect to durability. Tony still prefers the silicone, it's just absolutely critical that silicone be installed correctly otherwise durability issues arise.

They are in stock!

Chris
 

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Captain
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I dont think that theres anything deliberate about omitting this from your original post. But it would be nice to see all three versions compared.

You wouldn't see a flow difference between the hose barb and V-band connection outlets as those connection differences are outside of the flow path. That's why we pulled off the hose barb adapters -would have given an unfair advantage to our outlet vs. stock.

As far as the photo BQ posted -that's 335 vs. 135 outlets -dictated by fitment. We don't really care how a 335 flows vs. a 135, just how either of them flow vs. their respective stock outlet. :)

Chris
 
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