Ad: VTT GC's vs. "competitor x" back to back dyno (same tune)

Oct 24, 2016
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Scottsdale, AZ
A local customer stopped by a couple of weeks ago to inquire about swapping out his 4th set of high flow turbos from "competitor x" for a set of GC's.

You may ask why swap from perfectly good functioning turbos to new ones? We were told this was the customer's 4th set of "reliable" offerings, he got told no warranty if he posted about the failures (same story and treatment on sets 1-3) so he eventually decided to just pull #4 before they failed, and here we are with shiny new GC's on his car.

He dropped it off for the install, and before we started the work we threw it on the dyno for a baseline. No tune changes. This is a true apples to apples no tune change comparison, and really shows the difference between stock frame turbos and the GC's.

We strapped it down and ran it. Swapped the turbos for the GC's performed some maintenance items, put it back on the dyno and ran it again. Here are the results:

Dyno Comparison:

HF vs GC's.JPG



Car Specs:
2008 N54
6AT
Silicone inlets
VTT GC's
GC aluminum outlet
PI
MHD Flash
JB4
Exhaust of some brand, no idea which
 

The Convert

Captain
Jun 4, 2017
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What do you mean by “performed some maintenance items” and were the other VTT items already on the car, or were they added at the same time?
 

Asbjorn

Lieutenant
Mar 10, 2018
854
602
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European, based in China
Ride
Z4 N54 DCT
List of irellevant maintenance done
- Solved super minor (≤1bar) boost leak
- Tiny replacement of old vanos with slightly never used one
- Solved small issue related to PI not spraying at all before
- Downgraded from two old boost solenoids to working type
 
Oct 24, 2016
1,152
1,202
0
46
Scottsdale, AZ
What do you mean by “performed some maintenance items” and were the other VTT items already on the car, or were they added at the same time?
Gaskets changed for oil leaks, new turbo install kit, just basic stuff. The guy has the car already set up well for power, but as typical with these cars. They leave the stuff that needs attention. We suggested much more work when the subframe was out. Oil pan gasket, water pump T-stat, etc, etc. He declined.
 

The Convert

Captain
Jun 4, 2017
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Gaskets changed for oil leaks, new turbo install kit, just basic stuff. The guy has the car already set up well for power, but as typical with these cars. They leave the stuff that needs attention. We suggested much more work when the subframe was out. Oil pan gasket, water pump T-stat, etc, etc. He declined.
Damn. I would have bitten the bullet on those items to not have to pull subframe again. To each their own I guess.
 

nyt

Sergeant
Sep 15, 2019
331
1
289
0
Ride
2010 335xi
List of irellevant maintenance done
- Solved super minor (≤1bar) boost leak
- Tiny replacement of old vanos with slightly never used one
- Solved small issue related to PI not spraying at all before
- Downgraded from two old boost solenoids to working type

- set JB4 to higher boost map
 
Oct 24, 2016
1,152
1,202
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46
Scottsdale, AZ
Damn. I would have bitten the bullet on those items to not have to pull subframe again. To each their own I guess.

Me too, and not as an employee, just in general. Once you've been with this platform for a while, you see maintenance that needs to be done and just say... FINNNNEEEEE, and commence with thinning out the wallet, normally because it's preferable to NOT doing that stuff and seriously thinning the wallet out down the street. Speaking of that, it's time on my own car to pay the piper... ugh. FINNNEEEEE
 

TheFixer

Sergeant
Aug 16, 2020
493
352
0
Tennessee
Ride
2008 535i
You guys have a good product and great customer service. A lot better than most. I'm impressed.

I'm curious about what turbos that guy was running. I saw something on another forum about a guy who went through 3 or 4 sets. They were MMP. They probably are the worst company I have read about that sells turbos with the most failures and has the crappiest customer service.