So, I did some searching and have read about both, but I can't really gather which one people prefer more and/or which one is "better"


The DT Bypass Valve uses a stiffer spring and centering the butterfly door and adjusting the set screw.


The GTT Bypass Valve specifically says that it does not use a stiffer spring as that can be detrimental, and that they are the only one that truly re-centers the butterfly.


Anyway, has anyone had experience with both? Does anyone know enough about both to tell me your opinion?


Just trying to make an informed decision and get the best part for my car.

 

The butterfly is not cut from the same cast or material as the bore it resides in, so they cannot "truly center" the butterfly, because the surfaces are cut at different tolerances by different means, and of different material.

Our valve does change how boost comes on, and may cause a snappy on/off switch type transition from vacuum to boost. It has shown to cause a slight drop of fuel economy, but nothing substantial, doing a pulley hurts your economy more than our valve does.

If you wanted a valve that is "performance adjusted" without the stiffer spring, you can order one from us or Way, as the both of us adjust even the stock valves, and I'm sure that one of either of our stock adjusted valves is going to be cheaper than the GTT.

Our valve isn't for everyone, and we'll be the first to admit it. It does change the dynamics of how the car feels on and off boost, and some people don't like the snap between boost/vacuum in their DD. Our valve was designed to close quicker, more effectively, and to eliminate the yo-yo of a worn valve, and can be closer oriented to spirited drivers over people who are just in need of a stock replacement to fix their failed valve.

Nick

 

What do you mean by "snappy"? And I already have a Way reduced pulley so my fuel economy is already down some, I'm averaging 26mpg but like you said, it probably won't make much more difference. Hey, I bought the Mini to supplement my ~600HP diesel truck as my everyday driver...so anything is better than the 14mpg in that!


That's fine, I bought an "S" for the fun, not just fuel economy! I'm mainly doing it to fix the yo-yo that I am having right now though. I'm just doing little things for maintenance and upkeep right now, but also upgrading. After too much longer I'm going to start with more performance and really make it fun.

 

Depending on how you drive you may notice a more abrupt transition between boost and vacuum, it can seem a bit lurchy to some, but again, the valve was designed to fix the yo-yo effect and to produce quicker more efficient boost generation.

 

Yeah I have the 17% and DT bypass valve combo... when you let off the throttle, your car "jerks"... nothing major unless you're into a smooth ride, in which case you've bought the wrong car

 

Please provide your MCS's year and list the modifications.

 

Never mind if the OP bought a pre-05 MCS and that's what you meant by bought the wrong car.