Quote:
Originally Posted by s2d4
Yes, it is used to remove excessive pressure and likewise with the BOV and Which is why in certain setups, people just use the wastegate/screamer pipes to control their boost levels, regardless if it is surge or overboosting at given rpm. I was trying to demonstrate an issue which only exists for centri chargers due to that fact that it is belt driven.
It was just that your original comment was about the bypass valve (DV or BOV) for the Twinscrew which isn't a requirement due to it's placement and the instant torque. Unlike the centri, you do not need to use a smaller pulley to give you low end torque then use a wastegate to keep the top end boost down. You are also introducing more wasted heat and parasitic loss as the charger is now running higher rpm for no gain. Not only that, the centri actually needs the bypass valve like a turbo as demonstrated earlier (with a short path on the outlet, a wastegated setup can achieve the same). All Gem has done is forcing it to behave like a twinscrew and having to bandaid all the shortfalls of the centri.
The above contended comment was also referenced to the supposed "on-off" nature of twinscrew similar to the turbo. Both of these aren't exactly correct.
|
I understand where you are coming from now that you have explained what your thoughts were. I think really what has happened here though is that you read too deep into my use of the words "on/off". I can see where the confusion may have come from hence why I reiterated that I didn't mean it in the literal sense. Again I am not sure if perhaps there may be some confusion by what I meant because a bypass valve on a PD is not even used for the same purpose as it is on a centri. On a PD it is literally bypassing air around the screws or rotors in a roots. Mechanically it is more similar to an internal wastegate than a bov, recirc, or bypass. It may be that your terminology differs from ours and that two different things happen to be called the same thing.
I am not sure I agree that running a wastegated setup on a centri is necessarily a band-aid but rather a way to manipulate its intended function to achieve bits of character that other forced induction methods provide while maintaining the bits unique to the centri. No matter how you slice it turbos will never be centris nor PDs or vise versa no matter how you compare them but just as anything we as tuners find ways to squeeze power out of everything no matter how we find a way to do it. We tinker by nature. The excess heat generated really only becomes a problem if you really spin the centri out of its RPM range. You are without a doubt working the centri harder which in turn creates heat but this is where you have to manipulate with moderation. There is one thing I think we can all agree on and that is that all three methods (4 if you wanna add nitrous into the mix) of forced induction most commonly used provide unique characteristics that are accompanied by inherent pros and cons. There is always a way to manipulate them and this is where you can blur the lines a little.