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-   -   Wastegate Position / manifold design (https://www.nopistons.com/2nd-generation-specific-17/wastegate-position-manifold-design-59814/)

KillerRx4 06-06-2006 10:23 PM

Call me lazy if you like. https://www.nopistons.com/forums/pub...IR#>/blush.png



Would like to hear your opinions on this topic. >



http://ausrotary.dntinternet.com/forums/vi...ic.php?t=101806

1Revvin7 06-06-2006 11:12 PM

Not a good idea...

Nospig 06-06-2006 11:52 PM

Yea not a good idea , a good responsive turbo will boost creep. If the wastegate pipes have a good collector exhaust interference will not be a problem .

RONIN FC 06-07-2006 11:41 AM


Im in the process of making a new turbo manifold & im up to mounting the gate. I am thinking about putting the gate off 1 runner only to maintain a true divided setup.



Has anyone done this & had any trouble with the setup?



Its finished & fitted up now, I'll find out next week on the dyno if it does or doesnt work.
Im curious, what were the results? Im not totally convinced it will make high boost on 1 rotor with the WG open.

wankelTII 06-07-2006 05:55 PM

Thats stupid as hell!



If you have a divided turbine housing then the air has to go into the turbo and come backwards down the other runner to bypass the turbine. Even if there is no boost creep which i think there would be, its still stupid.



I dont know that it would make high boost on one rotar, but if it did it would probably be on the rear rotar and thats bad.

I dont know though, i dont really think it would, the exhaust pressure btwn the rear rotar and turbo would be higher but that just means alittle less new air would enter the rear combustion chamber (a very very small amount less). It would just cause boost creep is all that i can see, and that may not be bad either, but that set up just doesnt make any sense. Intake manifold pressure is equal on both sides, so boost pressure is the same on both rotars. Its still stupid though, if he wants to do it that way he needs to have 2 small wastegates.

KillerRx4 06-08-2006 03:06 AM

Nospig, I expect it to either work & hold boost @ the desired 20psi or will Creep. Will be 1 or the other I imagine. Another possibility I think might happen is boost might come on softer/slower.



Ronin, I havent put it on the dyno yet. Booked for this time next week. Will be sure to post results.



WankelTII, I dont think you understand how a turbo & wastegate work together.


Originally Posted by wankelTII' post='823018 (Post 730758)
I dont know that it would make high boost on one rotar, but if it did it would probably be on the rear rotar and thats bad.



More boost to rear rotor simply because that rotors exhaust runner doesnt bypass the turbine? Dude, Theres no intake restriction to the rear rotor so it will recieve the same intake pressure as the front.




Originally Posted by wankelTII' post='823018 (Post 730758)
It would just cause boost creep is all that i can see, and that may not be bad either, but that set up just doesnt make any sense. Intake manifold pressure is equal on both sides, so boost pressure is the same on both rotars. Its still stupid though, if he wants to do it that way he needs to have 2 small wastegates.



Ahha, boost creep. https://www.nopistons.com/forums/pub...R#>/tongue.png

wankelTII 06-08-2006 08:02 AM

Its a completely divided set up, (i assume that means the turbine housing is divided too) air from the rear rotar cannot get to the wastegate without actually going into the turbine housing and coming back down the front rotar's exhaust runner. I dont think the air can or will do that, so the creep wont just be a small amount.



Do you understand how wastegates work?!?! If the air cant get around the turbine then it will continue to spin the turbine wheel.



Someone else said there would be high boost on one rotar, i realized in a matter of 3 sentences that wasnt possible, i just didnt go back and take out my thought process. But your right intake pressure is intake pressure, ok duh.



Even if it works, I still think its a ridiculous way to do it. Its got to cause some wierd stress on the bearings or something to have way more exhaust pressure on one rotar. Why not just do it the normal way, or with 2 smaller wastegates? Neither are difficult, this just looks like you got lazy or something.

jefraney 06-08-2006 11:30 AM

A properly sized wastegate anywhere before the turbine will technically work.



Obviously, dont use a little 28mm wastegate on this setup. I would use the largest you can find. You have to remember that a wastegates function is to equalize the pressure before and after the turbine. The more pressure you can release, the more control you have (larger is always better in theis case).



Its not a good design, but it should do what you need it to, but you may have some creeping issues depending on the rest of your system.

wankelTII 06-08-2006 05:20 PM

Yes, but how does the pressure get equalized if the only way for it to escape the rear exhaust runner is to go through the turbo? There is undoubtedly going to be high pressure between the rear rotar and the turbine housing, I guess since the turbine is rather large and the front exhaust runner could possibly get close to atmospheric pressure when the wastegate is fully open, the creep might stop somewhere fairly reasonable, but i am willing to bet that the boost will be more than the wastegate spring was rated for.

RONIN FC 06-08-2006 05:40 PM

I think everyone is shooting down the idea before it even gets tested.



I have some theories about that setup and what it will do. Some positive, some negative that I think I will hold on to until it gets dyno'ed.


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