Sean, do you think there are any gains to be had by running dual wastegates? What would be the downside to only running one? And how important is it to synchronize dual wastgates?

Thanks
Allen

 

Running dual wastegates allows you to do a few things one is keep the manifold completely divided. It also allows you to run a more efficient(for lower boost) valve to diaphragm ratio. This offers better boost control. I think most people go over board on wastegate size. If it were me on your set up I would run on 44mm and be done. It is a good happy medium. Big enough to control lower boost settings and small enough to work with 38lbs. Dual wastegates are cool but not necessarily needed.

-S-

 

Ok, so lets start talking prices. How much money are we talking for a manifold that has roughly 2" ID tubing, 16-18" long, equal length, setup for a single wastegate, etc. Safe to say 1k+?

Hmmmm, maybe I should see if Ralph or Rob has one laying around. All this talk about faster spool, and more power sounds good.

CJ

 

Is there any importance to keep the WG runners equal as well?? Seems that could be very tough with space constaints. If not equal, are you creating more back pressure in one of the runners? If so, maybe it's not a huge issue but if you go thru the trouble of equal intake length, and equal exhaust length...why impose more back pressure at the very end of the system if you can avoid it?

maybe I'm way off base here, just the way things work in my head. I have to think dual WG and true fully divided has more to offer than just "cool". If the efficiency is seen at low boost, that's creating much more under the curve power. Maybe it's not so important in drag racing, I don't know...I'm just thinking at loud, if I'm misunderstanding something, please clue me in. Might be just as hard to fit dual WG's as it is equal WG runners

 

That was exactly what i was going to ask! I was wondering if the overall length as well as equal length of the wastegate runners had any benifits?

 

Ideally you would want to keep everything as equal as possible. Equal secondary runner length, equal length up to secondaries etc. This is a very hard thing to do when you are limited by space etc. You more than likely will have to mount them in different positions on the primeries. If done (located)correctly backpressure differential would be minimal. Is there some benefit? Yes. Is it worth the added mess and wieght under the hood? Not really. It's minimal. Ask your self how many pro built cars in most any form of racing are using more than one wastegate per manifold.

 

OK guys one last question (yeah right ). How would you determine the diameter of the tube(s) going to the wastegate? I am pretty sure you can go too small but is it possible to go too big?


Thanks
Allen

 

After several turbo swaps and many other changes my header is finally finished. I ended up with 16" primary length and a 2" ID.

 

WOW, that is fuggin bad *** man. very nice work indeed!!!!

 

very sexy MANIFOLD you have there.

 

Congratulations, she's a beauty.

Hope you get awesome results out of it. If it performs as good as it looks, I think you're in business!

 

Thanks guys, everything is starting to fall into place. I would also like to thank everyone who gave me advise in this thread.

Allen

 

What turbo did you end up with?

 

Damn did this thread turn into something special, nice job!!!

 

It is a Borg Warner S475. A little big for this motor but it will be just fine for the next.

 

Here is a pic of the finished product on the car.

 

wow Very nice. Congrats. I realise this thread is semi old, but I was wondering if he liked how it performed?

 

I don't really have much to compare it to but it does perform.

Check the vids in my sig.

 

Nice Vids ! what port u run ? it sounds like a bridge .

 

Believe it or not that was a stock port with a less than optimal midrange tune. At idle it purrs like a kitten but just barely crack the throttle and it goes to lopeing. I figure it is the fact that it has such a large intake and throttle body.

You can really tell on the dyno.

http://www.youtube.com/watch?v=Re_QuvMnR28

Here is a thread with the pics of the aftermath though.

https://www.rx7club.com/rotary-drag-racing-167/can-factory-reman-motor-run-9s-713563/

 

Didnt I see you using a stock series 6 intake in an earlier pic ? did you change it ?

 

Yes, now it has a 4 barrel intake and a E&J throttle body.

 

O ..Ok , I got the Pro Jay intake and TB , semi-pp motor and a GT45R , I wonder how mine will sound ??

 

another thing to think about when choosing runner length is egt temps going into the turbo and also the wastegate. a shorter runner manifold will have much higher egts on the face of the wastegate valve as well as the turbo. rotaries already tend to run very conservative ignition timing which increases exhaust temps. temperature kills everything so whenever you can keep temps down its a good thing.