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Are you seriously suggesting that the velocity increase of using one scroll for spool won't impart more exhaust energy on the turbine during throttle transition from low engine mass flow than normal?
As if people haven't been using quickspool setups for decades? The difference here is that after transition this doesn't present flow restriction or any significant additional volume in the system. It is clearly an intelligent evolution of the quickspool concept which when made in cast stainless will have excellent longevity too.
what benefit is there to the community in being willfully antagonistic? It is clearly far superior to any freely available gear for achieving the same thing.
I'm suggesting that if you wish to substitute something aftermarket that you made in place of a known HIGHLY engineered product that it would be beneficial to have some data to support doing so. Why do you think the EFR series is so incredible? Because Borg put ALOT of design work into every aspect of the turbo and its operation, and I can guarantee you that included thermal and fluid flow analysis used to sculpt the internal flowpath of that hot side housing to suit the turbine wheel shape (which was also designed for optimal efficiency using engineering analysis software).
Nowhere was I antagonistic in my question, I simply asked if it had been considered which is a valid question given that is how turbo manufactures design a turbo for performance and efficiency.
If your performance metric is quarter mile et, terminsl speed or lap time the 8474 will still win.
The s4 wasn't a divided manifold however. If there was an economical casting material at the time that could allow the less obtrusive flapper arrangement which also divorces the rotors i imagine mazda would have gone that way. You are also talking about pissy little factory turbos that are on boost at 2000rpm anyway.
Im having the same boost curve with the 8374 than with the stock S4 setup...ok porting might help here.
But Im not sure if you get it, when using a flap to close one runner to the turbine to reduce A/R to improve spooling, you also sacrifice the pulse charging effect, which imo is very strong on 13Bs.
So effects on spooling kinda cancel each other out. Mazda made this progress when going from S4 to S5 design, so why going back ?!
Quick spool valves do not shut off a complete runner, they reduce the size of the opening to focus the airflow path which, I could be wrong, but is supposed to create more velocity to spook up the turbo faster.
The pulses from the two rotors should still exist.
I didn't take skeese's question as antagonistic. While I think this new manifold with built in valve could be awesome, it'd be interesting to see if it's really better than existing quickspool valves and compare that to the price difference to buying a manifold and a valve vs this new design.
Quickspool valves aren't that common on rx7s (I've never seen a build with one), but a lot of supras sure have them. It'd be interesting to see how it really benefits a rotary. Are we talking 100 rpm shift or 500, or 1000.
My apologies then, perhaps I'm too used to seeing people pick at eachother on forums and just assume.
The reality is to assess stuff like this even a $15K/ year Solidworks flow sim licence is useless if you wish to assess anything other than steady state flow into the housing, even then it's unlikely you will be able to calculate an accurate energy imparted to the turbine (for a nominal smooth flow ~16 cylinder on a long/large volume exhaust manifold etc etc). You are probably looking at 100k in software and an engineer who has multiple years of sim work to get data which reflects differences near the accuracy of a well instrumented engine/chassis on an engine or hub dyno with consistent anbient conditions. I went down a path exploring something slightly different requiring high levels of accuracy for work and concluded it would need to be a Phd for me and my employer forking out for an entirely new software package that could do iterative solutions for combined flow/fea simulation to get close to a couple of weeks of comparative bench testing (with controlled clearance operation on one) on piston cylinder unit pressure gauges. The more you learn the bigger you know the holes/assumptions/fudge factors are. Sometimes moderately good real world data which can't answer all your questions is much more effective than months of fancy simulation.
Reason quick spool valves aren't common on the rotary are because the improvement in spool with a divided exhaust housing versus the log manifold required by a quick spool valve are well documented by Mazda (S4 vs S5 FCs) and in the aftermarket where both log and divided cast and tubular manifolds were present.
The Borg Warner and Turblown designs of putting the variable geometry swing gate in the turbo exhaust housing the allows for using existing divided exhaust manifolds and the associated advantages.
Only thing better would be to have a variable geometry and variable volume exhaust manifold. This would be consist of four smaller diameter runners (two front and two rear) so each turbo volute would be fed off both the front and rear rotor- then with the quick spool valve closed the runner would have small diameter runners to only one turbo runner for highest velocity.
Would be complex to weld up out of tubes, but fairly easy to investment cast such an exhaust manifold.
High end single turbo supras don't use old log manifolds like what came on the FC.
They have six runners, into a divided t4/t6 flange, and then they add this on to focus flow into only have of the twin scroll. I agree it's an abrupt flow blockage, but they do have proven results. The velocity at low rpm to spool faster more than offsets the less than smooth blockage. Then when it opens up its just like normal.
Not really much different than the borg Warner design, just a bit further from the turbo.
The one being designed and fully integrated into a cast manifold in this thread could be better due to improved flow. But the existing option of sound performance QSP can be had for $500. If the new cast manifold with built in QSP is not more than $500 more than a standard manifold and flows better than the QSP, then great.
I used the term "log manifold" because for a rotary that is usually the only reason one runs a pulse collected runner exhaust manifold on a 13B.
There is pulse collected runner manifolds for open volute turbos and there are pulse divided runner manifolds for divided turbos. Doesn't matter if cast or tubular or made from sections of pipe.
6-1 tubular manifold for a 2J is a collected runner manifold, a 6-3-2 runner manifold is a divided manifold.
On a 13B you have 2-1 for the collected or 2-2 for the divided.
The traditional quickspool valve has a divided flange and is to be used on a divided turbo exhaust housing, but must be used on a pulse collected exhaust manifold.
Please understand you cannot run a traditional quickspool valve on a divided turbo manifold on a 13B; when the quickspool valve is closed there would be no where for the exhaust gasses from that runner to go. Well, if it had a single external wastegate without divider the flow could back-up the wastegate runner and into the other wastegate runner and into the open exhaust runner- but that is super convoluted flow.
Moving the diverter valve into the turbo exhaust housing like BW and Turblown have done, a pulse divided manifold can flow both runners into one volute with the valve closed and each runner into each volute with the valve open.
That really appears to be a 6-3-2 pulse divided manifold and someone that doesn't understand that it won't work has placed a quickspool valve on it and taken a picture.
I have personally seen more than one on divided manifolds. The manifolds were divided at the flange, they were not 2 sets of 3 cylinders bundled together
Yeah, like I said all the exhaust flow from the front 3 cylinders is having to flow through the non divided wastegate passage around the divider and into the open turbo scroll at low rpm.
Luckily for that guy who has no understanding of physics his 6-3-2 pulse divided manifold isn't pulse divided because of the shared wastegate runner.
A real **** show.
If it were a proper 6-3-1 manifold (or just the divider cut out) the low rpm power would have been better.
Oh, wow. His design is even more wack than I thought.
So actually its kind of like a hybrid of a normal standard quick spool valve, the Borg Warner and Turblown valve and not having a quick spool valve.
At rest the valve does not close all the way so there is a 20mm gap for exhaust to flow from the front 3 cylinders into both turbo scrolls though the angle will direct it into the rear runner.
"closed"
open
Well, at least it helps keep it from being as restrictive to the front 3 cylinders, but it also isn't as effective as a standard quick spool valve.
I don't understand why he didn't use a standard quick spool valve that would totally seal off one turbo scroll and cut the divider out in the manifold for 6-3-1 collection...
There's some even stranger ones out there. When googling yesterday I found a few examples of merging all 6 runners into half of the divided t4 flange and then using a wastegate where the runners first join together to open up another airflow path to the other half of the t4 flange.
I like Turblowns new exhaust housing idea. Granted, they even said BW prototyped it and never brought it to market.
It creates a restriction when it want's to, and completely removes that restriction when called for. So it isn't this huge valve directly in the way of exhaust gasses like the QSV above.
Just because BW never brought it to market, doesn't mean the underlying engineering or theory is bad. It could have simply cost too much money for BW to continue to develop it for mass market, or mass production could have been way too expensive, or it could be a million other things that add cost and complexity when a large company creates products.
So a small and agile company like Turblown could come in and tailor it for a specific application, in small batches, for a small market, could easily be successful.
Yeah I'm not too sure about the antagonism and criticism either. Whether or not you have a chip on your shoulder for whatever reason, Turblown are developing this off their own back and it's a cool idea. You have to respect that. I'm almost certain even the nay-sayers will be very interested in this space.
There's some even stranger ones out there. When googling yesterday I found a few examples of merging all 6 runners into half of the divided t4 flange and then using a wastegate where the runners first join together to open up another airflow path to the other half of the t4 flange.
That is a design I can get behind though. In that set-up one maximizes low rpm torque (small collector diameter) and spool while taking a bit of hit on the top end exhaust flow.
Doing that with a T6 flanged turbo on a 2 rotor would make sense if you were on the fence as whether to run it T4 flanged or T6 flanged.
There's some even stranger ones out there. When googling yesterday I found a few examples of merging all 6 runners into half of the divided t4 flange and then using a wastegate where the runners first join together to open up another airflow path to the other half of the t4 flange.
x2 Could you post this? Awesome little find there!
01-18-19, 09:49 AM
