RGHTBrainDesign - Rotary Engine Development Projects
#26
Rotary Enthusiast
iTrader: (8)
So you mean the the butterfly plates in the fd uim? The very first thing anyone does when they pull a uim off is rip those out and toss them in the trash...
Their entire point is to ensure you dont see substantial throttle when the engine is cold regardless of what you do with the pedal, which can be countered with the use of a modern ecu.
If you are going to do that anyways for the purpose of having independent control of the secondary throttle plates why not use a FD tb in the first place? Under what tuning scenario would you need it to be different than the way the mechanical linkage works as it is?
Skeese
Their entire point is to ensure you dont see substantial throttle when the engine is cold regardless of what you do with the pedal, which can be countered with the use of a modern ecu.
If you are going to do that anyways for the purpose of having independent control of the secondary throttle plates why not use a FD tb in the first place? Under what tuning scenario would you need it to be different than the way the mechanical linkage works as it is?
Skeese
#27
www.AusRotary.com
#28
Banned. I got OWNED!!!
Thread Starter
So you mean the the butterfly plates in the fd uim? The very first thing anyone does when they pull a uim off is rip those out and toss them in the trash...
Their entire point is to ensure you dont see substantial throttle when the engine is cold regardless of what you do with the pedal, which can be countered with the use of a modern ecu.
If you are going to do that anyways for the purpose of having independent control of the secondary throttle plates why not use a FD tb in the first place? Under what tuning scenario would you need it to be different than the way the mechanical linkage works as it is?
Skeese
Their entire point is to ensure you dont see substantial throttle when the engine is cold regardless of what you do with the pedal, which can be countered with the use of a modern ecu.
If you are going to do that anyways for the purpose of having independent control of the secondary throttle plates why not use a FD tb in the first place? Under what tuning scenario would you need it to be different than the way the mechanical linkage works as it is?
Skeese
I think that DBW is the way to go for boost control, transient fueling calculations, efficiency, etc, but to each their own. I'd also rather trust a little set of 22ga wires in an aftermarket application than a custom cable when grafting in a motor into a car that didn't have it originally. That's MY perspective though, as I don't ever intend on owning an FD. Love your input, but I'm crystal clear as to WHY I think this is a smart decision for those with aftermarket configurations. On a factory FD, just run it with factory components... Go big or go home applies here.
#29
Rotary Enthusiast
iTrader: (8)
People seem to be getting this confused. What RBD and I are referring to are the secondary throttle plates in the manifold that are pressure actuated, not the secondary plates in the throttle body that are mechanically actuated. Hence (and he corrected me on this the other month because even though I've been looking at my manifolds and deciding on the DBW setup I'm a 'tard) using a DBW throttle and some sort of stepper/solenoid to open the plates in the manifold.
#30
Banned. I got OWNED!!!
Thread Starter
People seem to be getting this confused. What RBD and I are referring to are the secondary throttle plates in the manifold that are pressure actuated, not the secondary plates in the throttle body that are mechanically actuated. Hence (and he corrected me on this the other month because even though I've been looking at my manifolds and deciding on the DBW setup I'm a 'tard) using a DBW throttle and some sort of stepper/solenoid to open the plates in the manifold.
The thing this thread needs is MORE projects of value. I already have one figured out for us, so let's move on and continue progressing with engine control systems.
#31
www.AusRotary.com
People seem to be getting this confused. What RBD and I are referring to are the secondary throttle plates in the manifold that are pressure actuated, not the secondary plates in the throttle body that are mechanically actuated. Hence (and he corrected me on this the other month because even though I've been looking at my manifolds and deciding on the DBW setup I'm a 'tard) using a DBW throttle and some sort of stepper/solenoid to open the plates in the manifold.
Now, in RBD's approach, because he has a single plate DBW throttle body, he loses the mechanical staging but could potentially reintroduce some form of primary/secondary staging by controlling the UIM double throttle plates. Therefore, the comparison being done is between primary/secondary staging by throttle position alone (the OE setup) vs primary/secondary staging based on (potentially) multiple parameters.
#32
Banned. I got OWNED!!!
Thread Starter
I wasn't going to bring this up on here since I don't think anyone else is doing it, but the whole Throttle Mass Flow with the Emtron KV8 can utilize those Pre-TB and Post-TB MAP sensors as a high-flow Mass Air Flow, so my hidden agenda was to actually control this using throttle mass flow generated by those. The one that pertains to everyone though is MAP vs. RPM.
After hundreds of hours behind a laptop with the Honda doing secondary butterflies in the intake manifold and blending with VTEC, it became apparent to me that there should be more than just a TPS relation (mechanical linkage) to controlling primary/secondary transition. Going WOT on a factory FD throttle body will just dump open the secondary butterflies which as you can guess, will LAG the system.
I truly believe a 90mm DBW TB is superior to a factory FD or more specifically FC (in my case since I had a 13BT grafted into my 1st Gen Rx7), and therefore am building systems around it to give me power out of the hole on corner exit in tight mountain roads. That's what this ONE experiment is about. Just getting that low RPM torque out of a small displacement motor. Sure as **** works for the Honda, so believe me when I say we can do it better for the Rx7.
So this is good and done. Let's move on and continue development on another project. Any ideas?
Last edited by RGHTBrainDesign; 09-17-18 at 07:14 PM.
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KYPREO (09-17-18)
#33
Moderator
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you might think about looking at how Mazda did this with the Rx8, they call it an SSV
#34
~17 MPG
iTrader: (2)
If you don't mind a huge project, I think it would be interesting to try an intake setup similar to the E46 BMW M3. Those engines use DBW-actuated individual throttles near the intake ports plus a very large IAC solenoid. The IAC solenoid is so large they use it to supply all the airflow when cruising, the DBW throttles are completely shut. This seems to solve the problem of synchronizing lots of individual throttles at low throttle angles. If I had lots of time and money to burn I would try to build something like this for a peripheral-ported engine, possibly retain the OEM side ports but ideally I'd like to block them off completely.
On the more realistic side of things, I'm very interested to try an ECU-controlled exhaust cutout before the cat converter. If you haven't seen the Monsterbox build thread in the 3rd Gen section, it's one of the many cool things he's doing plus cheap enough that I could justify spending money on it. The car might have some hope of smelling OK at idle, and you could still have all the benefits of less exhaust backpressure at full throttle.
On the more realistic side of things, I'm very interested to try an ECU-controlled exhaust cutout before the cat converter. If you haven't seen the Monsterbox build thread in the 3rd Gen section, it's one of the many cool things he's doing plus cheap enough that I could justify spending money on it. The car might have some hope of smelling OK at idle, and you could still have all the benefits of less exhaust backpressure at full throttle.
#35
www.AusRotary.com
On the more realistic side of things, I'm very interested to try an ECU-controlled exhaust cutout before the cat converter. If you haven't seen the Monsterbox build thread in the 3rd Gen section, it's one of the many cool things he's doing plus cheap enough that I could justify spending money on it. The car might have some hope of smelling OK at idle, and you could still have all the benefits of less exhaust backpressure at full throttle.
#36
Banned. I got OWNED!!!
Thread Starter
If you don't mind a huge project, I think it would be interesting to try an intake setup similar to the E46 BMW M3. Those engines use DBW-actuated individual throttles near the intake ports plus a very large IAC solenoid. The IAC solenoid is so large they use it to supply all the airflow when cruising, the DBW throttles are completely shut. This seems to solve the problem of synchronizing lots of individual throttles at low throttle angles. If I had lots of time and money to burn I would try to build something like this for a peripheral-ported engine, possibly retain the OEM side ports but ideally I'd like to block them off completely.
On the more realistic side of things, I'm very interested to try an ECU-controlled exhaust cutout before the cat converter. If you haven't seen the Monsterbox build thread in the 3rd Gen section, it's one of the many cool things he's doing plus cheap enough that I could justify spending money on it. The car might have some hope of smelling OK at idle, and you could still have all the benefits of less exhaust backpressure at full throttle.
On the more realistic side of things, I'm very interested to try an ECU-controlled exhaust cutout before the cat converter. If you haven't seen the Monsterbox build thread in the 3rd Gen section, it's one of the many cool things he's doing plus cheap enough that I could justify spending money on it. The car might have some hope of smelling OK at idle, and you could still have all the benefits of less exhaust backpressure at full throttle.
#38
Banned. I got OWNED!!!
Thread Starter
The next real thing in my to-do list is an overdesigned intake manifold heatshield.
- Tri-layer Design
- Covers Top of Turbine Housing to Protect Hood, Full Exhaust Manifold, Wastegate Pipes (Wastegates need fresh air), and part of the downpipe.
- Mica Outer (closest to exhaust)
- Ceramic/Fiberglass Inner (Air Insulator)
- Mica Inner (closest to intake)
- Standoffs from Intake Manifold UIM/LIM Studs and Shock Tower (either side)
- Full Heat Transfer Equations on here... I'll compare materials and placement with real figures. Might as well throw real engineering behind the efforts.
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Laggy7 (08-27-19)
#39
Rx7 Wagon
iTrader: (16)
Heat shields are cool, but the intake manifolds are going to tend to get hot because they're strapped to the engine block. Nobody had had much luck with phenolic spacers on the lower manifold, but it might work with the upper. Even then, there's negligible heat transfer from hotter-than-ambient charge air and hot-as-the-block intake manifold, due to a relative lack of surface area and the sheer speed of the charge air.
Cool project though. Be interested to see what you come up with.
Cool project though. Be interested to see what you come up with.
#40
Banned. I got OWNED!!!
Thread Starter
Heat shields are cool, but the intake manifolds are going to tend to get hot because they're strapped to the engine block. Nobody had had much luck with phenolic spacers on the lower manifold, but it might work with the upper. Even then, there's negligible heat transfer from hotter-than-ambient charge air and hot-as-the-block intake manifold, due to a relative lack of surface area and the sheer speed of the charge air.
Cool project though. Be interested to see what you come up with.
Cool project though. Be interested to see what you come up with.
What I was referring to here was an exhaust manifold cover that's located between the shock tower, over the turbo, manifold, and downpipe, and connecting to the intake manifold.
Besides going with the HeaderShield cover for my entire setup, this will be a serviceable/removeable heatshield that is more for protecting paint and cleaning up the engine bay. I think the way Eric Xue (Corner Balanced) did his header heatshield is a perfect example. I'll link it here, just imagine it with two outer shells and a fiberglass/ceramic inner insulation.
I know he did a later video showcasing the work from my buddy (FFR Fabrication), but this is the one I could find.
#41
Arrogant Wankeler
Just as first hand feedback from a relatively repeatable exercise, i used to regulary notice a drop in torque while at "heavy cruise" up a steep hill near where I was living which corresponded with the engine reaching 70C. I had attributed it to charcoal cannister vent becoming active or a crude step in fuel/ignition trims in the apexi but the throttle staging makes sense, i would have to apply more throttle to then maintain speed. If I switch to a better ecu I will definitely map it. Even if the resolution on the combustion pressure sensors isn't great at those low loads being able to log 30 mins or more of data for averaging at lower engine speeds on the plex should give pretty decent results for genuine on road conditions.
#42
Rotary Enthusiast
iTrader: (5)
I have been planning out my next build and was also thinking about how to use and control the secondary throttle to retain the progressive nature of the throttle. I was thinking more along the lines of an electric motor control them with the ECU but your much further into it. Wish I saw this sooner. With all the modern ECU's being used these days, I'm surprised this has not been tried yet that we know of.
In your video I see you can open and close the secondaries without interference with the FFE adapter and GM TB. Have you check for interference when the DBW throttle butterfly moving thru its range? I know you mentioned turning the TB upside down, which would change the way the b'fly travels. I would think you want it so that the b'fly opens inward from bottom so the air would be better directed to the primary runners.
In your video I see you can open and close the secondaries without interference with the FFE adapter and GM TB. Have you check for interference when the DBW throttle butterfly moving thru its range? I know you mentioned turning the TB upside down, which would change the way the b'fly travels. I would think you want it so that the b'fly opens inward from bottom so the air would be better directed to the primary runners.
#43
Full Member
wow this is a very interesting thread, i need to read and re-read it over to get my head around it.
looks like ill be visiting my tuner this week with a bunch of questions!
i am very lucky to have a dyno at our workshop so theres lots of ability to test the absolute crap out of this on my s6 intake
looks like ill be visiting my tuner this week with a bunch of questions!
i am very lucky to have a dyno at our workshop so theres lots of ability to test the absolute crap out of this on my s6 intake
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