Ultra late to chime in on this, I've been swamped with projects in the shop and all "engagements & updates" done via Facebook & Instagram, a utter-shame as i heavily prefer the forum as a data-bank.
OK so a addition to all of the above.
Firstly!
RYU has been instrumental during R&D that first and foremost also we've gone trough so many updates and intricacies i won't even bore people with.
The idea and sketches for a street ITB kit have been around here in the shop for many years I just never-had the time to start with them until late late 2019
Let me elaborate on the why's and what's in the design layout.
Key point overview:
- Modular design
- Parts used tap into existing frameworks for cost reduction and make tuning simpler
- OEM Honda fuel rails and FPR retained
- this will allow OEM hardware to be reused, OE equipment such as FPR is retained
- Existing NSX Fuel-injector options retained
- The fuel rail mounts are infinitely adjustable in height
- Largest selection off the shelf trumpets
- All Jenvey flange trumpets fit given they are not wider than 100mm (due to cylinder spacing)
- The setup is designed so that existing ITB users can easily upgrade to my design
- Hayward & SOS
- This did make certain features of the prototype sketches disappear
- It's designed with tolerance and wall thicknesses so that forced induction won't be a issue
- the 45 degree off cylinder design make for a flat flange the billet's are more than thick enough to handle boost, big reasoning behind this is so you can bolt on a turbo plenum.
- Simplified airbox flange
- see above, it make a NA box easier too.
- OEM Style injector placement
- This is one of the huge improvement points over all other available ITB kits, be using port injection angled towards the intake valves we can ensure
- Maximum spray length > fuel cloud directs towards intake valve as to give the most time for incoming air charge to mix generating proper low speed AFR
- Incoming air has more time to stabilize after the throttle blade (smoother flow)
- Traditional NSX ITB kits used off the shelf injector placement in Jenvey throttles this is rather crude as it forces fuel charge on to the back of the intake runner, causing low speed fuel pooling in the runners (and diagonally in the narrowest portion!)
- Tune ability especially torque power-band
- This is the other reason for the 45 degree offset from cylinder, it give you a flat plane up until the hatch for limitless runner tuning and airbox design.
- 48-54mm throttle size range is larger than any other ITB kit (most are ether 48 or 50, RYU is running 50's, we have a number at 48 and Christian/ATR is running custom 54mm)
- Total length, due to the flange layout and the offset very very long runners can now be done so a engine builder/tuner can actually get a ideal runner length for a given cam setup. (That inherently allows for good airspeed)
- 12 injector version, two possibilities
- Throttle mounted injectors for high RPM those where featured on facebook last year.
- Velocity-stack mounted, the most effective way for very high RPM engines, like a F1 car
- Progressive throttle linkage
- On the mechanical throttle setup we spent a lot of time making a progressive nonlinear curve, this to mimic what Honda did on the 90-94 throttle body, so your low rpm and low speed throttle control is much improved (parking, etc)
- It's designed in such away the progressive portion can be replaced in future to accommodate customization in curves
- A number of adjuster holes are provided in all sides of the linkages to accommodate any special needs
- Throttle springs, this came up after testing at RYU's first runs we spec kits with special jenvey throttle springs to retain OEM feel.
- Ball bearings all way round, this to eliminate the flimsy setup Hayward throttles have
- My ideal design would have used spherical bearings and a custom throttle cable, and billet actuator levers, as you can imagine that would have tremendously increased cost and labor for any install
- Billet construction
- To ensure highest possible fit finish and standard, the whole runner is a solid billet 5 axis machined piece, off course this does cost tremendously more but in my opinion this is one of the defining features and allows for a lot of intricacies
- Every design modification had a number of 3D print stages (cutaway flange, cutaway vertical, full size) as to make sure the port match is as best we can.
- interesting thing came up, the head castings differ we had to average the fitment a set of manifolds was made so perfectly matched to one specific head they didn't match 3 other heads
- Not only is it finished in a mirror finish the inner runner is machined in length wise 5 axis passes with the air flow direction in mind!!
- Vacuum system
- The kits come with a 8 port vacuum manifold, this is a CNC machined extrusion.
- each runner has a dedicated vacuum port feeding in to a vacuum plenum intended to collect and buffer all cylinders
- MAP sensor taps into the end of this gallery so you have a steady map signal for part throttle of all 6 cylinders! (so you can actually get smooth operation and some fuel economy at part throttle and cruise!)
- FPR attaches to this "vacuum manifold" so the OEM FPR still functions as Honda designed it with port pressure compensation, so your fuel pressure is always relative of inlet manifold pressure
- 2 large ports, one is intended for IACV input the other for brake booster output (we recommend a OE off the shelf electric vacuum booster pump, this is a far superior method)
Detail pictures
Port fitment cutaway
Prototype cutaway featuring 12 injectors > this is the in throttle placement version, also clearly shows how we position injectors to give the best possible spray pattern
The inner runner machining paths of the 5 axis as described above:
A kit prior to shipment, the linkage and vacuum manifolds clearly visible
Prior to shipping kits are assembled on a C30A, note how the OEM fuel rails and FPR install seamlessly
Modular design in lengths exemplified by these full billet trumpets on a kit prior to being shipped out to HQ Engineering
