HKS RB26 Development

[White GTS-T]

So I thought the recent developments from HKS around the RB26 at the TAS for 2022 might be an interesting topic of discussion. For those that haven't seen it, this write-up on Speedhunters explains some of the points of difference with some detailed photos to boot. Here's the article in question; HKS RB26 TAS2022

It looks to include twin VCT, a  newly designed twin-chamber plenum, and electronic internal wastegates and recirculation valves,  just to name a few. 

[joshuaho96]

HKS talked about the engine last year I believe. It mostly looks like just a conversation piece for now. Can't tell if the mounting bracket for the electronic wastegate is some kind of weird 3D printed metal or plastic but I doubt that will actually work even as an engine dyno proof of concept. Those exhaust manifolds look like a prototype and will likely not last long either. The dual chamber plenum is probably the closest to reality and the dual 400cc injector setup is pretty interesting too. I don't know why they didn't just try and figure out a single injector with two cone spray doing 800cc/min instead but maybe that's too boring. You can basically achieve that just by taking a current mass production EV14 630cc injector and bumping fuel pressure to 5 bar.

I'm also super skeptical of the fuel economy claims. I doubt they can do it without cooled EGR to actually realize the passive TJI system they're proposing. Otherwise the sheer strength of the combustion event will likely beat the bottom-end to death.

[Dose Pipe Sutututu]

And odd they decided to stick to twin turbos..... lol

[White GTS-T]

Yeah, there's nothing really new here, I just thought it was cool to see them throwing everything they had to modernise the RB26.

Obviously fuel economy/emissions is one of their main focus points. Perhaps they're going for absolute control over injection timing, or even staging  the injection with the twin injector setup?

Having twin VCT eliminates the need for EGR when you as you can simply introduce more overlap to perform the same job. Interesting nonetheless.

[joshuaho96]

On 1/24/2022 at 11:27 PM, White GTS-T said:

Yeah, there's nothing really new here, I just thought it was cool to see them throwing everything they had to modernise the RB26.

Obviously fuel economy/emissions is one of their main focus points. Perhaps they're going for absolute control over injection timing, or even staging  the injection with the twin injector setup?

Having twin VCT eliminates the need for EGR when you as you can simply introduce more overlap to perform the same job. Interesting nonetheless.

You can achieve something similar with just the standard intake VCAM, especially if you go for the full 50 degrees of cam advance. I often see tuners unfamiliar with VVT just doing the full throttle pulls and interpolating from there which causes them to miss the bigger benefit of EGR at part load. Exhaust VCT does help, just not as much as you'd hope.

The twin injector setup I'm pretty sure their idea is to deal with a few different issues going on. One is that there's basically no such thing as an 800 cc/min twin spray modern injector on the market. To get there with commodity injectors (not some ridiculously expensive Bosch Motorsport thing that you can't actually buy) your options are either a Denso injector with a single cone spray and 6 hole diffuser plate at 850cc/min or the Bosch 040 980cc/min 7 hole diffuser plate with single cone spray. That's at 3 bar, obviously you can bump the fuel pressure of a smaller injector but even at 5 bar you probably don't have enough fuel. The better the spray pattern (the better the fuel avoids the intake walls), the less fuel that has to be accounted for in all kinds of transient scenarios like cold start, transient throttle, etc. The other issue is dynamic range. Smaller injectors are fine for this but a big injector these days may still have to idle rich just to stabilize the fuel delivery instead of having the idle chase itself all over the place. With staged injection they could just fire a single injector at idle and only bring in both injectors when the pulse width is large enough to run both of them in the linear regime.

One thing I have been thinking about for some time now is whether the Bosch 997.1 turbo injectors (0280158123) would be able to fit the RB26, combined with a 5 bar FPR and a fairly heavy duty pump like the DW440 brushless it should be able to sustain that high fuel pressure even with a decent amount of boost to get right around 800 cc/min of flow like this but without any complicated injector setup. It's a 3/4 length EV14 injector with extended tip so it's a bit longer than the traditional 040 980cc injector but otherwise it doesn't seem unreasonable to me.

Don't get me wrong, I think what HKS is doing is really interesting, I'm just highly skeptical that they will actually bring the important pieces to market like the exhaust VCAM or passive TJI retrofit.

Edited January 25, 2022 by joshuaho96

[Piggaz]

On 25/01/2022 at 1:15 PM, Dose Pipe Sutututu said:

And odd they decided to stick to twin turbos..... lol

 

[joshuaho96]

Looks like they put some more details on their Youtube channel. It's interesting how they actually bothered to completely rethink the airbox/intake piping end to end, usually those are left as an exercise for the reader to complete. Anyone know what that AVL capture is showing? I have strong doubts it's actually from an RB engine, would not be surprised to know if it's a single cylinder research engine.

[bigboss59400]

Anyone got any news ?