I think you missed read me, or maybe I wasn’t clear: I cannot get data on how much better is a GT
B2260 VS GT
D2260. Even if I see the specs difference and speculate on improved durability, it is hard to extrapolate how much difference it will make on the engine output. We would need 2 dyno for the same car running both turbo configuration with exact same specs. I am sure there are benefits, but I cannot even speculate how much.
For the spool, darkside claims a 100RPM difference between on a 4 cylinder between GTB2056VK VS GTB2260VK. Considering the 4 cyl gets full boost at 2700RPM where the 3.0 is 1700RPM, I would guess that the full boost could erase just under half of that 100RPM, so 1760RPM or something with the GTB2260.
Then, for the reduce back pressure, you are right, I mentioned “about” the same. I expect a small difference; I don’t think low end will be significantly changed. If I get full boost at 1750RPM instead of 1700 RPM, it is “about” the same for me. If you walk breathing through a large straw, you are being a bit chocked. Less than if you would be running, but still chocked. I believe the turbine is all the backpressure that diesel engine needs to be efficient. I know that on a gas engine benefit from increased back pressure at low range. Some Honda D15 engine were running on 12 valves under a certain RPM, and VTEC engagement engages 4 more exhaust valves.
This 2260 turbo upgrade seems to be the best bang for the buck I can see. A bigger turbo would require new injectors (2k$) and a more expensive turbo. That is +-2500$ for 40HP and a bigger dip on the very low range. Being OEM turbo for the same engine in Europe, I would expect the drivability to be very good.
With the extra rumble from the exhaust parts and a bit more fun under the pedal, this should be pretty fun. Not a game changer, just a 12.5% bigger smile.