NotoriousREV wrote: Tue May 21, 2019 8:15 pm
McSwede wrote: Tue May 21, 2019 7:56 pm
GG. wrote: Tue May 21, 2019 4:30 pm
Which this one still doesn't quite as its an inferior single turbo set up whereas the prior lump was a twin turbo! 15hp more from 25 years of advancement
It isn't a single turbo. It's a twin impeller turbo with each impeller looking after 3 cylinders. Very quick spool up and lots of torque. Mine for example was running just over 400lb/ft as standard which is a fair amount.
That’s not how Twin-scroll turbos work. It’s a single impeller but with the exhaust gasses split in two and delivered separately to it at different angles, with the blades angled to make efficient use of the flow from each nozzle. One nozzle works best for response, the other for high boost. Overall you end up with a turbo with great response and great top end flow.
Ok - but presumably boost limited because of the overall size of the single turbo despite the fact that the exhaust gasses are delivered in two streams to minimise lag - i.e. less tuning potential? I would also imagine swapping to a bigger turbo would not be easy unless compatible with the twin scroll setup?
Sounds like a clever solution to minimise cost whilst not succumbing to the lag typical of a single turbo. I expect fiddling with the exhaust plumbing upstream from the turbo is cheaper than fitting two which was the main driver behind doing that.
And of course, back to my overall point, ditching Toyota tech in favour of using a BMW setup.