Thanks CutisEmerry for the info, still hope you can get some flowmaps, meanwhile I did compare a few flowmaps my self as you can see in the pictures.
In red the BorgWarner 82mm billed wheel
In blue the BorgWarner 80mm billed wheel
I only did work out the part that I need for my application but I also based my conclusion on efficiency shaft RPM pressure ratio all based on information on paper so don’t shoot me if you think/feel different.
My conclusion on single stage performance:
BorgWarner makes a better 80 to 82mm compressor rating based on pressure ratio and shaft RPM.
Garrett run way more RPM putting more stress on the back of the compressor wheel that makes it more likely to burst on hi pressure or even if they compensate for this they will need more or stronger material to create the strength needed.
Compressor efficiency is not far of between the two brands.
If price is of concern I would lean towards the s500 88mm almost same specs as as gt55. The s400 turbine will not flow enough for what you are doing. There are also many turbine housing options.
Sounds like you have things ironed out pretty well. Looking forward to seeing the results!
Well on paper it all looks perfect but reality can be different. :huh::
I see no real relation between the small and big turbine, fact is we hit the surge line with the HX60 so we need to improve on that part so that’s why we going for other turbochargers.
Lower exhaust manifold backpressure helps engine breath better and moves compressor further away from surge. Or you can just use smaller 76 mm compressor. Thats stock 144 turbo then, small compressor big exhaust wheel. Have you tried different size exhaust housings?
BTW, why don't you use Scania marine exhaust manifolds made originally for twin turbochargers?
Well Lieffi lets look @ the theoretically part first. In order to move air for example you will need power and the formula to calculate this is Power = pressure x flow x efficiency
The shaft power we need to move 0,88Kg/sec is about 325 turbine shaft Hp, now lets go to a smaller compressor let say a 78mm that dos only 0.74Kg/sec and it needs about 291 turbine shaft Hp to make it.
Both turbochargers run the same turbine group so conclusion is the smaller 78mm compressor wheel needs less power so even with a lot les exhaust gas volume chance is you can running a bigger expansion ratio on the turbine housing dropping back pressure.
Now comes the efficiency thing. If we try to squeeze 0.88Kg/sec out of a 78mm compressor we will run it way off the compressor chard needing 347 turbine shaft Hp as the compressor efficiency is close to none and that part most tuners forget about and that’s why we look @ compressor discharge pressure/temperature and exhaust pressure and turbine speed and air to fuel ratio (AFR) to get the whole picture.
Now on our engine. We do not run a massive amount of fuel on our engine to get the Hp as we run only 660cc as to most other engines run about 1200cc per cylinder making less Hp even so conclusion could be we run more efficient having a lot less exhaust volume to work with resulting in smaller turbines and housings still having the same backpressure as other engines making the same boost ratio.
Our game plan is to keep efficiency up and try not to run it off the chard looking for a better chard baying or making a better product.
Flow chard of a S482 and the HX60 80mm in red hitting 0.88Kg/sec @ 60% efficiency 3.4 pressure ratio where the S482 still dos more than 65% @ a 5 pressure ratio.
Lieffi you mean a exhaust manifold that looks like?