I have a 2009 mini cooper s (stock) and am thinking about upgrading it but before i do i want to know if i could get a BorgWarner 73mm turbo in there and what upgrades i would have to do first to get to that point?

 

Why would you want to? It probably won't be very drivable and only good for posting large numbers on a dyno (if you could get it to spool before redline).

 

^+1 he is very right, such a small displacement engine wont be able to get the turbo to spool and minis are all about the handling not speed

 

Agreed. The biggest EFR you can run and retain a decent torque under curve is a 6258. Even with a twin scroll housing the 67 takes a while to get up to speed on a 2.0L engine. Remove roughly 30% of the energy to the turbine wheel by bolting it to a 1.6L and it will be abysmal.

 

Displacement isn't an issue with spooling that turbo, what exhaust housing specs are you talking about? 73mm doesn't generalize a turbos comp housing and exhaust housing. The problem you run into with running a turbo of that size is fueling hard enough to spool it, E85/E98 would broaden your ability to run larger chargers, but you don't want to spend the money on an ethanol setup & tune.

If you are wanting to do a big turbo build, a MINI is the wrong platform to work with. As above stated these cars are more about handling than straight line power.

 

Not sure if the turbine housing question above was for me but I was referring to the twin scroll .80 A/R housing with a T4 flange. It is not normally listed by most websites as an option on the 6258 but it is. I tend to agree in principal on E85, but with our engines being oversquare I think people are going to run into fuel wash problems on the cylinder wall / rings when trying to push big numbers and probably end up settling on a 50/50 mix. On a side note the SEMA Hyundai Veloster 1.6L that made 370WHP with an EFR6258 was running VP 101 plus methanol.

For the OP attached is a dyno run on a 2.0L Miata with same tune and boost levels 17-18psi 6258 vs 6758. The same 58mm turbine wheel but the difference in inertia when going from a 62 to 67mm exducer on the comp wheel is kinda obvious. In the real world or on a track I know which one I want.



The other thing to consider when going to a larger compressor wheel is the torque necessary to maintain the same boost level. Generally a larger compressor can maintain the same pressure at a lower compressor RPM but this is offset to an extent by the resistance applied to the blade tips which are now further out. Think Archimedes. So balancing this load to your turbine wheel and the energy available to it is critical.

 

It'll bolt right on trust me. Totally streetable too. Won't even need a tune. Just through that bad boy right on there. And please, when your done, post plenty of photos. After that, then and only then, start searching for problems with bigger turbos and tuning them.

 

Displacement is an issue. It would never spool up til after about and good 30 seconds.
They make maps/charts that tell you the proper size turbo for a given engine for a reason.

 

That's why I went with a.......wait for it... Wwaaaiittt for it, OWENS TURBO !! Cause it's perfect for that entire set up and it puts out more air than people realize.

 

If displacement is such an issue, then I would love to hear your explanation of how and why a 13B rotary is able to spool a 1.06 AR turbo? It has less displacement than a MINI, but is able to light a 1.06 AR charger by 5K.

I understand sizing a charger to the engine, what we have yet to hear is the AR size of said charger OP wants to run, Borg Warner doesn't have a 73mm charger with an AR smaller than .83, so short of running some sort of hybrid setup as well as race fuel or ethanol there is no way that it would be streetable let alone make power on the dyno.

Owens has multiple frame size categories with over 10 chargers per category, so a more generalized size of your charger would explain how you are able to spool it.

 

Lmfao. I'm not even gonna bother to try anymore.

 

A rotary engine fires once per revolution and a piston engine once every two revolutions. As such a 13B displacing 1.3L produces the same exhaust volume as a 2.6L piston engine at the same RPM.

 

Thank you Tigger, this is the answer I was looking for, not the cocky too good for this place attitude.

Variables, changes in dynamics. These are what is missing from what the OP posted, and these are what change the outcome of what works and what doesn't work..

 

The other question is will it actually physically fit in the stock location?

 

I had to cut out some of the hood "bracing" to get my GT2860 in there. A 73mm wheel is bound to need more space. As pointed out above, there's other "big" turbos available that should satisfy anyone's bolt-on power desires. Another consideration --- there's not much space left for a heat shield when using an oversized turbo. Expect things to melt, warp, distort, leak, etc. when going oversize and not shielding it.