BNR S1?
 

I was planning on buying this secondhand BNR S1 - pics attached.

The housing is K04-582 and was sold as a BNR S1 for an MS3 by New Age Autos in 2018.

Do BNR use the turbo housing from CX7 for an MS3 BNR S1?

I'm not sure if there has been some kind of mix up here....

I ran a BNR S1 to cure the smoking K04 woes. It is a great plug and play. I did the install myself, but did not notice whether the housing was Mazdaspeed specific.

Perhaps give BNR a call or email and ask. They have great customer service and are easy to work with.

i remember at the beginning BNR was asking for k04 core return...so maybe some returned cx7 core?

Differences are the compressor wheel inducer size smaller with a CX7 and the snail of the turbine hosing is also smaller. IF they use a different wheel, it won't change much if using a 582 instead 881/882 cold size as both need to be machined...
For the hotside, it seem to be a totaly new cast with the BNR engraved ? it won't matter much in that case too.

Bryan, the owner of BNR, is a member here. His company offers first class customer service. Just give him a call. He will shoot straight.

Since his BNR S1 gets a beefed up CHRA with Garrett 28 series wheels on both sides, and your turbo has a BNR hot side housing the question will be whether he opened up the cold side to allow for more flow. It’s possible someone tried to “bastardize” what you have after it left BNR, but that is highly unlikely.

Just call Bryan Nickells.

bnrsupercars.com