Hello all, I am considering getting a BNR s3 on my stock block. Was originally scared of upgrading turbo on stock internals, but have heard it can be safe if the torque is delivered in a certain way and boost is kept at a conservative level ? Does anyone have any experience with tuning their bnr s3 on a stock block with longer term reliability ?
Safe levels for BNR S3 on stock block ?
- Thread starter Jtotheonah
- Start date
Yes there are many threads about this subject. Ie what turbo do I get, k04 dying, BNRS3?
In the same section you posted this thread in, did you even try again look? Here are some other threads for you.
https://www.mazdaspeeds.org/index.php?threads/turbo-thoughts.10566/ further down https://www.mazdaspeeds.org/index.php?threads/gtx3076r-good-for-stock-block.10356/ and again https://www.mazdaspeeds.org/index.p...ocharger-decision-bnr-s2-vs-s3-vs-cst4.10114/
Again this time S4 stock block https://www.mazdaspeeds.org/index.php?threads/turbo-replacement-question.4021/
Yes the S3 is absolutely fine with the stock block, Infact it's more than fine it's a very commonly recommend upgrade/replacement for the k04 because of how well it does to increase power but play with the block well. any reputable speed tuner that you say BNRS3, stock block, I want to keep it that way will give you an appropriate power curve.
/Thread
In the same section you posted this thread in, did you even try again look? Here are some other threads for you.
https://www.mazdaspeeds.org/index.php?threads/turbo-thoughts.10566/ further down https://www.mazdaspeeds.org/index.php?threads/gtx3076r-good-for-stock-block.10356/ and again https://www.mazdaspeeds.org/index.p...ocharger-decision-bnr-s2-vs-s3-vs-cst4.10114/
Again this time S4 stock block https://www.mazdaspeeds.org/index.php?threads/turbo-replacement-question.4021/
Yes the S3 is absolutely fine with the stock block, Infact it's more than fine it's a very commonly recommend upgrade/replacement for the k04 because of how well it does to increase power but play with the block well. any reputable speed tuner that you say BNRS3, stock block, I want to keep it that way will give you an appropriate power curve.
/Thread
The maximum horsepower recommended by Mazda is 263 measured at the crank.
Thank you Awafrican, I did look it up but didn't find these exact threads.
S3 is a perfect turbo to have fun with stock motor and will light up very similar to KO4.
Forgive my ignorance, but are you serious? I’m just confused because I’m sure I’ve read that others limited horsepower on a stock block but it was over 300. And of course the Speed6 apparently has 274.
No I'm 100% serious Mazda spent a ton of money designing and manufacturing these motors to be reliable and durable making 263 horsepower at the crank
Ok, thanks! Once I’m able to get a new engine for mine I had also been pondering a few minor upgrades and a tune so what you’ve said has encouraged me to keep it close to stock
I enjoy fast cars but this one needs to also be semi-reliable.
S3 spool vs k04..That's really my most sought at answer.. Except for a super cheap China DP to maybe install. Ive done about as much as can be expected from k04...so I have to either get it....or get the 63 turbo corvair spyder I've got sitting in service bay now running well...... 
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S3 spool vs k04..That's really my most sought at answer.. Except for a super cheap China DP to maybe install. Ive done about as much as can be expected from k04...so I have to either get it....or get the 63 turbo corvair spyder I've got sitting in service bay now running well......
Two posts up from yours is this:
"Light up" refers to spool.....it's very similar to the k04 ie don't worry about it yes it will be within 100-200 rpm slower for full boost, buts it's also more boost at that point so I say again don't worry about it and the BNRS3 is absolutely wonderful with the stock block