BNR Stage 2 Turbo

[fiveight]

Hi all,

I thought I would update you on the latest work done to my Gen 2.

Back in December I was at a track day doing 6 lap stints when the OEM turbo let go. It was quite the sight. Oil smoke everywhere followed by Red Flags.

After a quick inspection it was a simple diagnoses. The turbo had blown a seal and turned into a second sump.

After getting the car towed back to Sydney and missing most of the day, I went without for 4 weeks while parts were sourced and fitted. The timing of Christmas and New Years didn’t help to be fair. MRT have done everything to this point so it was a simple decision to get them to do the turbo. They even gave me a loan car for the duration.

I had a couple of options. Mazda wanted something ridiculous for their turbo but given what had just happened it wasn’t really an option. I ended up going with a BNR stage 2. I was very clear with the guys at MRT that I wasn’t after any more power or torque. I just wanted a reliable car. The last thing I wanted was to start bending pistons and rods.

Along with the damaged turbo, I also ruined the Air Fuel Ratio Sensor and Oxygen Sensor. Aren’t these two a nasty side expense! The battery was also replaced and it spent a few house on the Dyno getting retuned using the EcuTek software. That, along with the hours of labour pulling it all apart, cleaning the exhaust and putting it all back together, made for an expensive exercise.

The result was what I expected. Despite not asking for more power, at 5200 rpm I gained an extra 6kw to 212kw. The noticeable difference is further up in the top end. At 6000 rpm power increased from 187kw to 210kw, so the overall result is a more consistent power band with no drop off at the top end. Torque has dropped off slightly at the bottom end but at revs over 4200 rpm I gain up to 15% more.

To drive the car I don’t notice a massive difference. The first time I got in it after a month off, I thought it was going to take off to the moon, but I think that’s more a reflection of what I had been driving.

The big difference I have noticed is the fuel economy. Around the city I’m getting 11.5L/100km and on the highway 8.9L/100km. I worked out its a combined 9.9L/100km which is bang on Mazda recommends and everyone know how inaccurate manufactures millage claims are. I’m getting 20% more power and torque with better millage than when I bought it off the showroom! Suitably impressed.

Once again I must say how happy I am with the job MRT did. They took their time and got it right. I was updated the whole time and even had the opportunity to walk through the garage with Brett one night after knock off to show me how they were getting on.

I have attached a Dynograph comparing the before and after turbo power and torque gains as well as some pics from the track day. Feel free to ask questions. And as I’ve always said, if anyone wants to take the car for a run one day, feel free to hit me up.

TK

P.S. Before anyone asks how much it all costs. One word. “Heaps”! But anyone who has been through what I’ve just done would know that and appreciate that it’s money well spent.

[SarcasticOne]

hehe, that's a LOT of smoke.... glad to hear car is all fixed though

but, maybe it's just me... but MRT dynos just arent impressive numbers wise... i would have expected more from a BNR S2....

[luke 3mps]

Thats at the wheels power i know it says 'Flywheel' but it has to be at the wheels other wise his last tune 200ishkw is just above standard. Sam you can requist more power and they tune it harder, but he didnt want more power...

[LittleredMPS]

Power is at the wheels, torque is at the flywheel.

[SarcasticOne]

Thats at the wheels power i know it says 'Flywheel' but it has to be at the wheels other wise his last tune 200ishkw is just above standard. Sam you can requist more power and they tune it harder, but he didnt want more power...

Power is at the wheels, torque is at the flywheel.

dyno graph MRT gave me:


that's untuned btw...

so either my car is a serious freak, or there is something not quite right...
anyways, at the end of the day, as long as TK is happy, that's all that matters

[luke 3mps]

dyno graph MRT gave me:


that's untuned btw...

so either my car is a serious freak, or there is something not quite right...
anyways, at the end of the day, as long as TK is happy, that's all that matters

Sam i made 211 atw untuned TH dyno

[fiveight]

Maybe there something different about your gen 1s to my gen 2? Not sure. They use a dynapack dyno like everyone else so all readings should be consistent. I was very specific when I said I wanted a reliable car. I'm not trying to build the worlds fastest mps. Just something goes, stops and turns better. I think I have that now.

It was noted to me that the turbo was actually detuned (note the small drop in boost) to match the oem internal parts of the engine. I have no doubt this thing could unload and if I wanted it to, mrt would've tuned it to do so, but what's the point of that if I'm going to spend $10k rebuilding the engine in 6 months?

[MRTBrett]

Its important to remember the engine and parts package WILL MAKE MORE POWER, but at the genuine RISK of engine and rod failure. Our opinion based on testing is Troys car is a "sensible tune"
Some people are willing to risk more and some ppl have cars that are hand gernads waiting to go off

PLUS, the fuel economy even amazed us!

[MPS2NV]

A few members are interested in the BNR option to upgrade their turbo's, Is the BNR due to oem design a simple replacement or are there small adjustments that need to be done to make it work?

Its important to remember the engine and parts package WILL MAKE MORE POWER, but at the genuine RISK of engine and rod failure. Our opinion based on testing is Troys car is a "sensible tune"
Some people are willing to risk more and some ppl have cars that are hand gernads waiting to go off

PLUS, the fuel economy even amazed us!

[luke 3mps]

A few members are interested in the BNR option to upgrade their turbo's, Is the BNR due to oem design a simple replacement or are there small adjustments that need to be done to make it work?

This^^^