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Leeky · 10-20-2011, 05:49 PM

Something i've been thinking about this evening.....

The Subaru is going to cost more than the Toyota - this is pretty much a given.

The new 2.0 boxer has been co-developed by both companies, so a lot of time and money has been spent. So both companies will want to use this engine. Neither will want to go and offer a different engine, especially as in Subaru's case they wont want to give this car enough power to take sales away from the Impreza STI.

So same car, same engine, but different prices. So perhaps there may be some truth to the whole story of the subaru getting more power.

I mean brand loyalty is one thing, but is your average Subaru fan going to hand over an extra 5k (25% of the Toyota) just to have the Subaru? - I dont think so. There has got to be something more to justify that price than just a nicer interior etc.

But as per the Autocar article i would say that any such difference in power is going to be purely ECU driven. Mechanically i would put money on them being 100% identical.

So lets say for arguments sake the Toyota is 200bhp and lets assume its mapped for regular 95ron unleaded - the cheap stuff - as after all with this kind of power and rpm there is no need for stronger fuel - your not getting into the NA detonation zone at only 7400rpm on a modern engine like this.

Now with the Subaru version lets assume we could be looking at a map for 99+ron fuel and Subaru explicitly tell owner that this car NEEDS 99 Ron or above. So it gets a noticeably more agressive map to take advantage of this fuel and advanced timing.

I dont know how direct injection works, but i would expect direct injection to be percentage wise more efficient the higher you go with the grade of fuel?

Assume adjusting the map and upping the power may naturally move the power band a lot higher up the rev range; which would require them to move the redline up along with the limiter. So lets be conservative and say another 500rpm. This could make a good 10-20bhp difference.

Using the ST205 as template (yes yes i know its comparing a Turbo car to a non-turbo, but stock for stock we're talking not too dissimmilar power to the FT86/BRZ), the UK Cars were rated at 239bhp (95ron unleaded) when they came out back in 1994 and the JDM version was 255bhp (100ron).

Thats a good 16bhp difference and i know for a fact that the ECU maps are the same but the ecu simply advances or retards the timing depending on the fuel you are putting in.

I've seen standard UK cars which simply run 99ron fuel and they dyno almost identical power to the JDM cars.

So what im getting at is I wonder if it'll be a simple case that the FT86 will be tuned for running on cheaper fuel, while the BRZ will be tuned for 99+Ron fuel?

In which case, who cares if the Subaru has more power?

I'll have the cheaper Toyota, then i'll run it on higher grade fuel and use an Apexi S-AFC to re-map it. I may even get more power than the Subaru!

10-20-2011, 05:49 PM	#52
Leeky 3S-GTE Junky Join Date: May 2011 Drives: Toyota Celica GT-Four ST205 Location: England UK Posts: 165 Thanks: 0 Thanked 5 Times in 2 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Something i've been thinking about this evening..... The Subaru is going to cost more than the Toyota - this is pretty much a given. The new 2.0 boxer has been co-developed by both companies, so a lot of time and money has been spent. So both companies will want to use this engine. Neither will want to go and offer a different engine, especially as in Subaru's case they wont want to give this car enough power to take sales away from the Impreza STI. So same car, same engine, but different prices. So perhaps there may be some truth to the whole story of the subaru getting more power. I mean brand loyalty is one thing, but is your average Subaru fan going to hand over an extra 5k (25% of the Toyota) just to have the Subaru? - I dont think so. There has got to be something more to justify that price than just a nicer interior etc. But as per the Autocar article i would say that any such difference in power is going to be purely ECU driven. Mechanically i would put money on them being 100% identical. So lets say for arguments sake the Toyota is 200bhp and lets assume its mapped for regular 95ron unleaded - the cheap stuff - as after all with this kind of power and rpm there is no need for stronger fuel - your not getting into the NA detonation zone at only 7400rpm on a modern engine like this. Now with the Subaru version lets assume we could be looking at a map for 99+ron fuel and Subaru explicitly tell owner that this car NEEDS 99 Ron or above. So it gets a noticeably more agressive map to take advantage of this fuel and advanced timing. I dont know how direct injection works, but i would expect direct injection to be percentage wise more efficient the higher you go with the grade of fuel? Assume adjusting the map and upping the power may naturally move the power band a lot higher up the rev range; which would require them to move the redline up along with the limiter. So lets be conservative and say another 500rpm. This could make a good 10-20bhp difference. Using the ST205 as template (yes yes i know its comparing a Turbo car to a non-turbo, but stock for stock we're talking not too dissimmilar power to the FT86/BRZ), the UK Cars were rated at 239bhp (95ron unleaded) when they came out back in 1994 and the JDM version was 255bhp (100ron). Thats a good 16bhp difference and i know for a fact that the ECU maps are the same but the ecu simply advances or retards the timing depending on the fuel you are putting in. I've seen standard UK cars which simply run 99ron fuel and they dyno almost identical power to the JDM cars. So what im getting at is I wonder if it'll be a simple case that the FT86 will be tuned for running on cheaper fuel, while the BRZ will be tuned for 99+Ron fuel? In which case, who cares if the Subaru has more power? I'll have the cheaper Toyota, then i'll run it on higher grade fuel and use an Apexi S-AFC to re-map it. I may even get more power than the Subaru! Last edited by Leeky; 10-20-2011 at 06:05 PM.