Maybe the FT-86 doesnt need massive power........

[Maxim]

Originally Posted by CyberFormula

I thought i read in another thread

that the Subaru's boxer engine produced equal hp/tq numbers...and its Naturally aspirated.

Negative Ghost Rider.

[Maxim]

Originally Posted by TriggerTRD

Maxim,

Take a chill pill buddy.
I didnt post this thread to start a flame war for the LF-A vs GT2 vs Vette, the reason I posted it was because if Toyota/Lexus can make a car that pushes less power than its competitors and is slower in a straight line than some, yet run a much faster lap, then surely some of the tech must have filtered down to this Concept.

All out horsepower and torque doesnt define a cars performance, its power delivery and balance, aerodynamics and mass also play a huge factor. If the FT86 is well balanced and handles as if on rails, it will be able to take in more speed through the corners and accelerate quick out also thus not requiring huge HP to overcome all out speed.

I apologise for not doing more research in regards to wikipedia, etc.

I'm also not trying to flame. I just come off as cross

But yeah....the tech that makes the LFA fast (except it's no faster than it's competition and costs SIGNIFICANTLY more) includes things like active aero, full underbody diffuser, extremely expensive brakes, lots of carbon fiber....none of those things have any chance at all of happening on a 25k sports coupe.

If anything, I'd use the LFA as an example of why I'm worried about this project. It spent forever in development, cost so much to make that they had to sell it at double the competition's price, and it only performs, at best, on par with the competition.

Then again, the LFA was developed by Toyota and regardless of whether it bruises people's egos here, the FT-86 development, by all indications, was handled primarily by Subaru.

[PAImportTuner]

Originally Posted by Maxim

If anything, I'd use the LFA as an example of why I'm worried about this project. It spent forever in development, cost so much to make that they had to sell it at double the competition's price, and it only performs, at best, on par with the competition.

Then again, the LFA was developed by Toyota and regardless of whether it bruises people's egos here, the FT-86 development, by all indications, was handled primarily by Subaru.

Just because you've mentioned it, I'd like to add the worse thing about that is Subaru actually listens to Toyota about power and performance and ae86 successor marketing BS and now you get a semi-low hp BUT "it's going to be fun to drive" car. Like WTF are they thinking, for at least the past 15 years they been making 260+hp performance models globally.

[WingsofWar]

Originally Posted by CyberFormula

I thought i read in another thread

that the Subaru's boxer engine produced equal hp/tq numbers...and its Naturally aspirated.

you are correct, the numbers are nearly the same for current subaru boxer 4 engines, unlike conventional inline or v configurations which power characteristics have a slightly larger rotational power difference in hp and tq relations. flat-6s have a larger difference compared to the flat-4s...but TQ characteristics are still unlike more popular engine configurations.

FB20 makes 148hp/144ftlb @6000
FB25 makes 175hp/178ftlb @6000
EJ20E makes 140hp/138ftlb @6000
Ej254 makes 175hp/170ftlb @6000
EZ36 makes 260hp/247ftlb @6000

vs

(ballpark figures at the same RPM)
I-4 2.0l makes 148hp/129ftlb
I-4 2.5l makes 175hp/153ftlb
I-6 3.6l makes 260hp/227ftlb

[Maxim]

Yes, however the state of tune for those engines is different than the state of tune for a 2.0L that produces 200hp.

The Boxer-4 that produces 148/144, when tuned to provide higher HP, will produce less torque. I doubt a 200hp 2.0L boxer would produce more than 165ft/lb. It's just the nature of the beast. This is true for all types of engines. It's one of the reasons why the 4 cylinders in trucks produce low HP numbers...the state of tune has the power spread out over a wider RPM band, which is better for pulling and easier on clutches and transmissions.

However, as mentioned, the HP/TQ ratio in a boxer-4 is better than an inline-4. So it's not going to be a complete dog down low like the 2.0L that was in the last-gen Civic Si (197hp and 139lb/ft)

This, however, does not address the fact that even if the torque figure is a respectable 170lb/ft, it's going to be reached at like 4000rpm, and the engine will not be very tractable below that.

This is why I want a turbo. A low-pressure unit like in my GTI would be great...they aren't that expensive, and you get all the torque as early as 2000rpm. Much less lag than a higher pressure unit like on the WRX and STi. And you can easily tune it for more if you so wish.

[PAImportTuner]

Originally Posted by CyberFormula

I thought i read in another thread

that the Subaru's boxer engine produced equal hp/tq numbers...and its Naturally aspirated.

Although that is true for the non performance lineup. You want that 2.0 to make 200hp you're going to have to give up some tq. The FB20 starts off at 14xhp/14xtq.

Current FB25
170hp @ 5800rpms
174tq @ 4100 rpms

For comparison
Hyundai N/A 2.4 liter four with 200hp 186lb ft gets about 35mpg hwy.

I would expect from the FR-S same HP, less TQ, more MPG for a smaller engine and lighter car especially using D4-S and the price premium.

[bofa]

Good discussion..... but now I'm losing optimism.

[WingsofWar]

Originally Posted by Maxim

I doubt a 200hp 2.0L boxer would produce more than 165ft/lb. It's just the nature of the beast. This is true for all types of engines.

true true..even the SOHC EJ204 coupled with AVCS from the legacy 2.0 makes 190hp/145ftlbs @ 7100rpm

but lets try this..take those same basic stats..and add

D4-S ~ to boost fuel efficeny and TQ
Dual AVCS DOHC
Narrow FB Cylinder Heads ~ to increase air flow
Asymmetrical rods ~ boost tq and displacement
lengthen the stroke ~ to bring the powerband down a bit.
Boost Compression Ratio to 12.5:1

We can't not gain more power and efficeny at that point starting from a baseline of 190hp/145ftlbs.....190-250hp/170-180ftlbs seems more likely at that point.

biggest boxer 4 dyno iv seen was from a shop down in australia, dynoed a fully built EJ204 at 288hp/240ftlb, i remember looking at the thread a few years back on a subaru forum.

[Fly Guy]

Originally Posted by Maxim

... and with summer tires the GTI pulls over .9g. The FT-86 won't produce higher grip.

What is your reasoning for this?

[Maxim]

Originally Posted by Fly Guy

What is your reasoning for this?

Physics. Lateral acceleration is primarily a function of mechanical grip, which is a function of contact patch and tire material.

The GTI is slightly heavier but has wider tires. The FR-S is slightly lighter but has narrower tires.

Additionally, the rim/tire package on the prototypes that are running around is not only narrower, but it is also smaller in diameter. People forget that a larger diameter tire ALSO produces a larger contact patch (lengthwise), it's not just the width.

Thus, given the tire size and probable weight of the FR-S, I find it unlikely that it will pull any better than the .93g that the summer tire package GTI does. Aerodynamics can dramatically increase tire traction by increasing friction without increasing weight, however neither the GTI nor the FR-S has sophisticated aero-tuning. Additionally, it makes no sense to include aggressive downforce in a 200hp street car: so little of the vehicle's life will be spent at speeds high enough to take advantage of the aero that the additional drag and fuel economy hit is simply not worth it.

Look at the Miata. It's even lighter than the FR-S but it also pulls less lateral acceleration than the GTI.

People talk about tuning the suspension for more grip, etc, but it's kind of misleading. You're not going to get very much effect in absolute grip from a suspension tune. The suspension set-up primarily determines how the vehicle behaves at the limit, you can tune in understeer or oversteer, but you're not going to get a large difference in absolute traction...the tires primarily dictate where that limit is.

That's why a wheel/tire upgrade is always the first thing that should be done when modding a car. It is cost effective and offers huge increases in performance.

[bofa]

^ Except we don't know the final FT tire size yet and compared to 3000lbs, the FT could end up weighing significantly less than the chubby GTI. Seems like arguing g's right now is a shot in the dark.

[Maxim]

Originally Posted by bofa

^ Except we don't know the final FT tire size yet and compared to 3000lbs, the FT could end up weighing significantly less than the chubby GTI. Seems like arguing g's right now is a shot in the dark.

I wouldn't say it's a shot in the dark. If the FT-86 hits the weight target of 2700lbs, that's still only 300lbs difference. That might make a .01-.02 difference in lateral grip....which is slightly less than the difference between a 225 tire (what the protos are running, I believe) and a 235 tire of equal compound would have.

I'm gonna guess that we'll see the major magazines reporting lateral acceleration figures of about .87-.90g for the FT-86 once it's released, based on the tire size of the prototypes.

Remember: The "feel" that Toyota is going for is antithetical to putting huge tires on a car. Wide tires increase grip but decrease steering feel. Just like the Mazda Miata, high ultimate grip is likely NOT one of the performance targets for this car.

It's been stated over and over, the target for this car is the feel....that means great transient response and steering feel....which are completely separate from lateral acceleration. There is no doubt in my mind that in terms of steering feel and transient response, the FT-86 will embarrass the GTI...however, without wider tires, it's not going to actually corner harder in stock form.

[Fly Guy]

I'm starting to understand now. Thanks, Maxim. There sure is a lot of give and take.

[Ryephile]

Damn, a lot of cats hissing at each other in this thread. Despite Maxim being a oversimplifying roll-center and general suspension geometry avoiding beeeotch about it, he finally got to the actual point that few seem to want to admit; the FR-S will end up feeling like a coupe' version of the Miata.

All this talk about 'ring lap times is utterly pointless. We're not trying to hang with Stefan Bellof.