LJD wrote: I can appreciate the weight/packaging/cost arguement for a normally aspirated flat-4, but I can't understand why the engineers wouldn't push the displacement up to 2.5L to make around 250 hp and 210 lb-ft. That 25% bump in displacement/power/torque wouldn't cost a lot, but could mean a world of difference in the stock performance of a relatively light car. Come on, man!
Maybe a 2.5L doesn't rev the way they want the supposed spiritual successor to the AE86 to?
ReverendDexter wrote:LJD wrote: I can appreciate the weight/packaging/cost arguement for a normally aspirated flat-4, but I can't understand why the engineers wouldn't push the displacement up to 2.5L to make around 250 hp and 210 lb-ft. That 25% bump in displacement/power/torque wouldn't cost a lot, but could mean a world of difference in the stock performance of a relatively light car. Come on, man!Maybe a 2.5L doesn't rev the way they want the supposed spiritual successor to the AE86 to?
And why wouldn't it? Displacement has near zero relevance to an engines ability to "rev". See DZ302, Boss 302 (old and new), Ferrari 458, LS7, Alfa V6, etc, etc, etc...
mistanfo wrote: Getting around fixed pricing is easy. #1- load up the dealer added options.
I think this is how Scion typically operates: The base price is fixed. They have some cars on the lots for test drives and maybe some equipped with popular option packages, but they encourage buyers to order their car with the options they want. Being squarely in Scion's target demographic (25), I'm on the fence about this. I like the idea of ordering a car with the options I want online and not have to deal with the dealership for anything other than test drives and picking up a car, but the options add up to the final price quickly.
ReverendDexter wrote: Maybe a 2.5L doesn't rev the way they want the supposed spiritual successor to the AE86 to?
It could also be for fuel economy reasons.
It's funny, when I was in my 20's Scion used to send me all kind of crap in the mail to get me to buy one of their cars. Now that they are actually going to have something I want I probably don't even exist to them any more.
Funny how different magazines give different info. C& D had this: Price est. $ 28000 Weight 2800-2900 lbs performance est: 0-60 6.0-6.2 sec. 0-100 15.5-15.7 1/4 mile 14.7-14.9 top speed 140 mph Est.t fuel eco : city/highway 19/27 But then again, it's not that far apart. HP is reported to be 210
Javelin wrote:ReverendDexter wrote:And why wouldn't it? Displacement has near zero relevance to an engines ability to "rev". See DZ302, Boss 302 (old and new), Ferrari 458, LS7, Alfa V6, etc, etc, etc...LJD wrote: I can appreciate the weight/packaging/cost arguement for a normally aspirated flat-4, but I can't understand why the engineers wouldn't push the displacement up to 2.5L to make around 250 hp and 210 lb-ft. That 25% bump in displacement/power/torque wouldn't cost a lot, but could mean a world of difference in the stock performance of a relatively light car. Come on, man!Maybe a 2.5L doesn't rev the way they want the supposed spiritual successor to the AE86 to?
Apples to oranges. If all other things remain equal except displacement, we either need a larger bore or a longer stroke to increase displacement. One increases piston speed significantly, which reduces the highest acceptable RPM for cylinder wall longevity. The other means a larger mass hanging off the rod and bearing which also creates a longevity problem.
Displacement does have a direct effect on RPM vs longevity considerations.
iceracer wrote: Funny how different magazines give different info. C& D had this: Price est. $ 28000 Weight 2800-2900 lbs performance est: 0-60 6.0-6.2 sec. 0-100 15.5-15.7 1/4 mile 14.7-14.9 top speed 140 mph Est.t fuel eco : city/highway 19/27 But then again, it's not that far apart. HP is reported to be 210
The low mass--Subaru says production cars will weigh a feathery 2500 pounds
I don't know what to think!
I wouldn't be surprised to see a 2.2 or 2.5 with similar power/more TQ a year or two down the road. See the WRX 2.0->2.5 or S2000 2.0->2.2 move. I would support this move.
I think bolt ons w/ the factory powerplant will make a very fun car.
I have my fingers crossed that it doesn't have typical Japanese "sport" gearing. 
Taiden wrote:Javelin wrote:Apples to oranges. If all other things remain equal except displacement, we either need a larger bore or a longer stroke to increase displacement. One increases piston speed significantly, which reduces the highest acceptable RPM for cylinder wall longevity. The other means a larger mass hanging off the rod and bearing which also creates a longevity problem. Displacement does have a direct effect on RPM vs longevity considerations.ReverendDexter wrote:And why wouldn't it? Displacement has near zero relevance to an engines ability to "rev". See DZ302, Boss 302 (old and new), Ferrari 458, LS7, Alfa V6, etc, etc, etc...LJD wrote: I can appreciate the weight/packaging/cost arguement for a normally aspirated flat-4, but I can't understand why the engineers wouldn't push the displacement up to 2.5L to make around 250 hp and 210 lb-ft. That 25% bump in displacement/power/torque wouldn't cost a lot, but could mean a world of difference in the stock performance of a relatively light car. Come on, man!Maybe a 2.5L doesn't rev the way they want the supposed spiritual successor to the AE86 to?
Not really. A 2.0L engine could have (as an example) an 80mm bore by a 100mm stroke for 502cc per cylinder x4 = 2.0L. To get my hypothetical motor A (We'll call it the HM20A) to a 2.5L (HM25A) I'd have to increase the bore 9.2mm to get an 89.2mmx100mm volume for 625cc per/cyl x4 = 2500cc = 2.5L.
A 9.2 mm bore increase is less than 1cm. In other words, 0.36" That's really not all that large of a difference and a lighter piston could easily be made to cover up the extra face volume. Stroke is even easier as you can lengthen just the rod. Combined is even easier still. My HM25B would need an 87mm bore and a 105mm stroke to hit 2.5L, increases of less than 10% on both sides of the equation, neither of which would really affect piston speed not rotating mass in a large manner, really. And they minor impact they would have could easily be engineered back out of it with lighter parts.
Wow, the M/T article mentions the motor sits 4.8" lower and 8" further rear-ward than the Impreza. Aren't Subaru turbos below and behind the motor? That could be the issue on why they are all N/A right now.
In reply to Javelin:
I found that striking as well. Only I was puzzled that the engine was only 8" further back, the article stating that the rear cylinder's bore center lines up with the front wheel center.
I know Subies normally carry their engines way forward in order to get the transaxle and front wheels to line up; and it is a very short engine fore-aft.
But why would the engine need to sit so far forward in a 2WD vehicle like this? Short engine, but still mostly forward of the front wheels?
I'm not saying it can't still be awesome, I'm just puzzled.
Javelin wrote:Taiden wrote:Not really. A 2.0L engine could have (as an example) an 80mm bore by a 100mm stroke for 502cc per cylinder x4 = 2.0L. To get my hypothetical motor A (We'll call it the HM20A) to a 2.5L (HM25A) I'd have to increase the bore 9.2mm to get an 89.2mmx100mm volume for 625cc per/cyl x4 = 2500cc = 2.5L. A 9.2 mm bore increase is less than 1cm. In other words, 0.36" That's really not all that large of a difference and a lighter piston could easily be made to cover up the extra face volume. Stroke is even easier as you can lengthen just the rod. Combined is even easier still. My HM25B would need an 87mm bore and a 105mm stroke to hit 2.5L, increases of less than 10% on both sides of the equation, neither of which would really affect piston speed not rotating mass in a large manner, really. And they minor impact they would have could easily be engineered back out of it with lighter parts.Javelin wrote:Apples to oranges. If all other things remain equal except displacement, we either need a larger bore or a longer stroke to increase displacement. One increases piston speed significantly, which reduces the highest acceptable RPM for cylinder wall longevity. The other means a larger mass hanging off the rod and bearing which also creates a longevity problem. Displacement does have a direct effect on RPM vs longevity considerations.ReverendDexter wrote:And why wouldn't it? Displacement has near zero relevance to an engines ability to "rev". See DZ302, Boss 302 (old and new), Ferrari 458, LS7, Alfa V6, etc, etc, etc...LJD wrote: I can appreciate the weight/packaging/cost arguement for a normally aspirated flat-4, but I can't understand why the engineers wouldn't push the displacement up to 2.5L to make around 250 hp and 210 lb-ft. That 25% bump in displacement/power/torque wouldn't cost a lot, but could mean a world of difference in the stock performance of a relatively light car. Come on, man!Maybe a 2.5L doesn't rev the way they want the supposed spiritual successor to the AE86 to?
If you can make the HM25A parts lighter, why not make them lighter in the HM20A as well? Apples to apples, the larger bore and longer stroke is going to increase the reciprocating mass at the same time that it increases piston acceleration and speed. You don't get to just "easily engineer" yourself out of that 
I suspect it's for fuel economy reasons. If Subaru can reach their power targets with a 2.0, then they'll use a 2.0. Otherwise we'd all be driving around with 8.0l engines if there was no downside.
Most stock cars rev like poo thanks to insanely heavy flywheels on stock cars.
A 20lb+ flywheel on a 4 cyl is insane.
Keith wrote:Javelin wrote:If you can make the HM25A parts lighter, why not make them lighter in the HM20A as well? Apples to apples, the larger bore and longer stroke is going to increase the reciprocating mass at the same time that it increases piston acceleration and speed. You don't get to just "easily engineer" yourself out of thatTaiden wrote:Not really. A 2.0L engine could have (as an example) an 80mm bore by a 100mm stroke for 502cc per cylinder x4 = 2.0L. To get my hypothetical motor A (We'll call it the HM20A) to a 2.5L (HM25A) I'd have to increase the bore 9.2mm to get an 89.2mmx100mm volume for 625cc per/cyl x4 = 2500cc = 2.5L. A 9.2 mm bore increase is less than 1cm. In other words, 0.36" That's really not all that large of a difference and a lighter piston could easily be made to cover up the extra face volume. Stroke is even easier as you can lengthen just the rod. Combined is even easier still. My HM25B would need an 87mm bore and a 105mm stroke to hit 2.5L, increases of less than 10% on both sides of the equation, neither of which would really affect piston speed not rotating mass in a large manner, really. And they minor impact they would have could easily be engineered back out of it with lighter parts.Javelin wrote:Apples to oranges. If all other things remain equal except displacement, we either need a larger bore or a longer stroke to increase displacement. One increases piston speed significantly, which reduces the highest acceptable RPM for cylinder wall longevity. The other means a larger mass hanging off the rod and bearing which also creates a longevity problem. Displacement does have a direct effect on RPM vs longevity considerations.ReverendDexter wrote:And why wouldn't it? Displacement has near zero relevance to an engines ability to "rev". See DZ302, Boss 302 (old and new), Ferrari 458, LS7, Alfa V6, etc, etc, etc...LJD wrote: I can appreciate the weight/packaging/cost arguement for a normally aspirated flat-4, but I can't understand why the engineers wouldn't push the displacement up to 2.5L to make around 250 hp and 210 lb-ft. That 25% bump in displacement/power/torque wouldn't cost a lot, but could mean a world of difference in the stock performance of a relatively light car. Come on, man!Maybe a 2.5L doesn't rev the way they want the supposed spiritual successor to the AE86 to?
Now now, boys. this is about as off topic as it can get. Let's also not forget, NHRA pro stock 500 cubic inch monsters accelerate at 4800 RPM/second (published, at least), so clearly they have more rotating and reciprocating mass than a lightweight four cylinder combo. Maybe... just maybe, there is more to the story here.
I'll go on record, again, as saying that RPM/s DOES NOT MATTER AT ALL. I would argue that you cannot even feel it. It has literally nothing to do with the way the car acts, even blipping the throttle is not a function of this, but rather throttle response. "Ability to rev" is some unquantifiable, Car&Driver created nomenclature that basically means throttle response. My PT Cruiser has terrible throttle response and yet my old 400 cubic inch, all stock rotating assembly SBC has amazing throttle response. Which had higher rotating/recip mass? Yup, and it "revs slower".
z31maniac wrote: Most stock cars rev like poo thanks to insanely heavy flywheels on stock cars. A 20lb+ flywheel on a 4 cyl is insane.
I'll give you that...
ReverendDexter wrote:LJD wrote: I can appreciate the weight/packaging/cost arguement for a normally aspirated flat-4, but I can't understand why the engineers wouldn't push the displacement up to 2.5L to make around 250 hp and 210 lb-ft. That 25% bump in displacement/power/torque wouldn't cost a lot, but could mean a world of difference in the stock performance of a relatively light car. Come on, man!Maybe a 2.5L doesn't rev the way they want the supposed spiritual successor to the AE86 to?
I've heard that cars in Japan are taxed based on displacement and weight. You go above 2 liters and you're in a higher tax bracket. I think the higher tax is a big enough deal that keeping an engine below 2 liters is a major design factor.
200hp N/A, 2600 pounds, rear wheel drive, limited slip....
sounds like a rear wheel drive integra type R and I'm not complaining.
In reply to tuna55:
Its not really a fair comparison though. A 500ci NHRA motor doesn't need to survive terribly long. You can make a 6.0L engine with a long stroke rev to 9000rpm, no sweat. Can it do so reliably everyday for 10 years and 100,000 miles? The small displacement, oversquare engine will likely have a much easier time meeting that durability target.
On the "ability to rev" and "throttle response" characteristics, that is fairly independent of displacement. A big V8 with a lightweight flywheel and well-adjusted cable throttle will do very well in both respects. A modern 4 cyl with a 20+ lb flywheel (as has already been mentioned) for NVH and driveability reasons (and not fun driveability reasons, but 'we also have to sell this car to people that refuse to acknowledge they can't drive stick and will stall it constantly' reasons) and drive by wire that is tuned for emissions, not fun, will not be nearly as fun in either category. Also, believe it or not, the two can be very different. You can have a very free-revving 4cyl with a high redline that has terrible response due to the DBW, and vice versa.
One of my favorite cars to drive, ever, was my '90 325i E30 that I had put an 8lb aluminum flywheel on and did a proper tune up, including new throttle cable, ignition, shifter rebuild, etc. Redline was only 6800, but it got there quick and you could just think gear-changes and throttle application and the car would do them perfectly. Idled perfect, easy to drive....just sublime. Right there with it was a 2003 S2000 (last of the 9K redline, pre-DBW), the high strung nature makes that car.
tuna55 wrote: Let's also not forget, NHRA pro stock 500 cubic inch monsters accelerate at 4800 RPM/second (published, at least)
Forgive my ignorance, but what the heck are you talking about?
And even if "rotations per minute per second" was a useful unit of measurement, it has nothing to do with anything that matters such as piston speed.
LJD wrote: I can appreciate the weight/packaging/cost arguement for a normally aspirated flat-4, but I can't understand why the engineers wouldn't push the displacement up to 2.5L to make around 250 hp and 210 lb-ft. That 25% bump in displacement/power/torque wouldn't cost a lot, but could mean a world of difference in the stock performance of a relatively light car. Come on, man!
Because bumping it over 2 litres in the JDM would move it into some weird tax/fuel bracket and make it really expensive. Remember, those stats are leaked from a JDM publication.
No telling what they'll do to the North American market version, but I suspect they'll have some kind of CAFE figure in mind here.
(edit: Glen beat me to it )
Jalopnik says that this is the BR-Z. I actually like it better than the FR-S... No word on the HP yet only as much as the underpinnings can handle.
http://jalopnik.com/5855323/subaru-brz-sti-concept-more-photos
GlennS wrote: 200hp N/A, 2600 pounds, rear wheel drive, limited slip.... sounds like a rear wheel drive integra type R and I'm not complaining.
This
/thread
...srsly
tuna55 wrote:Keith wrote:Now now, boys. this is about as off topic as it can get. Let's also not forget, NHRA pro stock 500 cubic inch monsters accelerate at 4800 RPM/second (published, at least), so clearly they have more rotating and reciprocating mass than a lightweight four cylinder combo. Maybe... just maybe, there is more to the story here. I'll go on record, again, as saying that RPM/s DOES NOT MATTER AT ALL. I would argue that you cannot even feel it. It has literally nothing to do with the way the car acts, even blipping the throttle is not a function of this, but rather throttle response. "Ability to rev" is some unquantifiable, Car&Driver created nomenclature that basically means throttle response. My PT Cruiser has terrible throttle response and yet my old 400 cubic inch, all stock rotating assembly SBC has amazing throttle response. Which had higher rotating/recip mass? Yup, and it "revs slower".Javelin wrote:If you can make the HM25A parts lighter, why not make them lighter in the HM20A as well? Apples to apples, the larger bore and longer stroke is going to increase the reciprocating mass at the same time that it increases piston acceleration and speed. You don't get to just "easily engineer" yourself out of thatTaiden wrote:Not really. A 2.0L engine could have (as an example) an 80mm bore by a 100mm stroke for 502cc per cylinder x4 = 2.0L. To get my hypothetical motor A (We'll call it the HM20A) to a 2.5L (HM25A) I'd have to increase the bore 9.2mm to get an 89.2mmx100mm volume for 625cc per/cyl x4 = 2500cc = 2.5L. A 9.2 mm bore increase is less than 1cm. In other words, 0.36" That's really not all that large of a difference and a lighter piston could easily be made to cover up the extra face volume. Stroke is even easier as you can lengthen just the rod. Combined is even easier still. My HM25B would need an 87mm bore and a 105mm stroke to hit 2.5L, increases of less than 10% on both sides of the equation, neither of which would really affect piston speed not rotating mass in a large manner, really. And they minor impact they would have could easily be engineered back out of it with lighter parts.Javelin wrote:Apples to oranges. If all other things remain equal except displacement, we either need a larger bore or a longer stroke to increase displacement. One increases piston speed significantly, which reduces the highest acceptable RPM for cylinder wall longevity. The other means a larger mass hanging off the rod and bearing which also creates a longevity problem. Displacement does have a direct effect on RPM vs longevity considerations.ReverendDexter wrote:And why wouldn't it? Displacement has near zero relevance to an engines ability to "rev". See DZ302, Boss 302 (old and new), Ferrari 458, LS7, Alfa V6, etc, etc, etc...LJD wrote: I can appreciate the weight/packaging/cost arguement for a normally aspirated flat-4, but I can't understand why the engineers wouldn't push the displacement up to 2.5L to make around 250 hp and 210 lb-ft. That 25% bump in displacement/power/torque wouldn't cost a lot, but could mean a world of difference in the stock performance of a relatively light car. Come on, man!Maybe a 2.5L doesn't rev the way they want the supposed spiritual successor to the AE86 to?
Did you ever think that a top fuel engine turns somewhere around 750 revolutions in a 5 sec run.
In reply to iceracer:
Yes. Doesn't really apply. My point is only that "ability to rev" can only be expressed by RPM/S, and can only be measured while not driving the wheels, and is mostly useless to measure or think about at all.
GlennS wrote:ReverendDexter wrote:I've heard that cars in Japan are taxed based on displacement and weight. You go above 2 liters and you're in a higher tax bracket. I think the higher tax is a big enough deal that keeping an engine below 2 liters is a major design factor. 200hp N/A, 2600 pounds, rear wheel drive, limited slip.... sounds like a rear wheel drive integra type R and I'm not complaining.LJD wrote: I can appreciate the weight/packaging/cost arguement for a normally aspirated flat-4, but I can't understand why the engineers wouldn't push the displacement up to 2.5L to make around 250 hp and 210 lb-ft. That 25% bump in displacement/power/torque wouldn't cost a lot, but could mean a world of difference in the stock performance of a relatively light car. Come on, man!Maybe a 2.5L doesn't rev the way they want the supposed spiritual successor to the AE86 to?
A lot of countries in Asia have different tax brackets at 1.0L, 1.5L and 2.0L. Europe is similar.
Brett_Murphy wrote:LJD wrote: I can appreciate the weight/packaging/cost arguement for a normally aspirated flat-4, but I can't understand why the engineers wouldn't push the displacement up to 2.5L to make around 250 hp and 210 lb-ft. That 25% bump in displacement/power/torque wouldn't cost a lot, but could mean a world of difference in the stock performance of a relatively light car. Come on, man!Because bumping it over 2 litres in the JDM would move it into some weird tax/fuel bracket and make it really expensive. Remember, those stats are leaked from a JDM publication. No telling what they'll do to the North American market version, but I suspect they'll have some kind of CAFE figure in mind here. (edit: Glen beat me to it
Good point. Subaru did bump the displacement of the USDM STi from 2.0L to 2.5L, mainly to keep it emissions compliant while still keeping the horsepower around 300. I think all versions, at least initially, will stick with the 2.0L H-4. European and Japanese emissions standards have since caught up to the US's, the FBTRZS emphasizes handling over horsepower, and there is no homologation standard an non-USDM version would have to comply with like the STi has for rallying.
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