Norm Peterson

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The WRX 4-cylinder is a boxer, not an inline like the Ford motors. They will always sound different because of the different configuration.

s-l400 (1).jpg


The point I was trying to make is that an inline-4 can only get so big. This is due to balancing and smoothness issues. Smaller displacement motors will naturally burn less fuel and produce lower emissions. The turbocharging myth is the loophole automakers have jumped through. Yes, you can get good power from a low displacement 4-cyl turbo. You can also get good fuel economy. The dirty secret is, you can't have both at the same time. When that turbo motor is producing 3 or 4 hundred horsepower, it's using just as much fuel as it's larger NA counterparts. Conversely, when it is sipping gas on the highway running at sub-1000 rpms in a high overdrive gear, it isn't making any power. At that point, it's the transmission that's getting good fuel economy.
There's more. An inline four cannot be completely balanced for both primary and secondary forces and moments - and this is exactly why flat-plane crank V8 engine designs really should be limited to somewhere in the 4.0 - 4.5 liter range . . . like two times the 2.0 to 2.3 liters for an inline four. IIRC, balance shafts started creeping into I-4 engines about the time mfrs started pushing their displacements out to 2.6 liters or so.

Thanks for the picture - and to think that people think the Coyote is a wide engine.

Turbocharging can be made to show better results during EPA testing, where the mpg data is collected. That's probably the main reason cylinder count has been headed toward fours and sixes, as the mfrs do have to satisfy the EPA (which, as an agency, doesn't give a rat's ass about car enthusiasts' preferences). It's not necessarily what the mfrs' preference would be in the absence of mpg requirements.


Norm





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IrishStallion

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They where making 1500 bhp from 1.5 liter bmw 4 banger single turbos back in 1986 F1. Two second turbo lag on 5 bar though... lol.
 

Norm Peterson

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They where making 1500 bhp from 1.5 liter bmw 4 banger single turbos back in 1986 F1. Two second turbo lag on 5 bar though... lol.
Crazy amounts of power per liter are possible if you don't have to worry about emissions or restrictive fuel economy mandates. Or having to blend fuel specifically for the engine.


Norm
 

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Exhaust sound character is very much a function of firing order, bank angle (if a V type engine which includes horizontally opposed engines where the bank angle is 180°), and how the pipes are merged. Making the exhaust either louder or deeper with a less restrictive exhaust system doesn't change this.

If you're old enough to remember when early VW Beetles were common you'll immediately pick up the same kind of sound coming out of just about any horizontally-opposed four (and trust me, the guys over on the Subie forums absolutely hate hearing that comparison). The STi gets a deeper tone, but the same uneven rattly rumble is present. I used to own a Subaru Legacy equipped with a slightly detuned version of the STi's EJ engine, and there was a certain combination of rpms and throttle that I'd go out of my way to avoid using for exactly that reason.


Norm
A buddy had an air-cooled Beetle that was lifted on VW microbus portal axles. The motor was straight piped, and actually sounded amazing. It was the fastest thing I've ever driven off road.
 

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Exhaust sound character is very much a function of firing order, bank angle (if a V type engine which includes horizontally opposed engines where the bank angle is 180°), and how the pipes are merged. Making the exhaust either louder or deeper with a less restrictive exhaust system doesn't change this.

If you're old enough to remember when early VW Beetles were common you'll immediately pick up the same kind of sound coming out of just about any horizontally-opposed four (and trust me, the guys over on the Subie forums absolutely hate hearing that comparison). The STi gets a deeper tone, but the same uneven rattly rumble is present. I used to own a Subaru Legacy equipped with a slightly detuned version of the STi's EJ engine, and there was a certain combination of rpms and throttle that I'd go out of my way to avoid using for exactly that reason.


Norm
I was born in the late eighties...Beetles were well before my time.

I think I'm at the point where at times I feel my EcoBoost sounds too quiet inside even on Normal/Sport exhaust mode (once I'm up to speed), but I still like that there's no drone in the cabin whatsoever. If anything, the loudest noises inside my car were interior trim rattles...and once I resolved those, it's really quiet for a Mustang.

Still, if active exhaust stays an option on the S650, and I decide to mod one beyond subtle aesthetics, part of me wants to consider trying to make a "sleeper-sounding" GT. Maybe make it as quiet (?) as BMWs/Benzs/Lexus'. But that's still a very long ways away for me.

I've never heard what the engine/exhaust of an STi sounds like from the inside of said car. And now that I've reheard what the WRX sounds like from the outside again, I realize that the differences are subtle to my ear, but the boxer-4 does sound different from an inline-4.

To close, I'll attempt answering the question I asked earlier...of why we don't see improved fuel efficiency for 6/8-cylinder engines compared to 4-cylinder engines. From a outsider perspective, more cylinders equals more oil/fuel to consume to keep those parts lubricated and operating optimally, which then equals quicker fuel consumption. (Close or completely off my rocker?)
 

Norm Peterson

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I've never heard what the engine/exhaust of an STi sounds like from the inside of said car. And now that I've reheard what the WRX sounds like from the outside again, I realize that the differences are subtle to my ear, but the boxer-4 does sound different from an inline-4.
The new WRX uses an equal-length header into the turbocharger inlet, so you get evenly spaced exhaust pulses. Think of this as being comparable to an X-pipe for a crossplane V8. The STi used an unequal header design because of its turbocharger location being off to one side of the engine, and this affects the timing of exhaust pulses from the two banks coming together. It's sort of like an H-pipe, for a V8 analogy. There's a company now making an unequal length header for the new WRX specifically to give it the old sound for the "Subie purists".

I suppose you could make an unequal-length header for an inline-4 hoping to insert a bit of rumble into its exhaust sound, but you'd have to get the cylinder pairing right.


To close, I'll attempt answering the question I asked earlier...of why we don't see improved fuel efficiency for 6/8-cylinder engines compared to 4-cylinder engines. From a outsider perspective, more cylinders equals more oil/fuel to consume to keep those parts lubricated and operating optimally, which then equals quicker fuel consumption. (Close or completely off my rocker?)
More cylinders generally means more friction and other parasitic losses (more rings, more bearings, more camshaft lobes/valves/valve springs, etc.). Plus, pumping losses are lower with a smaller displacement engine operating at wider throttle openings than with larger displacement engines operating at smaller throttle openings, so you're making efficiency gains that way as well. Assuming that acceleration response is still acceptable, of course.


Norm
 
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nastang87xx

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According to Ford Authority and their sources, it looks like the Mustang will stay on a unique chassis that instead incorporates elements from the CD6. This calms my fears about the Mustang becoming too large and gaining too much weight. What about you guys?

Ford Has No Plans To Use CD6 Platform For Smaller Vehicles: Exclusive (fordauthority.com)
The car already has gained too much weight and I don't see the trend stopping. FWIW, the ZL1 1LE is not much heavier than even a GT350 and yet it's even more well equipped and carries more fuel. Put a PD blower on a base GT350 and it outweighs a ZL1 1LE.

Ford sells Mustangs by the bunch in rental fleets and to people who just want a Mustang, not a hard hitting heart pounding animal. The Alpha Camaro fundamentally did what we WANTED Mustang to do, less weight, completely redesigned unibody and chassis (the S550 was an evolution of the S197, not a total rework), incredible suspension tuning, form following function. Challenger/Charger and Mustang ate it's lunch and lunch money into next week in sales. I still think Mustang should have utilized the F150's aluminum panel stamping techniques, or at least on the 350's. Aluminum doors and carbon composite roof. That would have put the weight down to about an SS 1LE.
 

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Crazy amounts of power per liter are possible if you don't have to worry about emissions or restrictive fuel economy mandates. Or having to blend fuel specifically for the engine.


Norm
That's a very lazy perspective. We have literally seen that perspective disproven by the innovations that all manufacturers have made with their engines. Ford, and just about every other manufacturer is proving that you can have both fuel economy, power, and a cleaner vehicle all at the same time.

The idea that emissions is stifling power or fun is a a common and incorrect argument. Sure, more displacement is going to make it easier to make more power, but it is not true that it is hurting the passenger car industry.

You have a traction limited 5.2L GT500 who literally can't put the power down and people are complaining about wanting more power. I don't get it at all. The Demon needed drag-specific hardware to even get close to putting it's power down. I think, like the BOSS 302 with it's live axle, we're at the point of diminishing returns on a front engine, rear drive platform like the Mustang. The only other option is light-weighting.
 
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Norm Peterson

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That's a very lazy perspective. We have literally seen that perspective disproven by the innovations that all manufacturers have made with their engines. Ford, and just about every other manufacturer is proving that you can have both fuel economy, power, and a cleaner vehicle all at the same time.

The idea that emissions is stifling power or fun is a a common and incorrect argument. Sure, more displacement is going to make it easier to make more power, but it is not true that it is hurting the passenger car industry.
You're missing the point.

I was commenting on 1500 HP coming from 1.5 liter engines. When you find a 5.2L GT500 putting out 5200 emissions-legal HP and not saddled with much of a gas-guzzler tax, check back in.

At something like 145 HP/L, the GT500's engine has a huge way to go to get to the crazy levels that F1 achieved (1000 HP/L). It's not even close to matching the raw 1500 number, and that's with having nearly 3.5 times the displacement.


Norm
 
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You're missing the point.

I was commenting on 1500 HP coming from 1.5 liter engines. When you find a 5.2L GT500 putting out 5200 emissions-legal HP and not saddled with much of a gas-guzzler tax, check back in.

At something like 145 HP/L, the GT500's engine has a huge way to go to get to the crazy levels that F1 achieved (1000 HP/L). It's not even close to matching the raw 1500 number, and that's with having nearly 3.5 times the displacement.


Norm
I did miss the point there, my apologies.
 

Mikthehun1

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You're missing the point.

I was commenting on 1500 HP coming from 1.5 liter engines. When you find a 5.2L GT500 putting out 5200 emissions-legal HP and not saddled with much of a gas-guzzler tax, check back in.

At something like 145 HP/L, the GT500's engine has a huge way to go to get to the crazy levels that F1 achieved (1000 HP/L). It's not even close to matching the raw 1500 number, and that's with having nearly 3.5 times the displacement.


Norm
To be fair an F1 engine doesn't last a whole season, let alone the length of a standard powertrain warranty. There are more analogous motors to the GT500 in the pro drag circuit. They can't even be dyno'd because:

1. Every dyno in the world would break

2. The engine would burn out before getting a reading anyway
 

nastang87xx

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To be fair an F1 engine doesn't last a whole season, let alone the length of a standard powertrain warranty. There are more analogous motors to the GT500 in the pro drag circuit. They can't even be dyno'd because:

1. Every dyno in the world would break

2. The engine would burn out before getting a reading anyway
Top fuel lol.
 

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