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Dootz
Dootz New Reader
5/4/19 4:18 a.m.

Just curious, since I hear that the turbocharger is responsible for the crap exhaust note and poor top end performance

STM317
STM317 UltraDork
5/4/19 8:13 a.m.

There are no good sounding 4 cylinders, only those that don't sound awful. The turbo isn't responsible for the crap exhaust note, it just mutes the junk that's there.

The turbo is sized to negate lag and provide mid-range punch. That's why it has no top end. Going to a larger turbo could make more power up top, but it would add some lag and make it feel "gutless" in the bottom of the rev range.

A supercharger can be responsive and torquey but it comes with the price of some power and fuel economy since its driven by the engine rather than the waste energy of the exhaust.

Knurled.
Knurled. MegaDork
5/4/19 8:16 a.m.
STM317 said:

There are no good sounding 4 cylinders

Except for the BDA.

BlueInGreen - Jon
BlueInGreen - Jon SuperDork
5/4/19 8:37 a.m.

Would the cost of swapping the turbo for a supercharger be less than the cost difference between the Ecoboost and a V8?

I’m guessing a V8 would solve the problem of a lame exhaust note cheeky

Knurled.
Knurled. MegaDork
5/4/19 8:50 a.m.

In reply to BlueInGreen - Jon :

V8s sound even worse, at least until you get to GT350 money.  And while I have yet to drive a 5.2 Mustang, every V8 I have ever driven was not very sporting.  Really crappy throttle response, no good acceleration like a 4 cylinder has.

 

"Acceleration" is not "power".  "Acceleration" I guess is throttle response, but in both directions.  Like, if you hit the accelerator, the engine needs to respond NOW, and when you lift, the engine needs to decelerate NOW, and if there is poor traction (because if there isn't poor traction, then you aren't cornering hard enough) then the engine needs to accept varying levels of grip NOW.

 

Reminds of what one of the guys who tried racing with surplus Allison V12s in the 1960s said.  It's horrible for accelerating, but it'll taxi all day at 150mph

NickD
NickD PowerDork
5/4/19 8:52 a.m.

Aside from maybe Rotrex superchargers, most superchargers (especially your big Roots-style) provide lots of  low end and mid-range and run out of breath towards the top of the power band, so a switch from a supercharger wouldn't address the lack of top end power concern. 

RollinM
RollinM New Reader
5/4/19 8:59 a.m.

This sounds like this would solve some of the issues (not the sound) and be a lot cheaper.

 https://www.americanmuscle.com/ford-performance-cai-procal-voucher-1517eco.html

BlueInGreen - Jon
BlueInGreen - Jon SuperDork
5/4/19 9:15 a.m.

In reply to Knurled. :

I just know I like what the v8s sound like as they pull away from me in traffic. I’ve also never actually driven any flavor of the current gen Mustang so I guess my opinion is worth exactly what anyone’s paying for it.

rslifkin
rslifkin UltraDork
5/4/19 9:23 a.m.

The current gen 5.0 is pretty good sounding IMO.  Not the best exhaust not ever and no comparison to the GT350, but it's pretty good. 

It's mostly low revving tractor motor V8s that sound bad.  Add a little more cam, make sure it's got enough compression and open up the intake a bit and they sound at least decent given a good exhaust layout.  IMO, x-piped or merged to a single sounds far better than separated duals. 

Keith Tanner
Keith Tanner MegaDork
5/4/19 10:14 a.m.
Knurled. said:

In reply to BlueInGreen - Jon :

V8s sound even worse, at least until you get to GT350 money.  And while I have yet to drive a 5.2 Mustang, every V8 I have ever driven was not very sporting.  Really crappy throttle response, no good acceleration like a 4 cylinder has.

 

"Acceleration" is not "power".  "Acceleration" I guess is throttle response, but in both directions.  Like, if you hit the accelerator, the engine needs to respond NOW, and when you lift, the engine needs to decelerate NOW, and if there is poor traction (because if there isn't poor traction, then you aren't cornering hard enough) then the engine needs to accept varying levels of grip NOW.

 

Reminds of what one of the guys who tried racing with surplus Allison V12s in the 1960s said.  It's horrible for accelerating, but it'll taxi all day at 150mph

I can tell you the canned LS 3 in my Miata has pretty wicked throttle response, both in terms of quality and quantity. And this is comparing it to a couple of high compression, individual throttle-bodied four cylinders I used to own. There’s no reason a good cam and high compression and good throttle mapping won’t equal good throttle response. 

Youre right about the BDA though. 

Keith Tanner
Keith Tanner MegaDork
5/4/19 10:16 a.m.
NickD said:

Aside from maybe Rotrex superchargers, most superchargers (especially your big Roots-style) provide lots of  low end and mid-range and run out of breath towards the top of the power band, so a switch from a supercharger wouldn't address the lack of top end power concern. 

They’re like turbos, it all depends on the sizing. It’s possible to have a laggy super that wails on the top end, and possible to have a turbo that’s all low end torque but no top end.

If we’re after better sound, we’d better not talk about the idle sound of a Rotrax :)

Kreb
Kreb UberDork
5/4/19 12:17 p.m.

Back when turbos were associated with lag and unreliability, changing to a supercharger made a certain amount of sense. Modern factory  turbocharger installations are so dialed in that practically any advantage you get through modification will mean not insignificant  disadvantages in other areas. Want more top end? Hello lag. If what you really want is a V8, trade in for one. If you want better throttle response and sounds,  there are mods that will help. But there's not much sense in buying a cat and complaining that it's not a dog. 

Wally
Wally MegaDork
5/4/19 12:23 p.m.

NickD
NickD PowerDork
5/4/19 12:28 p.m.
Keith Tanner said:
NickD said:

Aside from maybe Rotrex superchargers, most superchargers (especially your big Roots-style) provide lots of  low end and mid-range and run out of breath towards the top of the power band, so a switch from a supercharger wouldn't address the lack of top end power concern. 

They’re like turbos, it all depends on the sizing. It’s possible to have a laggy super that wails on the top end, and possible to have a turbo that’s all low end torque but no top end.

If we’re after better sound, we’d better not talk about the idle sound of a Rotrax :)

Yeah, the sound of the Rotrex is my least favorite part of having one. It sounds like a dying A/C compressor at idle, with a faint whoosh at throttle. Rotrex lists "quiet operation" as an advantage. I disagree. 

 

And maybe I'm crazy, but I don't care for the GT350 Voodoo 5.2L exhaust note. I much prefer the traditional 5.0L Coyote sound.

Knurled.
Knurled. MegaDork
5/4/19 12:38 p.m.

I'll have to sample an LS3 then.

 

And laggy superchargers do exist.  Try out a Thunderbird Super Coupe.  Positive displacement, and about six feet of plumbing between the blower and the engine.  Throttle response is decidedly non-linear since you have to wait for the air to back up in the plumbing before you get any boost.

 

Not as bad, I assume, as the supercharged Miata a friend rigged up, with an inlet-side throttle body and an intercooler.  It had response lag on both ends of the spectrum - let off the throttle and you'd have to wait a bit for the charge pipe to depressurize!

sergio
sergio Reader
5/4/19 1:23 p.m.

Lancia

Leave it to the Italians to build something wild and crazy

supercharged and turbo 1.8L AWD rally car making around 480hp 

Dave M
Dave M Reader
5/4/19 1:59 p.m.
 

And maybe I'm crazy, but I don't care for the GT350 Voodoo 5.2L exhaust note. I much prefer the traditional 5.0L Coyote sound.

Both sound great. The Voodoo literally sounds just like a Ferrari. Winner!

slefain
slefain PowerDork
5/4/19 9:26 p.m.

Swapped no, but Scott Hoag at MRT threw a  <strike>blower</strike> centrifugal supercharger on an Ecoboost Mustang already:

stanger_missle
stanger_missle SuperDork
5/5/19 1:00 a.m.
STM317 said:

There are no good sounding 4 cylinders, only those that don't sound awful.

The Fiat 500 Abarth would like to have a word with you cheeky.

I had an EB Mustang take off right next to me yesterday as I sat in the turn lane. It had aftermarket exhaust. I'm not sure if it was an axle-back or cat-back but it sounded pretty terrible. I don't think there is a way to make the 2.3T in the Mustang sound good.

Knurled.
Knurled. MegaDork
5/5/19 4:03 a.m.

In reply to slefain :

That's a centrifugal suparcharger, not a blower.  Biiiiig difference

ultraclyde
ultraclyde PowerDork
5/5/19 9:55 a.m.

All the modern mustang V8s need for damn sharp throttle response is the right tune. Factory has a lot of throttle delay programmed in to protect the drivetrain under warranty.  My old 4.6 has it all dialed out and it's a lot of fun. I can't imagine how much fun a newer 5L would be with a similar setup.

I agree that the EB motors sound sad but it's because of the cylinder count not the turbos. The new 5L sounds great to me, especially with a really good aftermarket exhaust instead of the normal cheap crap

 

Knurled.
Knurled. MegaDork
5/5/19 10:26 a.m.
ultraclyde said:

All the modern mustang V8s need for damn sharp throttle response is the right tune.

 

And a zero-weight flywheel and an ultralight rotating assembly.

 

Throttle response on acceleration is one thing, but the ability for the tires to regain traction on engine braking is another.  That is important if you're concerned with going around corners and stuff and driving just a little bit past the limit.  The only way to get that is to minimize engine inertia, so the tires can force the engine to speed up more easily instead of just sitting there sliding.

 

You could drive more conservatively, but that's not nearly as fun.

 

This is one area where four cylinder engines are very good.  Twice per revolution all pistons are near TDC/BDC, so engine friction reduces to whatever is in the valvetrain.  This makes for a somewhat vibrationy driving experience but it's also great for regaining traction.

frenchyd
frenchyd UberDork
5/5/19 10:29 a.m.
rslifkin said:

The current gen 5.0 is pretty good sounding IMO.  Not the best exhaust not ever and no comparison to the GT350, but it's pretty good. 

It's mostly low revving tractor motor V8s that sound bad.  Add a little more cam, make sure it's got enough compression and open up the intake a bit and they sound at least decent given a good exhaust layout.  IMO, x-piped or merged to a single sounds far better than separated duals. 

The sound of a V8 is a six cylinder with a stumble.  That’s because at least two cylinders fire right on top of each other.  Depending on the firing order any V8 will have adjacent cylinders between 90 degrees and 270 degrees of the adjacent cylinder. 

The only way to hear anything else is like NASCAR stock cars do with equal length headers exiting on one side of the car.  

Knurled.
Knurled. MegaDork
5/5/19 10:31 a.m.
frenchyd said:
rslifkin said:

The current gen 5.0 is pretty good sounding IMO.  Not the best exhaust not ever and no comparison to the GT350, but it's pretty good. 

It's mostly low revving tractor motor V8s that sound bad.  Add a little more cam, make sure it's got enough compression and open up the intake a bit and they sound at least decent given a good exhaust layout.  IMO, x-piped or merged to a single sounds far better than separated duals. 

The sound of a V8 is a six cylinder with a stumble.  That’s because at least two cylinders fire right on top of each other.  Depending on the firing order any V8 will have adjacent cylinders between 90 degrees and 270 degrees of the adjacent cylinder. 

The only way to hear anything else is like NASCAR stock cars do with equal length headers exiting on one side of the car.  

Not quite.  NASCAR still uses deivided exhaust, and interestingly one person tested a Cup engine with 8" stubs dumping into a 4" diameter log with no collector and no attempt to tune whatsoever, and found no appreciable power loss.

 

Most of the reason they dump out the side is because there is no room under the car for exhaust with the truck arms in the way.  The rest is probably thrust vectoring.

Appleseed
Appleseed MegaDork
5/5/19 11:29 a.m.

Sounds like a rediculus amount of work just to change an exhaust note.

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