Turbo Muffler on a 4cyl

In the summer I replaced the splitting muffler on my 4cylinder Ranger
with a Thrush Turbo. It was partially as a joke.

I remember Turbos on V8 cars getting gradually louder over time, but
on the 4 it seems to have hit a 'loudness limit' of some sort. At
first I figured that maybe it was a lesser volume of air, but in all
reality my 2.5L 4cyl is about the same as half a 5.0L V8 with dual
exhaust.

Something also odd- On V8 cars I remember the Turbo muffler being
quiet at low RPMs or a cruise with no load, but then 'opening up' and
getting loud when you put your foot into it. The one on my truck is
just the opposite- noisy at idle, half as loud at cruise, and when I
put the pedal to the floor it is completely silent!

Bizzaro!

-ph

phaeton wrote:
> I remember Turbos on V8 cars getting gradually louder over time, but
> on the 4 it seems to have hit a 'loudness limit' of some sort. At
> first I figured that maybe it was a lesser volume of air, but in all
> reality my 2.5L 4cyl is about the same as half a 5.0L V8 with dual
> exhaust.

My '89 Grand Marquis 5.0L is goofy. A year or so ago the car started making
a swooshing sound on acceleration, like something was pumping air through a
hose into the atmosphere. Turned out there was a BIG hole in the muffler
and the exhaust pipe, and the car was just not one to make a lot of noise.
It's definitely quieter with a new pipe and muffler, but even with the holes
it was quieter than many stock models of other cars.

--
Dec. 6 (Bloomberg) -- Government officials and activists flying to Bali,
Indonesia, for the United Nations meeting on climate change will cause
as much pollution as 20,000 cars in a year.

phaeton wrote:
> In the summer I replaced the splitting muffler on my 4cylinder Ranger
> with a Thrush Turbo. It was partially as a joke.
>
> I remember Turbos on V8 cars getting gradually louder over time, but
> on the 4 it seems to have hit a 'loudness limit' of some sort. At
> first I figured that maybe it was a lesser volume of air, but in all
> reality my 2.5L 4cyl is about the same as half a 5.0L V8 with dual
> exhaust.
>
> Something also odd- On V8 cars I remember the Turbo muffler being
> quiet at low RPMs or a cruise with no load, but then 'opening up' and
> getting loud when you put your foot into it. The one on my truck is
> just the opposite- noisy at idle, half as loud at cruise, and when I
> put the pedal to the floor it is completely silent!
>
> Bizzaro!
>
> -ph

It's the rpm difference, the V8 is cruising at the 4's fast idle and the
4 is screaming at highway speed instead of lower rpm roaring.

I put a turbo Dynomax on my straight six Jeep engine and it roars nice
under power, but only turns 1750 rpm in top gear at 65 mph.

Just my $0.02,

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
'New' frame in the works for '08. Some Canadian Bush Trip and Build
Photos: http://mikeromainjeeptrips.shutterfly.com

On Dec 18, 5:11 pm, Mike Romain > wrote:
> phaeton wrote:
> > In the summer I replaced the splitting muffler on my 4cylinder Ranger
> > with a Thrush Turbo. It was partially as a joke.
>
> > I remember Turbos on V8 cars getting gradually louder over time, but
> > on the 4 it seems to have hit a 'loudness limit' of some sort. At
> > first I figured that maybe it was a lesser volume of air, but in all
> > reality my 2.5L 4cyl is about the same as half a 5.0L V8 with dual
> > exhaust.
>
> > Something also odd- On V8 cars I remember the Turbo muffler being
> > quiet at low RPMs or a cruise with no load, but then 'opening up' and
> > getting loud when you put your foot into it. The one on my truck is
> > just the opposite- noisy at idle, half as loud at cruise, and when I
> > put the pedal to the floor it is completely silent!
>
> > Bizzaro!
>
> > -ph
>
> It's the rpm difference, the V8 is cruising at the 4's fast idle and the
> 4 is screaming at highway speed instead of lower rpm roaring.
>
> I put a turbo Dynomax on my straight six Jeep engine and it roars nice
> under power, but only turns 1750 rpm in top gear at 65 mph.
>
> Just my $0.02,
>


Makes sense. So I spose that the turbo muffler is sort of 'tuned' to
be resonant in the cruise range of the V8.


There's a guy round the corner from me with a late 80s Cherokee or
Wagoneer that sounds something like that- Straight six with a burned-
out Turbo or cherry bomb. It's pretty loud, and I'm sure it annoys
the hell out of everyone else on my street but I think it sounds
pretty cool.

Thenagain, I'm one of those weirdos that sometimes turns off the radio
so I can just listen to the vehicle. ;-O

-ph

phaeton wrote:
> On Dec 18, 5:11 pm, Mike Romain > wrote:
>
>>phaeton wrote:
>>
>>>In the summer I replaced the splitting muffler on my 4cylinder Ranger
>>>with a Thrush Turbo. It was partially as a joke.
>>
>>>I remember Turbos on V8 cars getting gradually louder over time, but
>>>on the 4 it seems to have hit a 'loudness limit' of some sort. At
>>>first I figured that maybe it was a lesser volume of air, but in all
>>>reality my 2.5L 4cyl is about the same as half a 5.0L V8 with dual
>>>exhaust.
>>
>>>Something also odd- On V8 cars I remember the Turbo muffler being
>>>quiet at low RPMs or a cruise with no load, but then 'opening up' and
>>>getting loud when you put your foot into it. The one on my truck is
>>>just the opposite- noisy at idle, half as loud at cruise, and when I
>>>put the pedal to the floor it is completely silent!
>>
>>>Bizzaro!
>>
>>>-ph
>>
>>It's the rpm difference, the V8 is cruising at the 4's fast idle and the
>>4 is screaming at highway speed instead of lower rpm roaring.
>>
>>I put a turbo Dynomax on my straight six Jeep engine and it roars nice
>>under power, but only turns 1750 rpm in top gear at 65 mph.
>>
>>Just my $0.02,
>>
>
>
>
> Makes sense. So I spose that the turbo muffler is sort of 'tuned' to
> be resonant in the cruise range of the V8.

I don't think its RPM. Most 4-cylinder cars I've rented recently cruise
at about the same RPM or only slightly higher than a v8. The big
difference is the firing pattern. When you use a turbo muffler on one
bank of a v8, it sees an irregular firing pattern because "90-degree
crankshaft" v8s (virtually all production v8 engines) do not alternate
between left (L) and right (R) banks, but fire L-R-L-L-R-L-R-R (repeat).
That's what causes the typical v8 "burble" exhaust sound even with
single exhaust. If you put the same muffler on each bank of a "flat
crank" v8 (never used in production cars because they vibrate like a
paint shaker) then it would sound like two 4-cylinder engines.

On Dec 18, 12:24 am, phaeton > wrote:
> In the summer I replaced the splitting muffler on my 4cylinder Ranger
> with a Thrush Turbo. It was partially as a joke.
>
> I remember Turbos on V8 cars getting gradually louder over time, but
> on the 4 it seems to have hit a 'loudness limit' of some sort. At
> first I figured that maybe it was a lesser volume of air, but in all
> reality my 2.5L 4cyl is about the same as half a 5.0L V8 with dual
> exhaust.
>
> Something also odd- On V8 cars I remember the Turbo muffler being
> quiet at low RPMs or a cruise with no load, but then 'opening up' and
> getting loud when you put your foot into it. The one on my truck is
> just the opposite- noisy at idle, half as loud at cruise, and when I
> put the pedal to the floor it is completely silent!
>
> Bizzaro!
>
> -ph

Don't buy the expensive/good turbo's. You want the cheap ones. They're
the ones that "burn out"/get a deeper/throatier sound with age. The
good ones are made to hold up longer and not change their tune. Years
ago I was buying Walker Universal Turbos for $15/$20 each and they
"burned out" nicely. Stocked the common sizes. (2", 2 1/4", 2 1/2",
center inlet/oulet, offset inlet/outlet) Turbos, not glass packs.
Glass packs don't burn out as much/any, and are a totally different
sound. (never cared for glass packs) Had a pipe bender and did alot of
dual exhaust.