STD Tuning Engine Big exhaust on your Mercs! PICS

Big exhaust on your Mercs! PICS

Big exhaust on your Mercs! PICS

 
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-Mackan-
GT2256V

117
04-24-2016, 10:29 AM #1
Hello!


Im going to start building my exhaust, what is the biggest exhaust you have managed to fit?

I think ill be using 3.5" all the way from the turbo?

Feel free to post pics on your exhaust systems!

------------------------------------------------
Cars currently owned:

1993 Mercedes Benz 300TDT W124
1992 Mercedes Benz 500E W124
-Mackan-
04-24-2016, 10:29 AM #1

Hello!


Im going to start building my exhaust, what is the biggest exhaust you have managed to fit?

I think ill be using 3.5" all the way from the turbo?

Feel free to post pics on your exhaust systems!


------------------------------------------------
Cars currently owned:

1993 Mercedes Benz 300TDT W124
1992 Mercedes Benz 500E W124

barrote
Superturbo

1,627
04-24-2016, 11:48 AM #2
i personaly use a 70mm, 1.5 thick wall.
that is close to 3inch, in my build there´s no need for wider, conservation of flow caracteristics.
sorry i dont have a pic of it.

FD,
Powered by tractor fuel
barrote
04-24-2016, 11:48 AM #2

i personaly use a 70mm, 1.5 thick wall.
that is close to 3inch, in my build there´s no need for wider, conservation of flow caracteristics.
sorry i dont have a pic of it.


FD,
Powered by tractor fuel

MartinB
OM605 Power

154
04-24-2016, 01:02 PM #3
3" (76mm) downpipe -> 2.36" (60mm) 
Garrett GT2359V
Attached Files
Image(s)
       

W210 E200CDI 185kW Manual, W203 C30 CDI AMG 210kW Manual
MartinB
04-24-2016, 01:02 PM #3

3" (76mm) downpipe -> 2.36" (60mm) 
Garrett GT2359V

Attached Files
Image(s)
       

W210 E200CDI 185kW Manual, W203 C30 CDI AMG 210kW Manual

Sultzi
GT2256V

102
04-24-2016, 01:16 PM #4
4" downpipe to 2x3" Smile Overkill? Yes, very much for the 2x3" section, downpipe better to be big enough than too small..

[Image: _medium.jpg]
[Image: _medium.jpg]
Sultzi
04-24-2016, 01:16 PM #4

4" downpipe to 2x3" Smile Overkill? Yes, very much for the 2x3" section, downpipe better to be big enough than too small..

[Image: _medium.jpg]
[Image: _medium.jpg]

Dark Hawk
TA 0301

51
04-25-2016, 10:48 PM #5
not a picture but very purist sacrilege  Big Grin  

https://www.youtube.com/watch?v=zXd7NtqnKHA

1984 300d 132k restormod project in the works
1985 300td 300k $600 off road adventure project
1999 land cruiser  235k, 33" mud tires, off road, towing, hauler
Dark Hawk
04-25-2016, 10:48 PM #5

not a picture but very purist sacrilege  Big Grin  

https://www.youtube.com/watch?v=zXd7NtqnKHA


1984 300d 132k restormod project in the works
1985 300td 300k $600 off road adventure project
1999 land cruiser  235k, 33" mud tires, off road, towing, hauler

seanyt
is300d He351ve

279
04-26-2016, 08:08 AM #6
ive gone with 3" all the way as 3.5" was hard to get from a supplier and then ran a 16" piece of 4" out of the exhaust.
No problems with power as of yet. dyno time in a month.
depends what your power goals are also
seanyt
04-26-2016, 08:08 AM #6

ive gone with 3" all the way as 3.5" was hard to get from a supplier and then ran a 16" piece of 4" out of the exhaust.
No problems with power as of yet. dyno time in a month.
depends what your power goals are also

ross
GT2256V

109
04-27-2016, 06:45 AM #7
Exhaust diameter will play a big part in the performance. Its a balance between getting it big enough for the flow.... but equally going too big will slow the gasses as they expand to fill the space.
ross
04-27-2016, 06:45 AM #7

Exhaust diameter will play a big part in the performance. Its a balance between getting it big enough for the flow.... but equally going too big will slow the gasses as they expand to fill the space.

Turbo
Holset

489
04-29-2016, 05:56 AM #8
(04-27-2016, 06:45 AM)but equally going too big will slow the gasses as they expand to fill the space !? Exhaust diameter will play a big part in the performance. Its a balance between getting it big enough for the flow.... but equally going too big will slow the gasses as they expand to fill the space.
This post was last modified: 04-29-2016, 08:30 AM by Turbo.
Turbo
04-29-2016, 05:56 AM #8

(04-27-2016, 06:45 AM)but equally going too big will slow the gasses as they expand to fill the space !? Exhaust diameter will play a big part in the performance. Its a balance between getting it big enough for the flow.... but equally going too big will slow the gasses as they expand to fill the space.

ross
GT2256V

109
04-29-2016, 11:08 AM #9
You've almost quoted me but not said anything?
ross
04-29-2016, 11:08 AM #9

You've almost quoted me but not said anything?

Turbo
Holset

489
04-29-2016, 03:53 PM #10
Roos Can you please develop what you wrote, I m specially thinking of the last part _" but equally going too big will slow the gasses as they expand to fill the space."
Turbo
04-29-2016, 03:53 PM #10

Roos Can you please develop what you wrote, I m specially thinking of the last part _" but equally going too big will slow the gasses as they expand to fill the space."

ross
GT2256V

109
04-30-2016, 06:03 AM #11
For best performance the exhaust needs to be matched to the engine. Too small and it can't flow enough. But going too big is also harmful due to exhaust velocity. You want the exhaust gasses to get away as quickly as possible, and by going too large a diameter you're actually slowing them down. It's all to do with what's called the 'ideal gas law'. To keep the energy and heat up in the exhaust you need to keep it moving, and going into too large an exhaust will slow it down and cool it as it expands.

Think about it a bit like this.... You can breath out at a certain rate but you have to blow down a pipe. Blowing into an empty bic pen is hard, breathing into a drain pipe means the air is going to be slow out of the other end but breathing out brought something like a large garden hose isn't hard to do and keeps the air speed up.

Hope that makes sense Smile
ross
04-30-2016, 06:03 AM #11

For best performance the exhaust needs to be matched to the engine. Too small and it can't flow enough. But going too big is also harmful due to exhaust velocity. You want the exhaust gasses to get away as quickly as possible, and by going too large a diameter you're actually slowing them down. It's all to do with what's called the 'ideal gas law'. To keep the energy and heat up in the exhaust you need to keep it moving, and going into too large an exhaust will slow it down and cool it as it expands.

Think about it a bit like this.... You can breath out at a certain rate but you have to blow down a pipe. Blowing into an empty bic pen is hard, breathing into a drain pipe means the air is going to be slow out of the other end but breathing out brought something like a large garden hose isn't hard to do and keeps the air speed up.

Hope that makes sense Smile

raysorenson
Superturbo

1,162
04-30-2016, 07:14 AM #12
Ross, I would agree if you were talking about pre-turbo exhaust sizing. Manifold tubing can get too big and reduce velocity. But after the turbo, the best exhaust is no exhaust. Corky Bell said the ideal exhaust post-turbo is a bellmouth.
raysorenson
04-30-2016, 07:14 AM #12

Ross, I would agree if you were talking about pre-turbo exhaust sizing. Manifold tubing can get too big and reduce velocity. But after the turbo, the best exhaust is no exhaust. Corky Bell said the ideal exhaust post-turbo is a bellmouth.

ross
GT2256V

109
04-30-2016, 07:48 AM #13
Well yes because no exhaust is no restriction and the exhaust gas is out of the system.

It still applies post turbo as well, you want the exhaust gas to keep moving otherwise the gasses that are still coming out of the turbo will be slowed.
ross
04-30-2016, 07:48 AM #13

Well yes because no exhaust is no restriction and the exhaust gas is out of the system.

It still applies post turbo as well, you want the exhaust gas to keep moving otherwise the gasses that are still coming out of the turbo will be slowed.

Tito
Holset

354
05-01-2016, 03:19 AM #14
The bigger the exhaust, the lower the pressure in the exhaust (after turbo of course). So the pressure difference is higher. Higher pressure difference means more flow. It's not that the higher the gas velocity equals more flow. Higher gas velocity is only achieveable by restricting flow.

The only place you want higher gas velocity is after the exhaust valve. The higher gas velocity of course helps spool the turbo, but can also suck remaining exhaust gas from the cylinders for better scavenging.
This only works when you have gas pulses. Not with continuous flow. It just doesn't make sense.

The ideal situation would be no gas flow after the turbo (no dp or anything) because this leads to a bigger pressure difference.  this is not possible but is it at a minimum with nothing after the turbo. 

So I'm wondering why would you want speedy exhaust gasses after the turbo?
This post was last modified: 05-01-2016, 03:24 AM by Tito.
Tito
05-01-2016, 03:19 AM #14

The bigger the exhaust, the lower the pressure in the exhaust (after turbo of course). So the pressure difference is higher. Higher pressure difference means more flow. It's not that the higher the gas velocity equals more flow. Higher gas velocity is only achieveable by restricting flow.

The only place you want higher gas velocity is after the exhaust valve. The higher gas velocity of course helps spool the turbo, but can also suck remaining exhaust gas from the cylinders for better scavenging.
This only works when you have gas pulses. Not with continuous flow. It just doesn't make sense.

The ideal situation would be no gas flow after the turbo (no dp or anything) because this leads to a bigger pressure difference.  this is not possible but is it at a minimum with nothing after the turbo. 

So I'm wondering why would you want speedy exhaust gasses after the turbo?

ross
GT2256V

109
05-01-2016, 04:55 AM #15
If the gases can expand into too large an exhaust they become cooler and have less energy, so are harder to shift on out of the exhaust. If the gasses aren't moving quickly after the turbo, then how are the gasses coming out of he turbo going to do so quickly!
ross
05-01-2016, 04:55 AM #15

If the gases can expand into too large an exhaust they become cooler and have less energy, so are harder to shift on out of the exhaust. If the gasses aren't moving quickly after the turbo, then how are the gasses coming out of he turbo going to do so quickly!

Tito
Holset

354
05-01-2016, 08:34 AM #16
You're saying that the size of the exhaust diameter determines after turbo temperature and that you want to keep exhaust gases as hot as possible by reducing exhaust diameter?
Tito
05-01-2016, 08:34 AM #16

You're saying that the size of the exhaust diameter determines after turbo temperature and that you want to keep exhaust gases as hot as possible by reducing exhaust diameter?

ross
GT2256V

109
05-01-2016, 09:45 AM #17
Yes it will have an effect. Keep the gasses hot and they'll not slow up.
ross
05-01-2016, 09:45 AM #17

Yes it will have an effect. Keep the gasses hot and they'll not slow up.

ross
GT2256V

109
05-01-2016, 09:48 AM #18
It's getting the balance between too big and too small.
ross
05-01-2016, 09:48 AM #18

It's getting the balance between too big and too small.

don
K26-2

44
05-02-2016, 09:04 AM #19
Not big by any means but the I redid the downpipe on my as the stock MB DP was hitting the bulkhead.

I took pieces of the stock DP (turbo flange and flex section) and added 2.5" SS 90° bends.  The rest of my exhaust is 2.5" mandrel bent stainless with V-Clamps.

Maybe down the road I will do 3" but even the 2.5" is close to the bulkhead and the front driveshaft.
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don
05-02-2016, 09:04 AM #19

Not big by any means but the I redid the downpipe on my as the stock MB DP was hitting the bulkhead.

I took pieces of the stock DP (turbo flange and flex section) and added 2.5" SS 90° bends.  The rest of my exhaust is 2.5" mandrel bent stainless with V-Clamps.

Maybe down the road I will do 3" but even the 2.5" is close to the bulkhead and the front driveshaft.

Attached Files
Image(s)
   

 
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