Shop4Parts - UK's largest online superstore for FIAT and Alfa Romeo parts

Technical Fiat 500 Side exit exhaust

Currently reading:
Technical Fiat 500 Side exit exhaust

S

Steve Honest

New member
Joined
Jul 16, 2020
Messages
7
Points
4
Location
Essex
Hi Chaps

I have a 2008 fiat 500 1.4 16v

its a great fun car and when bits come up i try and upgrade here and there.
so i have the exhast coming up for replacment and i wanted to ask for advice.

can I delete the back box and the pipe that goes over the back axle and have it bend round and exit the near side (UK) just in front of the rear wheel?

Im guessing sound will change, box deleted,
but i wanted to ask
will this improve exhaust flow?
Will i get the same emissions? for MOT
Will i see a tiny bit more power due to a silencer deleted?
any downsides to this?

thanks for your hep in advance

Steve
 
Easy answer - NO

Firstly, you cannot have an exhaust exiting to the pavement.

Now the less than easy bit.
The manufacturer has spent a lot of time and money, designing an exhaust to give the best compromise between power, and noise, having to meet regulations. Just cutting a bit off will not release power, unless very lucky. Quite likely to reduce power, as well as make more noise, and annoy everyone nearby. Then it should fail its next MOT.

As the exhaust exits the engine, past the exhaust valves, it rushes out, at around 180mph. Then the valve shuts. The gas keeps moving, creating a vacuum behind it. The gas stops, and withdraws a little due to the vacuum. This of course happens very quickly, and is followed by the next cylinder(s). This is why the exhaust 'pulses' at the tailpipe. For best cylinder scavenging, the exhaust needs to completely exit the cylinder. The 'pulse' arriving at the tailpipe affects this. Changing the length of the tailpie can affect the exhaust pulse, and can lead to inefficient scavenging of the engine. You don't want the reverse flow to interfere with the next outward flow.
People fit large bore tailpipes. These affect the flow, as the same amount of gas in a bigger bore will flow a shorter distance. If the larger bore luckily matches the pulse, it may work. This is why some large bore rear boxes make a lot of noise, but stifle performance. Ask any 16yr old on a loud moped. Usually slower than standard.

Fiat would not have produced the car with any significant resistance in the standard exhaust. Changing it really needs many thousands of pounds, a research workshop, and an exhaust engineer. Or you could just go for it, and prepare for disappointment, then have to buy a new standard system. Good luck.

100hp in a 500 is plenty, really.
 
portland_bill said:
Easy answer - NO

Firstly, you cannot have an exhaust exiting to the pavement.

Now the less than easy bit.
The manufacturer has spent a lot of time and money, designing an exhaust to give the best compromise between power, and noise, having to meet regulations. Just cutting a bit off will not release power, unless very lucky. Quite likely to reduce power, as well as make more noise, and annoy everyone nearby. Then it should fail its next MOT.

As the exhaust exits the engine, past the exhaust valves, it rushes out, at around 180mph. Then the valve shuts. The gas keeps moving, creating a vacuum behind it. The gas stops, and withdraws a little due to the vacuum. This of course happens very quickly, and is followed by the next cylinder(s). This is why the exhaust 'pulses' at the tailpipe. For best cylinder scavenging, the exhaust needs to completely exit the cylinder. The 'pulse' arriving at the tailpipe affects this. Changing the length of the tailpie can affect the exhaust pulse, and can lead to inefficient scavenging of the engine. You don't want the reverse flow to interfere with the next outward flow.
People fit large bore tailpipes. These affect the flow, as the same amount of gas in a bigger bore will flow a shorter distance. If the larger bore luckily matches the pulse, it may work. This is why some large bore rear boxes make a lot of noise, but stifle performance. Ask any 16yr old on a loud moped. Usually slower than standard.

Fiat would not have produced the car with any significant resistance in the standard exhaust. Changing it really needs many thousands of pounds, a research workshop, and an exhaust engineer. Or you could just go for it, and prepare for disappointment, then have to buy a new standard system. Good luck.


100hp in a 500 is plenty, really.
Click to expand...

Nicely explained, however!
I spent hours on the net trying to get a new middle box (baffles went) for out 0.9 TA 105 only to find there are 3 versions for the same car all dependent on VIN.
After speaking to Shop4parts ours obviously was the most expensive middle section and no back box was supposedly fitted. Whereas the other to part numbers did!!!!
Good old FIAT mentallity.
So for the same price we went for a bespoke full S/S system with centre box and no back box.
Does sound different but nowhere near what I'd call noisy.
1st MOT today so will see how it goes.
 
Hi

Thank you everybody for your replies , all of which are useful and informative.

cheers
Steve
 
varesecrazy said:
Twinair emissions are odd.. pandas seem to fail frequently.. :eek:
Puntos are good..

But the exhausts are TOTALLY different

Ecoburst : the worst.. exactly ;)
Click to expand...
With going for its 1st mot after exhaust and it passing got no worries now as lifetime guarantee as long as we have the car and the full system was the same price as just the OEM centre section
 
Most Easterly Pandas said:
Can you expand on this, as doesn’t seem to be an issue on dads WAV converted Qubo, although it does angle downwards slightly iirc.
Click to expand...

Not supposed to be blowing hot exhaust onto pedestrians. The tailpipe and the gas can get very hot, especially on catalyst petrols, so just a safety thing. Should exit away from kerbside, so a side exit needs LHD and RHD options. Possibly WAV converter couldn't get it across with the lowered floor, and has either a 'let' from the legislators, or maybe no-one's noticed.

My sister-in-law had a Berlingo WAV. Partof the conversion had reduced the fuel tank to about half normal size. Long journeys required frequent fill-ups. (Perhaps early practice for owning an EV:devil:) Her current Kangoo seems fine for range.
 
portland_bill said:
Not supposed to be blowing hot exhaust onto pedestrians. The tailpipe and the gas can get very hot, especially on catalyst petrols, so just a safety thing. Should exit away from kerbside, so a side exit needs LHD and RHD options. Possibly WAV converter couldn't get it across with the lowered floor, and has either a 'let' from the legislators, or maybe no-one's noticed.

My sister-in-law had a Berlingo WAV. Partof the conversion had reduced the fuel tank to about half normal size. Long journeys required frequent fill-ups. (Perhaps early practice for owning an EV:devil:) Her current Kangoo seems fine for range.
Click to expand...

If they go for a Qubo / Bipper / Nemo conversion get them to make the seller sell it with a full tank of fuel and check for leaks. Very common issue it seems across them all when full and fairly complex to repair :bang:
 
You must log in or register to reply here.

Similar threads

R
  • Poll
General Rear Suspension Fiat 500 2010
Replies
2
Views
114
Roguets50x
R
D
General Fiat 500 family
Replies
12
Views
529
DanG1989
D
A
General Fiat 500 twinair
Replies
19
Views
1K
d4zzl3r
D
Mikefraser93
Technical Fiat 500 voltage problems
Replies
15
Views
531
Mikefraser93
Mikefraser93
Alexier
Technical Fiat 500 2010 Cluster issue
Replies
10
Views
417
tacim
T
Back
Top