Just had a cat back system fitted to my 1.6 and it seems to lost a bit of power in 4th and 5th. i know i cant get my car through an mot if i was to have the cat removed but is there any chance i could loose more power if i was to smash the insides out the cat pipe? i cant find a decat for my car and to get one made would be about £180. where do the super1600 rally teams get parts for these cars i cant find any thing for them!
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lost power :(
- Thread starter Dannymonkman
- Start date
lol yeah its Monkman 
is there any restrictors things u can add to an exhaust to give it more back pressure rather then changing it again!!
is there any restrictors things u can add to an exhaust to give it more back pressure rather then changing it again!!tryed that but it didnt work any thing else i can try?
can you create more backpressure with a remap? is so would this slightly improve things or would it make gains with the new pipe?
Hows it help though - what does the back pressure do?
hopefully this will help
http://www.proficientperformance.com/tech_back_pressure.php
i should state my obove staement about n/a cars needing some back pressure applies to road cars in fairly stock trim,race cars can have more open exhausts because the engine's are built taking the exhaust size and flow rate into consideration
http://www.proficientperformance.com/tech_back_pressure.php
i should state my obove staement about n/a cars needing some back pressure applies to road cars in fairly stock trim,race cars can have more open exhausts because the engine's are built taking the exhaust size and flow rate into consideration
Cheers for that!
well i went from i think 1.5" to 2" cat back with only one silancer. am i right from reading that artical if ive lost back pressure it would be low down power? i dont understand it 4th dosnt seem to pull like it used to because my freinds car now pulls away(never used to) but i can get the same speeds on the same roads i used to :S
im guessing your accerating from low revs in these gears? because thats where it is usually noticable
yeah it doesnt explain it all mate but it explains it a bit better than i can lol
no its when were both giving it some :S so more high end up. changing into 4th about 5 1/2k
Just had another read of it
Quote:
Backpressure is the restriction of the exhaust gases that are produced by your engine while they are being released through your exhaust system.
End Quote
Surely this is crap. The back pressure is caused by the restriction on gas flow in the exhaust pipe, due to forcing lots of gas down a small diameter pipe. This causes a restriction on the engine as it is acting as the pump that forces the gases down the pipe.
This is why generally you are better off with a larger diameter pipe as this gives less resistance. However, you can upset the flow dynamics as the gases are sent down the pipe in pulses due to the nature of a piston system. I think this is what's causing danny's problems.
That article is nothing but ill informed marketing spiel
Danny, get your old exhaust back on. It was perfectly adequate
Quote:
Backpressure is the restriction of the exhaust gases that are produced by your engine while they are being released through your exhaust system.
End Quote
Surely this is crap. The back pressure is caused by the restriction on gas flow in the exhaust pipe, due to forcing lots of gas down a small diameter pipe. This causes a restriction on the engine as it is acting as the pump that forces the gases down the pipe.
This is why generally you are better off with a larger diameter pipe as this gives less resistance. However, you can upset the flow dynamics as the gases are sent down the pipe in pulses due to the nature of a piston system. I think this is what's causing danny's problems.
That article is nothing but ill informed marketing spiel
Danny, get your old exhaust back on. It was perfectly adequate
hmmm interesting about the hight revs mate,iv had it before but if im honest its not been as noticable as yours,was it directly after the exhaust was fitted? i mean is there another problem that could be causing it?
i wouldnt compare it to your mates car,from experience mine goes well one day,crap the next lol
i wouldnt compare it to your mates car,from experience mine goes well one day,crap the next lol
That's what valves are for? Please elaborate. Valves are there for a reason, not sure how they're supposed to eliminate back pressure though
is there any mods i can do that would compliment the exhaust and work better. say a ktec manifold? dont really wanna put the std system back on this one sounds great and its onlu 1/2 inch bigger must be some engine mod i can do to give it some more?
200sx s14a
hey danny you the kid who came round to mine to see my brother rich with james dennis or is thi another dnny monkman lol ?
Yup thats me hows your car going?
hows your car going?Danny, are you sure it's down on power or could it just be perception?
If it's bad enough for you to notice then it must be quite bad and I think you'd be silly messing around with other parts. Just take off the crap you've put on and got to an exhaust company that know what they're doing
If it's bad enough for you to notice then it must be quite bad and I think you'd be silly messing around with other parts. Just take off the crap you've put on and got to an exhaust company that know what they're doing
Gaz_
ClioSport Club Member
Extreme mode
correct! 90% of the time bolting on an exhaust or air filter will loose you power & performance, not gain you 10bhp each like people seem to think, you just sound like your going faster!
BMW M4; S1000 RR
Are some people alergic to physics ???
Backpressure is a bad thing. Full stop.
The best way I can describe it (as I would to my mum) is blowing on a straw.
Backpressure is literally just when the engine can't get the gas out of the tailpipe as quick as it can release it. It only needs a tiny amount to create a bottleneck in which you can easily free up some power by getting a wider bore pipe (not just cat back though).
The gas velocity is a tricky one, but if the pipe only has half of it's maximum capacity traveling through it then it's going to move around rather than travel straight out the exhaust, that's called turbulance, and turbulance in a situation where maximum flow is better is a bad thing.
The best way to get power for no cost though, is to just take your exhaust off. It'll be silly loud, and technically illegal, but the gases will be leaving the engine, into the manifold, and straight out onto the floor. I have seen a couple of cars with this setup but have a tailpipe attached under the rear bumper so it doesn't look suspicious..
Backpressure is a bad thing. Full stop.
The best way I can describe it (as I would to my mum) is blowing on a straw.
Backpressure is literally just when the engine can't get the gas out of the tailpipe as quick as it can release it. It only needs a tiny amount to create a bottleneck in which you can easily free up some power by getting a wider bore pipe (not just cat back though).
The gas velocity is a tricky one, but if the pipe only has half of it's maximum capacity traveling through it then it's going to move around rather than travel straight out the exhaust, that's called turbulance, and turbulance in a situation where maximum flow is better is a bad thing.
The best way to get power for no cost though, is to just take your exhaust off. It'll be silly loud, and technically illegal, but the gases will be leaving the engine, into the manifold, and straight out onto the floor. I have seen a couple of cars with this setup but have a tailpipe attached under the rear bumper so it doesn't look suspicious..
My 1.6 was shockingly slow and nearly stalled almost everytime I pulled off with no exhaust on!
