is there a de-cat available for standard exhaust system?

[Graeme GTR]

I know woody, it would be a nightmare living close to a race track, I can't imagine Its the most peaceful of places anyway.

something you know about a house before buyin it. No sympathy for home owners, its like living on a flight path or next to a railway. You know about it before you buy, if not, your a fool. :huh:

 

[ben_r1]

It may be against science or however you worded it but the reality is i used to get 44mpg, bolted the decat on and can only get 40mpg.

Could be ecu throwing a wobbly and messing efficiency up or black magic but its true.

 

[Gouldy]

sounds like the LAMBDA sensor throwing a wobbler because of the amount of difference from catted to decatted emmsions readings.

 

[Foxspeed]

for example, with exhaust restrictions you could be in 4th gear @ 3500 rpm @ 40 mph

or with no restrictions you could be in 4th gear @ 3000 rpm @ 40mph

could only do that if you changed the gearing !!!

dont you mean using a higher gear ie 5th due to the lower losses and then able to maintain the same but in a higher gear !

 

[Foxspeed]

It may be against science or however you worded it but the reality is i used to get 44mpg, bolted the decat on and can only get 40mpg.

Could be ecu throwing a wobbly and messing efficiency up or black magic but its true.

twin lambda system on clio first does the emissions the second monitors cat efficiency etc and emission failures

 

[Gouldy]

It wasn't a Clio specific gearing point wasn't that it was an example.

Have you tried sleevig the second lambda?

In theory that should work perfectly.

 

[Foxspeed]

It wasn't a Clio specific gearing point wasn't that it was an example.

Have you tried sleevig the second lambda?

In theory that should work perfectly.

either way its still a change in gearing to achieve the results !

 

[Fagan]

Wudnt bother with decat u lose to much back pressure on standard engine. Remove first silencer to get more noise

For the record, back pressure is a BAD thing, not a good thing.

 

[Ed...]

Hmmmmmm how is it bad? Renault have designed the exhaust to allow a certain level of back pressure, enough to keep the engine pressure high to enable good burning in the cylinders. More pressure more power in some cases but can have an adverse affect of too much back pressure that would cause bad fuel air mix and lumpy revving. Back pressure plays a missive part in low rev torque it keeps pressure in cylinders that's y u get a flat spot if u take the cat out. I learned this from a guy who builds race engines for a living so I can't argue

 

[Fagan]

Back pressure means the engine has to waste its HP to push the exhaust gasses out of the system (also known as pumping loss) so you will ALWAYS lose power with back pressure.

 

[Ed...]

The exhaust cam is designed to push it out on it's stroke. I'm not saying it's hp gains but torque

 

[Gouldy]

either way its still a change in gearing to achieve the results !

Your missing the point matey, the gearing has nothing to do with it, I made the gearing up for an example.

The point I'm making is that the less restrictions there is in an exhaust system, the more efficient you car should be in theory.

 

[boxster]

Just to share with you my experience living with a decat pipe on my 200, since I’ve installed one 6 months ago together with a V6 intake. As already been mentioned here, the flat spot can easily be sponged off by a proper remap, the sound and power delivery between 4500 rpm to red line is really amazing, the beast pulls really hard, and this is not a placebo effect. Indeed, downside is more fuel consumption, but then I drive the car much harder then when the car was standard, so this might be a cause on fuel burning up, secondly, the engine fan is now switching on more frequent for some reason, and engine bay feels hotter, but again maybe its due to my passionate driving.

Overall I’m delighted to have carried this mod, nothing but grins on face everytime I’m on the wheel.

 

[Gouldy]

Boxter; did you de cat the standard exhaust system?

 

[Foxspeed]

Your missing the point matey, the gearing has nothing to do with it, I made the gearing up for an example.

The point I'm making is that the less restrictions there is in an exhaust system, the more efficient you car should be in theory.

so the example was....pointless

be better ways to expalian improved "efficency" than an example of "gearing"....

 

[boxster]

Boxter; did you de cat the standard exhaust system?

Yes, did it on the standard system.

 

[dotty]

lol anyone who came on the welsh blas on sunday can vouch for how loud my exhaust i

they all thought it was a group N lol

its just standard with the center silencer removed, none of that decat rubbish

causes flatspot which has been mapped out slightly but worth it for the noise lol

not the best vid but you get the idea

http://www.youtube.com/watch?v=PHwmMkC1_n8

 

[B16OJB]

just make one!







http://www.youtube.com/watch?v=0ySyLwCSSv8&feature=related

sounds better now though hehe

also, still passes emissions!

 

[B16OJB]

ya sorted it?

 

[EviLNeeDs]

does it need any welding?