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what should a decat gain me..BHP?



  A Fast One!
Freebone said:
cool thought that was the case...how do i change the base timing then and is it really vital.

you need to get yourself a strobe light and then follow some instructions that you can get from a haynes manual about setting the timing. im not sure what the exact proceedure is on the valver as i havnt worked n one before

Alex
 
Gerry said:
If it has less emissions why would it fail???:S

Because it has the wrong TYPE of emissions!

A cat doesn't "collect" anything from the gases or it would "fill up".

Whatever goes in MUST come out, the cat just changes 1 form of gas you don't want, into another form of gas you don't want. It's a bit of a con really.

But in restricting the exhaust slightly you have to burn MORE petrol for the same journey, particularly when cold. In this way a cat produces MORE pollutants than without a cat.

Is that a good explanation?
 

Nafoff

ClioSport Club Member
Spykee said:
you need to get yourself a strobe light and then follow some instructions that you can get from a haynes manual about setting the timing. im not sure what the exact proceedure is on the valver as i havnt worked n one before

Alex

cheers mate..once the strobes under the bonnet i may leave it there...maybe some underneath the car to...ooohhh maybe a big spoiler..hang on i think i am onto something here.....
 
  V70 d5 beast
hi i've got a straigt through system on my 1.4 16v clio and i've fitted a de-cat and the mpg went way down to 27mpg instead of about 38mpg, my engine light comes on regulary after a few hundred miles or so, but i always end up deleting it, i haven't noticed it to get leaner, i know it's very rich (lots of white smoke in the morning when starting up)

how do i get it to run leaner? for better power?
 
  A Fast One!
Freebone said:
cheers mate..once the strobes under the bonnet i may leave it there...maybe some underneath the car to...ooohhh maybe a big spoiler..hang on i think i am onto something here.....

ROFLMAO!! im not on about fast and the furious stuff, im serious. the thing that you need to read the position of the rotor arm on the distributor against TDC on the crank is called a strobe sensor or strobe light!

check this out on the halfords website ;)

http://www.halfords.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10151&productId=178435&categoryId=31477

Alex
 
  A Fast One!
Simf40 said:
hi i've got a straigt through system on my 1.4 16v clio and i've fitted a de-cat and the mpg went way down to 27mpg instead of about 38mpg, my engine light comes on regulary after a few hundred miles or so, but i always end up deleting it, i haven't noticed it to get leaner, i know it's very rich (lots of white smoke in the morning when starting up)

how do i get it to run leaner? for better power?

you dont want it to run leaner, less fuel means less power usually. you need to tune it to balance it out. do you have electronic ignition on the car with an ECU? if you do, set the base timing using a strobe light as i have recommended to Freebone. if you dont have electronic ignition you will need a strobe light and a haynes manual for definate as the timing is set at specific RPM's which will be dependent on the engine you have in the car.

Alex
 
I wasn't going to give a progress report so soon but today I filled up and reset the trip. Drove for 3.6 miles in careful economic way (still fastest car on road inc overtaking but also following car for 1 mile at 35mph) and got 39.8 mpg on trip.

This is not much different to usual as mpg normally best after 1st filling up because engine already warm and usually leave mpg in view (keeps foot of acc)!

Indeed so far I'd be hard pressed to tell the cat's missing. No extra noise, possibly better power and perhaps better mpg but marginal.

Haven't been to MOT yet either to check emissions!
 
  V70 d5 beast
hi spykee my car is a 53 plate clio so it has electronic igniton with an ecu, what is the base timing and how do you adjust it? would it be best to just get a super chip etc as they can adjust it there and then?
 
Simf40 said:
hi i've got a straigt through system on my 1.4 16v clio and i've fitted a de-cat and the mpg went way down to 27mpg instead of about 38mpg, my engine light comes on regulary after a few hundred miles or so, but i always end up deleting it, i haven't noticed it to get leaner, i know it's very rich (lots of white smoke in the morning when starting up)

how do i get it to run leaner? for better power?
Are you sure about that?

That doesn't sound like a problem caused by the cat being removed. I suppose it's possible there is a post-cat sensor that confuses the ECU when there's no cat, but my 182 doesn't appear to have a problem. So far mpg about the same, no dash light and no white smoke when cold (The 182 does have a post-cat sensor).

Prove your theory,
Can you try putting the cat back in to see if mpg goes back to 38 with no white smoke?
 
  A Fast One!
Simf40 said:
hi spykee my car is a 53 plate clio so it has electronic igniton with an ecu, what is the base timing and how do you adjust it? would it be best to just get a super chip etc as they can adjust it there and then?

Sim,

you cant adjust the timing unless you have a distributor cap on the car. newer engines dont have one which is why everyone has to go for remaps and chips on their ECU's as there is no other way to adjust the timing/fueling etc..

you will have to get a remap done on your ecu or a chip like you said

Alex
 
  AB182, Audi A5 3.0
Dave finney said:
Because it has the wrong TYPE of emissions!

A cat doesn't "collect" anything from the gases or it would "fill up".

Whatever goes in MUST come out, the cat just changes 1 form of gas you don't want, into another form of gas you don't want. It's a bit of a con really.

But in restricting the exhaust slightly you have to burn MORE petrol for the same journey, particularly when cold. In this way a cat produces MORE pollutants than without a cat.

Is that a good explanation?

lol. its not a con, it changes the gas into safer/cleaner gases by providing a catalist for the gas's to bond. without them we would have alot more smog again...
 
J

jamesy

i would'nt be too bothered about how much more bhp you get from a de-cat just to drive it after having it done your see its worth it;)
 
The Fatty, it certainly IS a con and, by the sounds of it, the con's worked on you!

The gases without a cat are poisonous, so not good, but the gases with a cat are destroying the ozone layer. So you can choose short term health problems (no cat), or long term destruction of the planet (with cat).

You CANNOT get "safer/cleaner" gases with a cat, indeed the problem is WORSE with a cat due to the efficiency problems. But with other technologies we could make improvements.
 
  172cup
lol @ all this.



... so a decat is good then basically?? All you need to do now is tell me where to get one... what one to get... how much it is... and come round and fit it for me. :p
 
  MR2 2.0 N/A & Mk1 1.2Clio
im thinking about removing my engine, ive been told to expect a bhp increase of 20-30bhp? can anyone shed some light. as i dont want to make the jump and not gain much. cheers.
 
  Mégane RS
lol as clarkson said its not speed that kills, its suddenly coming to a stop ie tree lol
 
Because burning fossil fuels releases the chemicals the fossils contain, so it has to be non-fossil powered.

Want an electric car powered from wind farms?

The problem is we want fast cheap motoring but to save the planet we need to have expensive slow cars. We don't want to save the planet that much!

Fact of the matter is all the oil will continue to be burnt until it's all gone, then we will all say how stupid we all were to have completely f'ed the whole planet up. But we will be long gone by then so in the meantime we will all continue as we are.

Example ... a few pence on a litre of fuel would help ... but look at what happened last time that was tried. Would YOU support say 10p/litre more petrol tax?
 
  A Fast One!
Freebone said:
what has my thread turned into now a bloody argument about global warming or something.......bhp from a decat..simple...lol

well although i think some of the comments are quite funny its is going a bit OT! :S

i think that a decat can give more than a 2bhp gain that others have said IMO otherwise how would i have had 224bhp on an RR day with my CTR from a decat, catback and induction kit when its 197bhp as standard?!?

Alex
 
Sorry Freebone, I was only answering the questions!

But call this a "bloody argument"? You haven't been on the internet very long! ;)

Anyway. After 20 miles mpg down to 34.7 with lowest of 31.5. Now after 30 miles up to 36 mpg.

This is marginally less than the usual about 37 mpg but it's all been on short journeys in very cold weather. Soon I will be doing my usual journey to work where the real mpg will start to show.

I am starting to feel there IS more power but mainly in the midrange, the engine "picks up" better. Top revs do feel marginally better, though I'd have to re-fit the cat to be sure, but the mid + low revs are quite noticable. When over-taking the car just goes now where there was a little 'hesitation' before unless you prepared.

So far I'd say a reserved recomendation.
 

Nafoff

ClioSport Club Member
Dave finney said:
Sorry Freebone, I was only answering the questions!

But call this a "bloody argument"? You haven't been on the internet very long! ;)

wasen't getting at you guys....its just it seemed like it could spiral out of hand again..as most convo's seem to do on here...annoys the hell out of me
 
  Clio Williams
Dave finney said:
Because it has the wrong TYPE of emissions!

A cat doesn't "collect" anything from the gases or it would "fill up".

Whatever goes in MUST come out, the cat just changes 1 form of gas you don't want, into another form of gas you don't want. It's a bit of a con really.

But in restricting the exhaust slightly you have to burn MORE petrol for the same journey, particularly when cold. In this way a cat produces MORE pollutants than without a cat.

Is that a good explanation?

Very good cheers.:D
 
  GDI Demo 182, Rsi Spider
A decat on its own is never going to make changes to rave about

usual improvments as a singular unit are slightly better throttle response

however...... I have noticed more of a difference with cars that run more modifications.....

its a culmative effect and the cat at high rpm etc etc can start to restrict the power.

cats are also expensive, so quite a few people remove them and keep them safe for MOT believe it or not....
 
  Clio RS Mk1
This is how my double cat looks like:

17208katalizator.jpg


Where should the second lamba be? If there is any?
 


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