Hi all

I'm quite new to imprezas so have a lot of un answered questions.

One main question I do have is why is the BHP so low? My car is a 2002 Bugeye WRX AWD UK. If my research is correct it says the standard BHP is 215. Is that correct? And if so why? Can I still expect to get large BHP gains from full decat system, Walbro, STI TMIC, and a remap? Not aiming for over 300 but would like to get close to that number.

Cheers Don

 

thats right for the standard car the mods you listed above shoudl give you around 270ish

 

That's ok then, I was unsure if the web page I looked was wrong. Need to start saving for some bits I guess then. Is it a bad idea to try and increase the BHP on a engine with high miles?

 

Providing it has been looked after well there shouldn't be any issues with some simple exhaust mods and a nice safe map tweak.

 

Depends what you mean by high miles.

 

109k

 

That's not high miles fella.
Get a full de-cat, panel filter, 255HRC fuel pump, 7B plugs, STI up pipe, STI top mount and a map.
Will transform the car, will make somewhere between 270 and 290.

 

perfect, thats pretty much what i have planned for the car, now to start looking for bits and hoarding them in the garage so i can fit them all in one go then get it mapped

 

I can't understand anyone wanting to do a full de-cat these days. Because its now illegal and will fail the MOT test. sport cat is the way to go imo.

 

It has always been an mot fail so no difference now.
Most decat owners have a friendly decat mot man.

 

^^ correct ;-)

 

Yeah I would rather get a few more bhp and not have to fork out for a sports cat. Like mentioned above all you need is a friendly MOT man. Or worst case scenario is get the car on a ramp and fit the cat for mot time it's only a 15 min job. I can see why people take the sports cat route To be honest as it is hassle if you don't know a friendly MOT place. Do you still get decent gains with the sports cat?

 

As far as i'm aware not having a cat was not illegal and your car would pass the MOT if it passed the emissions test. With the new MOT regulations that have just come into force it's a fail if the car was fitting with a cat from manufacture and no longer has one in place. It's all well and good having a "friendly" MOT tester but i doubt the VOSA road side tester will be as friendly if your unlucky enough to get pulled.
It's also said the pollution in the vehicle cabin is 4x higher than at the curb side. This it quite worrying when you consider the toxins produced by burning the additive in unleaded petrol called Benzine are carcinogenic. Its the cat that neutralises this so it makes you wonder what you and your family are breathing while on your daily drive. All for a few more bhp's

 

I doubt theres much in it bhp wise from a de-cat and 100cell sport cat. I doubt there's much in it price wise either.
The down pipe de-cat is about £160. The sport cat is about £250.
http://www.japspeed.co.uk/Subaru-Imp...at/p-24-1-444/

 

A car with no cat would fail emmisions test on the mot.
Hundreds of decat imprezas about and none of us are dead yet but possibly some with brain damage.

 

 

How do the toxins get into the cabin? Surely they just go out the easiest route, the tail pipe.

 

Really? Where did you read this?

I could imagine if you were following a car with a de-cat then the fumes you'd be breathing in your car might not be quite so good as those from a car with a working set of cats. Generally that's why exhausts exit at the back of the car so the gases are safely blown away behind you.

I have heard stories that driving around without your boot / tailgate properly closed (e.g. while taking an oversized load to the tip) can cause exhaust gases to be drawn into the car but I suspect even that may not be true.

 

I read a paper back in 2000 from some professor regarding leaded vs unleaded fuels.The paper was distributed at Merton college while doing a motorcycle mechanics course. I think the issue of pollution in the cabin would be more from other vehicles especially while on the move but there is a chance you would be breathing in your own while your sat in traffic. I think the effects of Burned benzine build up in the body over time.

 

If we all worried about what "could" kill us we would be sat at home all day eating nothing but bread and water.

 

Next you will be telling us the 2.5 is a reliable engine.... .

 

It is, providing you keep it under 300bhp and 4000rpm

 

You lot don't much care for facts do you? Oh well if the op is happy having to bolt a cat on every year or bribe the mot tester to gain a few bhp over a sport cat then good luck to him.
Out of interest, any of you replaced the pollen filter on your cars lately? i did and the colour of it shows how much pollution gets intro your car.

 

Most of us are happy to bribe the mot tester every year.
Ive done it for the past nine and you know what i have neither lost a nights sleep or died.
The whole idea of decatting imprezas is to gain bhp otherwise there is no point doing it.

 

He is right though, the exhaust emissions are awful when they get in the cabin and really very bad for you.
I choose to chain smoke Lambert and Butlers while driving to disguise the smell.

 

i just fart a lot
well emmaroids does

 

Appreciate the advise so good to hear different opinions on the subject.

 

it is but as your sole point of decatting your car is to increase bhp its a cheap and easy thing to do.

join a local club and they will point you in the way of an impreza friendly mot station.

the decat really isnt a big thing mot time as you will find a lot of tuned imprezas are decatted and the new mot rules will make no difference.

 

Cats mmmm. They only really work well when the car is running a stoich mixture. Most impreza's even standard arnt once there on the move. None of them work until there hot enough. So miss Daisy running up the road to the shops. Or the school run a mile up the road is probably polluting as much as someone with a decat. Until every engine has a cat its poinless. How many generators,lawnmowers,leaf blowers,scooters etc etc are running every day. None of them have cats. None ever even have mixture checks. I know i run a generator at work for between 6 & 8 hrs a day.

 

You don't need to do the intercooler or fuel pump at those power levels. I ran 280+ for 4 years with no issues using the standard items.