Alright Guys,

I recently had a magnex exhaust from the CAT back and a K&N induction kit to my MY99 impreza turbo.

I was surprised to see that this has actually increased the amount of i miles i get per tank of petrol (optimax, as always). I used to get on average about 270-280 miles per tank, now with the mods listed above i'm getting 290-300+ which is a very pleasant surprise!

Has anyone ever heard of this b4, or could there be any problem, it just seems abit too good! (i know it's on the case on 20 odd miles, but we all know these cars are expensive to run!).

Any help appreciated,

Cheers.

 

Sounds feasible - your car should be running a little leaner with the breathing mods - leaner = less fuel burnt = more MPG.
Post this in drivetrain with a title like 'Improved breathing (decat+induction) = more MPG?' for a better/more educated response though.
Ta
Chuck

 

270-280 miles per tank. I only manage about 240 (that's my record) and I honestly don't razz my car...........much

 

Dunc 20....

Have you found that pedal that sits just to the right of the brake......!!!!?

How the hell do you manage 280 on a tank??? Presume all motorway?

 

Sounds feasible - your car should be running a little leaner with the breathing mods

Chuck, not picking on ya, but on a car with a MAF sensor, this would not be true. As much as I hate the buggers, they make sure that you run just as rich/lean with a VE improved car as with a standard one (up to the limits of the ECU maps of course).
The ECU sees a higher "load" (more air coming in metered by the MAF) and will adjust fuelling accordingly (pig rich if all is OK on an Impreza).

My guess is that the reduced backpressure would make the engine run more efficient, so less throttle is needed to get the same acceleration.

 

Its bound to be more efficient as its not having to SUCK as hard through the filter and its also not having to BLOW as hard through the exhaust, leaving more power to do what its supposed to do...
Imagine Linford Christie doing a 1000m sprint with a sponge in his mouth (and a cork up his ***) - same difference ??
Dan

 

No......can I imagine Jordan doing it instead

 

I found the same when I got my Mongoose full system and freelow filter. I used to get 170 - 200 miles, now I'm getting 200 - 230.
I believe it's got something to do with increased volumetric efficiency or something. Anyway I'm not complaining, better sound AND mpg.

 

Perhaps cats are a government scam to keep petrol cars as uneconomical as possible, that way we buy more fuel and they make more cash on the tax.....and the oil companies win too....

 

LOL, right after I posted this I realised what a dumb answer 'running lean' was, leaning out to the extent you extended the tanks range 20-30 miles would certainly be something!
C

 

And then again time to slap myself on the forehead ...

Missed the and a K&N induction kit bit

That however *might* indeed make the MAF sensor misread, depending on what kit exactly it is.

I'm currently testing out a K&N with STi cone (from MacsPower). So far it does not seem to lean out the mixture (reading on Lambdalink), but I still have to log a full run with the DeltaDash to be sure.

Lots of induction kits will indeed read lean at lower revs (proven & proven again).

So it could be a combination of both.

<hangs head in shame, mutters off, writes apology email to Chuck LOL>