BURBLE VS MPG ?

[barriesheene]

Hi all  :D Has anyone on here noticed a significant drop in mpg after removing the back box from there rangie ? Just came back from an offroading trip to a local disused quarry and used TWICE the amount of petrol that i used last time. The only diffrence being the altered exhaust system.Would the exhaust cause this big a diffrence or should I be checking for leaks ? Is there a way to check the fuel system ?
thanks Baz

[Guardian.]

BACKBOX WOULD Not cause twice as much fuel or anywere near, theres something else going on there.

[barriesheene]

[PooPoo] ! 

[Range Rover Blues]

Yeah, stop revving it to hear how cool it sounds.

I put a sports pipe on the LSE and it made it worse on fuel, but I kept getting everywhere faster.  Turn up the radio and stop listneing to the pipe ;)

[barriesheene]

 To be honest rangerover blue's I'm down on power to make it worse.

[Skibum346]

To be honest rangerover blue's I'm down on power to make it worse.

I'm no expert but to me that sounds like there is a mixture problem. I've heard that in some cases the ECU uses a "Get You Home" mode that ignores all the sensors and just chucks fuel down the throat of the engine... could that be it?

Skibum

[Range Rover Blues]

To be honest rangerover blue's I'm down on power to make it worse.

I'm no expert but to me that sounds like there is a mixture problem. I've heard that in some cases the ECU uses a "Get You Home" mode that ignores all the sensors and just chucks fuel down the throat of the engine... could that be it?

Skibum

The hot-wire EFi does have "redundancy" in the sensors, depending how many are fitted.  My LSE will run without an AFM and Blue has no Lambdas, road speed sensor or Air valve but it's quite economical, for a V8.

Barrie, if you are down on power then the lack of economy goes with it. Whether it's down to the exhaust I can't say, it's possibly you have overdone it though.

I know some engine tuners will test a big bore exhaust by fitting a restricter to the tail end (a narrower pipe) that will overcome the effects of an excessive bore, somehting for you to try.