jamieerst

I have a 2001 WRX UK300 with PPP

If i fit a boost controller, and turn the boost down to a lower psi would i get better MPG when drivin round town.. ??

anyone done this ??

Obviously this has a flip side, on the high setting it would be a fire breathing monster

Not told the missus that bit

Jolly Green Monster

iTrader: (4)

what boost do you run around town at?? lol

use the boost controller under your right foot..

jaytc2003

iTrader: (1)

Yeah right boot is the best boost control.
If it is a manual boost controller then its gonna be a hassle changing the controller under the bonnet everytime you want more boost.
As regards to fuel economy, if my thinking is correct it will make no difference at all and will probably make the car run like a dog, cos if the boost is turned down the car is still going to be fuelling for a higher boost situation when your foot is to the floor so will be running rich which could have the added effect of fouling your plugs.

Gear Head

iTrader: (2)

M8, if your worried about fuel economy, you've bought the wrong car!

alloy

So true, reducing boost won't help with economy! you'll still be boosting blair's economy with fuel prices!

Jolly Green Monster

iTrader: (4)

no.. it will access different parts of the ecu map at the low boost setting than it will at the current boost setting.. like when you use part throttle.

jamieerst

i would have it re-mapped, thats for sure..

so it may improve economy ?

i know its not the greatest car for economy, my other option is a legacy.

Hence my other post in general about moving to a legacy.

J.

Jolly Green Monster

iTrader: (4)

If you have no discipline and drive flat to the floor all the time, then reducing the boost would save on fuel yes.. but you would do better to drive it gentle when you want to use less fuel.. skint month.

jaytc2003

iTrader: (1)

even if it was a manual boost controller? If the right foot is flat to the floor, how would the ecu know if less boost was being used as the controller would be fitted after all the solenoids and electrics etc?

This learning stuff is good though

Jolly Green Monster

iTrader: (4)

lower MAP and MAF signals.. the ecu uses MAP and / or MAF to detemine a location in the look up tables for ignition and fuel.

jaytc2003

iTrader: (1)

Ahhh think Im getting this now, so does that mean then because the car is going slower due to less boost, but accelerator still on the floor, that there is less voltage being supplied from the maf due to a decrease in airflow/airspeed through the maf therefore it uses a different location in the look up tables ?

Jolly Green Monster

iTrader: (4)

nearly.. vehicle speed doesn't effect it.. assuming that is what you meant by "car is going slower". The engine will be consuming less air and therefore need less fuel, the MAF voltage will be lower so less fuel will be supplied as the table will be traversed less etc..

jaytc2003

iTrader: (1)

ahhhh with you now.
Whilst your on will I be okay if I set up the avcr to a lower boost setting so that I can switch between the 2 boost settings?

Jolly Green Monster

iTrader: (4)

Yes when I map I deliberately start at low boost setting and go up so that the fueling and ignition is set up for the boost I leave it on plus lower boost.

just watch for boost spikes on that turbo.. keep the duty low.

Simon

jaytc2003

iTrader: (1)

what turbo did I have again was it a vf22? Cant remember what it was

Jolly Green Monster

iTrader: (4)

some early Legacy IHI unit iirc.. no idea on model number