Greetings everyone,
I have a question in regards to tuning a 4.2l v8.

Up until the other day I was about decided on buying a Subaru Legacy spec.B. I saw a "S4" in a parking lot and decided to start researching Audi's. So bottom line is I can swing the payment fairly easily for a used S4 (like a 2004 with 50-80K) but the kicker for me will be gas mileage.
I've spent some time reading through the archives on this forum and it seems to me that ~20-21 MPG is TOPS expected mileage with mixed city/highway driving. More likely than not it will be lower than that? So I've been assuming more of a worst case scenerio of getting 15-20MPG on a regular basis and I think that will bust my budget.

I'm wondering has anyone successfully run different fuel maps in their ECU to improve fuel economy? (at the sacrifice of performance of course) Either through ECU flash or piggyback controller?

I.E. I'm a Nissan guy and there's a company out there that does a ECU prom flash for the 350Z. You can have up to 7 air/fuel maps stored and pressing a certain combination of cruise control buttons lets you cycle through each map. (economy, performance etc etc) I've used a piggyback controller which allows switching of maps via a auxilary switch instead of factory vehicle switches.

Are there any companies out there that offer similar tuning options for the 4.2L in the S4?

 

I don't think it's going to be possible to de-tune the high output 4.2.... mine is chipped and i at least still can get 20 on the highway.... gas millage is not great with this vehicle... average id say 12-15...when you step on it.... 5-8 lol... mine sits in the garage most of the time =)

the beast sounds like the **** though

 

Thanks for the response. What chip do you have? I contacted APR about their S4 tune. Theirs has multiple maps that can be switched by using the cruise control button(s). The rep that responded said that with their Stage 1 map (which is the 91 octane map) it will improve gas mileage 2-3MPG. So if I averaged 20 on the highway, 22-23 would be nice. However I fear I'll be in the same boat as you and probably getting 10-15. Sadly I think the S4 is slipping down my practicality list!! Back to looking at Legacy's I suppose. 4CYL with a turbo, 300-350HP and 25MPG......

 

i'm chipped by speedtuningusa.com

it's an expensive car to drive daily..... would probably handle better than the legacy though.... and waaaay better interior... subaru interior is basically like a honda or toyota.. nothin really special... what about a 2001 audi s4? better gas millage and can be way faster than both these cars