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Old 02-26-2014, 07:56 AM   #7 (permalink)
oldtamiyaphile
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Join Date: May 2009
Location: Australia
Posts: 1,510

UFI - '12 Fiat 500 Twinair
Team Turbocharged!
90 day: 40.3 mpg (US)

Jeep - '05 Jeep Wrangler Renegade
90 day: 18.09 mpg (US)

R32 - '89 Nissan Skyline

STiG - '16 Renault Trafic 140dCi Energy
90 day: 30.12 mpg (US)

Prius - '05 Toyota Prius
Team Toyota
90 day: 50.25 mpg (US)

Premodded - '49 Ford Freighter
90 day: 13.48 mpg (US)

F-117 - '10 Proton Arena GLSi
Pickups
Mitsubishi
90 day: 37.82 mpg (US)

Ralica - '85 Toyota Celica ST
90 day: 25.23 mpg (US)

Sx4 - '07 Suzuki Sx4
90 day: 32.21 mpg (US)

F-117 (2) - '03 Citroen Xsara VTS
90 day: 30.06 mpg (US)
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Quote:
Originally Posted by Daox View Post
The SG isn't about using it for the MPG IMO. I never have my MPG reading up. I use it for other things like monitoring engine load, engine coolant temp, and for my Prius some hybrid stuff. Ask anyone here who has gotten 100% over the EPA rating for their car, instrumentation is critical to get there.

Enrichment and ignition retarding isn't a myth, especially on turbocharged engines. Just ask anyone who has done their own tuning. It is true that most cars these days stay in closed loop quite a bit (especially naturally aspirated engines), but it does happen, especially if you're accelerating around peak torque.
I don't discount the need for instrumentation, I just feel that there's nothing at all wrong with the factory MPG display in most cases.

My turbo charged Fiat 500 stays in closed loop at WOT all the way to the rev limiter (as verified by SG). Most small Euro turbos are tuned for ecomony so I wouldn't be surprised if many of them do this. The Jeep and Merc also stay in closed loop at WOT, they may switch to open loop at well past sensible revs, neither would normally be revved anywhere near that point.

Given this I now simply accelerate at WOT which is a lot easier than aiming for 80% load or 14 inches on the vac gauge. The 80% load - stay out of enrichment idea seems gospel around here but in my experience it's not a blanket solution.

Now my R32 Turbo Skyline does enrichment, I can tell by the flames out the back But that's a 80's tech performance car, not really typical EM fodder.
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