29mpg turbo mkIII

Disced

Disced

Pie + NYQuil = FTW
Apr 5, 2005
500
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39
Edmonds, Wa
At one point in my trip from Indy to Seattle; We cruised @ approx. 95 MPH with 11.2 % throttle position for almost 4 hours. I had to double check my math when we stopped to get gas but; We went almost 360 miles and the gas tank only took 9 Gallons... Doing the math, that comes out to approx. 39.6 MPG.

I guess big single turbo's are better for fuel economy @ cruise; since I didn't ever get on the car into full boost, just cruised @ 95 MPH forever.
 
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turbodhbar

New Member
Sep 9, 2006
13
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0
Bainbridge, N.Y.
I got 29 mpg on an 45 mile daily commute at 65 mph when I first rebuilt my motor till it was broke in . Then it was boost all the up a 3 mile long hill and 75to 80 mph ,mpg dropped to low 20's but it was alot more fun to drive to and from "WORK".
 
aye mate

aye mate

Hiatus over.
Mar 30, 2005
1,926
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Maryland
Yea I usually get around 20 with mixed highway/city/backroads driving. Plus lots of playing on the weekends :naughty:
 
Insidious Surmiser

Insidious Surmiser

Formerly 89jdm7m
May 12, 2006
2,172
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Oceanfront
Jeff Lange said:
Yeah I get about 27-29 on the highway if all goes well.
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yep... pretty much, i calculated exactly 30 before, but it all depends how you drive :)


only mods were exhaust, and k&n drop in BTW
 
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ma71supraturbo

ma71supraturbo

Supramania Contributor
Mar 30, 2005
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Redding, CA
www.geocities.com
starscream5000 said:
Damn, I thought the slower go, the better the gas mileage... I thought mose vehicles get the best gas mileage around 60-70 MPH...:dunno:
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In theory, if you could maintain the rpm at your torque peak in your top gear, you would get the best gas mileage. This is ~4000rpm for a 7m, which I believe is in the 85mph ballpark (roughly -- memory is fading). However, the power required to overcome wind resistance is an exponential function, so you will reach a point where you are having to push more air out of the way than can be overcome by increasing engine efficiency. Historically, this was in the 55mph area, although cars with better aerodynamics are often closer to the 65mph range


Here's a tip: When doing 80mph+ on freeways, try to stay 1.5-2 car lengths behind another well-driven car (minivan preferably). Your wind resistance will drop down dramatically (you can see your vacuum increase on the boost gauge) and if you get nailed by radar -- the car in front almost always gets the ticket... But you'll need to knock off the cell phone usage/eating/ipod tuning and concentrate on driving
 
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dav_dman

old guy
Oct 23, 2005
107
0
0
louisville KY/so.IN metro area
drjonez said:
my old brown car would get high 20s all day long on the freeway....cruising 80ish.
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Okay question #2, guys:

Can I expect much of a difference from current TCCS driven lex/550 setup in fuel economy when i put an safc/wideband on it and dial it in? I'm not that interested in a few extra hp but if the investment pays off in fuel economy and reduced global warming emissions that's a little different..

heck if i can buy some low hour used high flow cats, i'm even thinking of putting on a y pipe with dual exhaust so i can put the dual cats on there...i'm blowin a lotta hc out the no cat pipe with this setup.

i love high performance but i like having a planet to live on too.
 
ma71supraturbo

ma71supraturbo

Supramania Contributor
Mar 30, 2005
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Redding, CA
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dav_dman said:
Okay question #2, guys:

Can I expect much of a difference from current TCCS driven lex/550 setup in fuel economy when i put an safc/wideband on it and dial it in?
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Under steady-state conditions, it should make no difference as long as you are still within a correctable range (something the Lex/550 setup was designed to do). At cruise (say maintaining 75mph) you're getting a steady supply of air. The O2 sensor is reading the air/fuel ratio in the exhaust, and the computer will make adjustments to the amount of fuel injected to compensate. If you try and lean this out with the SAFC, the O2 sensor will still give the computer exhaust readings and the TCCS will adjust the mixture to get back to ~15:1...

Now, anytime you make a change in throttle position or load, you will probably be running rich momentarily. This is your opportunity for less emissions/better gas mileage. Unfortunately, these conditions aren't as easy to tune with a SAFC -- this is really where the standalone comes in...
 
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drjonez

Supramania Contributor
Mar 31, 2005
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the motor city
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ma71supraturbo said:
Under steady-state conditions, it should make no difference as long as you are still within a correctable range (something the Lex/550 setup was designed to do). At cruise (say maintaining 75mph) you're getting a steady supply of air. The O2 sensor is reading the air/fuel ratio in the exhaust, and the computer will make adjustments to the amount of fuel injected to compensate. If you try and lean this out with the SAFC, the O2 sensor will still give the computer exhaust readings and the TCCS will adjust the mixture to get back to ~15:1...

Now, anytime you make a chance in throttle position or load, you will probably be running rich momentarily. This is your opportunity for less emissions/better gas mileage. Unfortunately, these conditions aren't as easy to tune with a SAFC -- this is really where the standalone comes in...
Click to expand...

good point, but as with most that just slap in the lex/550, they're probably running more rich than the ECU can deal with....
 
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