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sachilles
sachilles SuperDork
12/10/13 7:41 a.m.

You could be running rich from your modifications. Cobb really isn't the best solution. The generic tunes don't always mesh up well. There are variations with the cars, and many times a custom tune by someone that knows their stuff is warranted.

JAhmed
JAhmed New Reader
12/10/13 1:16 p.m.
sachilles wrote: You could be running rich from your modifications. Cobb really isn't the best solution. The generic tunes don't always mesh up well. There are variations with the cars, and many times a custom tune by someone that knows their stuff is warranted.

This did cross my mind at one point. Perhaps I will invest in one of the Torqued Performance maps, or something else (if anyone has any recommendations). The worst thing that could happen is I get more power...and worse mileage

irish44j
irish44j UberDork
12/10/13 5:24 p.m.
Aspen wrote: Wagons are always LESS aero than their sedan counter parts because of the sharp cut off at the rear. Usually about .01-.02 Cd. That aside, unless you two guys are driving the exact same route at the same time it is difficult to compare. A couple of additional traffic lights could make a big difference. Driving style will also make a big difference. Do you both use the same motor oil/weight?

Hmm...One of my schoolmates (in the 90s) used to race Volvo 740s in some Italian road-race series (I lived in Italy, if that makes more sense), and he said that the wagons were faster than the sedans on straights because of the better aero (granted, they ran a foot-long spoiler off the top of the hatch), but that they didn't provide as much rear downforce as the sedans with comparable spoilers. And he raced both types so I always took his word for it....

JAhmed
JAhmed New Reader
12/10/13 8:22 p.m.

I was under the impression that they used the 850 Estate in BTCC the first 2 years for this exact reason. When the BTCC didn't allow a rear decklid spoiler, the estate was advantageous as it was faster on the straights...as soon as the BTCC changed regulations, however, they switched to a sedan with a rear wing.

irish44j
irish44j UberDork
12/10/13 8:30 p.m.
JAhmed wrote: I was under the impression that they used the 850 Estate in BTCC the first 2 years for this exact reason. When the BTCC didn't allow a rear decklid spoiler, the estate was advantageous as it was faster on the straights...as soon as the BTCC changed regulations, however, they switched to a sedan with a rear wing.

yeah, I thought sedans had more drag in general in "stock" form - unless a rear wing, vortex generators, or other airflow changes were made. Would make for an interesting GRM test.....take two identical cars in sedan and wagon trim (like an 850) and test them against each other both on the track and in a wind tunnel.

JAhmed
JAhmed New Reader
12/11/13 7:43 p.m.

mmm...makes me want to get a Volvo again.

DirtyBird222
DirtyBird222 UltraDork
12/11/13 10:36 p.m.

A lot of thought going into this thread lol. I noticed a huge difference in gas mileage with a simple exhaust on my 2012 WRX and it was for an increase. Calculated by filling up to a full tank, going xx amount of miles, filling up again, calculate all those.

I did notice if I just drove like a normal human being I would get great mpgs but since I have foot made of concrete that was difficult to do on a consistent basis. I do miss the car but not the interior shortfalls. It was a blast to drive which makes it hard to achieve the frugal mpgs.

jere
jere HalfDork
12/11/13 11:18 p.m.

I see the TB and maybe even the other mods making a slight difference in gas mileage. The 0 toe is good for mpg, but with newer cars I have heard it is hard to improve on the intake's design in a good amount of cars. Some after market and homemade designs can mess with air flow sensors readings and also increase the amount of time it takes the car to warm up. The large TB's tend to let the driver put the pedal in the same place as before the upgrade, but with the increased air coming in can burn more fuel.

Also where in akron are you getting your gas? Hopefully not a BP

Kenny_McCormic
Kenny_McCormic UltraDork
12/11/13 11:30 p.m.
JAhmed wrote: Kenny, can the toe change you refer to be compensated for at my next alignment? Like toe in a bit on purpose static? sorry if this is a dumb question...

Assuming you get it on a hunter laser rack or similar, you can go under the car, put one hand on the leading shoulder of both front tires, push out, and see the values move a bit. The more, softer, rubber they have in the suspension the worse they do it. When aligning an 80s mercedes for example, there is a special tool you're supposed to use to put force on the tires. If you have ball joints, tie rods, etc at the end of their life, this effect is amplified.

I missed the part about the canned tune, that's probably the biggest part of it. Do you both run the same spark plugs?

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