Horrible gas mileage after installing GFB BOV

[kimmievo]

After having my GFB BOV sitting in my room for months, I finally got it installed a few weeks ago at WORKS, with the WORKS suggested setting. I don't know if this is a coincidence or not, but I have been getting HORRIBLE gas mileage lately. Before getting the bov installed, I would average about 230 miles to a full tank. The first full tank after it was installed I got about 137 miles. The second was about 170 and on the third I got 200 miles.

I am not constantly letting the bov make that cool sound, and I am not driving any different than I usually do. The Bov doesn't cause the car to bog or stall, but the rpm's at idle have changed just slightly.

Anyone else running this BOV or a different one notice any change in gas mileage? If it was only a few miles difference, it wouldn't bother me, but this is a pretty drastic change, and with gas prices these days...

Any suggestions or comments would help greatly.

Another thing is that it may not even BE the BOV, and something completely different. Feel free to chime in.


Thanks in advance!

Kimmie

[lqdchkn]

Kimmie I have it also and am still getting around 230 ish per tank. Mine is set at just a little less than 1.5 turns from the soft setting on the spring, and three clicks ( i think ) on the VTA.

[earlyapex]

Kimmie I have it also and am still getting around 230 ish per tank. Mine is set at just a little less than 1.5 turns from the soft setting on the spring, and three clicks ( i think ) on the VTA.

wow. I am excited when I get 200 to a tank, which is almost never. I guess I drive my car too hard.

on the track I get like 4mpg. :wink:

[kimmievo]

I'm going to call Tyler or Jaime at Works and see what they have to say.

[nebolic]

i get around 230miles to the tank and I have cams too, and around 200 miles to the tank with lots of playing time in the evo . . . sounds like your car isn't running up to par if its eating that much gas...

hope you get it taken care off soon . . .

nebo

[kimmievo]

If it's not the BOV, what else could it be?

The only thing I have added recently besides my P2 is the Magnecor wires. If they are loose, could that in any way be affecting my gas mileage? I think if they were in fact loose, I would feel a loss in power, which I don't.

[EvoVIII]

take out the BOV and run another full tank, then u will know

[r6bruin]

Hey Kimmievo,

Is the issue resolved? It doesn't seem to me that BOV alone would cause that huge drop of gas mileage... and from what you said with full tank of gas it does achieve 200 miles sometime, so I am not sure if it's other stuff (like stop-and-go traffic or constant use of air-con) causes that.

Please keep us posted, thanks :wink:

[vtluu]

Just a little thought experiment about mileage.

I know for a fact I can get over 30 mpg if I cruise at 60 mph. I also know my mileage falls off sharply to something around 25 mpg if I cruise at 70 mph. The main reason being air resistance, which goes up as a square function of speed.

Now, what would happen if I drove 60 mph but against a 10 mph headwind? Then the air would be hitting my car at 70 mph and I'd get 70 mph worth of air resistance--so I'd get about the same mileage cruising at 60 mph than I would at 70 mph on a calm day. If the wind were to blow in the same direction all the time, then on a commute I'd fight a headwind one way and benefit from a tailwind the other way--so the effect of wind is pretty much cancelled out. However, we all know wind isn't constant--it varies from day to day, hour to hour. Moreover wind direction can change predictably with the time of day, due to the effects of the sun's heat, energy retained/released by bodies of water, etc. So if you were particularly unlucky the wind might change direction between your morning and evening commutes and you might end up fight a headwind both ways.

I'm not saying that's why you suddenly got crappy mileage, just that it's possible that something as subtle as a small seasonal change in the wind pattern could have caused a big change in mileage. Unfortunately daily driving is about as far from a controlled laboratory environment as you can get; the only way to compensate is to increase your sample size dramatically--but of course a seasonal change might be in play, so you might need to average your mileage over a whole year to know for sure.

[kimmievo]

Hey Kimmievo,

Is the issue resolved? It doesn't seem to me that BOV alone would cause that huge drop of gas mileage... and from what you said with full tank of gas it does achieve 200 miles sometime, so I am not sure if it's other stuff (like stop-and-go traffic or constant use of air-con) causes that.

Please keep us posted, thanks :wink:



Hey Ken,

Well, after calling WORKS and Tyler suggesting I should reset my ECU by disconnecting the battery for about a minute or so, I went home and tried it. So far, I am averaging about 200 miles to a full tank, which is still about 25 miles less than what I am used to. I have been driving fairly conservative for now, but since the BOV does VTA, and makes the car run lean during VTA, it will affect gas mileage a little. I guess you just have to take the bad along with the good. I'm not gonna take my BOV out, and I'll just have to accept the fact I've lost a little bit of gas mileage.

[kimmievo]

Tam,

Thanks for the insight:) I know weather plays a big part on how our cars run, but I had no clue it would affect my gas mileage this drastically!

[r6bruin]

I see, thx for the update, Kimmievo :)

That said, my car never achieve 30mpg mark regardless what speed I drive on. I think the best I got was around 23mpg... and that's fwy cruising at constant speed around 65mph :(

[Eclipse]

I have been driving fairly conservative for now, but since the BOV does VTA, and makes the car run lean during VTA, it will affect gas mileage a little. I guess you just have to take the bad along with the good. I'm not gonna take my BOV out, and I'll just have to accept the fact I've lost a little bit of gas mileage.

Venting makes the car rich not lean. The car dumps the correct amout of fuel for the air you just dumped out to the atmosphere. Often accompanied by a big bog in throttle response.

I'd still bet you have a leak. The fuel lost from venting should be small and isn't really associated with acceleration as it's from a decrease in load and reduction in throttle opening. However if it's leaking under boost then you would be rich all the time you have positive manifold pressure.

[triple L]

HA!! i got the same bov and i set mine closer to negative on both.... it does seem like the gas mileage sucks after installing bov, 3" tbe, injen intake, lower IC pipe, upper IC pipe!! but hey u gain n u lose!!!

[dabaysevo]

Back from the dead. Damn three year old thread.

[--anonimuz]

:lol:

[izyzero]

hahaha