mods for mpg
mods for mpg I just bought a 99 SS M6 for a daily driver. I am not new to LS1 cars, as I have had my other 99 SS since 2001, however, my goal with the daily driver is mpg, not peak power. I have read on the forum where many people are getting 30+mpg out of M6 cars. I would like to know what can/can't be done as far as bolt-ons go for MPG improvement. The car is currently bone stock except for a K&N filter and a lid. I plan on doing full exhaust, underdrive pulley, and having it tuned. Has anyone noticed an improvement with the ram air kits that pull air from under the front bumper? I will be doing about 70-80 miles per day of hwy driving so I think I would be driving a speeds that would reap the benefits of the ram air kit. The pinion and carrier bearings are shot in the 10 bolt so I'm swapping it out for a low milage 3.23 10 bolt out of an auto car. I figure I should pick up maybe .5-1 mpg from this at least.
given your traveling that distance on the interstate, your sixth gear will still be usable and I would think it would help your mileage. And id say get a really good tune, cause a bad tune is gonna kill your mileage.
-Will
-Will
Joined: Aug 2007
Posts: 24,241
Likes: 89
From: Turnin' Wrenches Infractions: 005
6th gear is barely usable with stock gearing much less ungearing the car. Lugging the engine does not make mpg better. Most report more usable overdrives in M6s by adding gears.
Using a gear calculator, the difference in at 71 mph in 6th is 100 rpm. 1500 with 3.23s, 1600 with 3.42s. Is that really enough difference to affect in mpg? The main reason for using this 10 bolt is that its a freebie.
Launching!
Joined: Oct 2010
Posts: 257
Likes: 0
From: Ottawa, Ontario, Canada.
I went to 3:73 with my M6 and cruise at 1,300 in 6th at 120 kms. I can't comment on mileage but 5th and 6th are more usable and now don't lug, I can lane change or adjust speed for incline without down shifting comfortably. Les...
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Verdad Gallardo I would stick with a lid, catback, and maybe a TB and leave it at that. I had setup like that and got 31 on the highway. But although some simple mods help the majority of the MPG is going to be in driving habits
If you don't care about power, why mod it? Say you spend 1200 on bolt ons, that's on the cheap also, and gain 1.5 mpg.. even at 4$ a gallon, how long will it take to trade off?
e85? I kno it burns quicker but if you setup the car for it with the right injectors and tune; I would think you would save inn the long run.
Tune is VERY important for good mpg. fresh o2's and a great tune should help a decent amount I would think.
Best idea yet, lightweight foot mod! keep your foot off that right pedal as much as possible!
Tune is VERY important for good mpg. fresh o2's and a great tune should help a decent amount I would think.
Best idea yet, lightweight foot mod! keep your foot off that right pedal as much as possible!
Honestly, all of what has been said is correct. But modding JUST for better mpg is retarded. My car has full bolt ons and I gained ~1mpg city (I have no reason to go on the highway). If you gain 2mpg but have to spend $1000 to do so, how long do you think it would take before you break even? My guess is you'll have gotten rid of the car before that point.
If you want good gas mileage then stay off the throttle and lighten the weight of the car. Your driving habits will be the greatest factor in the equation.
If you want good gas mileage then stay off the throttle and lighten the weight of the car. Your driving habits will be the greatest factor in the equation.
TECH Senior Member
Joined: Feb 2009
Posts: 5,445
Likes: 4
higher tire press ,a tune,and a custom cam.stock gm lobes are not the best,try comp 54-408-11.E85 don't burn quicker,alcohol has half the BTU of gas and needs more timing ,and cost alot to convert to.E85 is great for forced induction.