badformulaLS1

iTrader: (1)

Just got an M6 01 Camaro and it has been pretty terrible on gas.... In the city I try my best to keep it at 2k rpms or less but that requires me to drive like a complete grandma. I've been reading for years now about people getting 28+ on the highway with manuals and now I finally have an M6 f-body but I drove about 50 miles highway this morning and blew through a quarter tank cruising at about 70mph at 1500-1600rpm. I'm coming from an A4 LS1 car that would take me a solid 70 miles on a 1/4 tank. Got 17ish city about 22 highway for an average of about 19-20mpg I guess. And even that was low for an auto compared to what I've read on here... I haven't taken the time to do the math for exact numbers but I know the Camaro is much much worse both city and highway and it's disappointing...

Anyone have any idea why? I've heard of losing some mpg with headers/ory but should it be this significant? Will it improve once I get it tuned? Any other reason for it? I always thought M6s were supposed to get better mileage than autos... guess not.

sick_tight

i was getting 28-30 mpgs with my old Z on the highway, you cant expect 4cyl mileage since it has a 6speed. your right foot determines how many mpgs you get

badformulaLS1

iTrader: (1)

But I said even on the highway cruising at 70 in 6th it was still eating gas bad... No right foot action there.

RevGTO

iTrader: (12)

You can't depend on how your gauge reads at 1/4 tank. Fill up and and check your mileage after full tank. I've had two M6 cars in addition to my A4, and my brother has one also. In my experience, M6 cars get better mileage than an A4. Yet your results may vary. The thread below has all the discussion one could want on the topic: https://ls1tech.com/forums/general-l...-f-bodies.html

badformulaLS1

iTrader: (1)

Good thread thank you. Seeing a lot of people claim 20+ mixed city/highway with some spirited driving many of which have more mods than me including gears... Next fill up I'll make sure to do the math, but at the rate its been going I can't imagine it being anymore than 15mpg mixed which is definitely not normal.

M4N14C

iTrader: (3)

Lots of different variables come into play when it comes to mpg. An A4 with an efficient running engine (Good tune, clean filters, new O2 sensors, clean internals) will get better mpg than an M6 without those. Looking at your sig, hope you got a tune for those mods, if not that's probably why your mpg is suffering.

badformulaLS1

iTrader: (1)

All of the modifications are recent (done within the last month) and I have not been able to get it tuned yet. Hopefully I get some good improvement after a tune.

Blackpanther99

iTrader: (8)

Tune will help the issue but your right foot can solve it

badformulaLS1

iTrader: (1)

You guys aren't understanding I said I've been driving really slow shifting at around 2k rpms all the time. Sometimes less other times no higher than 2.5k... If people with gears and more bolt ons are getting better mpg with "spirited" driving it can't be just my right foot causing it.

wilkes02SS

Also, if you are concerned with MPG don't plan on hitting al the gears. My route to work i have a few light and top speed of 50. Shift 1st moddest to second then short shift to 4th. I do that and still get over 23ish. I drive about 10 miles one way.

badformulaLS1

iTrader: (1)

Im going to try that thanks. A friend told me to try going 1-3-5. Is that a good method to try too?

RevGTO

iTrader: (12)

It depends on the flow of traffic and how quickly you want to get up to speed. I almost always go through the gears, except I'll go 4-6 after accelerating through a freeway on ramp.

Coasting also helps. I'll often throw it into neutral and coast to a red light up ahead rather than wasting gas on deceleration compression revs and braking.

wilkes02SS

Spot on. I short shift 1-2-4 like i do because there is no traffic so there's no need to bother with all the gears.my Speed areas gor from 35 to 50, at 45ish i generally shift to 5th. i have heard of 1-3-5 but never really dealt with it. i find 1-2-4 works really well for granny driving for some reason.

sick_tight

i usually hit 1-2-4 for city driving with my z28 one got you rolling and 2 got you up to speed and 4th you could almost take off from a stand still with no problem but id rather not haha

M4N14C

iTrader: (3)

Headers and a tune should be done on the same day IMO. You should get a SIGNIFICANT boost in mpg and power when you get it dyno tuned.

You actually get better mpg if you downshift when coming to a stop rather than putting it in neutral. The engine still needs fuel to run at idle but when you downshift you are essentially using engine breaking to slow you down and thus the fuel injectors are not firing and you use no gas.

https://ls1tech.com/forums/general-l...-coasting.html

A.R. Shale Targa

iTrader: (2)

I'd say 90% of the OP's issue is the desperate need for a retune, after plenty
mods designed to enhance performance...the computer is strugglung to com-
pensate for the drastic airflow differences. I'm also not a huge fan of such a
cold thermostat since LTs already move the O2s further away from the
engine heat that they need to work(read) properly. TUNE; TUNE; TUNE !!!!!
Aditionally I keep my tire pressures on the high side and creatively draft
larger vehicles. FWIW my C5 gets 30-32 with a high of 34 mpgs...all freeway

badformulaLS1

iTrader: (1)

The thermostat was on when I bought the car. I would've never bothered with it myself. Should I remove it or will I be able to get some benefit out of it when tuned? Besides the full exhaust I only have a few other bolt ons and I didn't consider that significant enough to require an immediate tune. Not to mention reading tons of posts on here saying its ok to do headers without an immediate tune.

sick_tight

youre safe with no tune but iirc the computer will compensate by richening up the tune.

its not tuned for the good airflo so it dumps fuel into the mix to compensate.


get it tuned and see where you are afterwards

A.R. Shale Targa

iTrader: (2)

Heat is the transformation of potential energy(fuel source) to kinetic motion
(crankshaft measured torque). For some old dogs they would remember a
fella named Smokey Yunich who experimented with reverse cooling long B4
GMs LT1 deal.....More recently Warren Johnson agreed with ol' Smokey that
an internal combustion engine makes peak power at between 188-192 deg.
Plenty will argue that a cooler thermostat makes more power on a dyno but
in your situation you are asking for fuel mileage at low rpms and low load(no
heat)...so to me the hotter thermostat combined with a cleaner tune would cause your EGT (exhaust gas temp) to elevate..thereby heating the O2s for
a more accurate reading to the brainbox. Also you have a catless Y-pipe yes?
Doesn't a tuner have to shut the rear O2s off to prevent the computer from
getting an innefficient cat reading ????

badformulaLS1

iTrader: (1)

So I filled up with 1/4 tank left. I made it about 150 miles in 3/4 of a tank with about 60 miles highway and I topped it off all the way last fill up. I've eased up even more on my driving, have been trying going 1-2-4 and have noticed some slight improvement even with a couple WOT pulls practicing my shifting... maybe 1-2 mpg better. Hoping a tune adds another couple mpg.