The Curly 1

I love my HHR but would like to increase the MPG.
My thoughts are
1. lowering car about an inch. That reduces the undercar turbulence and overall drag coeficient. Maybe 1 MPG or more at all speeds? Has anyone verified MPG improvements from lowering? Looks good to.
2. Complete exhaust and K& N intake filter. Some of the exhaust systems now days are like a potatoe in the pipe to make them meet emmisions and make them quiet. Maybe 1 to 2 MPG?
3. Tune, now in another thread here there are some claims of 5 MPG and I think that may be optimistic but if there is a verifiable real world improvement of 2 MPG then that would be significant.

Note items 2 and 3 would increase performance and mileage only IF you keep your foot out of it.

So if the above items could get an honest 4 or 5 MPG improvement then I think that would be worth it.

There are some things that I consider stupid such as drafting big rigs or going under posted speed limit that will save gas. Do those things please sign your organ donor cards.

I already try to keep my tires inflated up and try to keep my foot out of it but I do cruise at a safe speed and do not hold up traffic or create a hazard.

Also has anyone any definative proof of mileage increases with air conditioning off? Here in Texas it is 80* to 113* on the DIC about 9 months of the year so air conditioning off is not going to happen.

Look forward to your opinions. Curly

wxman

How many years does it take to break even in gas savings from those mods? 10-15?

There is no magic to better gas mileage. The best thing to do is drive smart. And, it's FREE.

I know what you're feeling though. The MPG display on the DIC is a curse. I never worried about it when I couldn't see it. I have to try to just keep it on outside temp and RELAX while I drive, like it should be, and not worry about picking up .2 mpg on this leg.

Lone Ranger

Unless you're also replacing the catalytic converter (illegal to do so before 50,000 miles) with a low restriction one (Random tech, etc), a catback exhaust is a waste, in my opinion but others may disagree.

A K&N will do nothing for your mpg. If it doesn't coat your MAF sensor wires with oil as recieved when you buy it, it will one day after you finally clean and re-oil it. I'm anti 'oiled gauze' air filters, but that's just me... I just don't like oily cotton in my intake air path.

General Motors has tuned these cars for the best fuel efficiency and emissions performance, why wouldn't they? They want to be able to advertise the best MPG numbers possible, it helps sell cars. Trying to out-think the GM Powertrain engineers on emissions and fuel efficiency is a waste of time-- they know what they're doing.

xzombiex66

I changed my Exhaust to a GMPP Cat back exhaust and changed my oil on the same day and used full synthetic and ever since my mpgs went up about 2-3 mpg in city and highway.

The Curly 1

A restrictive exhaust absolutly will hurt performance and mileage. The question is how much and is it worth the expense? Factory exhaust are quiet (restrictive) because most people want them quiet.
The factory has to make some sacrifices in performance and mileage to get it quiet and to meet all emmisions etc.

Snoopy

Actually sound levels are dictated by the Federal Government. So exhaust levels, as well as the intake levels (ala the big black plastic box under the hood), are "muted" to comply with the requirement. Aftermarket sales is a different scenario.

kornellred

I think Lone Ranger's comments sum the matter up quite nicely. But here in the land of the free and the home of the brave, you can do whatever you please to your own property.

02z28

I haven't found anyone yet that can comfortably tune HHRs that aren't SS models, but when I do i'll be happy to be their mule. I had great luck with tuning my z28, fuel mileage AND performance both went up significantly with a simple tune.

As for right now, I'm pretty satisfied with my mileage. I got 35 mpg on a trip from NJ to MD, most of the time doing 70 mph, AC on half the time. the DIC only said 32.5 and i was happy with that, but doing it the pen and paper way it was over 35. I realized then that my tires were only inflated to 28 psi (must have been from the dealer, haven't checked since I bought it) and I filled them up, waiting to see what the next tank will bring.

Clevelandhhrss

Hey curly,
What engine
What trans
What is your best mileage over one tank
Wha is your avg mpg usually
What is the terrain like down there
What is your average trip distance.
What do you consider "good" mileage???
What is the normal highway speed that you drive?
What is the highway speed limit down there?

I'm that dude who annoyes people by putting 87 octane into a loaded SS while getting 36 mpg overall 66%hwy/33%cty
Later :)

CarmanHHR

Most car companies tune their cars based mostly on emmissions. But obviously MPG is taken into consideration when they set up the fuel mapping. Most of the tunes I have run into with other car manufacturers are set up a bit rich or "safe". Keeps them from having to replace as many parts under warranty.
I'm new to the HHR but if there is a piggyback tuner out there that can interface with a laptop that allows you to adjust A/F ratio I would be interested in it.