I hear claims of great mpg with Corvettes and it raises some concerns for how I drive my own 2010 C6 Grand Sport. I have seen documented claims (2017 Z06 manual transmission) of obtaining an average of 35 mpg, however, the trip length measured was 40 miles, driving at 45 miles per hour. The tach is registering only about 900 rpm. OK, that cannot be much fun but I have always been of the impression that lugging the engine is not good for the life span of the motor. I try to keep my rpm's around 2000 rpm and the car seems to be happy and content. It certainly doesn't seem to be laboring in the least. What are the opinions for driving at low rpm's? The choices seem to be to downshift or go faster. I seldom use 6th gear unless cruising on the interstate.

 

In my opinion, 2000 rpm is too high and will just burn excess fuel and cause more wear. Unless you are going up a very steep hill with the ac on and need the extra power. I don't think lugging is as much of an issue with newer cars because of the variable computerized timing and knock sensors. On level road just cruising at 45 1000 rpm should be fine.

 

Thanks for your opinion and input on my issue. I am looking forward to some continuing discussion on this topic. I don't want to mishandle this tremendous machine.

 

A, If you bought a Vet for high MPG/worried about MPG, you bough the wrong car in the first place.

Yes, around 24mpg is the norm on long highway drives with the car left in OD (6th gear), if that is all the cruising kind of driving your doing, then should have bought a caddy instead.

So 14~18MPG average is about the norm for real city/highway driving instead.

And Ditto with the motor around 2K begin content; with chugging around 1k or lower just ending with the motor too low in rpms to really be able to control the back end of the car with the throttle for aggressive driving isntead.

 

"Lugging" is a real concern -- however -- in shade-tree mechanic land it is defined as putting a load on an engine while at a low RPM. Cruising down the highway at a low RPM with a 3200 lb. car with 400+ HP is not "lugging." If one doesn't have an instinct for when an engine is lugging, one should have an automatic -- which will not allow an engine to lug.

It's the same principle with tractors (engines are engines). When doing hard work, you should be at or near "PTO" on the tach which is the RPM the engine is designed to do its maximum work. It is nearly at max RPM. Anything much below that is to be avoided for heavy work (plowing, fitting, or any tools designed to run at PTO speed.)

The transmission is only used to adjust the speed (to suit ground conditions) as long as the RPM doesn't fall below the PTO speed on the tach. Back in the day, tractors didn't have tachs, so you ran them at full throttle when doing heavy work, letting the governor adjust the throttle opening for the power load.

 

Here is an interesting case study so to speak regarding the MPG subject and our LS2 A6 C6 Corvette with 19,000 miles. I didn't set out to precisely measure it but to all intents of purposes it was. I twice duplicated running a closed measured route leaving the same gas station with a full tank and filling up again at the same gas station at the end of the run. The total mileage traveled was identical both times. Below is a map of the route taken on consecutive weekends once with a cousin followed with my son in-law.

The total distance traveled was 360 miles and was a combination of 4 lane freeway and 2 lane interior rural roads with lots of curves, switchbacks and grades. The route is a spirited drivers delight and the change of topography and scenery is impressive. I normally try do do this run for the fun of it at least once a year but this time did it twice back to back. I drove about 40% of the distance and let my passengers drive the other 60% since they had never driven a Corvette and were anxious to try it out. The first run with my cousin netted 26 MPG and the second run with my son in-law netted 24. I attributed the difference to driving style since my cousins driving was smoother choosing to coast approaching a curve when my son in-law approached curves more aggressively having to brake to lose momentum and then having to accelerate after the curve. Both runs took about 7 hours including a stop for lunch so the pace was close as well.

I checked the EPA rating for the LS2 A6 C6 and found it was 15 City, 25 Highway and 19 Combined so it looks like we were right in the ballpark with the fuel consumption with the second run using nearly a gallon more fuel.

 

Any time I look at my AVG MPG (which I don't think has been reset in the last ten thousand miles) it says anywhere from 22-23 mpg.

This is on a LS3 in an '05.

 

My 05 C6 Z51 M6 has a more aggressive gearing than stock m6 which puts me around 1900 rpm for 75mph. I think the base gearing lets it do 1600rpm for 75mph.

When doing that speed, I am able to get around 29-31mpg avg where 31 is more likely on flatter roads and 29 when there are a bit of hills in the mix.

 

2000 rpm in the Z06 will get you a speeding ticket for sure. 1500-1600 is 70-75 mph, so 2000 will be 90+.

 

• RPM's MPG's & MPH are all closely related measures. And you are correct that at 70 mph you are below a 2000 rpm threshold. That's my concern. As a first time owner, I have been concerned about keeping the rpm's at or near 2000 for the optimal treatment of the engine, not so much concerned about mph. If you are really going to enjoy this vehicle then you need to feed it the fuel required. You could feed it lower octane fuel to save money but performance will suffer. Maybe that's a topic for another discussion. My concern here is with an emphasis on rpms.

 

What does that mean? How much fuel does it "require"? Have you never driven a stick before?

 

Same here on my 05, LS2, 6 spd manual,3.42 rear gear. Yours is an LS2 also unless it had an engine swap.

 

Yes, new engine.

 

LOL....This isn't really rocket science. It's been the same since the internal combustion engine was integrated into the automobile. Sure the C-6 gets fairly good mileage....IF YOU KEEP YOUR STINKUN FOOT OUT OF IT.....

 

 

Trust me...when you quit feeding it the fuel required it will quit.

 

Youre correct its not good for it at all, thrust bearings especially. Some think they are "saving" it whatever that means. Not.

 

The LS engines are happy to cruise at 900 rpm all day long. They are tremendously lazy like that. In a good way. Feel free to leave it at 900rpm.

 

Meaning simply this... If I was concerned only with MPG and drove accordingly I would have a very light foot always being concerned about the amount of fuel I was consuming. There is more to enjoy with this car in that to obtain its designed performance you are going to have to use an amount of fuel that it requires. Yes, I have driven sticks for about 60 years. So what is your point?

 

" . . . an amount of fuel that it requires." -- it doesn't even make sense. Yes if you want to go fast, you have to put your foot down farther, and it will consume more gas. Pretty basic.

What is it you don't understand?