Excessive Track fuel consumption?
 

So i did my first track day last weekend on my turbo Miata and the fuel consumption on track is kind of high.

I went through a full tank of gas the first half of day, drove to gas station during lunch and second half of day drove 30 miles on track, burning 5.5 gallons of fuel. that is 5.45 mpg.

Does this sound excessive for a turbo miata?

my AFR is kinda rich but nothing super rich, low 11's mostly under boost of around 10psi.

what kind of mpg are you guys getting on the track?

in not complaining, its just a pain to have to fill up twice in one track day just to make it through the whole day.

Cruising down the highway uses only(for example) 20hp. At the track youre using all 200 the whole time.

Ten times the output requires ten times the input.

Dann

How much do you idle the car in the paddock for cooldown purposes? That can consume a surprising amount, especially if you wander off to chat with someone and forget to shut it down.

I see around 5-6 mpg on the track, usually with my boost set for about 300 at the wheels.

--Ian

A little low, but not way off. Rover burns about 10 gallons an hour on track, which can be anywhere from 75 to 100 miles depending on the speed of the track. Tuned for 11.6-11.8:1 at full load. Low 11s would increase consumption by another 10%, which puts you pretty close to your figures.

Try a 350whp E85 car sometime. 6 gallons every 20 minutes. :party:

my bone stock na6 got like ~11 MPG at the track IIRC
my Cadillac got 4 MPG bone stock.. modified with E85 was damn near gallons per mile..

You're results don't seem out of the ordinary...

8 mpg @200 whp./// or about 1hr running down to fumes. //// 11.5 gallons per hour. Track dependent, this is worst case scenario at Mosport GP track, running 1:35's. @ 93 mph avg. speed.

Hmm my Boxster with 315 hp does 8-9 mpg.
Miata with 260 whp also does about 8 mpg.

I got between 8-10mpg on track between 160-220whp.

Thanks for the replies, i feel better now that im in the ballpark on fuel consumption.

This little car gets the same mpg on the street as my minivan! ~22mpg

Spend some time with your tune. your street mpg is pretty off.

my 220hp 1.6T was getting mid 30's. but down to ~10mpg or so when really beat on it. ~15-16:1 afr low load cruise quickly building to 13:1 slightly loaded (building boost in the 2-4psi range) and 11.8-12 : 1 WOT.

Yeah, I get about 8 mpg at Laguna seca, it's been in that ballpark everywhere I've run it. 230 whp.

my cruise AFR automatically settles at 14.7 as MS3 controls that. light load is around 13. low boost is 12 and WOT is 11-11.3 or so, so a bit rich, but nothing crazy rich.

I do about 230 miles on a tank, usually fill up 10 gallons.

I drive like a normal person on the street, a few boost accelerations, but no full WOT/Redline pulls. then cruise normally most of the time....

I have never ever seen more than 25mpg out of this car. ever.

My Non turbo 99 was getting around 24-25mpg and when i turboed, it dropped to about the same 22-23mpg. so i have no idea how people are getting 30+ mpg?!? This is my 6th Miata, 3rd turbo and i have NEVER gotten 30mpg on a tank of gas. and i am in flat florida, and rarely in traffic, and drive under 80mpg on hwy.

Street mpg is all about your right foot.

--Ian

You can set your cruise AFR to whatever you want with MS3.

Last time I calculated it I got like ~16-17 mpg on E85. I also didn't put a ton of effort into trying to maximize that.

https://cimg1.ibsrv.net/gimg/www.mia...6e2489f317.png

Heck, my supercharged 1.6 (worst of everything) gets 26-27 for my day to day driving and 30 on long highway trips. And this is with a piss poor street tune by someone who is still learning (me).

@borka, you have 640cc injectors.
Assuming you run them at 80% under full load, that is just a tick over 2 liters of fuel used in a minute.

With a 3 minute lap, it's entirely feasible to use up a gallon of fuel (3.78 liters) per lap, figuring in gear change lift, decel and braking.
Or, independent of track length, the same can be said for each 3 minutes of race driving with your injectors.

Please correct me if I'm wrong guys.

All else being equal, sure. But with a not-great tune, or a tune that's not optimized for low-load cruising, not quite. On our trip to Laguna two years ago Aidan got mid-30's and I got mid 20's, and only one of us did several burnouts on the drive (it wasn't me).

I do like burnouts

Well, obviously it depends on the course and car, but your average turbo Miata isn't going to see WOT for anything close to 100% of a lap. Maybe 35%.

--Ian