StoogeMoe

What kind of MPG can I expect to get running on the track? Has anybody measured what they get?

Lemming

I get around 8 mpg in Franky.

ausgeflippt951

Man you've got your priorities twisted if you're worried at all about what mileage to expect at the track! ...unless of course you're running an enduro or are wanting to know how much to fill the tank for the event...

However, you should expect to get: bad mileage, regardless of what it is...

Lemming

Not if you drive slow

Scootin159

I've always been curious of this as well. I know for auto-x use if I have 1/8th a tank, it's enough to run the event, but how much do I need for 30 min. of DE time? I know for myself it's been much better for right turns than left turns, as my fuel cap has had some issues

M758

I consume about 5 gallons every 40 mintues in my 944 spec car. I also ran a 90 minutes on less than a full tank. I figure I had at least 20 more minutes in the tank.

So to come up with some numbers. I ran 69 laps at 1.6 mile each. Race approximatly 110 miles. I figure I had another 20 minutes left in the tank. So figure another 15 laps so 24 more miles. That comes to 134 miles on a 17.4 gallon tank. That comes to about 7.7 MPG. This is at Firebird Main which has a 5/8 mile drag strip as part of the track and is probably full throttle for 75-80% of the lap.

Back in the days of DE I would fill my 951's tank to the top and drive all day. If I ran out of gas it was time to go home.

Van

I used to get about 13 in a NA at DEs.

Now I get 7 (or maybe a little less) in a turbo (DEs and racing).

shiners780

I figured my mileage just for kicks once, and it was between 5 and 6 mpg.

StoogeMoe

Wow, these MPGs are pathetic! I was expecting around 15-20 mpg. These are thirsty little buggers.

Obviously I'm trying to run as light as possible without running out of fuel. Does the lighter weight affect the balance of the car? Or is it too insignificant to affect these relatively heavy cars?

schwank

If I fill the tank I can get an entire day with 6 20 minute sessions and then still have about 3/8 tank or so left on the way home. If you trust the gas guage....

Oddjob

7-8 with a 944S
5-6 with a Turbo

Gas weighs nearly 7 lbs a gallon, so there can be a subtle difference in feel between an empty and full tank of gas on the track - with acceleration, cornering, and braking. Also, you generally do not want to run below a 1/4 of gas, especially on clock-wise tracks. The gas pickup is on the right side of the car, mostly right turns causes the fuel to flow to the left side, and the pump will suck air - can cause the engine to miss.

Scootin159

Full tank = 17 gallons
17 gallons * 6lbs/gallon = 102lbs
Weight of car (dry) = 3000lbs / 2 axles = 1500lbs/axle = 50/50 ratio
Weight of car (full) = 3102lbs or 1500lbs front axle, 1602lbs rear = 48 / 52 ratio

M758

I can certainly feel a big difference between empty and a full tank. My car is set-up for running in 1/3 tank or less. The car is not so much slower on full tank, but the balance is not as good and I cannot drive it at the very limit like I can with less fuel. I can't reall tell the differnece between light on and thank empty and 1/3 tank. For qualfying I try run less than 1/4 tank just to reduce my overall weight.

If the car has a stock suspension you will notice the weight of fuel or not. Fuel fuel lowers the rear end and creates understeer. Very little fuel raises the rear and creates oversteer. When I autocrossed my stock 83 on street tires I could tell the difference in balance. I once was light on fuel and had ovesteer. So I adde in 5 gallons of gas and went faster since I created more understeer and thus balanced the car better.

M758

I have never had a problem running low on fuel. The only time it was an issue was in a 2 hr enduro. I wanted to keep the car light and added 3 gallons at my required pit stop instead of 5. I ran something like 10-15 mintues with my reserve like first flickering and then being on solid all the time. I still had 5 minutes left so I kept going. I got a stumble in right hand corner and was able to coast out. Car got fuel again an I kept going. I figured I could squeeze out a couple laps and finish. Well I make 1 more full lap and 1 partial lap before the tank was dry. Not fuel at all even on level ground. Those laps were 1.5 mile laps so I was picking up fuel to the very end with very little needed in the tank to keep the pick up covered even in heavy cornering. Once the pick-up got exposes in cornering I think I probably had a quart of fuel left in the tank.

Oddjob

You must not have enough consecutive high speed right hand sweepers or carousels at the tracks you run, to cause this problem.

I have had various 944s miss (so I know its not just one particular car's pickup problem) at Brainerd and Road America. Brainerd has three consecutive right turns, first two are at or above 120mph, the third is a tight 50-60mph corner - car will usually miss apexing at the third turn. Gas low level warning light will flicker, gage shows empty. By the time you pull off the track, gage indicates nearly a 1/4 tank full (after the gas has flowed back through the baffles to the pickup.

Also possible that the early cars have different baffling in the gas tanks, than the later cars. Not positive, but I thought the factory changed the gas tanks at some point during production.