track mileage

[moneymanager]

Can anyone give me a guess as to racing mileage on an early 911 with a 2.7 and carbs? I'm guessing maybe 10mpg? Thanks, Jim

[Pete R]

My 2.5 liter 951 gets about 7mpg. I know that helps you in no way but I tell everyone because it shocked the hell out of me, considering it gets in the 20's not on the track.

[Todd Simpson]

I think it's going to be lower...6 or 7.

I should know better...but I've only done 2 days with my weber carbed 2.7.

My stock 3.2 was in the single digits with about the same power and much more efficient fuel delivery.

[Plavan]

Hey Jim,

I got 7.6 miles to the gallon at Willow Springs (2.5L that revs high). Pretty darn accurate since I ran out of gas on lap 38 (figuring its a 2.5 mile track)

[moneymanager]

Thanks guys. You're all a little below where I guessed I might be. Like most of you, I just put a few gallons in and run. But I thought I'd get a bit more scientific! I'm going to use 7.5 as a working number and see what happens.
Chad, what happened to you at BW? Didn't see you again after Sat AM.
More input very welcome.

[obrut]

I found working out my litre/minute rate (or gallon/minute equivalent) was more useful for track events.

ie. 8 lap race at 1m30sec/lap track = 12 litres plus a little extra for out lap and in lap.

My old carbed 2.7 used about 1 litre/minute.

[RichardNew]

Fill your tank and run for an hour. Then see how much it takes to fill up. Do the same calculations as you would too determine street milage.

Are you racing or running HPDEs?

Richard Newton

[JohnJL]

I get about 5 mpg in my carb'd 2.7

[moneymanager]

Richard - racing. Hate to race with a full tank. Lots of understeer and the car is heavy!

Looks like 5-8mpg is about right.

[JohnJL]

Originally Posted by moneymanager

Richard - racing. Hate to race with a full tank. Lots of understeer and the car is heavy!

Looks like 5-8mpg is about right.

I'm struggling with this a bit...car feels perfectly balanced on a full tank, but by the end of a session the front end is light and locks more easily.....

[moneymanager]

My experience is that these cars feel wonderfully balanced with a full tank but are slow. I'm not fighting front lock up at any point though. Maybe less grippy front pads?

[RaceProEngineer]

Originally Posted by JohnJL

I'm struggling with this a bit...car feels perfectly balanced on a full tank, but by the end of a session the front end is light and locks more easily.....

Here is one of the textbook reasons for brake bias adjustment. And, less "grippy" front pads will be a compromise with full fuel.

[RichardNew]

We have a 28 gallon cell in our Chumps car. We can run 2 hours. Well, the car can go 2 hours. The drivers get tired. What's up with that?

btw - a full tank of gas weighs roughly 170 lbs. That's a lot.

Richard Newton
Newton's Laws

[RichardNew]

We have a 28 gallon cell in our Chumps car. We can run 2 hours. Well, the car can go 2 hours. The drivers get tired. What's up with that?

btw - a full tank of gas weighs roughly 170 lbs. That's a lot.

Richard Newton
Newton's Laws

[campbellcj]

I guesstimate in the 6-7 range for my carbed 2.7 as well. I never cared to measure it precisely but I just know those jugs of expensive fuel do not last long... Soon it will be a crazier 2.8L and mileage could plunge to 5-6mpg I reckon.

[Plavan]

Originally Posted by moneymanager

Thanks guys. You're all a little below where I guessed I might be. Like most of you, I just put a few gallons in and run. But I thought I'd get a bit more scientific! I'm going to use 7.5 as a working number and see what happens.
Chad, what happened to you at BW? Didn't see you again after Sat AM.
More input very welcome.

I was just out there on Friday for the test day in our new BMW Chumpcar. The race car's paint was still drying
We have a 14 hour enduro in a couple weeks, and need to test it out on the track for the first time.
I should be at Cal Speedway at the end of June.