tammons

I am new to the 951 so excuse the ignorance please.

First off I drive like a maniac, and I am getting 10 miles to the gallon in the city.

Is this normal ??

When I blast down the on ramp getting on the interstate and see some black smoke out the back so I know its rich at full boost.

My car also starts rough then smooths out, and has a tendecy to break up at full boost over 4000 rpm. 2000 miles on wires, cap and rotor, and plugs. At first I thought this might be lack of fuel, now I am thinking its too rich.

I dont know what has been done to it as far as chips, injectors, etc, but it is a real rocket. I was keeping up with a ferrarri today and he did not look too happy. I gave him a thumbs up. Beautiful car though.

Also my AC is blowing the fuse. Is this a common problem related to something stupid, or could it just be the compressor clutch pulling to many amps. It blew the recommended 7.5 fuse and then a bigger 10 amp fuse.

bearone

if you have your foot in it all the time mileage will suffer.

if you wanted good mileage many non p-cars come to mind.

sounds rich.

don't put a higher rated fuse than it calls for. the fuse is a protection device.

have you checked hi/low pressures?
if freon/134 is low the low pressure switch keeps the system from working.

the compressor could be dying and seizing up.

Rob951

Yeah, when on boost you'll be able to pass everything but the gas station. And seeing as our cars don't drink water, it's premium only, which means uber $$$. Don't drive on boost all the time and you'll notice better mpg. But then, really, what fun is that??

bearone

i ran 87 in my dead "s" with 10.9 compression and it ran/started fine.

premium only, do you work for an oil compoany?

tammons

#1

If the compressor freezes that will not cause a fuse to blow. It might burn up a belt. An overamperage condition will cause blown fuses. like a short in a winding, bad compressor clutch winding, short, etc. I was wondering about something else. Porsche electrical systems can be flaky especially 928's. Not so sure about 951's though.

I have driven a lot of cars. 4 928's 2 of the turbo cars with custom FI. 72 pantera with 11 to 1 CR and a nasty cam, carburated. Actually all of those cars got better gas milage than my 951 in the ctiy except my pantera. It got 10 mpg in the city but then it was making 450 hp. Both of my 928 turbo cars got about 12 mpg in the city.

#2

Yes, but as I mentioned above a 928 turbo that gets better gas mileage ?? And a carborated pantera that gets the same. I know factory turbo cars really dump the fuel on boost. You dont get 200+ hp for free, but I figured I should get 12-14 even driving it hard ??

#3

You can run 87 in a turbo car if it is set up right, but I doubt a factory turbo car designed for 93 octane would do to well. The knock sensor would chime in all the time. For instance I ran my 928 turbo on 87 octane for just tooling around with no problems, but I was running it at 6-7psi and I had electromotive tec III crankfire FI.

tammons

Oh, forgot to mention I had a SVO mustang too, with some custom work. Heavier car, 2.3 motor, custom turbo. but I ran that car at 16 psi and it got better milage too.

F18Rep

Hmmm, you guys must really be pushing... I drive mine over a 120 miles a day, mostly highway and maybe that explains it, but I get an honest 27mpg all the time. I couldn't ask for any better. Im not exactly dinkin along in the slow lane either. I always hear that thing about no such thing as a cheap Porsche, but mine have been great. Fast, reliable, good on gas, good parts availability, great enthusiast community, low buy-in price; Is there something better than this?...;]

Robby

Check your plugs, wires, dist cap & rotor button- mine are worn out & I've dropped from a usual 375miles/tank (17.2g before light comes on) to ~300mile/tank now.... this happens for some reason- when my Integra's plugs, wires, etc, ,were gone, the gas mileage would sudeenly take a nose dive too... btw- I got 30mpg all the way to ST Louis once- 500miles exactly- I got there in 5.5hrs too & even played w/a 2nd gen 300ZX turbo for 40miles throuhg Nashville- 70 - 140 off & on for ~20 minutes or so... My car usually doesn't get much over 22mpg though... I think something's wrong- well... a LOT of things are wrong.... I think mostly highway should be a hair over 25mpg actually.... my car needs all kinds of work though.... in any case, it DOES take gas to make power- a car t hat makes 300HP will burn about as much fuel (when USING that HP) as any other car that makes 300HP (when using it...)... your car MUST have a few probs... hopefully minor....