Fuel ?

[bones]

That's very interesting Mark. The difference I have noticed in using Optimax in my relatively low compression 78 SC engine - 8.5:1 - is simply that it feels smoother and more responsive.

 

[ClubSport 911]

The best bit of posting on fuel, I have seen on this site. Great - thanks. I'm on optimax, and have a re-mapped ECU to take advantage of it. I still have some work to do to reach the limit on ignition timing.

Great fuel - great for the chancellor

Steve

 

[Guest]

Guys,
The oil company's must be laughing all the way to the bank --" Oh, look, here comes another Porsche owner who believes his car needs Our special fuel"!!
Its common knowledge that when Porsche design their cars, they make them for the world market. To do this they (Porsche ) need to ensure the car works best in all countries, so the timing and DME map is set to run on the "Best" fuel standard.
As has been said all before on previous threads, you can get the porka to run on standard by dropping the timing back to '0' degrees on the crank.( standard setting is '3' degrees ATDC) Do this via the DME switch at the rear of the DME under your passenger seat. Why else do you think Bosch made the DME with a selector switch?
My car runs on standard ( the poor person fuel) unleaded, has done for nearly 2 years, & produces 232bhp at the rear wheels (actual). I see no need to use anything else, and wonder why does anybody else?[]

 

[zwhitea]

Peter, I'm interested in what you say about altering the DME.. Which setting do you run your car at...

Switch Position Fuel Correction Ignition Correction
0 (stock)..................0.........................0

1...........................+3.1%...................0

2...........................+6.3%...................0

3...........................-3.9%....................0

4.............................0......................-2.79° (Stock for UK Market Option Code M 240)

5..........................+3.1%.................-2.79°

6..........................+6.3%.................-2.79°

7..........................-3.9%..................-2.79°

(Table from Steve Wongs Site.. http://www.911chips.com/fuelsys.html )

I'm temped to run our coupe at position 7 or 3 to see what happens as it is running rich and no one can find out why.. even after a £4k engine rebuild.. and compared to our Cab idles very uneven.. feels faster though..[]

 

[Guest]

ORIGINAL: peter915

Guys,
The oil company's must be laughing all the way to the bank --" Oh, look, here comes another Porsche owner who believes his car needs Our special fuel"!!
Its common knowledge that when Porsche design their cars, they make them for the world market. To do this they (Porsche ) need to ensure the car works best in all countries, so the timing and DME map is set to run on the "Best" fuel standard.
As has been said all before on previous threads, you can get the porka to run on standard by dropping the timing back to '0' degrees on the crank.( standard setting is '3' degrees ATDC) Do this via the DME switch at the rear of the DME under your passenger seat. Why else do you think Bosch made the DME with a selector switch?
My car runs on standard ( the poor person fuel) unleaded, has done for nearly 2 years, & produces 232bhp at the rear wheels (actual). I see no need to use anything else, and wonder why does anybody else?[]

You missed the point in one of my earlier posts - you are kidding yourself if you think you are actually saving that much money by using the "poor person fuel". Work it out, do the math, your savings over the course of a year are f*ck all compared to the cost of running and maintaining one of these cars properly. I just don't see the point in being tight over this one.

Also, if you run a chip and have the fuel quality setting correctly adjusted, the extra octane is in fact quite a useful (if not essential) safety measure.

BTW, how are you getting 232 rwhp from your 3.2? That's 250-260hp at the crank. I am puzzled.

Richard

 

[thboxster]

For my own peace of mind, i've just done the maths. (Oh has life really got to that stage)

Based on 12k p/a and the average fuel consumptoin based on 95Ron agains Optimax. (Note that this is averages and not absolutes and is based on a static fuel price), the results were:

1 years worth of 95Ron used, cost = £1409.71
1 years worth of Optimax used, cost = £1403.77

So, as I said previously, go for the one with the best promotions!

 

[944Turbo]

Yes I was going to add if you optimise the ignition timing for the higher octane you will get better economy as well as more power, provided you do not use all the performance all the time, which is difficult outside of a race track.
Tony

 

[ClubSport 911]

That's 250-260hp at the crank. I am puzzled

Me too.

Unless of course, you have the new "infinite probability drive" gearbox fitted - zero losses etc...[]

 

[Guest]

Ok, I stand corrected;
The actual reading at the wheels was 206.3bhp.
Crank was 230.8bhp ( I was quoting from memory - not like it use to be?)
Max torque was 215.1 lb. ft.
That makes sense as around 22 -24 ponies are lost in the "box".
To answer Zwhitea's question, my timing was on setting '1' at 3.1%, adjusted back to 0 setting = 0 degrees on the crank.
Motor is equiped with headers and full flow muffler. (as Richard has said before -- "Its a Billy Boat exhaust -- " yeah I know - they did have problems... but you can't beat the Tri-flow manifold![:-][:-][:-] So there![:-]
It just puzzles me why or how these people are determine to mess with something that is, and always will be one of the best engineered motors ever produced?