What mileage do you get from your 32v 928's?
#2
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Automatic here:
16 mpg around town or short distances
22-23 mpg when traveling with mainly rapid freeway driving
I don't think there is a significant difference to my previous GT - particularly not on the freeway.
16 mpg around town or short distances
22-23 mpg when traveling with mainly rapid freeway driving
I don't think there is a significant difference to my previous GT - particularly not on the freeway.
#3
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Mine is an automatic and exactly mirror's Nicole's experience. 16 in town and 20 - 22 on the highway if I stay below 100 mph and drive it like is about to break. If I drive the way it is intended to be driven on the open road, I get about 18 to 19. And if I get anywhere near the desert, I can almost watch the guage drop........as my face cracks from the grin.
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5 speed here:
17-19 around town. I haven't had a road trip in a while and didn't log mileage when I did, but I'm sure it's in the low 20s.
My new fuel chips are supposed to be more fuel efficient, but I have to say my mileage will suffer if I don't stop winding it up in 2nd and 3rd before shifting.
17-19 around town. I haven't had a road trip in a while and didn't log mileage when I did, but I'm sure it's in the low 20s.
My new fuel chips are supposed to be more fuel efficient, but I have to say my mileage will suffer if I don't stop winding it up in 2nd and 3rd before shifting.
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#6
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I think it more depends on your final gearing. With my 2.20 I get 19 to 20 around town and 25 if I keep cruising at 70.
23mpg at 90mph. Errr estimated. Yeah that's it.
23mpg at 90mph. Errr estimated. Yeah that's it.
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I got 25 on the highway to SITM, going 75 mph with the 2.20
I wonder how good it would be if the "batch firing" was changed to individual injectors firing when needed...
I wonder how good it would be if the "batch firing" was changed to individual injectors firing when needed...
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#8
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You wouldnt see much of a difference with sequential.
But if you lean it way out, you can get very impressive numbers.![Stick Out Tongue](https://rennlist.com/forums/images/smilies/tongue.gif)
When I had the setup on my 86 engine with the 2.20 and a 27.1" rear tire I was able to get over 30mpg. Every stop we made with the rest of the group I was always a few GALLONS less in fuel to top up. And we were not going slow either.
But at cruise, I was able to run 17.5-18:1 AFR with no real load on the engine. Having disassembled this engine there is no sign of any detonation or preign. Not in the bearings, rings, pistons, heads, etc.
But if you lean it way out, you can get very impressive numbers.
![Stick Out Tongue](https://rennlist.com/forums/images/smilies/tongue.gif)
When I had the setup on my 86 engine with the 2.20 and a 27.1" rear tire I was able to get over 30mpg. Every stop we made with the rest of the group I was always a few GALLONS less in fuel to top up. And we were not going slow either.
But at cruise, I was able to run 17.5-18:1 AFR with no real load on the engine. Having disassembled this engine there is no sign of any detonation or preign. Not in the bearings, rings, pistons, heads, etc.
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Very interesting...I have also a Alfa Romeo Brera 3.2 (260 bhp) that gets 11-12 mpg around town with ease. Unlike italian performance cars , Porsche makes performance cars with decent consumption.
#10
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Just another example of how these cars were ahead of their time.
#11
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My mileage is consisten with others-- 17 in combo driving, 20 on the highway. In sustained highway cruise mode, with a gentle foot, I can sometimes squeek 22. This is auto with 2.54 fdr. This is also with Cali gas. Real fuel inproves those numbers by about 8%. I can map the mileage differences between seasonal fuel blend changes here.
Colin, With modern ignition it's possible to run those lean A/F's in low load/steady state operation. You really need to have a drive-by-wire option on the throttle to make all the tailpipe numbers work with that though. On pedal depress or any anticipated or measured load increase, the mixture needs to go closer to ideal -before- the load is actually added. That would do a lot for detonation/pinging, but more importantly it would eliminate the heavy puff of NOx at the same time. This method is what allows decent mileage from the bigger BMW V8's, for instance. The lack of instant throttle response on those cars, at least the early ones, is a fringe benefit of the technology. The newer models, along with those from other mfrs, are a whole lot better than the early ones. I credit a lot of the improvement to faster computers that aren't saddled with Vista...
Colin, With modern ignition it's possible to run those lean A/F's in low load/steady state operation. You really need to have a drive-by-wire option on the throttle to make all the tailpipe numbers work with that though. On pedal depress or any anticipated or measured load increase, the mixture needs to go closer to ideal -before- the load is actually added. That would do a lot for detonation/pinging, but more importantly it would eliminate the heavy puff of NOx at the same time. This method is what allows decent mileage from the bigger BMW V8's, for instance. The lack of instant throttle response on those cars, at least the early ones, is a fringe benefit of the technology. The newer models, along with those from other mfrs, are a whole lot better than the early ones. I credit a lot of the improvement to faster computers that aren't saddled with Vista...
#14
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Dr Bob,
Yes I do agree, and this was with standalone EFI, with EDIS-8. And yes I was richening it very quickly with TPS/MAP blending and from datalogs I was able to completely remove any leaness from when I first stepped on the pedal.
And I hear the comment about Vista it is a pig. And I just love how it randomly put itself into spanish keyboard mode.![banghead](https://rennlist.com/forums/graemlins/banghead.gif)
edit:
Forgot to add, I am not really worried about what comes out of my tailpipe on that car, I had two maps, one for emissions, one for driving.
Yes I do agree, and this was with standalone EFI, with EDIS-8. And yes I was richening it very quickly with TPS/MAP blending and from datalogs I was able to completely remove any leaness from when I first stepped on the pedal.
And I hear the comment about Vista it is a pig. And I just love how it randomly put itself into spanish keyboard mode.
![banghead](https://rennlist.com/forums/graemlins/banghead.gif)
edit:
Forgot to add, I am not really worried about what comes out of my tailpipe on that car, I had two maps, one for emissions, one for driving.
Last edited by Lizard928; 07-10-2009 at 12:41 PM.