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Rpm's at 70 mph?

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skidog

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How many rpm's should I be turning at 70 mph with a 1979 Midget? I am turning about 4300 that sounds high to me. What kind of mileage can I expect from the car? I am driving from Michigan to the MG rally in Tennessee in June and am preparing the car, trying to optimize fuel mileage and go over the car so we make it without incident (and back). I am looking forward to driving the tail of the dragon.

Thanks,
Mike
 
That sounds about right, but it depends on the rear end ratio and size tire. When going on long trips I always carry two spare gallons in the trunk in case I can't make the next filling station. I've only had to use it once.

I'll be heading down there too. See ya there!
 
Mine shows about the same at that speed. I have heard a broad range of MPGs for the car, but I would guess you should be getting in the mid 20s at least.
 
yea, that's right. With my tires it's more like 5000RPM /ubbthreads/images/graemlins/laugh.gif

I'd keep it at 65 for long stretches. Mine really feels like I'm flogging it if I go the speed limit on the interstate (75MPH)
 
The '79 should have a 3.7 rear gear in it. 4300 @70MPH sounds like a 4.22. I only turn about 4000 with a 3.9 at 70.
I would expect a 3.7 to be running about 3800 at that speed.
I'm running 175 70 13 tires.
Jeff
 
Based on the above chart, you may have a 3.9 rearend.
 
Thanks for the info! It will be nice to have when I take it on it's first drive. I wish my car would be ready for the June Rally but I'm finding it was easier taking the car apart than reassembling it.
 
I thought my 1978 was getting about 30 highway and 50 city. This one seems to get about mid 20s highway and 30 in the city. But then again the gas guages read way differently. One was empty as soon as it hit the red area and the car I have now was deep in the red and still had a couple of gallons in it. One of these days I will run it empty to find out where empty is.

Mike
 
I just ran the car with my GPS and it seems the speedo is off so I am actually running about 4000 rpms at 70 mph. not 4300. The speedo is off by about 5 mph.
 
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