What mileage do you get? Wondering about my car!
10-15-2017, 11:50 AM
#1
What mileage do you get? Wondering about my car! I have a '70 Chevy Impala, I have installed a 6.0L LQ9, all stock except for a Magnacharger blower, and a 4L80 trans. Rear is factory stock 2.73 ratio. Computer was re-programmed by Speartech, then tuned by a pro shop in Canada, car is lively and pleasant.
I am kind of wondering about the mileage I get, I use my car mostly for drives in the countryside, I lay a little rubber once in a while but not often and not much (tires are expensive!).
I am now in France, so the roads are not like in the US, here the roads are very twisty, narrow with plenty of villages (with plenty of speed bumps...), so there is no smooth cruising for hours!
My last 2 fills, I got 9 mpg (good roads, around 50 mph, drove through 1 town) and 6 mpg (smaller roads): what do you guys think? It is about right or do I have a problem? Yes, it is a heavy car and I need to accelerate a bit after each curve to stay with traffic, but...
What numbers do you get?
I am kind of wondering about the mileage I get, I use my car mostly for drives in the countryside, I lay a little rubber once in a while but not often and not much (tires are expensive!).
I am now in France, so the roads are not like in the US, here the roads are very twisty, narrow with plenty of villages (with plenty of speed bumps...), so there is no smooth cruising for hours!
My last 2 fills, I got 9 mpg (good roads, around 50 mph, drove through 1 town) and 6 mpg (smaller roads): what do you guys think? It is about right or do I have a problem? Yes, it is a heavy car and I need to accelerate a bit after each curve to stay with traffic, but...
What numbers do you get?
10-15-2017, 01:35 PM
#2
TECH Regular
Yea that’s pretty bad. I have an e36 bmw with an lq4/4l60e 3.91 gears and get about 16-18 mpg avg. but no Maggie on mine. Are you always in boost? Bypass valve stuck shut?
10-15-2017, 05:17 PM
#3
Teching In
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In all honesty I think you need more gear. With the 4l80 there's really no reason to only have 2.73's, so it having to lug against the gearing to get back up to speed after the corners really isn't going to help you any. And I have a 1950' Ford F-1 with a 5.3/4l60e and 3.73's and get 16-18 mpg average.
10-15-2017, 07:35 PM
#4
Car in sig; 3000 lbs, 3.55 gears w/.625 5th, stock LS3. 18-20 around town (7 tanks in a row); 25-27 on the highway.
Biggest variable by far is driver and conditions. If you're running it hard AND have a lot of stop and go I could see 6-10 in that blown, heavy beast with such a long rear gear. But I can't see any reason that thing shouldn't get at least 20 (easy) on the highway at legal speeds.
Biggest variable by far is driver and conditions. If you're running it hard AND have a lot of stop and go I could see 6-10 in that blown, heavy beast with such a long rear gear. But I can't see any reason that thing shouldn't get at least 20 (easy) on the highway at legal speeds.
10-15-2017, 08:12 PM
#5
66 Impala convert.....LS2/Edelbrock supercharger.....4L65E......3.55 rear........Just drove 2,880 miles on the Good-Guys road tour.........23.7 MPG for the Tour
Ken
Ken
10-16-2017, 04:25 AM
#6
Thanks for the input, it all gives me hope it can get better!
I will have to take a look at the bypass valve, on the Magnacharger, it came set-up from the factory, they say... Anything special to check it?
I also know that the rear end is too long, that is the one that came with the car and could never afford to change the gears since I did the engine swap... The engine is indeed lugging a lot, most of the time and it does not even feel very pleasant! Well, at legal speed, at least!
I will have to take a look at the bypass valve, on the Magnacharger, it came set-up from the factory, they say... Anything special to check it?
I also know that the rear end is too long, that is the one that came with the car and could never afford to change the gears since I did the engine swap... The engine is indeed lugging a lot, most of the time and it does not even feel very pleasant! Well, at legal speed, at least!
