: Northstar fuel economy?



Buzz3
09-06-04, 03:03 PM
Sorry for the intrusion, but I have the GXP Bonneville with the 4.6 Northstar in it. We are averaging 15 MPG with it. It has 6000 miles on it so far. I was told that the Northstar engines are tight and need breaking in so I figured I'd come on over to ask the people that have them. Are any of you have fuel economy issues? Thank you for your time.

etcCanuck
09-06-04, 05:36 PM
I have a 1997 Eldorado ETC, I get 13 mpg in the city (I have a lead foot) and 25 mpg on the highway (still with a lead foot) Problem with using the fuel economy computer in your dash is that it factors ALL your driving, including when sitting in traffic at idle. Normal equations dont factor that stuff in.

1500cc
09-06-04, 05:37 PM
There's not too many Northstars hiding under the hoods of CTSs ;)

Might want to check out the Seville/STS forum.

majax
09-06-04, 05:58 PM
My Northstar 300 gets 19mpg on average. You have the 275 so you should definatley get 19 avg I bet. Give it a little time I guess, that engine is rated at 18/27.

Buzz3
09-06-04, 06:32 PM
Wow... I guess I am not reading enough. The CTS doesn't use the Northstar? My bad. Thx for the input guys.

BeelzeBob
09-08-04, 12:20 PM
Sorry for the intrusion, but I have the GXP Bonneville with the 4.6 Northstar in it. We are averaging 15 MPG with it. It has 6000 miles on it so far. I was told that the Northstar engines are tight and need breaking in so I figured I'd come on over to ask the people that have them. Are any of you have fuel economy issues? Thank you for your time.


Understand that you are never going to get "great" economy with the GXP....it has big brakes (more drag) big tires (more rolling resistance) and the 3.73:1 final drive (more engine RPM under all driving conditions). Plus....it hauls ass and the temptation to put your foot into it all the time is great. Accelerating a relatively heavy car fast takes a lot of gas....but it is fun to drive.

The fuel economy rating per the EPA is carried over from the Cadillacs with the LD8 engine and the 3.14 final drive and lower rolling resistance tires, etc....so it is a bit high for an estimate of the GXP package.

I drove a GXP for several months and averaged about 15-16 in urban driving and usually about 20-21 on the highway with lots of WOT accels in between...just merging of course.

Otherwise, how do you like the car??

UK-STS
09-09-04, 02:28 PM
Best I've had is 18.2 on a long (240 miles) motorway (freeway) trip.
Worst is 11.2

The STS is by far the least fuel efficiant car I have ever owned. I have had a Lincoln Towncar, fourth gen Camaro Z28, third gen Camaro convertible, third gen Firebird V6 and an 81 Mustang 2.

In the UK petrol prices are about $8 per gallon in US money.

Hardly a suprise there are so few STS's in the UK.

Regards

STS-UK

Spyder
09-09-04, 03:04 PM
My 94 STS is quite possibly the most fuel efficient car I've ever owned...right at 21 on the highway, 14 or so around town... hmmmm, '63 T-Bird (406 and 2 four barrels), '63 Merc Monterey (390 4 bbl), '66 Lincoln (462 4bbl), 2 '60 Dodge D-100's -- both getting around 8 mpg, '68 Plymouth Sport Fury (383 HP) among others. The Lincoln got 6 mpg whether I was running at 70 down the freeway or driving in heavy San Fransisco traffic, helluva car though! But then again, I was only paying a buck nineteen a gallon for that car, and I was a high school senior and had nothing to spend my hard earned Thunderhill Park flagman money on but gas. :) I don't think I'd have stuck with ANY of those cars, even at the prices I'm paying for fuel now! Sorry, just reminiscing about the good old days...