S70 fuel economy or lack of it...

[kcodyjr]

jblackburn, have you been watching for changes in mileage since you switched to 89?

Not that I'd ever challenge what a moderator says. I've read in other threads that a turbo will behave correctly on the 89, but you might just get a couple miles per gallon less due to the ECU adjusting timing to prevent knock.

If you've got numbers saying the situation is better than that, I'm gonna stop buying 91 for my GLT.

[jblackburn]

I got 30 mpg just last night doing 75-80 for 3 hours. Windows down, sunroof open.

I don't mind being challenged; feel free to correct me if I'm wrong. I just don't see the point in running 93 in mine if it's not summer. I DO notice a difference between 89 and 93 during the summer when I'm running the AC and it's 100 degrees out; then, the octane makes a difference. But the rest of the year, I don't notice any difference unless someone puts 87 in it.

Experiment around; different cars behave differently. One tank of different grade gas isn't going to kill it; your car's computer will correct for it, and detonation probably won't happen as easily on one of the 2.4T engines at the 2.3 at heavy throttle when the compression numbers are bumped up like crazy.

[kcodyjr]

As OP is a good long way south from either of us, outside temperature might be an issue. Either way, for diagnostic purposes, I'd go strictly by the book, that way you know for sure it isn't the problem.

I'll have to give it a try while it's still cool, then. I've been running 91 octane year round, and the only thing I've felt weird from the go-pedal is the intermittent sticky waste gate solenoid.

As to the 2.4T being less sensitive, I dunno... knock is also a function of load, and the 2.4T sees a hellish lot of that coming off the line, especially when the guy next to me is in a Civic with a 1.8L four-banger engine and a 4" exhaust, and their hatchback jumping an inch off its seals from all the subwoofers he's got where the back seats are supposed to be.

Boom ba-ba-Boom-ba-ba (STOMP!). They're in my rear view just long enough to see their jaw drop.

[elchopperfreak]

Kcody
Thanks for the help, I dont mind the drilling at all, help is what I asked for.
I will check the alignment, but wanted to do so when I checked the joints, etc.
Will see with high octane fuel if theres a big difference in numbers..and thanks for the advice, not that I mind driving the car hard. I have an 850 and thought the s70 turbo would be better in gas mileage.

Jblackburn, this is full on ac year round..a friend who runs a fuel tanker gave some additive, ill have to look for it.
Ill have to check, I read about the oxygen sensor, the car has right under 50k miles, but it was parked for some time, I am also planning on changing the timing belt and adding a k&n filter.

One more question, is the t5 turbocharger the same as the regular s70 turbo?

Again, thanks for the help

[jblackburn]

Theoretically, with the addition of variable valve timing on the 1999, the mileage should be a little bit better than a similar 1998 T5 or 850 Turbo. BUT you've also got the equation of the electronic throttle thrown into the mix, which tends to apply a bit more throttle than you would normally with a mechanical throttle car like your 850 with very little pressure on the pedal.

The "T5" is essentially the renamed "Turbo" model - they did away with the turbo badge in the 1997 model year of the 850. The S70's also came in a light-pressure turbo model known as the GLT.

I'd say get everything you can fixed up first - do the timing belt, change the air filter, etc. Probably with AC running, your fuel mileage is about right for stop and go driving - it generally knocks 3 mpg off of what I get. If you still feel that it's a bit low, then the O2 sensor might be next on your list.

[elchopperfreak]

Sadly, we use to have super cheap gas, the only places I could get cheaper gas was Kentucky, some places in TN and up in Iowa. Our fuel never went over a dollar a gallon (25 cents a liter, or maybe, when high, 35 cents a liter) i remember not too long ago filling up my dually in Kentucky at 99 cents a gallon, the most expensive from Jacksonville to Sturgis Sd, was actually Rapid City at $1.65 a gal.
So it was not a big deal.. now it is..

The thing is, my chevy trailblazer does about the same avg fuel, and its a 4.2, thats why it sounded like the t5 is burning way too much..

[kcodyjr]

It's also possible your AC system is malfunctioning, and eating up way more than 3mpg. Is it at all noisy?

Try driving awhile with the AC off and see what happens. Do you have the trip computer installed?

[elchopperfreak]

I ask about the turbo ( by the way, the 850 is non turbo) is because I had to change it, the turbo misteriously died, but I do not remember if the one I got was from a t5 or just a glt, ( asking just in case) but if everyone witht this same car is getting similar mileage then is a no biggie, it is what it is, will try it on the highways soon, with 91 octane ( wish me luck) and see if theres changes, although it might give a couple more miles with me being lighter on the pocket.. ( some places here are $1.05 a liter for premium already!!!!) its insane.. And to think, we can drop a pipe to Venezuela and get fuel for 25 cents a gallon....


the ac is not making any more noise than normal,(at full blast)
You mean the computer in dash that gives all the data, or something else.. BTW theres no check engine lights, only the SRS light sometimes..

[kcodyjr]

Full blast or not shouldn't matter, I mean any noises coming from under the hood.

Yes, the computer in the dash with the"INFO" rotary switch. It'll tell you instantaneous miles per gallon, more or less, which should give you an immediate idea if your AC is eating fuel.

As for the turbo, if it was out of a GLT you'd know it: all your torque would be at the bottom end, and it would run out of oomph around 4500RPM. I'm not sure if there was more than one larger turbo that year between the T5 and the R.

[elchopperfreak]

Yeah, ill check into it, i mostly leave it in miles per tank so my wife kinda knows.. Funky though, when I switch it to actual consumption, it can be weird, but ill try it out in a long road at constant speed..
Another thing, the low fuel light turns on when the computer shows 50 miles left for the tank????