Normal fuel milage??

vaprobe87

Registered User
What is the normal fuel milage for 1989 SC? Mine is a 5-speed with factory 2:73 gears. Only modifications are a CAI and a intercooler fan.

I was getting around 20 MPG which I thought was not too bad for a V6 in a big car. Last week I pulled the blower to change a worn out snout coupler and noticed the EGR was loose and I had some bad vaccum lines and some were loosely connected. I mades ure the EGR was tightened down properly and put hose clamps on every hose when I put it back together and also bypassed the coolant line to the throttle body.

I just filled up and check my milage and it came out to 25.2. Im going to double check again next tank to make sure my math was right. I knew the EGR and bad vaccum lines had to have been hurting it some but didnt think I would pick up 5 MPGs from it. Anything I might be able to do to pick up a few more MPGs?

What is everyone else getting for MPGs?
 
Your one of the lucky ones I only get around 16-18 town maybe 18-20 highway but I have a bit more bolt ons without a tune
 
mileage

With a smoke check,The only vacuum leak mine has is at the bypass blade linkage and its small. And not easy to remedy. Runs idles good and I get about 18 around town 20-22 on the hwy. I have 73mm maf, cai, 75mm tb, 10% od, raised top, ic fan, 2 1/4 down pipes into 2 1/2 dual in/out res and true duals. All the way back,and a conservative tune from dave, which means runs a little rich until I dyno it and get it re flashed.
 
Mine usually gets around 24 or so on the highway. Haven't checked it after the top end overhaul, but I would guess the same.
 
I believe low to mid twenty's on the highway is normal. There are some members running good HP numbers with a tune of course and still get about the same.

Around town, thats a different story!:D
 
My 89 gets 24-25 mpg on the highway. Still has stock gears, but thats about all thats stock on it. I've never checked it other than on trips, but i'll guess about 15-17 with the way my foot moves :eek:

chris
 
Last edited:
All I can say is mine probably deserves a gas tax....hahaha. My mileage sucks, but hey mines is just a toy.
 
Last time I checked it was 17.9mpg unknown on highway with the new tranny. But with the factory setup was 14 city and 18 hwy, could get as low a 10 when having fun. MPII, MP plenum, 2.5-3-2.5, 42# injectors, 90mm MAF, 85mm TB and 3.73s
 
327 Rear. With a little, Mostly hiway with some push over 85 (to stay in traffic- fairly often) about 18. (no tune)

273 Rear, Stock, Mostly Hiway 76-75 CAI MPX Mr McGoo about 26 (with tune)

5 spds

327 Auto Totally Stock, Mostly HiWay 23

US Galloms 500 plus Miles

Paul
 
95 auto

about to make a 600 mile trek to houston so ill get a good reference... but im getting 17-20 no matter hwy/city. i had a 90 without cats or resonator that would get 26 on the hwy.. starting to wonder just how much new o2 sensors would affect mpg.. im sure mine are original
 
24-26 Highway. with Cruise set at 75-78.
90 Auto, 3.27 rear, CAI, 36lb injectors, Stock MAF, 75mm TB, Headers, 2.5" Mandrel bent duals.

Around town... I don't care as it gets more than my truck so it is a positive.
 
My Stock 90 W a 5 speed would get 25-27 with strict Highway milage. My best was on a trip which I drained a full tank and topped the speed for about 10 miles.
Around town with mixed freeway and stop go it would do 19-21 mpg.
 
Last edited:
The only good roadtrip I've taken with mine, I got 28. The local driving I do, I'm guessing I get around 22-23 since it's still mostly highway/interstate.
 
i think i can get better but i get about 19 on track drives, drive it there 3k whole way, make about 7 passes, drive er home. thats with 3.73's, 3k stall converter, and my c4. i think thats pretty good. but i think it can get better cause it runs pretty rich when i go uphill, according to afrs..
 
On the trip to bring my stock 93 5 speed down south, I had the cruise set at 80 mph for 95% of the trip, and I averaged 25.9 mpg. It was a lot better than I was expecting...
 
95

Let's talk about what WhiteBird has: CAI, 73mm CL, 70 mm TB, MP intake with plenum polished runner, s ported blower with 90 pulley, KW DIC, 42#/HR INJs, stage I Comp cam, shortty headers. 2.5 to 3 to2.5 exhaust with Flowmaster resinater resinator And turbo mufflers, and stock gears.
What it does not have: a TUNE. It got 24 mph for three hundred mi of freeway driving yesterday.
Ya I'm happy.:D
 
Back
Top