20MPG on SVO, no-boost/gentle driving?

[In2Fords]

Just filled up the SVO. 315.3 miles on the tank, took 10.864 gallons up to fill.

29.02 MPG

That's all local / moderate speed driving (<50 MPH). And I baby the car (most shifts are around 2500 RPM).

I'll check it again and report back in another week or so....

That's nice numbers, what I'm hoping for

[SVO4PWR2]

Hey Joe,
This also fits you

FoxChassis
But what do you need a turbo for if you're going to drive it like your Grandmother?

-RICH-

[BLK BRD 88]

Just filled up the SVO. 315.3 miles on the tank, took 10.864 gallons up to fill.

29.02 MPG

That's all local / moderate speed driving (<50 MPH). And I baby the car (most shifts are around 2500 RPM).

I'll check it again and report back in another week or so....

Wow Joe that is terrific mileage!
Ron

[EJSVO]

Joe:

Good MPG Numbers anyway you look ay it

[KevinK]

I just completed a 460 mile trip to the Reno MCA Mustang show. My SVO got over 30 MPG on the trip. I know I only hit high numbers mpg once or twice since buying the car new because I don't get out with my car often. This trip was over some big mountains too. Speed was kept down as my wife was following with a trailered 88 Mustang.

[In2Fords]

I have been getting an average of 24 in town since the turbo upgrade but have only been running a conservative 9 psi and on the same cap/rotor/plugs since i built the motor and thru all the test and tuning over the last year.
I just replaced the cap/rotor/wires/TFI/PIP and plugs this week.
Im going on a 300 mile trip on Wednesday, Im still on 9 PSI, lets see how I do. in a few weeks I will go back up to 16 PSI. Im try to be easy on the ET trans and original ujoints untill I swap in the 5 speed.

[MAPSVO]

Just made a trip to a show this past weekend, 210 miles almost all interstate, steady 70-75mph, 24.8mpg average with premium fuel. 86 SVO, stock.

[teal95]

I keep track of the mileage on all my cars. I have a spreadsheet that has a tab for each car. (Yes, I'm anal, I'm an engineer. No, I was never in the military.) Part of why I have had a TurboCoupe as a daily driver for the past 10 years is the mileage I could get out of them. I regularly get 30 mpg. Drafting does play a part and you can be a lot farther back then you think and still get benefits. Most of my cars have tripminders in them. It really helps you see what works and what doesn't when trying for MPG. The TurboCoupes do seem to get better mileage than the fox cars. I haven't used my SVOs much lately but I have been driving my '84 GTturbo since winter ended. It won't get the same mileage that the t'bird will even though it has a higher final drive.

As for speed dependency there is an issue with the EEC going open loop around 3000 rpm. I have had stock TC's (0.86 OD with 3.55), and several converted with different setups. Some with a 4 cylinder T5 (so 0.86 OD with 3.73 rear) and usually with a V8 T5 (0.68 OD with 3.73). I also had an auto that I put 4.10 rear gears in and them later put a V8 T5 in. Most of them the MPG would drop off of a cliff at 70 mph. The one with the V8 T5 and 3.73 rear gears went from Indiana to Oregon and back. With the higher final drive it was perfectly happy going 75+ out west. But 5th gear was barely usable at 55 mph so it made driving in town a chore.

For some reason the O2 sensors in the '84 GTs were 3 wire (signal + 2 heater wires) while the SVOs were all single wire. The '87/8 TC were also 3 wire. (I don't know about the earlier TC since I've never had one.) I would usually get a newer O2 sensor that was a 4 wire. The extra wire was a ground. I would then put another pin in the connector (they were all 4 pin connectors) and run the wire to the ground connection on the compressor housing of the turbo. This guaranteed that I had a good ground.

steve

[Shredding Rubber]

Our 85.5 SVO averages 24-26 mpg per tank in daily commuting in the Phoenix area. Even driving the car to Las Vegas, it still gets in that same range since our speed is generally 70-80 mph for most of the trip. I suppose if we made the drive at 60 mph, we'd get closer to 30 mpg.

Fox Mustangs are not aerodynamically efficient. In fact, they are so bad Jack Roush ran the bubble back Capris instead of the Mustangs in SCCA Trans-Am and IMSA GTO.

The Fox Thunderbirds were slicker through the air compared to the Mustangs also.

When the national speed limit was cut to 55 mph in the 70's, it was for fuel economy reasons. Above ~55 mph, aero drag becomes more pronounced compared to other losses such as rolling resistance of tires. It was only after a few years of the 55 mph speed limit that statistics for traffic fatalities began to reveal how much speed factored into death rates. Even when fuel prices stabilized, the government kept the speed limits low specifically to keep death rates lower. As cars have become safer, the speed limits have gradually increased.

The capri's had less drag than the mustangs even before the bubble back version. I had a hard time believing it since they are the same platform but I came to find out that the Capri had less drag.
Interesting for sure.

[KCoker]

I keep track of the mileage on all my cars. I have a spreadsheet that has a tab for each car. (Yes, I'm anal, I'm an engineer. No, I was never in the military.) Part of why I have had a TurboCoupe as a daily driver for the past 10 years is the mileage I could get out of them. I regularly get 30 mpg. Drafting does play a part and you can be a lot farther back then you think and still get benefits. Most of my cars have tripminders in them. It really helps you see what works and what doesn't when trying for MPG. The TurboCoupes do seem to get better mileage than the fox cars. I haven't used my SVOs much lately but I have been driving my '84 GTturbo since winter ended. It won't get the same mileage that the t'bird will even though it has a higher final drive.

As for speed dependency there is an issue with the EEC going open loop around 3000 rpm. I have had stock TC's (0.86 OD with 3.55), and several converted with different setups. Some with a 4 cylinder T5 (so 0.86 OD with 3.73 rear) and usually with a V8 T5 (0.68 OD with 3.73). I also had an auto that I put 4.10 rear gears in and them later put a V8 T5 in. Most of them the MPG would drop off of a cliff at 70 mph. The one with the V8 T5 and 3.73 rear gears went from Indiana to Oregon and back. With the higher final drive it was perfectly happy going 75+ out west. But 5th gear was barely usable at 55 mph so it made driving in town a chore.

For some reason the O2 sensors in the '84 GTs were 3 wire (signal + 2 heater wires) while the SVOs were all single wire. The '87/8 TC were also 3 wire. (I don't know about the earlier TC since I've never had one.) I would usually get a newer O2 sensor that was a 4 wire. The extra wire was a ground. I would then put another pin in the connector (they were all 4 pin connectors) and run the wire to the ground connection on the compressor housing of the turbo. This guaranteed that I had a good ground.

steve

The 84 svo's had three wire 02 sensors too.

[BLK BRD 88]

Kendal, I am glad that you chimed in with that info because I was wondering why my 84 has a three wire unit on it.
Ron

[In2Fords]

I recently drove from White City Oregon to Newport on the coast for work. With only having a 4 speed and 3.45'ish gears, stock tires on ten holes, I am doing 2700rpm at 65, 3K at 70 and 3300 at 75. The trip is a little over 260 miles. The first 100 miles is freeway with a lot of steep hills, ofcourse big rigs like to go side by side on the hills bringing it down to 35mph each time I would get frustrated and jam it at 75mph as often as posible, lots of slowing down and speeding up, I hate driving during daylight. The next 100 miles are nice flat even ground, all freeway, I did a constant 68-69 mph, it was nice the last 60 miles are a mix of long straights and lots of twisty hilly roads to the coast with speeds varying between 35-55.
I got 23 at my first fill up after 100 miles, I got 27-28 mpg after the second 100 miles and 20-21 for the last 60 miles.
I know I will do a lot better with a fifth gear and taller tires or taller gears.

[BLK BRD 88]

I recently drove from White City Oregon to Newport on the coast for work.........I hate driving during daylight...........

If I remember correctly from driving in that area years ago it was no fun driving at night either, because there were deer standing on or beside the road at almost every curve.
Ron

[In2Fords]

If I remember correctly from driving in that area years ago it was no fun driving at night either, because there were deer standing on or beside the road at almost every curve.
Ron

Yeah, I see deer more often then I like but still prefer night driving, so far I've been lucky and only see the deer beside the road. During the day the idiots from Washington and the crazies from Cali are out, normally they go and hide at night

[EJSVO]

I enjoy driving at night , conditions permitting, as well.

Here in the East , and where I did most of my youthful driving , The Pocono Mountains of North East PA.

We used to call Driving at Night on State Highways "Deer Dodging"

Fortunately for me I was a good "dodger"

[BLK BRD 88]

I don't seem to be able to get more than 22mpg out of my 84 SVO even when it is all highway travel at & below 70mph.
I have tuned it & it runs great now, but I can never get near the mileage that some of the rest of you are getting in your SVOs.

For better mileage with 91 octane should I put the switch on regular to retard the timing, or is it better to leave it on premium fuel whenever it is running premium?
Ron

[JTurbo]

I always run my car in regular mode, but I need to use 89 octane to keep the low RPM/heavy load pings away. Keep in mind that I have a ported / big valve head on my car....

JT

[In2Fords]

For the last few weeks I have been driving very, well, aggressive, yeah, we'll use that word. Got my intown MPG down to around 14, now this town is mostly 25-35 MPG and while my gps says Im not speeding my speedometer quite often spikes up to 45-50, I might have a problem though, often while leaving from a stop my engine revs up to 5500rpm, my speedometer says 40-45 but Im not moving very fast and theres this smell of burning rubber? also I think there's a weird problem that my speedometer is linked to my suspension, in the parking lot at work when ever my speedometer says we are going much faster than the gps says we are my suspension does this weird thing and my car goes sideways, around turns, in circles and my car goes sideways down the whole length of the parking lot, im not using my brakes so those seem to be ok, weird right?
yeah, now that I think of it I most definitely have a problem but there is absolutely nothing wrong with the car
Working 85-90 hrs a week for the last 6 months is getting to me and I have abused the streets in retaliation.

[merk]

For the last few weeks I have been driving very, well, aggressive, yeah, we'll use that word. Got my intown MPG down to around 14, now this town is mostly 25-35 MPG and while my gps says Im not speeding my speedometer quite often spikes up to 45-50, I might have a problem though, often while leaving from a stop my engine revs up to 5500rpm, my speedometer says 40-45 but Im not moving very fast and theres this smell of burning rubber? also I think there's a weird problem that my speedometer is linked to my suspension, in the parking lot at work when ever my speedometer says we are going much faster than the gps says we are my suspension does this weird thing and my car goes sideways, around turns, in circles and my car goes sideways down the whole length of the parking lot, im not using my brakes so those seem to be ok, weird right?
yeah, now that I think of it I most definitely have a problem but there is absolutely nothing wrong with the car
Working 85-90 hrs a week for the last 6 months is getting to me and I have abused the streets in retaliation.

my cars have the same problem but are also accompanied by excessive rear tire wear I blame it on all my cars having a weird alignment phenomenon that cause the the rear tires to where 4:1 to the front tire

[BLK BRD 88]

Well, I never did hear back from anyone on this thread about whether it is better to keep the switch on regular, or on premium when running 91 octane.
I ran it for three months with the switch on regular while burning 91 octane & averaged about 20mpg.

Two weeks ago I switched it to premium and while burning 91 octane & on the past two tanks, so far, I have gotten 24+mpg each.
Ron