How to build the most effecient Mark VIII

Calabrio

Calabrio

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What can a Mark VIII owner do to improve the fuel efficiency of their vehicle? Which modifications not only improve performance but also improve the abilities fuel efficiency?

Will a low restriction exhaust improve performance and fuel economy? What else can you think of, and what kind of improvement will you get?

After keeping the car tuned up, what other aftermarket parts will offer both of these advantages?
 
Well an intake system would definately help. Exhaust would work as well, just don't make it too free flowing, modular motors need some back pressure.
Some maintenance:
New fuel filter
Fuel System cleaner
New air filter
 
i my self had new exhaust k&n air filter and all synthetic fluids i average about 26.5 on hiway
\\


chris
 
Who else has either installed a new exhaust system, or just mufflers, and experience mpg gains?
 
Dominus said:
No engine needs back pressure. I assume you meant to say that modular motors need exhaust velocity.
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I could have sworn they need back pressure to work properly, again I'm no expert.
 
Common misconception. It's an easy one to make though. A smaller, properly sized pipe has greater velocity, which scavenges better, and oversized pipes don't have as much velocity, which leads to decreased scavenging, so people assumed it was because of back pressure.

Of course, if you are the kind of person who likes big top end, oversized pipes work because exhaust velocity will be highest where the engine produces enough exhaust volume to properly fill the pipes.

Works the same way as intake runners, except on the other side, basically.

There's a lot more to it than simply that, but I'm not going to type up a giant page about it.
 
KD00LS said:
I could have sworn they need back pressure to work properly, again I'm no expert.
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your not wrong, its just the laymens term for exhaust scavenging.


id say, exhaust, 3.55 gears, tune (the gears because this is a heavy car to get movin, and takes a lot of gas to start from a stop. 355's cuz they are low enough to maintain good mpg on the highway, while giving a slight increase in city mpg)
 
Try a Tornado or a gas magnet. With the money out of your wallet you'll be lighter.
 
Id really like to hear if anyone has got gains from air filter and exhuast, Im planing on doing this with in the month, remove resonator and silencer on intake, get k&N airfilter, and have my 3rd cat,resonator and mufflers removed. Right now I average 15-17 city and 27-30+ highway. It has new trany fluid, oil, new tires, and I think up to date plugs and wires Ive been meaning on asking my friend that I bought the car from that was like a yr ago lol. But I think there should be increase in efficientcy by freeing up restriction and having the vechile breath in and out easier,idk.
 
I'm still only getting 23-24 mpg on the highway. I definitely need some improvement.
 
Calabrio said:
I'm still only getting 23-24 mpg on the highway. I definitely need some improvement.
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What yr mark you have? What octane do you run, list some specs. Mines a bone stock 95 LSC with 108k and I got 32 one time doing 65 with crews on and I heard ppl getting even better gas mileage doin like 75 with crews,lol. But when was the last time u had oil change, check tire pressure youd be suprised how much as something as tire pressure can increase economy,lol.
 
I too get higher milage with cruise on.................

95Marklll(Kingcobra) said:
What yr mark you have? What octane do you run, list some specs. Mines a bone stock 95 LSC with 108k and I got 32 one time doing 65 with crews on and I heard ppl getting even better gas mileage doin like 75 with crews,lol. But when was the last time u had oil change, check tire pressure youd be suprised how much as something as tire pressure can increase economy,lol.
Click to expand...

But that takes all the fun out of driving. I average 20MPG when I drive the car by myself. With cruise on during a highway trip I can get as high as forty five. Economy is not why I bought this car. If I want economy, I drive the Harley. If I want fun, I drive the Lincoln.
 
bufordtpisser said:
But that takes all the fun out of driving. I average 20MPG when I drive the car by myself. With cruise on during a highway trip I can get as high as forty five. Economy is not why I bought this car. If I want economy, I drive the Harley. If I want fun, I drive the Lincoln.
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Im the same way, I bought the car becuase its a 2 door sport luxury with a motor that can make the car scoot pretty good. But on the days im not punching it I like the fact Its decient on gas and If I can make It better and make It more powerful too, then Im really happy.
 
bufordtpisser said:
With cruise on during a highway trip I can get as high as forty five.
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What ever you are smoking dude, I want some.

WTF...45 :eek:

Btw, your car will get worse gas mileage on cruise control vs foot throttle. By lightly fethering the throttle, one can keep the car in 'vacuum' mode which will increase your gas mileage.
 
MonsterMark said:
What ever you are smoking dude, I want some.

WTF...45 :eek:

Btw, your car will get worse gas mileage on cruise control vs foot throttle. By lightly fethering the throttle, one can keep the car in 'vacuum' mode which will increase your gas mileage.
Click to expand...
45mpg with light cosistent down hill. You'll never maintain that for a long period of time.

Cruise sucks for gas mileage as every hill its mashing the peddle to keep the speed, and lets of abruptly if the speed drifts high.
Kinda how a truck driver will speed up to approach a incline so the momentum will carry futher up the incline, without having to mash it or down shift.
 
Like wouldent new o2 sensors help mileage if there old, and how do you know if there not up to date? I never figured that part, how do you know?
 
Calabrio said:
Who else has either installed a new exhaust system, or just mufflers, and experience mpg gains?
Click to expand...


I installed Geno's exhaust last week, and I have seen noticeable gains in fuel mileage over stock. Full catback 2.5 OD.

Before that I was getting 30 on the highway, now I get much better mileage in town.
 
I was only getting about 22 on the highway, then I found that the lower o-rings connected to my fuel filter were probably leaking. I'm not up to about 24mpg.

I'm pretty sure my tire pressure is fine. The car is aligned. The plugs, wires, air filter, fuel filter, oil, oil filter are all fresh.

My immediate next step will be replacing my transmission. I know that the torque converter is shot. I suspect there might be some damage within the unit itself too. I suspect this is resulting in some loss of efficiency as well. Possibly with the replacement of this I'll be up around 26 mpg.

And after that is done, as mentioned in another thread, I intend to change the exhaust system. I'm just now looking into the cost and the process.

If I can get 30mpg on the highway, I will keep this car forever.
 
MrWilson said:
your not wrong, its just the laymens term for exhaust scavenging.


id say, exhaust, 3.55 gears, tune (the gears because this is a heavy car to get movin, and takes a lot of gas to start from a stop. 355's cuz they are low enough to maintain good mpg on the highway, while giving a slight increase in city mpg)
Click to expand...

3.55's? LMAO! Are you kidding Andy? YOU were in my car when we were doing 65mph and showing 28.7 mpg with 4.10's?

3.55's are CRAP and aren't even worth the aggg of putting in, its almost like no change at all. We have 3.55's in the SuperMark but thats Supercharged so it reacts like 4.10s.

If I set my cruise at 60mph I will get 31 mpg all day, at 85 mph I get 27.0.

We pick up around 3.5-4.5 mpg or better average between our chip maf kit and our exhaust. ALL our mods pay for themselves in a short time.
 
I got 4:10's in my Powerstroke, and can't get over 14mpg, at any speed or load, I thoght they were supposed to get around 20..., I can see where you could increase around town, but I would still expect a drop on the highway,... I guess it depends where your power range is, mine is exceptional for two lane passing, (witch actually is the most important thing( don't want to get stuck out in the oncomming lane too long))
I know performance and economy are very closely related, it's all about efficancy(or something like that).
 
95Marklll(Kingcobra) said:
Id really like to hear if anyone has got gains from air filter and exhuast, Im planing on doing this with in the month, remove resonator and silencer on intake, get k&N airfilter, and have my 3rd cat,resonator and mufflers removed. Right now I average 15-17 city and 27-30+ highway. It has new trany fluid, oil, new tires, and I think up to date plugs and wires Ive been meaning on asking my friend that I bought the car from that was like a yr ago lol. But I think there should be increase in efficientcy by freeing up restriction and having the vechile breath in and out easier,idk.
Click to expand...

hey you dont want to remove the resonator if you remove the mufflers you will get puylled over the minute you go by a cop it is waaay too loud. I tried that b4 and had to put a resonator on the car. like4 i said b4 remove the "2" small cats and get a high flow main cat which is the 3rd cat and keep the resonator it will be loud but nice sounding and you wont get :q:q:q:qed with by the cops or the inspection station
 
MonsterMark said:
What ever you are smoking dude, I want some.

WTF...45 :eek:

Btw, your car will get worse gas mileage on cruise control vs foot throttle. By lightly fethering the throttle, one can keep the car in 'vacuum' mode which will increase your gas mileage.
Click to expand...

true, but after a while you lose focus and start using more gas than cc.
 
gangstaMK8 said:
hey you dont want to remove the resonator if you remove the mufflers you will get puylled over the minute you go by a cop it is waaay too loud. I tried that b4 and had to put a resonator on the car. like4 i said b4 remove the "2" small cats and get a high flow main cat which is the 3rd cat and keep the resonator it will be loud but nice sounding and you wont get :q:q:q:qed with by the cops or the inspection station
Click to expand...

I have a few friends with no cats were I live they dont check Im lucky,lol. One friends work van is a 97 chevy van 30 with a 454 no cats just straight 3 inch pipes into 40 series. My other friends dad has a 87 5.0 convertible no cats just straight pipes into flows and his grandpa is in the works on making his 94 5.0 just have x pipe into flows. And my friends 5.0 is pretty loud but has cats soon to be gone prob,lol. Were lax around here and theres no sniffer tests at all, Dont hate me lmao. Oh yeah seen this guy in a 87 town car no exhuast at all just headers lmao It was nasty to bad looked like crap,lol.
 
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