[Woodward]

ok i'm new to this forum, been reading for a while but only just registered, and i was wondering if i could any thoughts on this issue. I'm trying to add as much HP as possible, but can't afford to have my mpg be any worse than it already is. What is the best bang for my buck under this stipulation? I also have to worry about installation cost, and I already have an exhaust system. any thoughts you guys have would be really helpful!

[1slo5.0]

Find a 4 cylinder daily driver or a bicycle.....or leave the car stock


If you are worried about fuel economy you shouldn't be trying to get any more power out of your car.

[Eagle2000GT]

Originally Posted by Darrell If you are worried about fuel economy you shouldn't be trying to get any more power out of your car.

Why not? I went from around 235 rwhp to 385 rwhp and only lost 1 mpg. Factoring in the cost of 93 octane gas, I estimate I added about $5.00 extra fuel cost for 270 miles of driving. That's less than 2 cents per mile for 150 rwhp.

[Woodward]

Can i ask what you did to start for your mods eagle? I was looking at cams, any idea on how that would affect mpg?

[KingChronic]

i have 590-700+RWHP on my different boost/tunes and i still get 25MPG highway.

i do have that extra gear though.

[Mach Boy]

Under drive pulleys slow down the accessories in your car freeing up horsepower that is otherwise directed elsewhere. Most UDPs claim they give 8-10hp and 3-4mpg gain. Whether or not the numbers are true, I don't know. But as long as you are driving it like a DD then I don't see why you wouldn't gain more MPG using them.

[Trick Tuners]

Get a turbo. They have very little parasitic losses during normal driving and should retain near stock MPG for highway driving. City will probably take a hit depending on how fast you drive.

[TheUNZippee!]

I only have minor mods, but adding exhaust, a CAI, and a 93 Octane to my 07 I still get 22-24 mpg on the highway. With a 91 octane torque tune (adds power to the lower/middle part of the powerband) I get 25-26 mpg highway.

Even adding something like a SC or Turbo won't change your mileage much under normal driving conditions.

Now, things like upping your compression, and adding a really stiff cam, huge injectors or carb, and having your car set up for the track will of course drop your mpg drastically. But it is possible to add lots of power on a street type car and still have affordable fuel economy.

[Eagle2000GT]

I bought the car with the intent of supercharging. My plan was to not spend money on other things but to buy the supercharger first. Otherwise, I wouldn't have saved enough for it. The car came with Flowmaster Cat backs (which was good) and other mods (which were bad). I talked to several shops in planning the upgrades. Most said that gears were not really necessary with a forced induction setup. (Lower gears affect gas mileage.)

I started with 13" Cobra brakes because my front brake calipers were shot. After I finally decided upon a ProCharger (instead of a twin-screw), I bought a 75mm throttle body and plenum. I thought it might solve an rpm hang problem that was driving me crazy and it was something that wouldn't be replaced later. I had also read independent tests that said the TB/Plenum combo, while giving very little horsepower gains to a stock motor, will get 18-20 rwhp FI. The little gasket that came with the kit mostly solved the rpm hang problem.

Off my mod list were gears, cold air intake, underdrive pulleys, fuel injectors, fuel pump, cams, heads and exterior body mods. The ProCharger comes with its own CAI, injectors and fuel pump and superchargers do not work well with underdrive pulleys. Cams and heads are unnecessary. The rods and pistons will only hold so much power and the supercharger is capable of pushing a stock motor well past that.

I decided to have the gages installed with the supercharger because I wanted an interior mod that showed the car was different. I also had subframe connectors installed as well. After the supercharger I thought I would get long-tubes headers, a catted mid-pipe, a shifter, and better wheels and tires.

I did not plan the electric water pump. I bought it to solve a supercharger installation problem. The previous owner had installed underdrive pulleys and I was having a hard time finding stock pulleys. I ended up buying a stock crank pulley from Ford and replacing the water pump entirely.

The reason my gas mileage wasn't affected much is that I'm running a stock motor if I stay out of the boost. I can't really speak for cams, there are too many variants.

[Doc8224]

FI and Nitrous are the only ways to get BIG power without sacrificing too much mileage. Building a N/A car i.e. HC pistons, bigger cubes, cams, will net you less mileage in the end. The best thing to do is balance your power mods with mods that lower paristitic loss. Get a TB and a good cold air kit, then do something like UDP's or an aluminum DS. Then get an aluminum flywheel if its a manual, round it all out with a good tuner and that should get you close to what you want. Then you can run a hardcore tune for the weekends when you wanna go hunting, and run a little more conservative tune for the work week to save mileage, use the computer and car to its full potential. You can program these things to run on 89 so well and get great mileage just take your time and think all the mods out.

[gsjohnson]

Originally Posted by KingChronic i have 590-700+RWHP on my different boost/tunes and i still get 25MPG highway.

I call BS on this claim. And no I don't want to see your sausage.

[gsjohnson]

I installed a P1SC-2 in a stock motor and dropped 2 to 3 miles per gallon keeping my foot out of it. Went a little rich on the tune at the dyno to be safe. 386 RWHP

[pa.ulB]

any kind of induction will not hurt your mpg much and will net you alot of hp

[1slo5.0]

Originally Posted by KingChronic i have 590-700+RWHP on my different boost/tunes and i still get 25MPG highway. i do have that extra gear though.

Yeah, right.

I was born at night, but not last night....

[1slo5.0]

The potential is there to retain fuel economy with mild forced induction set ups. But the chance of ever seen any fuel economy will probably not exist because your gas pedal will be stuck to the floor feeding your adrenalin needs.

[Doc8224]

Originally Posted by Darrell The potential is there to retain fuel economy with mild forced induction set ups. But the chance of ever seen any fuel economy will probably not exist because your gas pedal will be stuck to the floor feeding your adrenalin needs.

+1 Especialy since a lot of people go with the can tune when they get their blower and the can tune is a P.O.S tune that is so rich on the top end you will never get good mileage.

[Trick Tuners]

Originally Posted by Darrell Yeah, right. I was born at night, but not last night....

Too bad ford can't adapt chevy's strategy of turning off injectors during cruise.

7.0-liter V-8 ZO6 is estimated at 15 mpg city/24 mpg highway.

I have a customer that gets 23mpg highway with at KB at 12psi. Probably around the 450+hp range.

[KingChronic]

well people are intitled to there own opinion, but thats what i get in my car with the cruise on at 65-75MPH without too many hills and all. step in it though, and just watch the needle go down.

[SWEET2KSTANG]

certain mods will help with the mpg and help with hp. those mods help with mpg and hp, but it is the same mods that people complain about not giving them hp#'s too.