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I was wondering if any of the community's members drive souped up cars with aftermarket parts and such. E.g. skirt kits, exhausts, nitro, etc. How does that affect your mpg performance? Any tips for those folks specifically?

Guess you'll be interested in reading and seeing what Basjoos has done to his Honda Civic.

I don't think nitro is a MPG enhancing agent. I think it would decrease MPG, and be pretty expensive to install and refill.

What is your experience with it?

So you are basically asking if there are any rice rockets?

Exhaust, my guess, will improve MPG a bit. Assuming the exhaust is wider diameter than stock and less restrictive. Reduce exhaust restriction reduces the amount of energy needed for the motor to expel exhaust gases.

Nitrous Oxide obviously wont have any effect when if it is not being sprayed.

Spoiler probably reduce MPG by increasing the vehicles drag coefficient.

Bigger exhaust will probably not help your fuel economy at low rpm since there simply isn't enough air flow out of the engine to require it. Likely you will actually hurt your milage because you will kill too much back-pressure. The engine is designed to operate with a little bit of back-pressure.

CAIs wont help because you want warm air, not cold (exception, maybe: 115deg summers). High flow filters will probably help at full throttle, but not part throttle where you drive for economy.

The vast majority of engine mods for power are designed to increase flow at high rpm/throttle. Since fuel economy is made at low rpm and moderate throttle, these mods will not likely help and more likely will hurt your fuel economy.

I'm a wannabe tuner. Theres lots of stuff I'd like to do to my Lancer Ralliart but I can never justify it with the wife. I've contemplated autocrossing with it but its a hike to get to any of the locations where they race. I like spirited driving though, but not so much now that I am hypermiling and have a baby on the way.

I was wondering if any of the community's members drive souped up cars with aftermarket parts and such. E.g. skirt kits, exhausts, nitro, etc. How does that affect your mpg performance? Any tips for those folks specifically?


Those parts negatively affect your FE.
If you are trying to maximize your car's horsepower output, the energy (horsepower) comes from something - that being gasoline, nitromethane, alcohol, whatever.
There is only so much energy in fuel.
The more horsepower desired, the more fuel required (volume/distance). (oversimplifying, of course).
The more fuel required, the lower the FE.
The lower the FE, the less disposable income one has.


Those parts will not help your FE at all.
If you're after a ricer, qua Fast n' Furious, look - then graphics certainly will not be a detriment to your fuel economy. :D

The exhaust I put on my car helped a bit I think, Though it could've been the difference in my driving. Note: The exhaust I put on my car was a Porsche Tequipment part (made specifically for my car) and thus was tuned for it. I think the body mods you mention would have a neg consequence (drag, weight). Suspension and wheel mods may not be a bad idea if done right (lighter wheel debate).

Have fun, drive smart.

I was wondering if any of the community's members drive souped up cars with aftermarket parts and such. E.g. skirt kits, exhausts, nitro, etc. How does that affect your mpg performance? Any tips for those folks specifically?

nitro? i think you have the wrong website. you must have us confused with someplace else. :confused:

It depends on what you mean by "souped up". I guess you could consider that my car is souped up for increased mpg's. I have skirts on my car, but they are of my own design for drag reduction, not a kit bolted on for looks. My exhaust has been modified to help it to better fill in the miniscule eddy behind my car, not for increased noise or power. No nitro on my car, my engine is totally stock. A fringe benefit of all of the drag reduction on my car is that it has a greatly increased top speed and the engine runs more relaxed because of the reduced wind load when maintaining fast highway speeds on those rare occasions when I run with the speeders in the left hand lane (while still getting close to 60mpg).

If you can get an exhaust that bumps your torque up at low RPM (say, 2000 RPM), it may help FE. Most aftermarket exhaust makers will gladly sacrifice that low RPM range for gains up near the redline, so they will hurt your FE.

CAI will hurt, until the air temp gets over 100F. Some folks around here put a WAI on their car to help FE.

Lowering the car will help reduce aero drag somewhat, at least in general.

Wide tires will increase aero drag and rolling resistance. Grippy tires will also increase rolling resistance.

About 90% of the "aero" mods you commonly find out there increase drag. There are a few that decrease it, but telling which ones do can be difficult.

Internal engine mods to reduce friction and pumping losses will help FE. (Boat-tailing the mains, knife-edging the crank, port-matching oil passages; tons of little things.) The effect will likely be pretty small, though. Higher compression can help FE a little, but generally at the expense of requiring higher-grade fuel.

Nitrous? Umm, probably not. ;)

-soD

Most of the people here are not in to the car Modding and do not know much about it.

I know very little.

I can tell you there are some wrong generalizations on this thread that is mostly due to the thing that most people are used to seeing and reading is ricer / redneck hotrodding useless crapola that people do to their cars without knowledge. and that is what gets the most attentions on Tv magazines and whatnot...


there are many things you can do that will increase performance and fuel efficiency, but this changes BIGTIME depending on each application.


" Bigger exhaust will probably not help your fuel economy at low rpm since there simply isn't enough air flow out of the engine to require it "

This is very true in most cars, with most common exhausts that you see out there, melon launcher size monsters that only make noise , but not true on all applications.

on force induction cars a larger size exhaust will be very good for performance and fuel efficiency . but you see , once again , this is not always true since materials and design of the these systems plays a part too. A bad design system even larger may create turbulence on the exhaust side, the material may not retain / spread heat properly and cost benefit of the system size for the power gains needs to be researched.

My car has complete exhaust system reworked (among many other things) , I took apart the cast iron headers and spent 10 hours porting and polishing them, I purchased extra parts of every part i was going to upgrade, had them ported, polished, coated, wrapped and copper binned , and then i swapped them.

why did I not buy aftermarket ones that have better flow and higher power gains, because of the low end torque (FE) and quicker spool from heat retention in the cast iron vs aftermarket welded pipes, this can also apply to non force-fed engines as a 4 2 1 system may benefit it more than the usual 4 1 system more oem use.

I can help you out a bit, if you like, what car you have, what are the goals, what is your budget, daily driving ? what is your usual distance ? heat wrap ? ceramic coating ? hone extruding places close to where you live ? do you have other mods of transport or space parts to take on the project ? all this also will determine what you can do. in my case.

I’m sorry , I wrote a book :( im such a nerd.


CLIFF NOTES: YES THERE IS . how much time and money do you have ?

here is a webpage where i keep track of the stuff i have done to my car just in case you are wondering

http://saab92x.com/viewtopic.php?id=7094




^^ what a nerd and show off , ignore this guy ... hehehhe :lol:

How's this for a souped up car! This was my 1972 Chevy Nova that I used to have back in the 1990s. The stock version got a respectable 20 MPGs before these modifications...
Intake Mods: functional hood scoop to cram air into the K&N velocity stack into the 750 CFM (cubic feet per minute) Holley carb into the Edlebrock racing intake manifold.
Exhaust Mods: large chrome dual headers
Other Mods: Higher output electical (plugs, wires, distributor), Oversized racing cam, 350 cubic inch block bored out to 383 "stroker", tracksion bars on the rear, custom wheels, lots of shiny chrome parts under the hood.
End result: low 14s on the quarter mile (enough to beat the Corvettes), getting attention :cool: (particularly cops who pulled me over :eek: for no reason), and 10 MPG on my best tank (and that's on a highway road trip at 60 MPH).
Moral of the story: Souping up a car generally kills your FE , but was a lot of fun when gas was cheap! :D At these gas prices, I recommend going to car shows to see souped up cars as an alternative to souping up your own.
http://www.cleanmpg.com/photos/uploads/3724/72ChevyNova2.jpg

Hi All:

___I have yet to hear of an exhaust yet that can improve upon stock FE in a low RPM, high load scenario so who cares? Basjoos’ tranny swap for the taller gear was the best thing he could have done after the aero and there is big savings in that other than the upfront costs. Most of the FE savings come from the bag of water between the accelerator pedal and the steering wheel as has been proven time and time again. It depends on how bad you want it or not. Even a Z series Vette can pull incredible nubmers when pushed but not when you are street racing light to light :(

___If it is a need for speed, a 250 Rice Rocket will destroy just about anything in the streetable drag arena and still pull 70 + when driven right. A 600 + will destroy the streetables unless modded with tens of thousands of after market add-ons which would make its streetability about nil and its FE worthless.

___Good Luck

___Wayne

my Camaro has a fair amount of stuff done to it, underdrive pulleys, ignition system, cold air intake, high flow throttle body, headers, high flow cat, catback exhaust, drag wheels, lightweight drive shaft, taller gears/limited slip diff, boxed lower control arms, panhard rod, weight reduction... I'm sure I'm forgetting some stuff, but you get the point

as for the effects on my FE... most of the gains or losses were not noticible, the wheels, and the drive shaft improved my acceleration a great deal and also improved my FE, and the ignition system helped also

My Grand Prix with STS turbocharger gets similar MPG as to when it was in stock trim. Which was not all that great to begin with.

Of course that is only when driven "normally", but that is not why I modded the car. I changed it to make it fast and fun. It will turn 12.7 seconds at 107 mph on the 1/4 mile drag strip.

So this is my Play Car and my HCH II is my work/date car.

Well, my Dad had a '73 Mustang Mach 1 for a daily driver in 2004-2005. It was a 351 Cobra Jet motor with a 5-speed stick. His mileage was...13mpg city/13mpg highway. The ports in the cylinder heads were massive, and the valves were huge as well - 2.19" intake and 1.84" exhaust, if memory serves. You might think this weould be great for pumping losses, but apparently not so much...

Well, my Dad had a '73 Mustang Mach 1 for a daily driver in 2004-2005. It was a 351 Cobra Jet motor with a 5-speed stick. His mileage was...13mpg city/13mpg highway. The ports in the cylinder heads were massive, and the valves were huge as well - 2.19" intake and 1.84" exhaust, if memory serves. You might think this weould be great for pumping losses, but apparently not so much...

Though I'm a mopar fan I'd have to say the 351 Cleveland had the most potential of all the available small blocks back in the day, as you said the ports were huge. Had a friend in highschool in 1980 that had a 70 mustang with a warmed over 351 Cleveland that was the fastest car in my class.

I've always wondered what Ford was thinking though, there engine planning was pretty weird. They went from a 427 in 1967 to a 428 in '68, added a 428 Boss in '69 for 2 years, switched to a 429 in '70 while still retaining the 428.

Similar with the small blocks producing a 351 windsor and a 351 cleveland concurrently for years?

Oh, it was quick. Very quick. But you had to keep the tach pointing over 3500, otherwise it was a super-boring engine, not an ounce of torque to be had under 2500 or so. Probably why the economy wasn't good in my Dad's, it was power or nothing :D . The dyno put it just shy of 300hp to the wheels running lean on the secondary jets.

As for mods (sorry forgot to include that), it was .030 over with an Edelbrock aluminum intake, port plates to eliminate dead space in the rather poorly shaped ports, full MSD ignition system, Hooker headers with a full 2.5" h-pipe duals sporting Magnaflow mufflers, a Comp Cams "RV" cam (never did get the specs on it), and a Holley Street Avenger 670 carburetor. Rear-end was a 31-spline 9" rear end sporting 3.5:1 gears and a Tremec 5-speed with a .75:1 overdrive.

OK, here's my toy.:D

http://hometown.aol.com/worthywads/myhomepage/chally21.jpg

I bought her in '92 and have redone almost everything except the body/paint.

Engine is a late model 360 bored 0.20 with 10.3 compression. Cam is a Hughes hydraulic roller .520/.544 266/270 which is very streetable with a high lift from the rollers but mild duration for decent efficiency. Edelbrock air-gap dual plane, again decent efficiency. Carb Holly Street Avenger 670, again mild. DUI ignition.

Heads are ported (by me) Magnum R/T heads, a high flow over the shelf factory head with roller rockers.

Exhaust is by TTI, ceramic coated step headers with cross-pipe and 2.5" exhaust with dynomax mufflers. I love the ceramic coating, after 5+ years they look brand new.

Rear end is only 3.23 but a tremec OD 5-speed is in the works with probably 3.55 or 3.73s part of the plan. Currently 727 auto with a transgo shift kit.

Doesn't see to many miles, mostly to car shows and Bandimere speedway. I've only averaged a tank a year for the last 4 years.

Best time is 15.0 @ 94.5. That translates to 13.9 @ 102 at sea level, mile high air ain't so good.:( 5-speed, gears and tires should cut .6 seconds, I'm currently hitting 3rd gear in the traps.

As for FE, my one trip of 2 tanks at highway speeds netted 18.3. but a mediocre 11.7 over 2500 since the new motor.

OK, here's my toy.:D

http://hometown.aol.com/worthywads/myhomepage/chally21.jpg

As for FE, my one trip of 2 tanks at highway speeds netted 18.3. but a mediocre 11.7 over 2500 since the new motor.

Sweet ride! But I can see why you hypermile your truck around, as 30+ MPGs is a huge savings over 11.7.

Some of us just like to tinker. The most effective proven MPG mods are to add aerodynamic slickness and reduce friction. Reducing weight helps town mpg while improving maximum acceleration, little mpg gain on the freeway.

While Basjoos explores the current outer limits of such mods there are several less drastic but still effective things that can be done. Undertrays, grille blocks, mirror removal, lowering, synthetic lubes, tire pressure, slick wheel covers are some.

The aftermarket hasn't yet organized on the FE mod market. What there is is disjointed or product specific, like HHO kits. So what you see advertised in the rod mags is biased toward getting higher rates of fuel and air through the engine, not maximizing lower power output efficiency.

... The ports in the cylinder heads were massive, and the valves were huge as well...You might think this weould be great for pumping losses, but apparently not so much...

Large ports and large valves allow you to flow a lot of air through without "choking" the flow. However, they do not promote air velocity through the port--and that is one of the keys to engine efficiency. High flow rates in the ports mean more air in and out for the same amount of engine turning, and high flow rates in the intake ports help fuel vaporization. Liquid fuel doesn't burn that well; it needs to be a vapor.

Your dad's motor was a monster at (relatively) high RPM, and not so good at regular "cruising" RPM.

Some exhausts, particularly on very old cars, are not designed very well. Going to a good aftermarket set of headers can actually help at the RPMs that are used for hypermiling (i.e., up to 2000 RPM or so). As I have mentioned before, a friend of mine with an old Mustang Fastback got better FE when he installed headers. Most of the exhausts on modern cars are tough to beat, though.

Turbocharged cars are something of an exception to this rule, among many others. As AbACUZ pointed out, there are potentially significant gains to be made in the exhaust of a turbo'd car. Turbos seem particularly sensitive to exhaust flow, which makes sense, as that's what they use to drive the turbocharger...

Most exhaust FE gains on "naturally aspirated" cars would be quite small, particularly on a modern car.

-soD

Well there are many posts on this thread, but i do not think many of them are quite related to what the OP intended, talking about garage queens that rarelly get driven is one thing, heck, i would not care if it used up 20 galons to do 20 miles if i drove it once a year. but making a power monster that can be driven everyday, thats another story.

As Some other Dave said, older cars where made , kind of , not too efficient, so some modern upgrades will for sure increase the power and efficiency.

http://chuckb.1le.net/racing/drivers_edge/02_07-08_04_de_ta/29DSC_8230_cropped.jpg

When my Trans Am was making 380rwhp (small cam, headers, bolt-ons) I drove it from Dallas to St. Louis, and pulled a best leg over 28 mpg. On the low end it it has been in the 5's on the track lol.

Some data is here: http://chuckb.1le.net/01_trans_am/gas_mileage.html

Here is a dragstrip pass from 2004 (http://chuckb.1le.net/racing/drag/052404_hpp_ennis_ta/1257_hpp.wmv)

And one (http://chuckb.1le.net/racing/nasa/10_09-10_04_texasmile_ta/166.348mph.wmv) of a pass at the Texas Mile.

The GPS after a practice run at Big Bend last April
http://bborr.com/2008/chuckbuehler/170mph.jpg

I am not a drag racer but I am (or was) an autocrosser. You can gain fuel econ with a user-customizable flash tuner and a experienced professional tuner that knows your car, your modifications and how to adjust your transmission, air/fuel mix and timing. I personally have put in money into suspension modification so that I can coast for greater distances by reducing the amount of braking I have to do (and thereby retain momentum when coasting in neutral). Having done that has helped, but outside of that my intake has a higher flow conical air filter but is stock tubing after the mass air sensor, and I have removed my air intake silencer so that the engine can breathe more freely, thereby increasing low end torque and throttle response.

Anyhow, in short there are a few mods you can do to increase fuel econ... for instance a lightened driveshaft and halfshafts, lower final drive gear, light weight clutch and flywheel would all increase economy due to less parasitic loss.

Hope that helps.

Ghost

Hmm... I wonder if there is a way to make the Throttle less sensitive?
So I can control the pitch of the Butterfly more precisely?
Perhaps maybe adding more resistance to it?

If your car has a cable-actuated throttle, you can change the attachment of the cable to the butterfly valve. Some cars came with eccentric pulleys (think shaped a little like a cam lobe) that changed the amount of opening of the valve per amount of cable pulled depending on how far open the throttle was.

For an e-gas setup, you'd have to monkey with the software most likely.

-soD

changing spring resistance will allow more precise throttle control but a heavier foot will be the result..

If your car has a cable-actuated throttle, you can change the attachment of the cable to the butterfly valve. Some cars came with eccentric pulleys (think shaped a little like a cam lobe) that changed the amount of opening of the valve per amount of cable pulled depending on how far open the throttle was.

For an e-gas setup, you'd have to monkey with the software most likely.

-soD

Its a Electronic Butterfly. :(