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TOOSTUBBORN2FAIL 09-14-2009 01:08 AM

Project 100mpg
So I guess its time to update this, as plans have significantly changed. New plans start on page 6. I would change the title the tread, but I cant seem to do that.

So i guess its time to start a project log for this car. Im currently over the EPA mileage, and have always been since i bought the car.

1998 Dodge Neon R/T
5 Speed (3.94FD, .81 5th)

Modfications done as of today that might affect gas mileage;
Partial grill block
Power steering partial delete (impeller removed, pump still attached as in idler pulley to keep a/c)
Unorthodox racing underdrive pulley
Mufflerless (loud, but a noticable improvement in gas mileage)
Warm air intake based off the stock intake box
No wipers or antenna
Removed rear wing (coastdown testing showed a 1% improvement in coastdown times, which could be a slight change in conditions, however in addition to the 1% coastdown change, the things heavy)
Mopar Performance ECU (advances ignition)
Slight weight reduction (muffler, wipers/wiper motor, antenna, winshield washer resevoir, muffler, passenger seat, spare tire/jack, side mouldings, sway bars)

Modifications that shouldnt affect gas mileage;
Maddog short throw shifter (65% reduction)
Spherical rod end shift cable ends
Mishimoto aluminum radiator

Currently im running Kuhmo KH16's, in a 195/60-14 size, on stock 14x6" aluminum rims, if anyone knows the rolling resistance of this tire and size that would be great.

Immediate plans (ones to be finished this year);
A more effective grill block, including ducting for the radiator
Mirror deletes using inside mirrors
5 Speed tranny from a base model (3.55FD, .72 5th, drops cruising rpm on the freeway from 2500 to 2000)
Aluminum flywheel, kevlar 4 puck clutch and heavy duty pressure plate (saves 6.25 pounds of rotating weight over stock)

Future plans (ones that will take longer, and more money);
Lightweight rims and low RR tires
completely redesigned front bumper
boat tail
full undertray
alternator delete
lower the roof 3-4"
Side skirts/wheel skirts
more weight reduction
lower the car about an inch

Currently im getting around 42MPG average, being careful and going 55 on the freeway, where most of my driving is done. EPA combined is 29, with 37 being the freeway number. I included one pic for now, of the car with the temporary mirror deletes and grill block, more pics to come later this week when i take them.

Daox 09-14-2009 10:13 AM

Nice work so far. I'll be blown away if this thing ever reaches 100 mpg. You got a lot of work ahead of you! Good luck. :)

TOOSTUBBORN2FAIL 09-14-2009 04:44 PM

thanks, im aiming for 5 days to work and back on one tank of gas by dec, which would mean just over 55 mpg. The transmission is a big deal tho, im cruising at 55mph right now, and im at 2500 rpm. The other transmission should drop me to right about 2000 rpm.

Ryland 09-14-2009 11:53 PM

The only reason that your lack of muffler is helping is that if you give it to much gas it will deafen you, a tuned straight pipe would help, or a megaphone (it would be quieter then nothing) but the lack of muffler is making your exhaust shorter so it's going to be more efficient for a higher revving engine, you most likely want it small around and long for slower RPM's, but mostly you want it tuned for your engine and engine speed, the cost is not that much higher for larger pipe, if a larger exhaust pipe really gave you better mileage, more power and girls chasing you down the street, then wouldn't it be standard on every car? no, because the people who designed it were good at math.

check out what tires are avalible in 165/60 R14 I think that is the correct size, tires for the Insight and for the Prius.

Christ 09-15-2009 12:06 AM

If you want to make money while getting better mileage, sell the R/T to a ricer and buy a SOHC Expresso or base model.

I don't remember which way it goes, but you can use 2.4 cams in your engine. I can't remember if they're better for low-end or high-end, though.

Maybe, if I decide to go EVan with my Caravan, I'll have a pair available.

For cam swap information, you can check out,,

They all have the swap info.

TOOSTUBBORN2FAIL 09-15-2009 05:12 AM

ryland - i havent shortened the exhaust any, i just used a straight pipe in place of the muffler, its still as long as stock was. Again, this was when the car was stock that i did the measurements on gas mileage for the muffler, so it might have made more of a difference then then it will when the car is finished. Final plans are for a moroso spiral flow muffler, since its supposed to be the best at cutting sound down without killing flow, and an insulated exhaust tunnel to keep the flow as quick as possible

christ - i decided to use the R/T because its clean, on the inside. The expresso would probably be a little worse, as its a little heavier then the R/T, a base would be ideal, but the problem which base models around here is 90% of them are autos, which in california makes them illegal to swap to a 5 speed. I tried that route, and got my car dinged as illegal. The other 10% are usually just trashed.

I was actually looking at both the stratus cams, and intake manifold, as its a super long runner with a small plenum, should move the torque down as low as possible.

TOOSTUBBORN2FAIL 09-15-2009 05:36 AM

as a side note, id love to go ev, but my commute and other drives wont let me at this point in battery technology. For example next month my finance and i will be driving 800 miles round trip to get married.

one of my main goals other then gas mileage is to try to keep the interior as nice as possible, no gutting for this car. My old gutted car got 45 mpg at 75mph, and it was an inch higher then stock due to the gutting. And has the windows down due to no ac. That car was a sohc neon with the same tranny i plan to put into this one, with a much larger throttle body, cold air intake and header. Car weighed 2000 pounds, compared to this ones current weight of about 2430.

When i rebuild the engine, im going to be going through a lot of things, such as fixing the restrictions in the oiling system and cooling system, such as the bedplate to block oiling port. Im also going to be using lighter rotating parts, and using swaintech coatings to both reduce friction and keep more heat in the combustion chamber. I also have an idea on reusing some of the heat from the radiator. The manifold should help, although ill have to keep the stock neon manifold for smog, cause no way will the stratus one pass visual.

RobertSmalls 09-15-2009 09:40 AM

Hmm, looks great so far, and you appear to have the least thirsty Neon here. I'm looking forward to some fuel log entries.

I would prioritize the tires (+ junkyard wheels if needed) and coroplast aeromods over the clutch and engine overhaul, as the bang:buck ratio is far higher.

100mpg is >300% of the EPA rating. I hope you really are too stubborn to fail, but not too stubborn to revise some of your constraints to get there.

Tygen1 09-15-2009 12:18 PM

I'd focus less on the motor and more on the EOC. Check out COZX2 over on Gassavers. He was able to get over 100mpg out of a mechanically stock ZX2. He only aero modded it and perfected the EOC. No boat tail on that car, just fender skirts and magnehilic testing to extend the coasts.

BackroadBomber 09-15-2009 12:59 PM


Originally Posted by TOOSTUBBORN2FAIL (Post 127875)
The manifold should help, although ill have to keep the stock neon manifold for smog, cause no way will the stratus one pass visual.

REALLY? is california really that bad? anyways, keep up the work and post alot of pics!

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