Ok guys my 97 talon is my dd so I have been doing all that I can to get the best mileage possible. On the highway I normally get about 33-36 mpg. In the city I get about 25-28 mpg. I know this is good but I want to see just how good I can get. There are quite a few things that I have done to the car already to help but I just wanted to get some opinions on what else I can do. So far I have:

-checked compression (195-200 psi across all cylinders)
-changed fuel filter
-k&n air filter with holes drilled in air box
-new spark plug wires
-seafoam (cylinder soak, through pcv, in crankcase, and in gas tank)
-new spark plugs
-I always make sure my tires are inflated properly probably a little high actulally (40 psi front 35 psi rear)
-I also normally drive like a grandma shifting @ or below 3000 rpm
-new pcv valve and gas cap (more on this)
-new front o2 sensor

There are a couple of things that I have thought about doing to help me out.
-First I have a few large cracks in my exhaust manifold, would I be better off getting a cheap header or just replacing the exhaust manifold with a used un-cracked unit? I don't really want to spend very much, this isn't my race car, I have a vr4 for that.
-I have heard however that people have picked up a few mpg's with a cat-back exhaust system, is there any truth to this, and would a high flow muffler (gst?) do just as well?
-Also, I have a code 31 cel hence replacing the gas cap and pcv. obviously that didn't fix it, is there any possible way this could be hurting me even a little?
-What about and underdrive pulley, would slowing down the accessories be more efficient?
-Last, I am currently using regular ngk spark plugs, would I see any difference switching to a different brand or even platinum plugs?

Let me know if you guys can think of anything else to make my car a gas sipper!

Originally posted by spartan
First I have a few large cracks in my exhaust manifold, would I be better off getting a cheap header or just replacing the exhaust manifold with a used un-cracked unit? I don't really want to spend very much, this isn't my race car, I have a vr4 for that. -I have heard however that people have picked up a few mpg's with a cat-back exhaust system, is there any truth to this, and would a high flow muffler (gst?) do just as well?

You might be able to pick up a little bit of mileage from a less restricted exhaust yet at the same time, for the price of a full exhaust, you're probably better off just replacing the manifold with one that is not cracked Otherwise, for a complete exhaust you are most likely looking at at least $400 (unless you use a gst catback)

Couple free options:

-Have you done any weight reduction? Granted its understandable people don't want to get too crazy with stuff on their DD, but less weight means greater efficiency.

-Also, you may want to consider losing that high rise spoiler as it may be creating some unneccesary drag.

I wouldn't expect to see much of an improvement from either of these, but you seem to be looking for any little bit so worth an attempt considering it won't cost you anything (depending on how crazy you get with weight reduction. You could go crazy with CF/fiberglass hood, fenders, hatch)

I really wouldn't worry about the CEL either unless you have to go for an inspection. It's a very elusive one that IMO is not worth the time or money trying to fix/diagnose. People have replaced their entire evap system and still haven't been able to get rid of this code in the past. Hell the last time I had to go for inspection I just reset the ECU and by the time I got there I passed :D

http://forums.2gnt.com/dcboard.php?az=show_topic&forum=4&topic_id=89530&mesg_id=89530&listing_type=search

Since doing this analysis, I have logged several tanks averaging 38-39 MPG. Around 550 miles to the tank. A lot of the time I was in traffic too, so my highway MPG was probably in the low 40s.

This time around, I went with the same mods, but altered my driving technique. Slow acceleration and slow braking, maximum 65 on the freeway, and generally just crusing non-aggressive driving. My mods were the same as listed in the above thread. I also ran on the 14s during that time (thin width tires, no spokes, the hubcap probably is low drag :) ) I definitely wasn't styling, but I could stick it to big oil with the best of the hybrids.

keep those regular ngk's I never saw any difference between platinums and the standard ngk's. fix or replace the manifold. the Udp's help a little, but you won't notice much.

I'd suggest an exhaust system upgrade, but only along the lines of El Cheap-o Performance. Based on ez's in-depth report in the link above, sounds like it might be worth your while.

Aside from the downpipe and an additional resonator, the only other difference between the exhaust system in a 2nd gen GST and NT is the rear section of the exhaust with the dual tip muffler. Piping diameter is the same size, but speaking from personal experience, the stock GST muffler sounds really good on a 2GNT. Also keeps the stock look and prevents most asshats from wanting to race you.

If a GST muffler is hard to come by, consider the rear section from a 3rd Gen GT. I know a couple running that one and it bolts right up with minimal tweaking. Sounds pretty good too. Either will reduce backpressure in the stock exhaust and cost relatively nothing compared to some kind of stainless steel aftermarket c'mon.

I've always felt the low coefficient of drag offered by these cars has been the biggest factor in our mileage. Our slippery shape means we don't need as much power to maintain speed. On a mixture of city/hwy driving, my Talon (a far cry from looking as sharp as yours) never gets less than 400 miles to a tank. On long hauls where I'm actively driving with the prize in mind, I have crossed the 500 mile marker a couple times. I think my personal best ever was 520-something. Of course, the next day, I lost a wrist pin lock and the car was down for over seven months, but I digress.

Let's see the GVR4 while you're at it. I've made mine the daily driver while I slowly, but surely detune the Talon and get 'er legal again. It also helps me to get 195 sorted before I go crazy building the hell out of it. I hate the gas mileage in the Galant. I'm lucky if I get 300 miles on the highway in that turd and it's no faster than my 2GNT. :P

EDIT:
I knew I'd seen you on GVR4.org. You did that custom grille last summer, right? I remember thinking that was pretty slick. I also dig the way you have that little battery mounted in the bay so you can use the intake you chose. :thumbsup

Thanks for the kind words DR. My galant has been in storage since January really, I was busy this winter removing the abs, ac, and doing some other general clean-up. Unfortunately it's going to be in storage for while longer too, as the turbo is smoking out the ass and I refuse to put any more money into it until I graduate college (December). I will definitely keep my eyes open for a different manifold and rear section now that you guys are saying it should help. Here are some pics of #1699

quick thought, how many miles does your car have? if you're over 100k a fresh O2 sensor can make a difference

Originally posted by spartan
Thanks for the kind words DR. My galant has been in storage since January really, I was busy this winter removing the abs, ac, and doing some other general clean-up. Unfortunately it's going to be in storage for while longer too, as the turbo is smoking out the ass and I refuse to put any more money into it until I graduate college (December). I will definitely keep my eyes open for a different manifold and rear section now that you guys are saying it should help. Here are some pics of #1699

Very nice ride, man. I've got a cracked radiator, blown head gasket, and possibly some shatty valve seals. Smokes at idle and annoys the hell out of me. (Makes waiting in drive thrus really tough.)

Good luck with getting it back on the road soon and with the economy project for the Talon. :thumbsup

It may not be something that you want to do, but put the 14 inch steel rims and hubcaps back on. I have a 97 as well, and when I took the rims off and put the steel rims back on my mileage went up to 44 highway and around 36 city. Car is a manual with 136000 miles.

dont EVER romp it and you should see some results. Also keep from using the breaks as much, use the engine as a break, and slowly decelarate until you are almost at a complete stop. Clean air filter, clean injectors? try running some seafoam in your car. Make sure all your fluids are topped, friction is the main enemy inside the engine! :P

edit: well i see you already did seafoam and filter, sorry.

Good point about the GS-T mufflers Brian; they are getting about as scarce as the cars themselves (still plenty of NTs around, but since 85% of 2Gs were NTs that is what you would expect).

Ok, as for improving mileage, even the muffler helps (I like the idea of the 3rd gen muffler if your short on money), and anything you do to help the car breathe better (within reason) will help as it improves volumetric efficiency.

I did notice a little improvement with the under drive pulley, the cold air intake, and the muffler. They all add up for noticably better mileage. The modded intake manifold and high flow cat probably helped too, but I'm not positive about that. (Doing ANYHTING to help our intake manifold is a good idea in general) Staying on regular sized tires (the size that came with the car) should help too; less rolling resistance and weight compared to heavy rims and tires.

When the car was stock I could get a best of about 33 mpg on the highway. Even with all the mods on my car now I know I can get 35 mpg on the highway. I got 37 or so mph on the highway when I was travelling back from the shootout one year but I don't remember exactly which year, or what mods... I'm getting old or something...


Hmm, you could get a used SAFC and lean it out a little while at part throttle, but I don't know if that will help much since pretty much every car's computer is tuned from the factory for best mileage at part throttle.

There are a couple of somewhat inexpensive mods you could do.

1. Windage tray for your oil pan would free up some friction
2. Definately use Mobile 1 full synthetic 5w-30
3. The best fuel system cleaner is made by BG (44k) is about $25 per can but is well worth it.
4. There is a rumor that the vents you see cut in the back bumpers of some cars (allthough very ugly) releases trapped air that collects at the back of the car (cutting drag) - I did find one interesting article; http://www.tprmag.com/issue/13/13_aerodynamics.shtml

Good luck with it all, and let us know how it all works out. I'd love to stick it to the big oil people.

By windage tray do you mean something like a crankscraper? I have heard of them but haven't really looked into it at all. I ended up getting a 2.5in catback system used for $100, cut off the fart can and put on a dynomax muffler. It is still kind of loud for my taste so I will be adding a resonator soon. I have ordered everything for my head gasket change, so that should hopefully be fixed next week. I am also trading the fart can muffler to someone for an uncracked exhaust manifold.
Interesting thing happend last weekend when I was coming back from picking up the exhaust. I was running late for a tee time so I decided to see how far I could go once the gas light came on. I ended up making it like 60 miles and still didn't run out before I put some gas in. Man it was weird seeing the needle like 1/8" below the E!

Dont know if anyone said it but a 3:55 final drive would help.

Good point on the 3.55 trans, but while close to stock NA it kinda bogs down the engine, and the farther you have to put your foot into the "GO" pedal the more fuel you'll use. it's something I've learned with the WRX that it's better to be in a lower gear and get into the boost a little to accelerate with less pedal than to be in a higher gear where you have to put your foot to the floor just trying to get the car to move.

well, if replacing your header will not make a difference just keep it the same, if you cant afford it. you said there is a few cracks, i had the same problem. i saw a big crack so i ordered a new header but when i took the stock one off nothing was showing on the inside. the crack was just the surface weld cracking, but i liked the new header. it looked alot better.

Originally posted by RoninEclipse2G
Good point on the 3.55 trans, but while close to stock NA it kinda bogs down the engine, and the farther you have to put your foot into the "GO" pedal the more fuel you'll use. it's something I've learned with the WRX that it's better to be in a lower gear and get into the boost a little to accelerate with less pedal than to be in a higher gear where you have to put your foot to the floor just trying to get the car to move.

True, giving it a bit more rpm's wastes less fuel then loading the engine more.

Pretty much, anything you can do to get the air in faster (less effort) and more of a "mix" in the cylinder, will help.

If you want to go crazy... higher comp.

Avoid lightened flywheels. - well depends on your engine and driving

Originally posted by Chamuko
Pretty much, anything you can do to get the air in faster (less effort) and more of a "mix" in the cylinder, will help.

I've heard match porting the head and intake manifold with the jeep throttle body helps a bit, reduces the restriction and improves the flow a bit, but I don't have any proof to back it up

Originally posted by spartan
Interesting thing happend last weekend when I was coming back from picking up the exhaust. I was running late for a tee time so I decided to see how far I could go once the gas light came on. I ended up making it like 60 miles and still didn't run out before I put some gas in. Man it was weird seeing the needle like 1/8" below the E!

I've had the needle disappear completely before filling up. now that makes you a bit nervous.

Ok so I forgot a few things, and I had a chat with an old friend that was very sharp with fuel milage. Again, some cheap mods;

1. Ignition improvements - Multiple spark discharge (Crane Fireball has the highest energy output) and Also include a new MSD coil and wires. As for plugs, if you choose to use NGK try a hotter plug and "index" the gap on all plugs to face the intake valves. Or, you could try the Bosch platinum 4+ (I used them before I went turbo and noticed a smoother daily drive and better W.O.T. response) And a racing secret (shhh, don't tell) is that if you DO have the MSD or Crane ignition box you can actually significantly widen the gap (you have much more spark energy to bridge the gap) and that's also why I think the combo of an ignition box with the Bosch 4 prong plugs would work very well to burn all the fuel.

2. Fuel improvements - Don't ever believe the myth that your engine will explode if you ever use less than 93 (or here in Denver 91) octane. The manual suggests 87 octane. The car runs GREAT on 87, it won't knock or ping, and it will turn out a better emissions test and better milage than higher octanes. There is a common misconception that high octane fuel gives you more power and better economy, and that is false: Higher octane resists preignition and detonation, however it also burns slower and less efficient. If you have a high performance motor (Corvette Z06) with high compression, your sensors will detect lower octane knock and hurt performance, example if you purchace 85 octane (I've only seen it in Colorado) it could set off the knock sensor, which will cause the ECU to cut timing, (that's how the octane myth evolved). Remember our cars only have 9.6:1 compression - a typical Honda motor is 9.9:1 if not 10:1 and those motors run fine on 87. And if you want to spend a few bucks, there are fuel additives like "Ethos Fuel Reformulator" which I know some stage 3 SRT guys love for drag racing. Or, there is the Fitch fuel catylist that installs inline like a fuel filter and garuntees better economy.

3. Drop the suspension - Allthough most people drop the ride height for looks, it really does have some aerodynamic improvements (less air going under the car) And if you complement a drop with a camber kit (all 4 wheels) to keep your tires running at factory camber (less rolling resistance - a 2" drop will make you ride the edges, and destroy tires quickly) To demonstrate, some years back I was having a bad Vegas trip, so I left all pissed off and speeding back to LA, I ended up at 146mph and still climbing very slowly (about 50 miles from Vegas on the I-15). All I had then was the AEM cold air and a Borla cat back and a 2" drop (no camber kit) And I imagine the car could only have been 115 to 123 whp. That (dangerous and stupid move) I attribute to good aerodynamics.

4. Underdrive pulley - A BIG pain in the ass to install, at all engine speeds it could save a little off your fuel consumption

5. A FREE trick - keep your windows rolled up for better aerodynamics, and use outside vent air to keep cool.

And about the 3.55 gear ratio tranny - the truth is that it's a real pain in the ass for daily driving. And, it's a lot of time an money to find one and get it in your car. My '98 is constantly in "perma-spool" because of it, and my milage went out the ass. With 270cc injectors and the Hahn 16g I get about 18 to 22 mpg. I could be driving a Hemi with better milage! I really miss how I could drive all week and get 450+ miles per tank.

Originally posted by Wiley Coyote
and Also include a new MSD coil and wires. you could try the Bosch platinum 4+

the MSD coil hasn't been proven to be any better than a stock unit, there has been MUCH discussion on this. also the bosch 2's and +4's along with irridium plugs tend to work horribly in the 420a engines, many reports from tons of members here on this site getting nasty misfires, myself included. maybe it was the combo of an ignition box :shrug:

Originally posted by Wiley Coyote
2. Fuel improvements - Don't ever believe the myth that your engine will explode if you ever use less than 93 (or here in Denver 91) octane. The manual suggests 87 octane. The car runs GREAT on 87, it won't knock or ping, and it will turn out a better emissions test and better milage than higher octanes.

very good point! being at higher altitude also affects what octane you can use, the higher you are, the less octane you need. Wiley, I'm in Parker (southeast denver metro area) and my car runs GREAT on 85 up here.

another trick is to find a NON-ethanol fuel station, even the 10% ethanol that they throw in normal gasoline reduces fuel mileage a decent ammount. out southeast of where I live is a Phillips 66 station in a non-emmission regulated county that sells straight gasoline, NO ethanol. Every chance I get I fill up there, and I usually average an extra 100 miles to the tank.

Originally posted by Wiley Coyote
And if you complement a drop with a camber kit (all 4 wheels) to keep your tires running at factory camber (less rolling resistance - a 2" drop will make you ride the edges, and destroy tires quickly)

actually more camber gives less rolling resistance, but it will greatly upset the handeling of the car, which can decrease fuel mileage just from the extra resistance all that extra steering causes

Originally posted by Wiley Coyote
And about the 3.55 gear ratio tranny - the truth is that it's a real pain in the ass for daily driving. And, it's a lot of time an money to find one and get it in your car. My '98 is constantly in "perma-spool" because of it, and my milage went out the ass. With 270cc injectors and the Hahn 16g I get about 18 to 22 mpg. I could be driving a Hemi with better milage! I really miss how I could drive all week and get 450+ miles per tank.

you might want to check that your injectors aren't running at maximum duty cycle (never closing) that's really piss poor low, even with a 3.55. 270 injectors seem small to me.

Originally posted by RoninEclipse2G

Originally posted by Wiley Coyote And if you complement a drop with a camber kit (all 4 wheels) to keep your tires running at factory camber (less rolling resistance - a 2" drop will make you ride the edges, and destroy tires quickly)

actually more camber gives less rolling resistance, but it will greatly upset the handeling of the car, which can decrease fuel mileage just from the extra resistance all that extra steering causes

Running extra camber won't upset the handling of the car as long as you ensure that you have 0 toe. All the extra camber will do is make the inside of the tires wear about 3/16" more than the outside of the tire over the life of the tire.

Too much toe on the other hand will scrub all the tread off the inside of the tires in a few hundred miles. Even if the tire is brand new.

I'm speaking from what I have seen as I do have a friend that runs about 5 or 6* negative camber on his car. There is slightly more wear on the inside of the tire. Typically by the time it becomes a problem the tires need to be replaced anyway.

I wouldn't run more than maybe 3* total negative camber up front (that's about 1.5* more than stock) just because with a double wishbone suspension setup, you will add more negative camber every time you turn the wheel allowing the car to have a flatter contact patch.

Sorry about hijacking this thread.

Thanks guys for the tips. I am actually right in the middle of tearing my car down to change the headgasket/ timing belt, and then also install some gr2/ tein setup. I am hoping that they will lower the car some but that I also won't need a camber kit to go with them. I have another question though. In my stupidity of never using a puller before I put the arms on the outside lip of the pulley and now I have two chips in the lip of it. I am just wondering if I need a new pulley now? I am assuming that the pulley needs to be balanced but I am not sure if these small chips will really affect it. Let me know what you think ASAP so I can order an udp like today or tomorrow if I need to. Thanks guys...

Yea, i would get the udp to be safe. i wouldnt want broken parts on my car. Would probly screw something up fast.

That's EXACTLY how I ended up having to buy the underdrive pulley. That stock pulley just doesn't want to come off easy. It may have helped if I had the proper sized gear puller (a small one) but yeah, I'd get a stock replacement for cheap. (I really didn't notice anything with the AFX underdrive, except $150 less in my bank account)

Thanks guys, I ended up ordering one last night. I have another question though. I am in the middle of trying to set the timing with the new belt, and I am wondering how much deflection there should be between the cams. I have the timing marks aligned but when I slip the belt on it can almost touch the hole for the viewing bolt. Is this too loose? I really don't want to mess this up as it is my first time. Thanks