CosmosZ

I just bought a 90 HF CRX. ARe there any mods that will INCREASE the mpgs on this car? How does a header and good exhaust affect the mpgs on these cars? Not looking for power, just wondering if helping the engine breath will result in more mpgs.

BiG ChOr!Zo

iTrader: (1)

you already get about 45 mpg if its still the stock hf motor...just add a el cheapo air intake and a egay header and you should be fine...!!!

CosmosZ

Thats what I was thinking. I can't leave anything stock. lol

~sp33~

I think that Honda's' engineering skills surpass anything you'd buy on eBay. I'd leave it stock.

Increase your tyre pressures, don't drive with your windows down, tailgate everyone. That might give you another 3mpg lol.

DPSJosh

Strip it! Lighter cars get better mpgs!

*ctrlaltdel

wow, you want better mpg yet don't want to leave it oem? you should figure out your priorities. plus, you get what you pay for. doesn't mean spending 500 dollars on an exhaust will make it so much better than someone who decided to bend their own.. spending money on an intake and exhaust is counterproductive. spending roughly 500 dollars to maybe get 1-2 mpg, doubt it, doesn't make sence.

DPSJosh

I don't think an intake would help too much because introducing extra air into the motor would require extra fuel, as the 02 sensor is going to read lean. Seems like a header WOULD help because if there is less restriction, the engine doesn't have to 'pump' as hard to get the exhaust out of the cylinder. If the exhaust becomes too large, you lose velocity and scavenging from the cylinders though, so it's a double-edged sword. Any time you can make the engine more 'efficient' without needing to add more fuel it should get better mpg. If you can make the car lighter, that would be the easiest way to make it get better mpg, especially in the city.

ALLxMOTOR EG

Stock is the best way to go if you want good mpg.

Clean your stock intake box filter or get a new filter.

Do the basic tune up like spark plugs, spark plugs wires, and put in injector cleaner.

Also by the way you drive it will vary on your mpg.

AJxr

x2

0ne-Cam

Change the fuel filter. But has anyone ever installed an aftermarket FPR and adjusted the psi? Will that do anything to the mpg?

dacrxguy

if you are shooting for mpg i would not mess with the exhaust manifold. the manifold/cat combo is there for a reason get your cat warmed up fast for best emissions and you o2 warmed up fast i would leave that at that. there are other ways to get the best mpgs but they require alot of money and are not really worth it

dacrxguy

air fuel mix wil lbe affected to rich to much psi to lean not enough psi

ed4doorcivic

when did u get it? did u get it from a dude that works at toyota? and his girlfriend drove a BMW?

CosmosZ

You serious? Got it from my roomate.

ed4doorcivic

ya i was serious, but i thought u were sum1 else, my boy just bought a 90 hf crx 2 nights ago

DPSJosh

Fuel pressure wouldn't do too much. If you pull pressure, your 02 will see lean and open up the injectors more. On the other hand, when your car is not looking at the 02 sensor and going off factory maps, it would lean out some and may not fully compensate.

Yes the factory exhaust was designed to get the cat to operating temperature, but that's for emissions, not neccessarily for MPG. Honda's are pretty dang efficient to begin with. They run pretty close to 'lean' from the factory meaning you are getting decent gas mileage. Of course there are always a few mpgs that are sacrificed to 'comfort' such as a quiet intake and quiet exhaust.

dacrxguy

the factery o2 is placed really close the the engine and you have to remember that you are dealing with a unheated o2 sensors(one wire) and the faster you get that sensor heated up then the faster you can get out of closed loop which will get the best mpgs manty after market header place the o2 farther down and are made of different materials that disipate heat faster so you have to take that into consideration to

OneBadTurboCRV

Now you are all going in the wrong direction, with the right tools. IF you knew anything about cars you would know what the answer to the OP's silly question is. Any novice would know the answer is all in the tune.

This is the only true way to gain mileage with-out getting extremely drastic and changing a lot of things. You may gain .5 MPG here or 2 MPG but collectively you might only end up adding 2-5 MPG. What a waste of time and money. Also, OP I told you about these pointless posts would happen... but already? Yikes.

(If you disagree with what I had to say, then tell that to the kid getting 80 MPG with a HF and shooting for over 100 that is on here.)

DPSJosh

https://honda-tech.com/forums/showth...ht=hypermilers

OneBadTurboCRV

HELL NO!!! The guy I am talking about has a regular looking car. I am pretty sure it is turbo charged as well...

DPSJosh

WTF, are you saying that car doesn't look badass? I've been at it all day and mine looks very close to it now. The only difference on mine is that I used cardboard and aluminum foil so it's shiny.

No, I have not searched, but maybe someone has had some luck on this site with an HHO setup.

OneBadTurboCRV

Post pictures of that, NOW!!! LoL...

CosmosZ

Ick. lol

N3va3vaSatisfi3d,

I agree that a tune wouldn't be worth a basically stock car just to increase mpgs. If it gave me 10 mpgs more it may be worth it.

88Hatchy

best bet for better mpg is to do a tune-up, lower it, add a lip, passenger side mirror delete, get some vx wheels and put 50 psi in the tires

OneBadTurboCRV

I worded that wrong, as I now see. I meant all those low MPG additions would be from things like exhaust. The true way to get MPG is in the tune. Adding things or changing things will only force the stock computer to try and compensate. You get around this with a tune. It forces electronicly what you are trying to do mechanicly. The guy on here is also trying to run almost 25:1 AFR at cruising speed! Yes, I understand that is extremely lean, but if I recall correctly he was at around 20:1 and getting about 80 MPG. So if you invest in one thing, get a ECU setup that allows you to tune. If you don't know how to tune, learn. It is easy if you understand engines. Most people that don't, just learn through trial and error. You have to understand how fuel, ignition, and engine load directly effect the motor for starters. Regardless, I personally only use S300 out of the lot; mainly because it uses the OEM computer and is very user friendly.