Does an upgraded exhaust affect fuel economy?

tinytim · Postby **tinytim** » November 20th, 2004, 2:44 pm

As it says above, how does upgrading your exhaust to a 2" free flow system affect gas mileage? The vehicle in question is fuel injected and N/A with a cold air intake upgrade.

At first, I was of the opinion that upgrades to the intake and exhaust would simply make the vehicle more efficient at producing power and would not negatively affect gas mileage. However I was advised that the opposite is more likely to be true.

To those that have already done these upgrades, what are your experiences with regard to gas mileage before and after? Any feedback on this would be appreciated.

Postby **MISHI** » November 20th, 2004, 3:31 pm

yep! More air goin out means more air to inhale. More air means more fuel to make more power.

I really can't say for before and after. I just changed from 1.3 Carb to 1.8 EFi. the Gas consumption is slightly better, but still drains pretty fast (that's my fault...too heavy a right foot :lol:

) I do have an aftermarket filter and yes it does feel different..but only slightly.

blu-rolla · Postby **blu-rolla** » November 20th, 2004, 10:12 pm

the ecu only allows you THAT much more fuel. yes you'll burn a bit more, but not to bust your pocket. if you start diggin up in your fuel system then yuh talkin gas guzzlin, just ask me.
but what really tends to happen is that with freeflow intake and exhaust, you tend to rev and 'mash dong' allot more like a fool, ER-GO, an increase in fuel consumption. (just ask me :mrgreen:

)

Rx · Postby Rx » November 20th, 2004, 10:29 pm

yeah bro......i have 2" exhaust and there's not much of a difference in gas consumption........but the car feels more ready to launch !!

free flow all the way !!!!!!!! :wink:

plex · Postby **plex** » November 20th, 2004, 11:22 pm

Not much difference in gas, but one thing exhaust does sound nice. But after all air flow is more efficient compared to OEM intake and exhaust.

Rx · Postby Rx » November 20th, 2004, 11:47 pm

the engine feels a whole lot better in terms of performance too..

Toysport · Postby **Toysport** » November 21st, 2004, 12:12 am

kes_vtec · Postby **kes_vtec** » November 21st, 2004, 3:17 am

yes

you'll be driving harder....

tinytim · Postby **tinytim** » November 22nd, 2004, 1:13 am

Just the kinda feedback I was looking for... thanks for the opinions. Gonna go ahead with my project.

Spyrogyra · Postby **Spyrogyra** » November 22nd, 2004, 12:15 pm

Timm-aaaa, read this first

http://web.tampabay.rr.com/redroby/3liter/exhaust.html

X2 · Postby X2 » November 22nd, 2004, 1:06 pm

The larger exhaust will have you run slightly leaner and make more power to boot. You shouldn't notice any difference it is so slight... BUT...

If you make more power, you will either:

A) Drive less aggressive since you don't want to break your neck from the massive surge of acceleration from your bangin' new muffler...saving gas

B) Drive more aggressive cuz the new found drone makes you feel like you're driving in an F1 effort...killing gas.

C) Drive slow so you can hear the subtle 'PaX ! PaX !' everytime you let off the gas... thus letting off the gas alot.... thus...saving gas !!!

:lol:

I crack myself up.

kes_vtec · Postby **kes_vtec** » November 22nd, 2004, 2:07 pm

X2 wrote:
C) Drive slow so you can hear the subtle 'PaX ! PaX !' everytime you let off the gas... thus letting off the gas alot.... thus...saving gas !!!.

i love C

Postby **MISHI** » November 22nd, 2004, 2:23 pm

HAAAAAAAAAAAAAAAAAAA

TK! · Postby **TK!** » November 24th, 2004, 1:46 pm

X2 wrote:C) Drive slow so you can hear the subtle 'PaX ! PaX !' everytime you let off the gas... thus letting off the gas alot.... thus...saving gas !!!

heheh. I really like to hear the harder, louder 'Pax' that rally cars make. Would someone go into a lil explaination about this sound and how to get it in your car?

hilux junkie · Postby **hilux junkie** » November 29th, 2004, 1:23 am

anyone know what size a ek3 97 civic non vtec exhaust pipe is.. i looking to take out d cat converter and upgrade d exhaust size.. x2 what is a safe size to run i have a 1500 d15b non vtec cvt.. with a cold air intake..

tinytim · Postby **tinytim** » November 29th, 2004, 10:23 am

2" - 2.5" depending on weather you getting mandrel or crush bends.

slustarlet · Postby **slustarlet** » December 2nd, 2004, 5:58 pm

the pax pax u hear from a rally car is anti lag keeping the turbo spooling when off the accelerator.

X2 · Postby X2 » December 2nd, 2004, 6:21 pm

civic boy wrote:anyone know what size a ek3 97 civic non vtec exhaust pipe is.. i looking to take out d cat converter and upgrade d exhaust size.. x2 what is a safe size to run i have a 1500 d15b non vtec cvt.. with a cold air intake..

I wouldn't recommend over 2.25" MAXIMUM crush bent, or 2" mandrel bent. Use a 18" resonator, no cat and a straight thru muffler... should be good to go and handle most bolt on upgrades you can throw at a 1.5

The pax-pax on the rally cars is normally the anti lag as mentioned, but the pax-pax you hear on street cars is normally caused by a rich condition. After the power stroke, sometimes, if the car is running a bit rich, unburnt and/or still burning fuel remains in the exhaust and gets pushed out the exhaust port... it's actually REALLY loud, but gets muffled by the exhaust system.... so it just sounds like 'pax-pax'.

tinytim · Postby **tinytim** » December 2nd, 2004, 6:28 pm

What's the suggested upgrade to replace a stock 1.75" mandrel bent exhaust with. In this case I'm going with crush bends, so I was thinking that 2" crush bends would have no effect, since with the crush bends will offer no big difference really.

Also, what's the difference between using a "trush barrel" and a resonator. Does the resonator also restrict the air flow? I'm going here on what I was told by the muffler man.

X2 · Postby X2 » December 2nd, 2004, 6:51 pm

If you already have mandrel 1.75", I wouldn't go with a crush bent anything if you're still on stock internals because 2" crush will be not smooth at all and really offer no big bonus. 2.25" crush will be better, but the 1.75 you have already has good flow characteristics. I say spend the money on a header rather than change what you already have.

A resonator is basically a straight thru muffler (prolly what he meant by 'trush' barrel.)

The big difference is that an actually 'muffler' will have more material between the perforated pipe and the outer shell. A resonator will have less material, but does the same job, just not as much as a muffler.

tinytim · Postby **tinytim** » December 2nd, 2004, 7:00 pm

Just what I thought... for now I want to swap out the catalytic converter for a resonator though, keep the stock piping and maybe put in a free flow muffler.

tinytim · Postby **tinytim** » December 2nd, 2004, 11:49 pm

My bad X2, stock is actually 1.5" mandrel bent. What you think... leave it and just replace the cat and muffler, or go with 2" crush bends? Oh... and I am on stock internals.

X2 · Postby X2 » December 3rd, 2004, 12:15 am

tinytim wrote:My bad X2, stock is actually 1.5" mandrel bent. What you think... leave it and just replace the cat and muffler, or go with 2" crush bends? Oh... and I am on stock internals.

Oh, stock piping ? You sure that's mandrel bent ? To my knowledge, honda only used mandrel B pipes and axle backs on the type R's. If your piping isn't mandrel and 1.5"... then I'd say definitely give 2" crush a go.

sleepertercel · Postby **sleepertercel** » December 4th, 2004, 6:12 pm

Changed my Exhaust to 2", added k&n filter and put in iridium plugs...didnt notice a significant increase in fuel use.

VW_Exec · Postby **VW_Exec** » December 5th, 2004, 1:28 pm

2.25" pipin from flex come back with a 2.25" resonator (blocked centre for added restriction)....N/A cars dont really like really large free flowing systems...u lose compression & torque

and k&n on a (1.6 DOHC)

no problems to date..just more power and swingin higher RPMS than with stock 1.5" - 1.75" piping.

fuel consumption is only more due to foot heavier on pedal...likin the VROOM VROOM sound...

:mrgreen:

TK! · Postby **TK!** » December 5th, 2004, 7:05 pm

i have upgraded 2.5inch all de way to aftermarket headers. meh air intake also upgraded.

i get approx 330 km on $125 premium with gas treatment ($15). running rich.

as the fellas say... mash hard = more gas. jus take yuh time :-)