Rocan

Neofate, that post was very very good. Thumbs up to ya!

Neofate

iTrader: (1)

Thanks.. just what I've learned from experience on other engines -- but the same theory applies to even the Lexus. An engine is an engine,.. Alot of people get the impression that a 'performance' mod automatically = loss in fuel economy, when the opposite is true with some of the more basic modifcations.

The first steps in modifying a stock engine is to simply make it more efficient than the factory design. This gives hp/torque and by virtue of being more efficient allows for better fuel economy with a 'light foot' -- (Often not the case, because who wants to drive like a granny with new performance mods.. but nonetheless it is there if one were to drive proper)

Rocan

the thing is, a better flowing engine requires less power to move, so your post is right. you dont need to have the pedal down as far as with the stock engine, so you get better MPG.

nosechunks

X amount of fuel can produce X amount of energy, an engine makes that conversion. the only way to increase fuel economy is to make the same fuel produce more energy, assuming you don't run a lean cruise of 15-16:1.

Improving airflow will only improve fuel flow assuming air fuel ratio is maintained by the ECU at 14.7:1.

Neofate

iTrader: (1)

You would think that no matter the air flow it would directly, proportionately, cause a downward curve in fuel economy.. but it doesn't always.

I'm trying to think of a good explanation why heh..

More air, the computer spits more fuel, logically.. More fuel = more gas wasted.

But, if the air + fuel combination is creating a significantly more efficient combustion cycle, then that cycle might be propelling the drive shaft with X power that offsets the increased fuel. Make any sense at all? (This is off the top of my head..)

Umm. I know if you open up the breathing in general.. intake/throttle/all the way through headers/cats/mufflers/tips -- It generates better fuel economy. In fact the best fuel economy modification is based around breathing. If you do it all, you'll get a significant amount of efficiency.

The key word here is efficiency, not the amount of fuel the computer is burning per (whatever). Its the efficiency of the overall engine with these mixtures.

Slap on a turbo, and you have a huge air displacement change, thus a huge need for fuel (so much so that the factory fuel system isn't enough generally, and could cause a lean condition) -- So then slapping on larger injectors, fuel pump/higher psi and so on.. lower fuel economy..

Though with the proper application , using the spill/wastegates very efficiently.. Turbo's can also improve economy.

The sad thing is I just don't know enough to prove my point

Oh well

jcrome04

Well I'm content with the stock set-up,

I have no intention or want to start cutting holes in things and ducting in new pipes and crap.

And as far as the mufflers go, I'm just changing the mufflers. I'm not looking for a performance increase. I just want the look of some nice chrome tips back there, and maybe a bit of sound.

skperformance

iTrader: (6)

Be content unless yo find a shop to do it properly for you.
I have a fully ducted cold air intake on my ls with the exhaust reworked to reduce the restrictions to only the pipe diameter of 2.25 and not the curves and merges.
I also get unbelievable gas mileage with a heavy foot.

Alan D

I have owned a few vettes and you always had to reset the computer or drive for over 200 miles to get the computer to "learn" the new mods. Don't know if that applies to the LS though. Seems like it would be worth trying.

PureDrifter

iTrader: (10)

yea, either driving a few hundred miles or resetting the ECU and driving maybe 100 miles will let the ecu relearn the car+your driving style.

jcrome04

Hey SKP do you have any photos of your intake set-up??

TJW98LS

iTrader: (1)

I filled up a couple days ago and my Average is 13.8 MPG for he tank...how terrible his that. The majority of the driving is trying to find a damn parkingspot on a moutain campus + people here drive like 25 MPH under the speee limit causing traffic jams thus sitting in traffic = worse MPG...

BTW,anyone see the WKU vs. UCLA game... I think the Bruin got the best of ole big red...

jcrome04

13.8????????? Ouch! Sorry man.

Oh, and my mileage is back up to a 21-22mpg avg with the stock intake back together.

Got my mufflers yesterday, I'll get pics online and post em up soon!

steveski

Yeah 13.8 is tough - I still get over 24 MPG and on the last tank got 26 MPG even with Lexkost's intake Mike - you should get paid a royalty since you are a bit of a celebrity with this modification

LiCelsior

iTrader: (32)

i would put back the stock airbox back in BUT my HID ballast are sitting under the filter and too lazy to find another place to put em . but with my exhaust leak, it sounds better inside but i have no idea outside.

Rocan

where the hell is this mod anyway?!

i plan on opening up my ls4 as soon as i get it. i like it when things breathe.