GXlexus470

Has anyone tweaked their exhaust system... ie. headers, modified muffs, resonators... etc? on their GX. has there been performance improvement? Mileage improvement? how about noise levels... Any suggestions?
I am looking at this one from AeroExhaust. Anyone out there has these or similar one to their GX?
http://aeroexhaust.com/honda_accord_exhaust.html

cmarshack

Here is the thread that I put out for my new exhaust:

https://www.clublexus.com/forums/sho...ight=magnaflow

And there is definatley a MPG gain as well!

GXlexus470

SUPER JOB!!! Thanks for the reply, much appreciated. I am just hoping I can find a shop that can do one just like yours out here. Thanks again!

purplehazek4

Cap and I are also using the Magnaflow 14586 muffler. It's dimensions in size,inlet, and outlet are almost identical to the stock muffler which makes installing the muffler to the oem b-pipe a breeze for muffler shops.

Dan

GXlexus470

Great! Thanks, purplehazek4. Any comment on noise levels from inside and mileage?

tyoung88

Based on my brief initial searches of 14586 on the TundraSolutions forum it seems that there may not be any effect on mileage or performance with a new muffler. I'd be interested in reports from GX owners whether their experiences differ.

Skip

You will get nothing but noise by changing the exhaust. It will do nothing for performance or mileage. I would bet that you probably will loose gas mileage by messing with the exhaust.

A couple of years ago I installed a Magnaflow Cat Back on my 99 Ford Lightning. Made a dyno pull before we put it on and another pull a few days after it was installed. Magmaflow claimed 30 hp increase. What I saw was a 14 hp loss and about the same amount of torque loss also. Truck was louder than hell and it drove you crazy in the cab. Everything was data logged before and after and conditions were the same for both dyno pulls. Needless to say, I put the stock Ford muffler back on. This was done at Swanson Performance in Torrance Ca.

Leave your GX alone and just enjoy the ride. It is a cruiser, not a racer.

GXlexus470

Thanks for your comments. I will definitely research more into this before doing anything.

Lexmex

Exhaust systems have to really well thought out for power. It is often a balance of exhaust/intake, a continuing process on my RX.

purplehazek4

I have a True Flow filter, and with the Magnaflow i've gained about 2mpg. As Lexmex said, it is a balance...Engine draws in air with less restriction, and exits through the muffler with less restriction.

GXlexus470

Thanks, purplehazek4. I will look into it.

Lexmex

I would design something myself for the GX, but the only thing I have to really look at in person down here that is any comparison is the 4 Runner (no Lexus in Mexico).

I had a buddy a few years back who used to hit low 17s and also one of the local Toyota dealers was gracious enough to let me test one of their 4 Runners on the track and I was able to run a 16.9 after some general stuff (removing spare, shutting off electrical things like radio, low gas tank). Compare that to my best 17.931 in the 1/4 mile (we are at 7,411 feet). I am very sure I could get a 4 Runner in the 15s up here with a little work.

I'd have to take a look at some photos of the engine bay and take look underneath.

Generally, I like to have a y pipe after the resonator or cat (easier behind resonator) and additional widen the pipe between the resonator and main cat (anything else upstream depends on the state you live in), but generally I don't advise things like headers unless you are going to make some serious intake modifications (you don't have to have a supercharger, nitrous or turbo necessarily).

Inevitably, your best gains are always from the exhaust over the intake (i.e., only so much food you can fill into your stomach, but as far as what comes out when you take a dump...skies the limit).

GXlexus470

Thanks, Lexmex for your input. I will give it a careful thought and maybe ask for your advise when the time comes for the upgrade.

Lexmex

Always happy to help.

Skip

The bigest restriction in the exhaust is probably the cats. High altitude kills power but does not seam to hurt mileage. Less air, less wind resistance. The computer trims back the fuel so you are not running too rich. My Lightning made 9# of boost at sea level and only made 6# at 6750 ft. (Big Bear Lake).

To make a GX really run you would need a lot of power because of all wheel drive and the weight of it. If it ran about 11.90 and was dead quiet it would be a fun ride.