dtaylor

07 GX470, 140k on the clock. I have no exhaust system issues, but wonder about exhaust options that may lead to a little better sound, and possibly more performance. I'm old school and in the past built from scratch several hot rods and even a few ricers to perform better than stock. The process usually begins with intake and exhaust. Never modified any Lexus vehicle for more power, so I would like to know if any of you have had success with building more power with the GX. It certainly isn't under-powered like my old 96 Land Cruiser was, but being a life long lead foot, I always want more power out of whatever I'm driving.

I've seen a few posts here about headers that look like that brings trouble, and others that say there are manifold problems. How about K&N intakes, cat-back systems, or just ideas on a better performing muffler-back?

Thank you in advance. I find this site to be a wealth of knowledge and experience.

LoneHiker

Toyota builds the 4.7 to get everything possible out of it, it's not like the American V8's where you can bolt on a bunch of cheap power mods and wake it up. This is mainly due to the dual overhead cams and variable valve timing.

The GX has 4 cat converters. The stock manifold and cat setup are designed to optimize torque in the normal driving rpm band. Switching to headers will cause scavenging to suffer. You'll lose a lot of driving band power in order to pick up a tiny bit of top-end horsepower.

The nice thing is that with 4 cat converters, basically anything goes after the cats. You could straight pipe if you wanted to. When my muffler rusts out or I get bored, I'm thinking of using straight pipe in place of the muffler while leaving the resonator in place.

If that doesn't work, the best muffler setup I've heard on youtube is the Magnaflow 12288 with resonator in place:

People with the Gibson say it's too loud, but you might like it:

Some people have gone dual exhaust, which is a lot of effort for almost no difference in sound or performance lol:

chiph9

Agree. The 4.7 in the GX is a torque motor, not a horsepower motor. Has to be in order to get it's massive weight moving.

Chip H.

dtaylor

Pretty interesting, and useful. Thank you gentlemen.

dtaylor

So, after hearing both with and without resonator, I went with Magnaflow, no resonator, and a 12 inch chrome tip. LOVE the sound. Reminds me of some of my old dual exhaust cars / trucks. Currently doing a gas mileage test just to see if any difference on mileage. I'll post a video as soon as someone here can tell me how to upload it. Do I need to post it to Youtube first? Better done with GoPro or Iphone?

Next service will be brakes. Next add will be intake. LED bulbs in all places.

MrTorgue

Reviving this thread instead of creating a new one I’ve got a question.

What I’d like to know is would cutting out 2 or 3 of the 4 cats (4 cats?) throw any codes? I’d like to just replace the muffler with a magnaflow and take out some cats. Just want a tiny bit of noise. While I like the power gains from a full header back system that’s more $$ than I want to spend. This isn’t a drag racer so it’s pointless to pay that kind of money for what we will be using it for in my opinion. If I wanted more power I’d just supercharge it. Though I am interested in a tune but more for road trip economy reasons than power gains. I’ve got my ‘18 Charger R/T if I want excessive noise and speed.

Thank you in advance for any info.

maddtv

Which manga flow did You go with? Chrome tip?
Links will be greatly appreciated for purchase. Thank you, sir.