YODAONE

Stock Lexus exhaust systems incorporate exhaust dampers... see item # 17581. If you remove these, you will notice more drone and vibration on even a stock exhaust. Different configuration for various Lexes models . See previous posts from YODAONE. Also, a lot of discussion about how tp modify a standard LS400 exhaust. Attached is diagram of LS430 exhaust system. Cropped portion depicts what appears to be a post catalytic Y pipe which appears to have an H pipe, albeit short. Arguably the LS430 exhaust (not including exhaust manifolds..reversion to log configuration) represents an improvement... No doubt the OEM spent engineering time on this. Fewer parts....less extreme angles and diameter transitions.

Benen

Cool, i might see if i can find some dampers while its out of the car.
Im not modifying the standard exhaust however, ive made a complete new one but am following the stock exhaust configuration for space, ease of manufacture etc.
What im trying to find out is if anyone else has a similar setup or know if putting a resonator in will reduce the drone on load that im experiencing.
The LS430 diagram is a good reference, im looking to do the same thing but at the moment on the #17410 diagram i have just a straight pipe which is where im looking to put a resonator similar to the two in the following Y pipe.
Just hoping someone has done similar and has any comments

bwells79

I have a 1999 LS 400 and it makes a lot more noise than it should. I thought it was leaking at the Cats, so removed and re-installed with fresh Silicone. No significant improvement. Each of the pipes that goes back to the 'Y' before the first muffler (?) has thin sheet metal cover. One had the original clamps and the other had hose clamps. I removed those and the insulation was completely deteriorated. The pipes are also showing significant rust. Should I replace these? Is it possible to get the insulation and refurbish that way?

There was a comment about the dampers. After 18 years, can these get hard and become less effective?

PureDrifter

iTrader: (10)

If you have extensive rust you probably have a hole somewhere in the system, take it to an exhaust shop and have the rusted out section replaced.

Stanislav

Hi all, renewing dead thread
Everybody talking just about muffler delete or complete new catback exhaust. I'm wondering about removal only two pre-mufflers, leaving rear two mufflers in place. Has anybody tried that?

Why I want that? Because after long readings, comparing youtube videos etc. I realiased that removing only rear 2 mufflers makes sound not so nice, too high tone, something simmilar to 6cil BMW. Removing all 4 makes sound better, low tone, but too loud for daily car. Also pre-mufflers makes sharp edges, exhaust without them will be more straight, so maybe it would be a bit better for performance. And it would be easier to make, just weld a new pipe, no need to think about mountings. Ant last more personal reason is because mine rear mufflers is like new, although pre-mufflers is in bad condition, rusty and damadged.

What do you think?

lowstrife

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Stanislav

In this video I think is complete custom exhaust.
I mean to remove only pre-mufflers leaving everything else stock. Or in their place install simple universal resonators.

Moarpower

Its a lot easier to remove the rear mufflers and it is still quiet enough

Stanislav

I'm wondering not just about volume, I'm wondering more about sound tone. In many youtube videos after "rear mufflers delete mod" sound is more like from metal bucket, not like deep low V8.

Moarpower

I removed mine and it was quiet at idle and sounded great under load. The pipe diameter is too small for a real low tone. I have since rebuilt mine using all 2.5 inch to the 1st muffler set, then 2" out to the rear of the car and it sounds like a mustang. I also added an x pipe in place of the y pipe

Moarpower

the video you posted was only moded from the rear axel. They removed the rear mufflers and installed the canisters at the very back, leaving the first muffler set in place.

Stanislav

So, have been experimenting with my exhaust
Firstly cutted holes before rear mufflers. Sound was nice, deep at low rpm, but at revving it was not so good, almost the same as stock.
Then removed all four mufflers just for test. Sound was cool, like muscle car, but too loud for me, because car is daily and sometimes I drive long distances.
Then I've installed back rear mufflers, removed pre-mufflers and installed simple universal resonators. So now exhaust system is pretty much the same as newer model LS430.
Also installed nice looking muffler tips on stock mufflers.
Now sound is only a bit louder than stock, it's quiet on slow driving and nice when revving, like true V8. I'l try to drive more, but I think next mod will be changing rear mufflers to some aftermarket, because car is still a bit too quiet.

Parts used:


Resonator from inside:


Now looks like this:




Also we removed those tin-plates and found bad news there:


All pipes behind them was very rusty. It's because water is staying there and makes corossion. I suggest you to remove them as fast as you can if you don't want to spend money on repair.

Also here were discussion about middle part - is it resonator or third cat. I can confirm it's a resonator.

About performance - I felt a bit improvement, just I think it's not because pre-muffler delete, it's beacause we repaired all holes, because n/a engine without exhaust looses it's power.

That's all, I hope this info will be usefull for someone. And sorry for mistakes, I'm not english speaker

Stanislav

Update: removed rear mufflers, welded straight pipes instead. Sound is very deep and very very nice, but a bit too loud for highway driving. In future will try to put some aftermarket mufflers or big resonators.