fastegg

I just took out the rear mufflers to see what it sounds like.... it sounds like a cop car when its idling.. not loud, maybe a tiny bit of drone but easy ok... I decided to drive it around for a few days and to my disbelief the fuel computer is telling me its getting 10% better economy on the highway. Normally sitting on 120kmh it gets around 10L per 100km.... After a 315km highway run it was reading 9L per 100.... and, its 315km to my mums... 630 return... plus about 20km driving around up there. I have never been able to drive there and back on one tank sitting on 120kmh but when I got there (315km) it was telling me there was 350km left... It has NEVER even come close to that... So the exhaust is exiting immediately after the 2 center mufflers.
its telling me Im using less throttle to get the same speed...
Is it possible that this is really happening ?.. Is it possible that 10% of the fuel is being used to push the exhaust out the rear pipes and mufflers ?

Rdrcr

I removed the rear mufflers on my '94. I did the same to my old '96. I like the sound.

I haven't noticed any improvement in MPG. But, depending on the condition of your mufflers, I could see a possibility for an improvement.

Mike

cnynIS250

I did this recently too and the sound was nice and subtle. Didnt really notice an improvement in mpg though...

Ultimately i ended up putting the mufflers back on because i noticed the exhaust gases were now shooting out directly at the CV boots which wouldn't immediately cause a problem but im sure over time, it could. Exhaust gases are corrosive and over time could dry out the boots. I would recommend just having an exhaust shop weld on some additional piping so that the gases can point away from any critical components.

dicer

And your getting more corrosive exhaust on all the rest of the underside of the car, and possible into the car as well through trunk vents. There is a reason it is suppose to exit where it does from the factory.

cnynIS250

Same comment at the same time. haha

Rdrcr

^^^^
I'm working on getting someone to do some custom pipes from the delete to the bumper.

Mike

PureDrifter

iTrader: (10)

the muffler delete has been done for years, no issues on stock cars, including axle longevity.

sndlight

After i ripped my rear mufflers off I have noticed more and more corrosion on my rear quarters as the months go on. I regret doing the delete now because of the extra rust. But it sounds great

PureDrifter

iTrader: (10)

While the two events (you removing your rear mufflers and you noticing corrosion on your "rear quarters") may correlate in chronological order, the mere fact that they happened in that order does not give causation.

aka: correlation is NOT equal to causation.


I'm curious how corrosive you believe your exhaust to be? Given that it struggles to rust through your exhaust tubing but somehow in lower concentrations is corroding the painted chassis of the car...

rick1987

iTrader: (1)

Isn't the lexus factory exhaust stainless?

It was my thought that a lot of Toyota exhausts are stainless. They seem to last forever.

fastegg

I have added pipes from the rear mufflers to exit at the rear of the car. Still sounds good.. sounded better with just the short pipe exiting the mufflers though.... I didn't want to leave it like that for all the reasons mentioned above. When I get the car registered in my state, I want to go 2.5" after the front resonator with a 2.5" muffler at the rear (where it fits)
*** Yes, the Lexus exhaust is full stainless

timmy0tool

iTrader: (7)

i was curious as to the longevity of the axles due to a muffler delete, as i was thinking there has to be some degradation on the axles and the exhaust being so close to it, like extra moisture onto the axle boots perhaps? the pipes are turned down so it may just be enough to clear the axles entirely!