Exhaust Recommendation

[pos450]

Heyo,

Just picked up a supercharged LX450 that's supercharged. The exhaust need to be replaced and cant find any threads covering this.

I've seen some recommendations for 2.5" to 3". Just wondering what others have done.

Thanks!

 

[LXDOC]

Probably should specify Manifold back or Cat back for your needs.

 

[reklund5]

Find a competent local hot rod fabricator or exhaust shop and have them do a custom setup.

I've installed a "Brexhaust" setup (Magnaflow) for a friend, and it failed within 6 months. They have warranted it, which is great...but now I gotta do the work again. It was a direct bolt-in setup, and was pretty cheap...

I'm putting a turbo on my truck next week, and the exhaust from the downpipe back will be custom fabricated stainless steel, with v-band clamps and nice hangers to make it easy to service.

 

[COS80]

Find a competent local hot rod fabricator or exhaust shop and have them do a custom setup.

Brace for it, though... I practically had to sell a kidney to cover the bill for my custom 3" catback. Muffler shops cost a fortune now.

 

[pos450]

Brace for it, though... I practically had to sell a kidney to cover the bill for my custom 3" catback. Muffler shops cost a fortune now.

Do you have any videos of your 3" exhaust? Most videos i can find are for 1FEs with turbos.

 

[COS80]

Do you have any videos of your 3" exhaust? Most videos i can find are for 1FEs with turbos.

Double Magnaflows, exits behind the driver's rear tire.



That's the best I have and I won't be able to make a new one for months (laid up).

 

[pos450]

at's the best I have and I won't be able to make a new one for mo

Double Magnaflows, exits behind the driver's rear tire.



That's the best I have and I won't be able to make a new one for months (laid up).

That works! Sounds great.

Did you consider doing a 2.5in over the 3in?

 

[mehbohdi]

Exhaust Shop did a custom 2.5" over the frame with a Magnaflow Muffler and new HiFlow Cat $1500 sounds great no drone.
Notice your in Seattle, Shop in Mt. Vernon did work Ben Richards Fabrication and Exhaust talk to Forrest

 

[Wompom]

Keep in mind if you have a stock motor, you should not change the back pressure with a catless or larger ID exhaust unless you are running a different ECM/tune. It will probably run and drive but poorly.

 

[COS80]

Did you consider doing a 2.5in over the 3in?

No

 

[pos450]

Keep in mind if you have a stock motor, you should not change the back pressure with a catless or larger ID exhaust unless you are running a different ECM/tune. It will probably run and drive but poorly.

My 1FE is supercharged!

 

[Wompom]

My 1FE is supercharged!

still applies if you’re running a stock ecu

 

[COS80]

Mine is also supercharged, stock ECU, and it runs perfectly.

 

[LXDOC]

Never met a boosted engine that wasn’t happier with less exhaust restriction.

 

[Rifleman]

Keep in mind if you have a stock motor, you should not change the back pressure with a catless or larger ID exhaust unless you are running a different ECM/tune. It will probably run and drive but poorly.

I did a test by installing some test tubes in place of my 2 cats on my 94 Land Cruiser. My 94 uses wide band O2 sensors before the inlet on the cats, with a closed loop voltage of 2.5 to 3 volts before i removed the cats.

I can say that the reduction in the back pressure had an effect. First my gas mileage went up from 9 miles a gallon, to 13 to 14 miles per gallon. Then it dropped down to between 11 to 12 miles per gallon.

When the mileage dropped in hooked up my Snap On MT2500 code scanner (this scanner shows live data as the engine is running) to again check what the the O2 sensors voltage was reading. Both sensors were reading 5 volts which is rich, i think this was due to the lack of back pressure making the engine think it was running lean. This condition in my test did NOT trigger any trouble codes, so no check engine light on the dash.

So it would seem you might be correct, the lack of back pressure on a stock engine does make a difference in the voltage the O2 sensors are sending to the ECM, thereby adjusting the amount of fuel the injectors spray into the engine.

 

[Malleus]

I did a test by installing some test tubes in place of my 2 cats on my 94 Land Cruiser. My 94 uses wide band O2 sensors before the inlet on the cats, with a closed loop voltage of 2.5 to 3 volts before i removed the cats.

I can say that the reduction in the back pressure had an effect. First my gas mileage went up from 9 miles a gallon, to 13 to 14 miles per gallon. Then it dropped down to between 11 to 12 miles per gallon.

When the mileage dropped in hooked up my Snap On MT2500 code scanner (this scanner shows live data as the engine is running) to again check what the the O2 sensors voltage was reading. Both sensors were reading 5 volts which is rich, i think this was due to the lack of back pressure making the engine think it was running lean. This condition in my test did NOT trigger any trouble codes, so no check engine light on the dash.

So it would seem you might be correct, the lack of back pressure on a stock engine does make a difference in the voltage the O2 sensors are sending to the ECM, thereby adjusting the amount of fuel the injectors spray into the engine.

How are you connecting the scanner to the ECM?

 

[Speedytech7]

How are you connecting the scanner to the ECM?

MT2500 is an old Snap-On OBDI scanner, he might have the Toyota plug and chip (they used little game cartridge looking things containing the definitions for the manufacturer) for it actually, which is fairly rare. You can also measure and graph the O2 voltage response from the Diag port in the engine bay as well.

 

[alia176]

Heyo,

Just picked up a supercharged LX450 that's supercharged. The exhaust need to be replaced and cant find any threads covering this.

I've seen some recommendations for 2.5" to 3". Just wondering what others have done.

Thanks!

i think a 2.5" over the chassis done by a competent exhaust shop is the ticket, and yes, this SHOULD be expensive. The factory uses 2 1/8" pipe size, I believe but most seem to favor 2.5" if they're reworking the exhaust system. Instead of using the crappy flanges/gaskets at the intersections, I vote for V band clamps at each joints for future serviceability, and yes, those USA made clamps are also mucho $$$$. Mine were $30/each from Kartek offroad. A hi flow cat that has 100 cells/sq inch vs 200 cells/sq inch should work but it might trip the DTC P0420. Yeah, ditch the OEM cats for something more modern that helps the SC breathe better while being EPA compliant. The back pressure produced by the aging OEM cats is plain redonk.

 

[PeterTheBeater]

just a heads up, my muffler had a loose heat shield so I’ve had it replaced with a offset magnaflow. It sounds good but it is incredibly obnoxious on highway

 

[Speedytech7]

just a heads up, my muffler had a loose heat shield so I’ve had it replaced with a offset magnaflow. It sounds good but it is incredibly obnoxious on highway

My magnaflow was stupid annoying after a little while too, I put a Vibrant UltraQuiet resonator in the system and it took the drone out of it almost entirely.