Exhaust modifications--your results (1 Viewer)

[jmarlo]

Before committing to a cat back system on my LX that promises greater horsepower and mileage, I would really appreciate hearing anyone's experience that has done this.

Did you really notice a gain in power over stock? How about fuel mileage? The claims the exhaust companies tout are just that, claims. Any real world experience from you guys would be very appreciated.

A new system will look better and will sound better, but without perceptable performace increase, may not be worth it to me. Thanks.

 

[SWUtah]

Before committing to a cat back system on my LX that promises greater horsepower and mileage, I would really appreciate hearing anyone's experience that has done this.

Did you really notice a gain in power over stock? How about fuel mileage? The claims the exhaust companies tout are just that, claims. Any real world experience from you guys would be very appreciated.

A new system will look better and will sound better, but without perceptable performace increase, may not be worth it to me. Thanks.

You might not know this but the exhaust system on your 100 series is a high grade stainless and will last the life of the vehicle. Any after market system that you might replace it with in my opinion will be a downgrade.

 

[jmarlo]

The system on my vehicle does not appear to be stainless, but if it is, I am surprised. Regardless, yours is a good point--I imagine Lexus/Toyota would not design a cheapo system. On the other hand, it only seems logical that larger diameter pipe and a less restrictive muffler, and removal of resonator, all add up to increased flow cat back. Increased flow should equal better performance, unless a specific amount of backpressure is designed into these systems, and if this is the case, I should leave it alone.

 

[hkeller]

I am not certain of this, but I recall from an earlier discussion that the 100's system was designed to create a certain amount of back pressure to help in proper valve train activation. If that is true, you don't want to tamper with the factory system.

 

[SWUtah]

a specific amount of backpressure is designed into these systems, and if this is the case, I should leave it alone.

Your system is stainless, and the system is designed to get the best performance. If you change the exhaust system you will need to change other parts, intake programing to increase performance. Not worth the cost versus the benefit. If you do a search you will not find many threads where members are changing out their system.

 

[spressomon]

The exhaust on my '99 is definitely not SS. Aside from that I would be really carefull about freeing up the "flow" as without stock backpressure you WILL lose torque/power based upon what I am learning about the 4.7L. There have been individuals here that have chased the HP/power increase 'goose'...with only a lighter wallet to show. If the shop that is going to sell you the cat back or any other system designed to enhance power and HP is so confident then maybe they should also step up to the plate with an unconditional risk free guarantee...that'll usually change their stance regarding how much HP improvement they promise.

 

[SC Joe]

Not to derail the thread, but what about a cold air box for the intake? Has anyone recognized any real world increases from that?

 

[Drinkin40s]

on another tangent - I was looking through the Performance Products Catalog over the weekend and see a "Jet Performance" upgrade. Looks like they do a reflash or something to increase power - has anyone had this done?

 

[cruiser88]

off the showroom floor it is stainless .even stainless will have surface rust so you may not be able to tell.the best you will get will be sound,not much airflow difference,if any you will notice very little if any at all

 

[mscott]

Many on this board, as spresso indicated, have tried to improve the exhaust system only to find that what they had assumed was a so-so system was actually an extremely well designed system. Any changes seemed to be neutral to negative relative to improvement on the stock system.

 

[jmarlo]

Thanks for the great responses. Looks like its a no brainer to leave well enough alone. I just wish the stock muffler was not so huge. The thing looks like a 25 gallon drum.

 

[spressomon]

I bashed both my muffler and resonator...and thus was the reason I went with the flatter/oval/lower profile Flowmaster with a small round glass pack style resonator. FYI: My set-up doesn't seem to have effected the very low range torque/power curve...but more so the middle RPM range say when ramping up to the interstate etc...but some of that maybe all the extra weight I have added

 

[jahmaka]

I have a 98 and the exhaust was not SS,the muffler alone had rust holes in it like a damn strainer.I have installed a intake and TRD SS exhaust and i can tell the differents in low end torque.
Has anyone look at a stock exhaust compare to a TRD/Borla one?The less bends and smoother bends you have the better the flow is which will free up some HP and TQ.So the freer the engine breaths and the faster it releases the gases,equals more HP/TQ.
ON normal asperated engine you can not use too much of a big diameter exhaust because you need some back pressure,so back pressure can be your friend and your enemy.

Oh and forgot the stock muffler weights about 40lbs.

 

[macneill]

Stock is perfect for what it's intention was, like all OEM products, but who wouldn't want to hear their V8 rumble a little more? IMHO, Borla is the way to go.

Doubt you'll notice that much performance increase in a vehicle this heavy without mods to the aspiration. I have the K&N Aircharger and I never noticed any difference.

 

[kane.sheldon]

There is no stainless muffler on a 2000...

It does have a hole the size of a golf ball in the muffler though. Borla on the way...

 

[EdsCruisin]

Gotta admit - those Dodge Hemi's sound pretty cool.

The backpressure can be maintained in the Y-pipe alone, leaving you to expand the remainder of the system. The catalytic converter is designed to chemically change the output, and not to add backpressure. Likewise the muffler and resonator are expansion chambers, not restrictors, unless the pipe size is reduced at the tail end. Many cars have smaller diameter pipes at the rear for some reason. Another issue is constriction due to many bends made on a bending machine, rather than mandrel-bent.

I have never measured the LC system, but if the pipes are of similar diameters throughout, a replaced muffler or resonator will do little more than make it sound different (cooler).

 

[1loudLX]

sure the K&N intake and borla dont add power, but then how do i explain the fact i raced to 50mph a stock 2000 LX(like mine) and won? I had an extra 44lbs off the front + alot more crap inside the cargo area. After the 50mph pull we did a slighty faster one and i still came out a truck length ahead. I compared fuel levels and i had 7/8 while the other guy was below the 1/4 mark.

Yup, these things dont add any more power and just suck your wallet.

 

[calbo]

I'm with 1LoudLX on this one. Internal combustion engines are air pumps. Increase the throughput and you increase the performance.

I would go so far as to opine that the need for backpressure is a myth.
There's a reason why race cars have little to no restrictors in the exhaust system.

 

[moooooooo]

I'd contact Bullet Cars
They've done a lot of performance work with the 4.7L V8 over the years both with their own Bullet Roadster and the LC100/LX470.
i think the email addresss is tom@bulletcars.com
cheers
peter