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For me it would not matter........ The center muffler & catyolic converter also help with the back pressure.

Right now Im trying to get pipes made so I can remove my catyolic converters.

Lord of the Celsiors is running straight pipe...... his is still running good if it wasnt he would of put something back to help with the back pressure.

JBrady

Mike, the silencers are the biggest choke on the LS400s hence the discoloration. If you remember there were 2 distinct areas of discoloration, one at the Y section that split the exhaust back into duals and the other in the silencer case itself. A single decent Y section feeding either dual pipes or dual straight through resonators would be a good choice. Of course that still leaves the bottle neck of the first Y section and 50mm center resonator.

I am actually leaning towards dual pipe set up, after my custom cat back parts, plumbed into my existing rear mufflers. Those mufflers are so easy to remove I can do it at the strip for back to back testing. Also, I intend to place pressure probes at various points in the system. Since I will be replacing EVERYTHING from the cats back (except for the rear mufflers for now) I will have a chance to do a variety of tests... I like having good reliable test information.

NOW... PLEASE... ONE MORE TIME... to other peoples posts in this thread... engines do NOT need or want backpressure. This is an incorrect assumption made by people with partial information. It has been said so many times that many people just assume it to be correct. The PROBLEM is that large pipes LOWER velocity. It is the loss of velocity that hurts low RPM power. The solution is to build the best flowing lowest restriction system from the smallest diameter pipes cabable of supporting the high RPM power output of the engine. This is why I recommend 2.25" pipes and not 2.50" pipes. So please, everyone, stop saying an engine needs exhaust backpressure.

RA40

iTrader: (6)

Thanks John-

One of these days I'll run it by the exhaust shop and see what it is gonna take. I'd love stainless piping but I suspect it will be $$ if it is readily available in the 2.25" size.

lspower

granted this is an old thread but i wouldnt want people to read this and believe it because it is far from true, NO car needs backpressure, every car need good scavinging for power...!!

example sc300.... inline 6, n/a, 2.5in from the header (ex: xerd header) w/o cats back would be perfect

same only with 3in not good loose power

morgsss

here is mine they make it go fast

gtfour43

I hope your not turbo cause with all that pressure coming out of your exhaust you might pull wheelies and thats very dangerous

PureDrifter

iTrader: (10)

i just did this mod (thnx to lextreme's guide) and it sounds MUCH better. only thing is, to anyone who has heard an LS w/o rear mufflers, IS IT TOO THROATY??

i ask this because i am 16 y.o. and driving my own lexus. the last thing i want is to have cops all over me.

also, just to make 10000000 percent sure, this mod IS legal in SoCal? RIGHT??!?!

sry, just some random confusion.

thnx in advance
-Annant

Pagong

The sound is very throaty and mellow at the same time.

It doesnt overpower the cabin at all.

I bought LSpinoy's mufflers and they sound great.

PureDrifter

iTrader: (10)

http://www.leginfo.ca.gov/cgi-bin/wa...ction=retrieve



this states that a car has to have a muffler.

now, since the car still has the silencers and center mufflers on it, do those get counted as mufflers?????????

if they dont, im putting the stockers on this weekend and looking for a cheap used exhaust.

-Annant