Boob

Ello ello, I found out yesterday that I can legally remove the twin cats & put a straight pipe in to replace. Any known issues with doing this on a 93 LS400? Hoping it's as simple as removing the buggers!

hotdawwg

Might have a check engine light come on... You could add foulers to space the o2 senors so they dont trigger the Check Engine Light!

Boob

Can easily not touch the o2 sensors & remove cats as they are post the flange. Are you suggesting I might run into that problem anyway?

PureDrifter

iTrader: (10)

other than it being pointless and giving you minimal gains (since the cats in the LS are of very high quality) no.

though you will need to buy some O2 simulators so the car runs in closed loop.

Boob

1) Do you not think the cats will get clogged as the mileage ticks over? Pretty sure all cars suffer from that?

2) I'll be happy with the minimal gains. Did it to my BMW 325i a while back, was well worth it.

3) I found a thread about it after I made this thread & others seem to have positive experiences & 02 simulators were not mentioned. You also participated in that thread with no mention of that.

PureDrifter

iTrader: (10)

1- no that's not common, that happens when you dump raw fuel into them or otherwise overheat them.

3- https://www.clublexus.com/forums/ls4...r-removal.html O2 sims are mentioned, as are the problems with the ECU.

mikes7ke

iTrader: (1)

There's the obvious pollution issue. Why not at least throw in some high flow cats? They're not expensive.

Boob

Down with the Hippies, Up with the Queen!!!

Shigen

I like the sound the 4.0 makes when its straight piped. I think the simulators are a good
idea since there is little worry when it 's time for an emissions test. (and efficiency loss
if it's staying in open loop?) High flow cats are really good, I'm thinking of the Super
Catalyzers that apexi and TRD put out. but they're damn expensive.

Dranom

iTrader: (7)

That's gonna be loud as hell without cats. You gonna straight pipe it all the way back?
If so the drone inside the cabin might be too much

hotdawwg

Yeah the drone will be bad!

PureDrifter

iTrader: (10)

uhm if you want sound then get the exhaust redone, the LS has 5 mufflers/resonators PLUS the cats, straightpiping the cats won't do a lot of good for sound lol.

TRD doesn't make sport cats. they do make mufflers, though not for the LS.

Shigen

TRD has been producing them in Japan for years now.
They got em for the SXE10, JZX100 and the ZZW30
Google TRD sports catalyzer.
Though I would be hacking it apart to use on the LS. Lol

PureDrifter

iTrader: (10)

ah TRD Sports makes them.

TRD USA doesn't sell or advertise them, and they wouldn't be legal in any CARB-controlled state regardless.

timmy0tool

iTrader: (7)

not sure on the OBD regulations on cars in NZ, but i'm assuming you have O2 sensors in which, as already pointed out, will need to be tricked or fouled into thinking there is a cat present. all it is if i'm correct is that you pull the sensor away from the exhaust stream far enough to "trick" it into reading a same amount of O2 as before. a fouler is simply a spacer or riser for the O2 sensor bung. at least this is how the open downpipe turbo guys do it when running with the stock ECU.