hondaxr650

Just about a week ago I became the proud owner of my first Lexus, a 2000 GS400. Right now I am in the process of selling the remains of my 5.0 mustang, and so I have been looking around for upgrades to buy with the money i should be getting from the sale of my mustang.

Right now, I think that instead of installing a cat-back exhaust system, I want to install electric exhaust cut outs before the cats. Is this a difficult or easy thing to do with the way the car's stock exhaust is laid out? Also, i tried to search through most of the previously posted exhaust threads, but never saw any mention of a system using cut outs. Is there some reason this is unpopular? It seems to be the ideal setup for a sleeper car.

Also, i was just wondering, what is the power ceiling for a basicaly stock motor? By this i mean, how much horsepower can you get out of a basicaly stock v-8 through forced induction(most likely nitrous) without making the car unreliable.

Choritsu-shi

I think it's a great idea, those electric exhaust cut-outs are really cool! Although an uncapped 1UZ motor is EXTREMELY loud and the cut-outs will need to be installed after the cats, cause the secondary O2 sensors are mounted in the cats. In addition the stock exhaust piping is less than 2" in dia and clearance to the chassis is minimal. The electronic cut-out assemblies are quite large and use domestic 3-bolt exhaust flanges.... these will require more under-chassis space typically found on domestic vehicles.

Not saying it can't be done.... I can assure you it will be awesome if you can.... but it's more practical to install a cat back exhaust.

Reliability is not based on "what is installed" rather "how it is installed".

Sensei

SoCalSC4

I've thought about this as well, but I would like to make the electric cutout bypass (with piping running parallel to) the resonators, mostly for more noise when I want it, but for normal operation the exhaust would pass through the resonators.

I can say that bypassing the cats will make for a LOUD Lexus (were you thinking of just dumping the exhaust out right there?), and heed Sensei's advice on the O2 sensors. If you want more power and you're going to run Nitrous, why not nstall some headers with custom hi-flow cats with a mandrel bent exhaust? If you want it loud, just don't run resonators, blow it straight out the back to a pair of cans. THAT will be loud.

ElitistK

iTrader: (4)

exhaust cut-outs placed before the cat is ideal for turbocharged cars because that's just like an open downpipe.
with na cars, it's good for high rpm but your low rpm might suffer a little.

PureDrifter

iTrader: (10)

too little backpressure in a NA 1UZ has been shown to reduce the tiny amount of low-end torque we already have, and on top of that the 1UZ coming out of factory headers+cats doesnt sound all that great

kit cat

iTrader: (6)

JeffTsai did it.

hondaxr650

I was afraid the lack of undercar space might prove to be a problem. The exhaust cut outs i have been looking at - http://www.mccordcg.com/mpp/mpp.htm - seem to be small enough to install in relatively tight areas.

Yah, I first considered cut-outs for my High-Pressure Turbo volvo 850 t5-r. They were a pretty common setup among the members of the volvo forum i was a member of, but i see how having an exhaust dump directly after the headers would be more productive on a turbo car. While having direct dumps after the headers might eliminate the little air restriction of most aftermarket exhausts, but i bet that gain is offset pretty badly by the loss of torque. The main reason i was considering cut-outs is because its a good way to have both the least restrictive, loudest exhaust possible as well as the stock quiet exhaust at the same time. But since the gains over most aftermarket exhausts would be minimal, i think i will just go with a full cat back setup.

While im on the subject, i've been looking for a good aftermarket exhaust that is loud when you punch it, but relatively quiet otherwise. Would anyone have any suggestions? Right now, I am kind of thinking i might go with the Tanabe Touring Medallion, but im not really sure.

hondaxr650

oh and also, i am planning to put on whatever exhuast system i decide on in addition to an SRT intake and either springs or headers.

And on the second question in my initial post, i was more wondering how much horsepower an engine that has only a few small upgrades, such as cat-back exhaust system and intake, could handle. I was also considering throwing a small shot of nitrous into the parts combo im about to buy for the car, and i was wondering how much my engine could handle as is without causing problems in reliabilty. I drive the car as a daily driver, and i drive it hard, so putting excess stress on the engine would be a very baaaad thing for my car.

Raph TT

thats the problem with cat backs, what if you buy one and it sounds like crap??