I took my car to get it smogged. i found out that theres straight pipes on it. this sucks because they took the back cat off which caused my car to do horrible. But the sound the pipes makes is really nice. Do these pipes add any power though? i was told that they do and me taking them off will reduce my hp. will my car do a lot better on smog when i get one put back on?

 

If your car is NA and otherwise stock, then being completely straight pipe is not a good thing. You lose low end power, so no, the pipes don't add HP. Even if you have muffler(s) on your car, it never hurts to have at least one cat on there--with just resonators off you should still get a wicked sound.

But in reality, not enough info to answer the question properly-- is your car 1J swapped? nat-t? is it an sc400 or 300?

 

Having cats without resonators sounds great and is easy to do. I've done it on 400's & 300's

 

i cut the exhaust off right after the cat and it sounds amazing, under a bridge or tunnel it sounds like an F1 car

 

My setup on my 94 300 is straight pipe into vibrant ultra quiet resonator to y to tips. So, speaking from experience, you do gain power on the higher end of your power band but like stated before, lose some low end.

If you are N/A, YOU DO have enough back pressure just having it extend to the rear of the car.

What year is your sc? It may be running bad if it is missing some sensors but I dont have any problems.

 

well i have a 92 400 and the two resonators are still there they just removed the back cat and put on a straight pipe and it sounds louder than i thought a lexus would or do the SC v8s sound loud stock?

 

the v 8's sound loud once you start removing exhaust stuff.
personally I would have kept the cat, and deleted the resonators for sound, not the other way around.
theres no point in killing the environment if your rocking a stock car, maybe on a race car but even then people run a cut out so they are using the cat most of the time.

 

^^ +1 on that

I removed my resonators and mufflers on my 95 sc400 and it sounds loud and awesome enough.

 

the cat was off when i bought it so i gotta get a cat put on to pass smog then see where to go from there. are magnaflows good to put on a sc or is there a better brand ?

 

do a search for magnaflow in the SC performance section, there are many threads which will tell you the exact model magnaflow to use and pictures and videos of completed setups.

like this thread
https://www.clublexus.com/forums/per...best-bang.html

 

Actually, the 92-94 model SC400's didn't come with a third cat, this was only in the 95+ models. I had a bone stock 92 SC400 that I installed an exhaust on, and it just had a large resonator where you have your straightpipe. So it should still pass smog just fine as nothing on the emissions control side was altered.

 

To be clear, my 92 was a California emissions car. Only two cats by the engine that dumped into an h-pipe/crossover/resonator thing which branched back out to two resonators back to the mufflers.

 

OP; do ypu own a 3 or 400?

 

i have a 400. i was told that it came with three cats and that i need my third one put on but also the check engine light says its the egr valve so which is more likely to stop me from passing smog?

 

just weld in a magnaflow high flow cat, they work great. you need the california approved one though, which is gonna cost you extra, but it should get the job done, earlier i thought you were talking about magnaflow mufflers.
Most places you don't fail for a Check engine light on odb1, only if you fail the smogger portion, but since you are in CA, I have no idea if that applies. you probably need to fix it. search for egr and resistor if you want to turn off the light.