billkmiami

we just had a guy drop an excavator off of a trailer- no one hurt- but an awesome sight!
no cats- love the smell of sulfur from an unrestrictive exhaust system! but you are right about the smog and pollution and you have to start somewhere on the pollution control but the smell of an unrestrictive exhaust is just too much plus the engine will work more efficiently without restrictions unless your budget is limitless!

Erik Beeman

I'm running straight pipe in my 88, no cat, to two FMF GSXR1000 mufflers. It throws no codes, and I notice no power gain or loss. Just sounds really cool.

You can see in the background the clean part of the exhaust is where my cat used to be.

91Toyota

Interesting, i've got no cat and a straight pipe...after 20k miles should I still expect my CEL to come on?

klbeans

Previous owner had a straight pipe. I just replaced it with an aftermarket cat in order to pass emissions. It threw no codes prior to putting the cat back on and I did notice a decrease in power with the cat on. The exhaust smells cleaner as well.

All in all, I think I'll be leaving the cat on. Depite the noticable gain, it's not so earth shattering that it'll prompt me to go back to a straight pipe.

Justinlhc

I have no cat at all, Thorley headers and a turbo muffler dumping right above the rear axle, pointing back(and slightly down). I absolutely HATE it. I'm going to put my cat back in and possibly put a glasspack on. I pretty much have to shift before 3k because of the horrid sound it makes and to be perfectly honest with you, it really feels like I'm losing power as soon as that horrid sound starts up. It sounds like a jake brake on a big rig as soon as I hit right around 3k. I'd rather have the stock exhaust tham what I have now. At least with the stock exhaust I could drive and not be embarassed having to cross the 3k line on the highway.

Where I live we have no emissions inspections and cat converters aren't required, but I'm putting mine back on anyways. There just isn't enough back pressure for this tiny little V6.

herdnerd

Cats are required everywhere! I have no doubt that there are performance gains to be had from removing a 15+ year old cat. But thats like comparing apples to turnips. The things do wear out. Now if you compare a newer high flow cat to no cat you are comparing apple to apples and I doubt that you will see much gain if any.

Granted its a ricer but...Removing Cats

Justinlhc

As per "federal" sure you can argue that, but locally, they are NOT required to LEGALLY drive or register a vehicle on the road here. Don't start with the federal crap because I can guarantee just about every vehicle on the road will be violating federal regulations in some way.

Fink

While I was crawling around under the '85 the other day I noticed that I don't have a cat either.
No CEL surprisingly.

When I get the funds I'm going to replace it with a Magnaflow high flow along with a new muffler.

Just spend the $60 and get a cat, better all around.

Fink

Grunnen

I ended up cutting the cat off and putting in a straight pipe. My exhaust needs to be redone in next 6 months so Ill get a new cat and muffler when I bump up to 2 1/4". Overall I like it, combined with the ISR mod I noticed a huge difference. With the stock 4.88's this thing was turd to drive around town but now its almost fun.

Thanks for everyones input.

billkmiami

check out the photos- "test pipe" installed in place of the cat from LCM and a 02 simulator from URD= no cat to steal and no codes coming on and I have a noticible gain in power from this 4 banger! Sound level increased a bit but not a big deal!

Grunnen

same thing i found. not much more sound but a more power. maybe my cat was just full.

axelkoup

i wouldnt expect it to, b/c more than likely, you dont have a downstream o2 sensor, being downstream, or AFTER your cat..... therefore, the ecm doesnt read what happens after the cat, and no check engine light...if the systems and OBD-I, 98% chance it'll pass emissions without a cat, AS LONG AS, there is NOT a downstream o2....mines been fine for a little over 20k also.....

hjkmotor

how are those mufflers? iv never seen that or even thought about sport bike mufflers on a car

billkmiami

the test pipe replaces the cat converter- there is a downstream o2 sensor- the simulator tells the computer that the now missing cat is working fine- I still have the stock muffler- so sound is not too bad- but the power gain with no cat was noticible!