Pre-Cat Questions?

"Tuned-Port-Injected-Rage" (Tuned-Port-Injected-Rage)
03/21/2016 at 19:43 • Filed to: Question

Hey there Oppo, long time no see. It’s about that time of year again when I’ll be getting the Corvette out of storage and on the road again. It’ll be going to the shop to get the valve seals and a few other niggling things done to get it back in tip top running shape. Long story short, I was thinking about possibly getting a new Borla Front Y-pipe, since the one on there is stock, but I have a high flow cat and a Borla cat back system after that. Now, obviously, the original system has pre cats, and I would be looking to get rid of them with the new Borla one.

Now here’s my question: are shops allowed to take off pre-cats? I know that they cannot remove the main cat, but I’m not sure on pre cats. Now, keep in mind, I still have a main cat, so I am not just completely ditching my emissions stuff. It is just that the stock Y-pipe is very restrictive, and I’m sure those pre cats are pretty shitty. So, what do you think?

TL;DR: Can shops take of a front y pipe with pre cats and replace it with one that has no pre cats?

DISCUSSION (16)

crowmolly > Tuned-Port-Injected-Rage
03/21/2016 at 19:51

Technically speaking, no shop is legally allowed to remove or disable emissions equipment. AIR, EGR, whatever.

You might find one that will do it, though. I’d dump it. I think maybe ‘85s have the same y with no cats?

JGrabowMSt > Tuned-Port-Injected-Rage
03/21/2016 at 19:52

I mean, you can do anything you want, it just depends on if you want to pass inspection.

Are there high flow cats available? I intend on dropping a set into the Magnum, and they’ll pass inspection just fine once they’re warmed up.

You could go with a straight Y pipe and high flow cats for a much better flow out of the motor. It’s not a dual exhaust with an X pipe?

Birddog > Tuned-Port-Injected-Rage
03/21/2016 at 19:57

I’m pretty sure they can only remove converters if they’re bad. It wouldn’t be hard to argue that they’re bad going on the age of the car.

Your best bet would be to find a “cash only” shop and see if they’ll do it.

Tuned-Port-Injected-Rage > crowmolly
03/21/2016 at 20:06

Damn, that sucks. Was maybe hoping to ditch the AIR system too, but really wanted to get rid of the pre cats.

Yep, ‘85s have the exact same y with no cats. If I can get rid of it, I will, but I really don’t know any local shops that will do so.

Milky > Tuned-Port-Injected-Rage
03/21/2016 at 20:12

Does your state emissions test? If not you can find a shop to do anything.

Tuned-Port-Injected-Rage > JGrabowMSt
03/21/2016 at 20:13

I don’t have to pass any inspection, as Michigan really doesn’t care about any of that.

I already have a Magnaflow high flow main cat on the car, so that’s not an issue. What I planned on doing is a straight Y at the front (the aforementioned Borla pipe) and then my existing system out the back. As I said, though, the issue is finding someone who will ditch the pre cats.

Tuned-Port-Injected-Rage > Birddog
03/21/2016 at 20:17

Yeah, no doubt there. I’d love to find a shop that would just say “screw it”, but I don’t know of any shop I trust around here that would do that.

Tuned-Port-Injected-Rage > Milky
03/21/2016 at 20:18

Nope, Michigan doesn’t really give a damn. Like I was saying to Birddog, I really don’t know of any shop around here who would do that who I also trust with my car, though.

JGrabowMSt > Tuned-Port-Injected-Rage
03/21/2016 at 20:20

Just find a good custom shop and say what you want done. If you don’t have to worry about inspection then the shop isn’t going to care most of the time. They’ll probably feel you out as a precaution, whether they think you’re being shady or not, but my friend’s custom shop would probably do it as long as it’s a track car. A DD, not so much, but it depends on the setup.

Tuned-Port-Injected-Rage > JGrabowMSt
03/21/2016 at 20:30

I dunno, I’ve had quite a few shops get a little weird with that kind of stuff. It’s not exactly a track car either. More of my weekend/nice weather/fun car.

Milky > Tuned-Port-Injected-Rage
03/21/2016 at 20:44

Come to Detroit and pull into any shop, they got ya covered.

I don't know where you are but there more than a few people running straight pipes around here.

TheD0k_2many toys 2little time > Tuned-Port-Injected-Rage
03/22/2016 at 00:37

find the right shop and yes. Also it Michigan so don’t need cats. I don’t have one on my Miata, my diesel never came with one and my beater rusted out before the cat.

Tuned-Port-Injected-Rage > Milky
03/22/2016 at 07:35

Yeah lol. There’s plenty of people running straights around me as well, I just gotta find a place to do it that I trust. Hopefully the Corvette specialty shop I’m taking it to has no issue doing it.

crowmolly > Tuned-Port-Injected-Rage
03/22/2016 at 08:37

Since the car is old and you have a new regular cat you might be able to have a shop do it. Explain you have a brand new cat and you need a new y pipe. Don’t give away too much info. The car is an ‘86, that’s past cat service life anyway.

The Stig's former college room mate > Tuned-Port-Injected-Rage
03/22/2016 at 10:09

In upstate New York, once it’s older than 25 years, all bets are off. No emissions testing at all.

Tuned-Port-Injected-Rage > The Stig's former college room mate
03/22/2016 at 20:31

Yeah, no emissions testing here either. Just some stingy shops.