Well, since you are installing a DP, you are getting rid of your stock cat. I can tell you by experience that the stock DP with the stock cat reduces the noise ALOT.

Since you are designing a fit for a cat not in the stock location (I pressume, i dont' know where the hell you'll be putting it tho ), the noise difference between a high flow and a normal cat would be negligable IMO

As far as performance, there will be a diff. Not sure how much with a standard cat. I have gone back and forth with my berk from stock dp/cat to 3" DP w/no cat and I can definetly tell a performance difference. I'm not sure how much is the from the DP and how much is because of the cat restriction.

My 2 cents.

 

I will be adding a cat to my berk exhaust this spring, I will be sure to post how and any differences I notice (noise, performance, ect).

 

not that this is the same but on my 4age i had no cat. I added a cat for inspection and noticed no difference in noise.

i think the way the stock dp/cat is designed has a lot more to do with the sound level change than just having a generic cat.

also my 5sfte is very quiet i think with a ko dp and 3" ko exhaust no cat
i got pulled over by a state cop for speeding and he said oh you have an aftermarket exhaust let me hear it, and it got the OK. Which in Massachusetts from a state cop is like omg really.

 

Thanks for reply all!!

So it seems that the main noise factor boils down to the down pipe. :smile:

What are the quietest downpipes, which will fit a Berk exhaust system, out there?

Also, does anyone know if I set up my Berk exhaust and add a cat to it (somewhere), will it still be classified under stock class for autocross? If not is there any way to add a Berk exhaust and still be under stock classification?

So basically, I like the tones of the Berk dual exhaust, but would like to quiet it down for daily driving and I would also like to be able to autocross in stock classification. Probably too much to ask for, damn!!

Thanks.

 

i dont know about autocross since my car would go straight to SM2, but if you have stock engine mounts you will be fine for not too noisy on the street, If you happen to have speed source mounts like me its going to drone like a mofo inside the car but wont be bad outside.

 

Stock class allows a cat back exhaust, which for our cars means from stock replacement muffler like the Greddy SP (I think I have that right). Anything that removes the secondary cat / changes the B-pipe will bump you to ASP (I'm assuming you have a turbo).

As for downpipe differences, they are all just a pipe, I don't see how any of them will sound different from any others. But any downpipe that works with the stock exhaust (I think all of them) will work with the berk exhaust.

 

Yeah, I have a 91T.

So basically even adding a cat to your Berk won't let you remain in stock class??

 

Yeah, I have a 91T.

So basically even adding a cat to your Berk won't let you remain in stock class??

Nope. Its not about the cat, its about the power gain. I'm sure that a 3" exhaust with a 4" cat will flow WAY better than the stock B-pipe.

Now, the general rule is you can run in whatever class you want untill you beat someone who cares...

If you are new to the sport chances are you won't be competative for a while anyway, also if you don't plan on running race tires you wont be competative in stock class, and if you are just out to have fun it doesn't really matter what class you are in. I don't know if any of that applies to you.

 

I am in this same boat, i also want a nice flowing exahust, that will pass emissions and is quite as possible.

Here is the idea that came to mind:

Start with one of the Ebay Berk knock off's and ATS DP. Then add a cat to it somehow (is this even possible? where would it go?). Then adding one of these to it:

http://cgi.ebay.com/ebaymotors/Apex...m200257623741QQitemZ200257623741QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

With this setup i think that i should meet my goals:

Quite as possible, stock or quiter perferably (if all else fails i will add some normal tip silencers as well), pass emissions, get a lot more flow for performance (and if the above ebay link makes it quite enough, i can adjust the noise/power level on the fly). And still be at the cost of a new berk.

Any thoughts on this?

 

If you're looking for something quiet and improve performance, I'd just change the stock b pipe with the ATS one. I believe they either have a high flow cat on it or a fake looking bulge. Nonetheless, the bulge could be replaced with a cat, if it's not already one.

As it is believe Berk exhausts are the quietest after market exhaust systems out there. The knock offs are bound to be louder. I am going for Berk, because I like the tones it has, but am looking to decrease the DB level of those tones.

Right now I am looking at adding a DP, Berk system and 2.25 inch high flow Magnaflow cat. I think shaving the ends of till the inlet gets to 3" should help it fit either the b-pipe or the DP. Not entirely sure yet. I know that it should shorten the cat to about 6" from 8", which should be manageable.

 

I will say that the ebay dual exhausts/EMS powered Exhausts are quite a bit louder than the Berk Exhausts. Not that it makes them worse, but some people like it loud, and some people dont

If you are wanting a quieter exhaust, dont go with the ebay exhaust.

-Ty

 

i have both the berk exhaust and dp on and its not THAT loud....its more like a really low growl

 

Right now I am looking at adding a DP, Berk system and 2.25 inch high flow Magnaflow cat. I think shaving the ends of till the inlet gets to 3" should help it fit either the b-pipe or the DP. Not entirely sure yet. I know that it should shorten the cat to about 6" from 8", which should be manageable.

This is exactly what berk did for me on the cat I ordered from them. I'm not sure if they started with a 2.25" or a 2.5" cat, but they got the overall lenght down to 5.5" on mine! I also bought one of their 4" flex sections. If I have to I will remove the standard flex section and replace that lower straight section with the short flex section and the cat. I KNOW that will fit. But with the cat as short as 5.5" I may be able to fit in in the part that goes up to clear the cross member, in which case I wouldn't have to use my new flex section.

I would contact Bryan about this. He cut me a good deal on mine (100 shipped for the cat, custom cut to length). Cheaper than anywhere else I found, and customized to boot.