I can get all new (larger) exhaust piping done for next to nothing. If I go to a slightly larger size but keep the stock muffler will it really make any difference?

 

The stock muffler is not that restrictive at all. That's why most catback systems only add a minimal amount of HP over stock.

I have the NISMO which is a 3" pipe vs. the stock 2-5/8". It's supposed to be a 7-9hp gain. From what I read, most of the gain is in the more efficient Y-pipe than anything else. I suspect if you went to 3" pipes, you would only see a small difference in performance. Especially if you don't do the Y-pipe right.

 

i was thinking the same thing, i dont know if my car is breathing right now that i have a turbo...

 

I took the muffler completely off and made up a pipe to direct the exhaust downward. The car sounds incredible and makes a great gurgle when you let off the gas... free mod and saves weight (although I have no idea if there was a power gain or loss).
BTW - the muffler is definitely restrictive (although that doesn't mean less restrictive always = more power)

 

+1

It's why I'm keeping mine until it falls off or starts to leak, because of rust/holes. At that point, I think I'm going to upgrade with NISMO. Similar design to stock, just bigger, better and lighter.

Zquicksilver

 

Most of the gain is in the Y as said above, the stock Y is not all that smooth and the bends seem restrictive. The rest of the stock Calsonic system is straight thought perf tube type mufflers and piping.

Chris

 

i would say the cats are the most restrictive part of the stock exhaust....if you want the most for your money get high flow cats

 

that's the same thing that i heard as well.

 

If you really want gains that you can feel out of the exhaust side, install a set of good headers!! I guarantee you will be happier with that than a catback, y-pipe or test pipes and it helps deepen the exhaust note too!!

 

I go the Crawford headers and highflows put on awhile back and kept the stock exhaust for a bit. The car felt faster, but also felt like the stock exhaust was way to restrictive at that point. After a week I got the Borla TD and the car felt so much smoother and powerful. Stock exhaust is ok, but in my opinion after you get headers and highflows the stock exhaust just does not cut it.

 

The shop here tried a couple of mufflers with their y-pipe & mid pipe combo and no difference other than tone of the exhaust the power gained was from the y-pipe and the mid pipe, if interested here is more info on the pipes https://my350z.com/forum/group-buys/131732-gb-on-japtrix-y-pipes-and-mid-pipes.html

 

if you go just high flows you will notice the most gains....and its also a lot cheaper than headers or a quality catback.

ideally, you would obviously want to do the whole exhaust system...but i would start with the cats...imo you get more for your money this route

 

There is a local guy here that put down 411rwhp with the stock cats and exhaust on a greddy tt z @ 8lbs, so it can't be that bad

 

i don't see the correlation....if he had aftermarket exhaust and cats he probably be putting down another 25 HP. but heck, if your putting down that much hp and your happy then thats cool. those cats are really restrictive even with na applications

 

I agree with you 100%, he probably could have another 30hp and 30ftlbs or more under the curve with another exhaust and test pipes.

 

THis thread is so great, it is informative and clear.
I see there are different feel about the mod, but can I ask you gurus who have made the mod already
draw out a recommend picture of the exhaust mod, so guy likes me who is still re-searching have the lead down the path.
I meant, like

first: headers : crawford
2nd: y-pipe ...

Thanks in advance.

 

you should of installed a y-pipe and see how the car felt