Was thinking about just getting a ams test pipe and downpipe with stock catback for my 03 evo since i dont see the point in replacing the whole system as i dotn really plan on doing major work on the car, just looking to maybe get it a bit louder than stock with some hp gains...also would i need a tune if i did this????

 

what's the point? you won't make much more power than stock with that setup

 

I can see the stock catback being a bottle neck. But, I'm no expert. I suppose is DP and TP helping a bit.

 

Yes, this setup will make more power than stock.

 

I am running megan 02 housing,
Megan downpipe,megan test pipe, hks hi power mid pipe and stock axle back. There is quite a bit of of restriction but love how its not overbearing and annoying. It's still pretty loud on cold start though.

 

I'm not sure if those parts you are considering will even bolt up to the stock cat back exhaust.
Normally you open the furthest part of the exhaust first and make your way back to the turbo to prevent the bottle neck effect.

 

I've done this and still do with a slight variation.

More power? Not noticeably. Maybe a little from the test pipe.

The main question is why?

I had to do it because I got pulled over too often (usually going the speed limit or not moving at all. I got pulled over at a gas station when I started it up). The exhaust system read at 95db.

I now use a 3" DP, test pipe and stock cat back. I also have a boost actuated cut out.

It's fairly quiet at idle and cruise (exhaust rattle from the cutout), and extremely loud when over 10psi. More power? Yes. Noticeable power. I did a thread on here. I'll have to look it up.

 

I did this a while back, got pulled over for a full turbo-back after having it for 2.5 years. It sounds really good but I ended up dropping $1k on a MAP 3" cat-back with the Varex remote muffler and love it.

 

Here's the link to a thread I did a while back. https://www.evolutionm.net/forums/ev...t-o2-dump.html

If you're on a stock rom, then I'd get a tune regardless if you get a DP and test pipe. If you go this route ^^^, then get a tune. We can help you out with that.

 

I was running stock cat back on my Evo 9 daily driver. It was a torque monster. I like that it was quiet and still had some *****. Here's a video, I did end up running an 11.42 with the same mods, just better track conditions.

 

How old are you? I also love the quietness of the OEM exhaust system. It did feel it took off better.

 

I was running almost the exact setup you are talking about... I had a 3" DP and 3" test pipe into the stock mid-pipe, and then had the Works axle back. I personally liked the sound as it had no muffler but two resonators, but I was constantly blowing exhaust gaskets at the bottle neck. I got sick of it and went full 3" and it was a noticeable difference, I couldn't be happier. I second the idea of starting at the exhaust tip and working towards the turbo, this would give you time to plan out what parts you really want. Good luck.

 

I'm 36 now, I think I was 30 when that video was taken though. I prefer to keep it quiet, especially on a street car

 

Hks sport exhaust ..granted I have cams but its very quiet