This question my have already been asked but i'm to lazy to look for it. Is a down pipe really needed. The only mods I plan on making to my evo are exhaust and re-flashed ECU. How much power does a down pipe add. I've heard that it actually takes away power?

 

If your too lazy to look then you shouldnt be asking others to do it for you man. Happy researching.....

 

Get the damn DP. 3in DP have made around 10whp with stock exhaust and reflash. Check out the Helix DP. Grouppe-S has it for $270 shipped.

 

The Helix 3in downpipe is the one that I was looking into getting. How it is it with an aftermarket exhaust?

 

LOUD. But, much better top-end.

 

3" DP makes more hp and LESS torque (with no other support mods)

 

Don't let the less torque fool you. It's not much. If fact, you won't even miss it; but once the turbo spools, you'll notice the power. Just remember the V8's, lots of low-end torque but still slow since they lack high-end power due to lower rpm redline. Evo's are disigned for low and mid power but lack high-end. So you want to get the high-end up. It's very hard to break 12 sec with stock exhaust even with all the ecu upgrades.

 

I'm getting an aftermarkert catback exhaust and ECU upgrade. I was debating the downpipe. Just heard that sometimes a downpipe can take some power away (I want to add more). If it's not then I'll get the downpipe also.

 

I'm a big advocate of not going with the 3" downpipe if you plan on sticking with the factory turbo, you will miss the torque. I went with the HKS, which is around 2.6-2.7". It has worked great for me. Most JDM builders using the 16G turbos are using the slightly smaller downpipes for a reason....my two cents.

 

The only mods I plan on making to my car are the Cat back exhaust and ECU then. I really don't want to lose any power by adding a downpipe then.

 

The stock dp is great (for the stock turbo). However a Buschur 2.5" DP or HKS 2.65" is better. Take your pick. They are mandrel bent (not crush bent) and flow better to make more power (the exhaust gas still remains just as "hot" as inside the stock DP but it is expelled more "efficiently" with these two aftermarket DP's - yielding boost engagement in lower rpm's and better torque over the stock DP. Well worth the money.

1) Do a turbo back exhaust (maintain the same diameter throughout, 2.5" DP, your stock cat is 2.5", and do a 2.5" axel back or muffler delete pipe (or) do a 2.5" DP mated with a 3" HF cat and 3" cat back exhaust.
2) Do your ECU flash...
3) Get a manual boost controller of some kind. Turn up the boost...

Then call it a day. That is, unless you're gonna be unhappy with 265-285 wheel hp

 

Don't believe that you'll miss any power lost when your at 150mph it keeps pulling believe me

 

Ahh.. I didn't feel any power loss but felt all the power gain. But if you drive like a granny shift below 3k all the time and drive slow in the city traffic than you might miss the low end torque. But when a modded WRX passes you that low end torque won't help you there.
Currently, I can out run lot of modded WRX's without doing a launch. They might get 2 car length head start but after a block, I'm 2 cars ahead. Now when I launch, it's not even close.

 

So with hks cat back,hks dp , apexi cone filter, mbc don't know what company, dynoflash. What are we talking whp wise?

 

Well, for now my budget is $1600.00 (wife's orders). This is what I am planning to get:
- Espelir JGT500R Cat Back Exhaust
- HKS 2.75 downpipe
- XFlash Re-mapped ECU or Works P2

How much HP/Torque do you think I should get with that...