Without a tune u will run super rich. I ran a test pipe with stock exhaust for a few months and didnt notice any huge power gains. Installed a full catback and had it dyno tuned at modified by kc. 335 awhp & 323tq with only mods being catback and test pipe.

 

you would just haina few hp if you runa test pipe with a stock exhaust.....it's better to change to full exhaust to notice the hp increase

 

Isn't the largest restriction in the stock exhaust the cat?

 

Yes, it is by far the biggest restriction. There is a ton of misinformation in this thread.

Evo IX same tuner pre and post, I had a friend make 12whp with just the addition of an Ultimate Racing test pipe. Lots cooler EGTs as well.

Same thing with an Evo X, put a turbo-back on it and tune both ways with a HFC, you'll make 12-15whp more with a test pipe. The restriction is the worst at high rpm.

 

Bro get a TBE!!!Just save up and get the whole thing!Last year I got the UR Cat-back exhaust then just 2days ago I got the last UR resonated testpipe!along with my AMS DP the this TBE is gr8!!!Large power gain...but I couldnt dyno/tune becuz this other guy was abotu 2do a E85 tune and i wasnt about to sit there all afternoon...ill go back another day to find out my numbers now but I can surely feel the gains + the fluttering i was gettin from my wastegate becuz of my 3-port boost solenoid went away!

Save up and do it at once...a testpipe + a stock exhaust that was proven 2b super restrictive seems like a waste of time 2me...but thas just me...

 

Drew,

check out the Magnaflow catback for the Evo X. It looks almost identical to stock. And it's cheap too.

 

I did this, it made a nasty sound at WOT sometimes tho. Super stealth, that + intake, uicp, 3 port got me 402wtq

 

Nor sure this is correct, chances are if you go with a down pipe and best pipe, you will experience some over boosting and creating knock.

I personally wouldn't want that for my car, so I went with catback for now until I am good and ready for a tune.

 

I ran a TP and O2 DP with the rest of the exhaust being stock for a stealthy look...with Cobb's stage 2 tune, the gains were good. Prepare yourself for the smell though...

 

Tell us how you really feel about those that run test pipes

 

Can you run a stage 2 on the AP with just a hfc or tp on a stock exhaust? I went to a shop and they said it would create a lot of back pressure or something like that aka not good...