[mofoSTI]

I plan on getting the DP then installing an exhaust cut out before the muffler in back. That way I can be quiet when I want or loud as I want. As I recall on my 04 STI I did the helix catless dp and thought the exhaust note was noticably louder, but not too loud at all. Very tastefull sounding infact. A catted dp wont make as much as a change as a catless one, but you might be happy with the exhaust note with just a dp.

[GilMikalian]

Originally Posted by RallySportDirect

Yes a DP and a Stg2 reflash are perfectly safe. You will be off target boost by 1-2psi. But thats nothing to worry about.

If I may just add to the above...A CATTED DP (with otherwise stock exhaust) and a Stage 2 reflash are safe (don't want to say perfectly but that's just me being too literal). With this setup, you have a safer than a full turboback setup, in terms of boost creep, while saving some serious coin. Besides, the stock catback opens up a bit after some miles and the growl is nice when you're WOT and subdued in traffic.

In fact, I like this setup so much, I'm not even entertaining the thought of an aftermarket catback and will be going with a Protune to lock in my setup for the best possible performance while retaining long term reliability and safety. I figure this way, I don't need a boost guage (with memory) which saves me another 3 bills or so, which makes the Protune all that much more attractive since it buys me peace of mind AND some additional noticeable power.

[karleric]

What kind of dyno numbers can one expect to put down with this "poor man's setup"?

[GilMikalian]

Originally Posted by karleric

What kind of dyno numbers can one expect to put down with this "poor man's setup"?

Not sure but I'm thinking around 5 or so less than a "proper" Stage 2...which I can live with given the added safety from boost creep. With a Protune, I'm expecting to MORE than make up the power difference!

Besides, I've read in more than one place that the stock catback is quite efficient so an aftermarket unit will not add significant power.

[chmura]

Where are you going to get a Protune at?

[mofoSTI]

I wonder how this setup would sound with headers?

[bigd]

For those worried about boost creep, on my 04 I had installed a catless Invidia 3" TBE with a bellmouth. It has some pretty bad creep... I solved the boost creep by porting the wastegate opening, I can't remember where I got the idea but it worked perfectly.

Building on what was stated before, the problem with a catless exhaust is that it flows SO much easier, that the wastegate on the stock turbo can't keep up at high boost levels. There's so much exhaust flow, that the wastegate simply doesn't allow enough of it to escape before it goes through the turbine. Since the exhaust flow can't be bypassed, its forced through the turbine, overspinning the turbo and generating too much boost. The engine CAN'T get rid of this problem, since the wastegate is already flowing at 100% so the excessive boost risks blowing the engine.

The problem was solved by removing the exhaust housing and using a dremel metal cutting bit to grind the opening a bit larger, but most importantly remove the sharp edges to create a smooth flow when the wastegate is open. As it is designed stock, the wxhaust had to flow over a sharp 90° edge, making it impossible for the air to "cut around the corner" to get out through the wastegate. I rounded off any sharp edges, so the air can "adhere" to the curve allowing the wastegate to function significantly more efficiently. (Same idea that allows water to stick to a curves surface as it flows downward). Boost was held solid after the modification. I am not certain if the 08's VF48 turbo have the same problem, but I would suspect it does.

The porting job isn't difficult, anyone handy with a dremel and confident enough to remove the turbo can handle it. Some shops will even do it for less than $100 bucks if you bring them the turbo already out of the car.

[GilMikalian]

Originally Posted by chmura

Where are you going to get a Protune at?

Harman Motive in Torrance.

[chmura]

Originally Posted by GilMikalian

Harman Motive in Torrance.

Yeah thats where I'm going to go.

Keep us updated after you get the protune from them.

[RjsSti]

Originally Posted by GilMikalian

Harman Motive in Torrance.

After a few months...
How's the protune??
Was it worth it after performing a stage 2 flash?
I was planning on just sticking with the OTS Stage 2 mapping from Cobb and would like to hear about your thoughts/results after the protune. My local shop says to hold off on the protune and stick with the OTS map until after cbe.

RJ

[inpuressa]

most likely going to do this "poor man" stg2 in the near future. Guess I gotta ask, after driving it for sometime, has it given any problems so far?

[Fletch07STI]

I just need a catted dp because im going the poor mans stg 2!

[spongebobnopants]

What if you just got the front from Perrin and gutted the rear cat or kept the rear cat and got the Maddad catless front?

These would be the least expensive ways to go. This would be strictly for off-road use of course.

[GilMikalian]

Originally Posted by RjsSti

After a few months...
How's the protune??
Was it worth it after performing a stage 2 flash?
I was planning on just sticking with the OTS Stage 2 mapping from Cobb and would like to hear about your thoughts/results after the protune. My local shop says to hold off on the protune and stick with the OTS map until after cbe.

RJ

Stage 2 is definitely worth it. Absolutely no regrets. The car is transformed and is an even more fierce beast.

About the protune, according to Dan, the owner of Harman Motive, he said "good news for you, bad news for me." He said the Cobb OTS map was so spot on, I would not gain any appreciable advantage from doing a protune. Honest guy, to say the least. He has since stated that he has protuned others' 08s with Stage 2 with some success so it just appears that I was lucky in that I got a strong car out the gate.

FOR ME, running Stage 2 OTS with Cali 91 fuel (if you can call it that), I'm at 294 wtq and 256 whp so I'm at full turboback levels with my "poor man's" Stage 2.

I've had no issues except for an overboost code when I was WOT in 6th heading uphill on the 405. No issues since reflashing to v1.01.

[98ss]

Here is my poor man stage 2.
Stock injector, stock pump.
Base Run is downpipe with Cobb OTS map. Drop in panel filter.
Test Run is after GM BCS and protune.
21 PSI max.
2005 Sti.

Downpipe is catted in the 1st section, 2nd section is prodrive catless pipe. Bellmouth type.
Mustang Dyno @ GST