dump pipe + mid pipe + stock muffs

[pips06]

I own an 07 tb STI and was wondering what peoples thoughts are on upgrading to a phat dump pipe and mid section but leaving the stock mufflers on? Im looking at definately getting the dump pipe but was wondering whether there'd be any performance gains to be had upgrading the mid section aswell. My main reason behind leaving the standard mufflers on is the noise.

Oh, and i'll be looking at getting a tune done afterwards either way.

[gtspec]

i got a 07 GTB but not a STI thou, and from my experience i have only changed to the phat dump pipe (stock mid and muffs) and just from that i noticed a big difference in response and the power delivery up top end..

i would 100% recommend doing this..

[pips06]

Yeah, as i said, i'll defiantely be doing the dump pipe but was wondering if i should do the mid section aswell.

[GTSPECB STI]

I have a tuned by sti Lib, Phat dump pipe, 3" centre pipe and was running the stock sti quads. That set up was a big improvement over stock in terms of power and somewhat sound but not optimum. I bought the Hitech quads and I must tell you I got improved throttle response due to reduction in back pressure created by sti quads. It also was a huge improvement in terms of exhaust note...pure boxer sex now. When you pull the stock sti quads off you will understand what I mean.

[pips06]

So for the cost of the mid section, say $800, would you say it's worthwhile if i was going to leave the stock mufflers?

Or better to just go with a dump pipe and tune?

Obvisouly im not going to get the same results as if i replaced the mufflers.

[GTSPECB STI]

So for the cost of the mid section, say $800, would you say it's worthwhile if i was going to leave the stock mufflers?

Or better to just go with a dump pipe and tune?

Obvisouly im not going to get the same results as if i replaced the mufflers.

Dump pipe is the best bang for buck power mod in my opinion if combined with a proper tune for it. Stock tune is very rich and retarded for obviously reasons. My centre pipe was fabricated from 3" s/s pipe and tig welded with one resonator in it. Cost was $450 from Allstar Garage in Perth. If you do the dump pipe then I suggest you do the centre pipe as well as the stock one is very restrictive.

[suff]

So for the cost of the mid section, say $800, would you say it's worthwhile if i was going to leave the stock mufflers?

Or better to just go with a dump pipe and tune?

Obvisouly im not going to get the same results as if i replaced the mufflers.

The stock mufflers are the biggest restriction.. I ran a 3" DP and 3" Centre pipe going into a standard Y-Pipe & Mufflers on my wagon for some time.. recently ditched the Y-Pipe and mufflers and installed a full 3".. the difference with the mufflers was very noticeable (both in sound & performance)

In short, don't leave the OEM mufflers, they really are not fit for purpose!

[pips06]

I realize that but i don't want the added noise that comes with aftermarket mufflers regardless of the performance gains.

Im trying to establish whether there's any noticable benefit by replacing the mid section (bearing in mind im getting a dump pipe and tune) and whether it's worth the money.

[GTSPECB STI]

I say it is def worth the doing the centre pipe if you are doing the dump. I did all three and mine is pretty quiet at idle still and your standard deep boxer rumble when on the throttle. The stock mufflers are horrible in terms of the baffles and size.

[suff]

I realize that but i don't want the added noise that comes with aftermarket mufflers regardless of the performance gains.

Im trying to establish whether there's any noticable benefit by replacing the mid section (bearing in mind im getting a dump pipe and tune) and whether it's worth the money.

You will still get additional noise if your doing 3" TB.. as you are trying to force through a more exhaust gasses through a narrow section.. this will result in an increased noise level

[pips06]

Surely not to the point of after market mufflers though?

[smythie]

One or two over here have actually noticed a reduced amount of noise going to the higher flowing mufflers Jim has organised. I guess the lower back pressure from the new mufflers has reduced the amount of work that the resonators need to do?

[Boxer]

i got a 07 GTB but not a STI thou, and from my experience i have only changed to the phat dump pipe (stock mid and muffs) and just from that i noticed a big difference in response and the power delivery up top end..

i would 100% recommend doing this..

Out of interest have you had an ECU tune? If not any dyno time to check vitals (A/F ratio, boost spikes, torque curve)?

Interested to see - yes before everyone jumps in - I know a tune will make the most of it, but I have strong suspicions the stock ECU is smart enough to handle this safely.

Also on the TBSTi - I'd be inclined to try keeping the stock muffs - the dump and centre are obviously restrictive, and sure the cans would open up a bit more, but seeing as its two 2" pipes on the stock TBSTi mufflers I dont think it'd be huge with such a small turbo on a 2.5lt car. From what GTSPECB is saying its along the same lines. I wouldn't want a loud rumble - IMHO the Liberty doesn't suit a loud exhaust note like say a WRX does

I have it on good authority (well lets say 'reasonable authority' ) the GTB mufflers and TBSTi mufflers are the same internally, but I dont see how - as the TBSTi mufflers are twin pipes all the way into the muffler body (its not just the twin outlet on the end plate of the can)

[smythie]

as the TBSTi mufflers are twin pipes all the way into the muffler body (its not just the twin outlet on the end plate of the can)

eh? are you saying that from the y at the diff, each muffler has two pipes? I know the 06 TBSTi doesn't

[Arith]

as the TBSTi mufflers are twin pipes all the way into the muffler body (its not just the twin outlet on the end plate of the can)

How did you come to that conclusion?