im looking at upgrading just the front half of my exhaust (BF Sedan, 4" dump, cat, 2 x 2.5" merge pipe) currently stuck at 300rwkw, looking for around 330-340rwkw. not sure if the stock cat back will be a restrction.

I was hoping to hear from someone who has done the front half first, but then later down the track decided to upgrade the cat back to find out that;

a) it made no difference in power, and the stock cat back was ok for this power range

b) the stock exhaust was a restriction and it made a decent power gain on the same boost.

currently have stock cat back with 2.5" hotdogs front and rear, so I have noise already!

Cheers

Edited January 9, 201412 yr by Vrdesign

already have 100cpi 5" cat on the std dump...

Just a quick update, fitted an xforce front half of the exhaust, 4" dump, cat and merge pipe. Car was tuned at 14psi, boost now hits 18 psi! Massive difference, response is much better, and power comes on a lot earlier. Time for a re tune!

Fitting wasn't too hard, the only issue I had was 1 of the 5 bolts where it connects to the turbo (bottom) was a pain to access with any normal tool. And had to modify the heat sheild which covers the steering arm.

How much Rwkw did u get once done the dump pipe

I would not give it a hard time until you get a retune and re adjust some parameters to suit the new hardware, otherwise at 18lb on the old tune it may GRENADE.

So originally you were making 300rwkw on 14 psi?

Yeah 14 trailing to 13. I'll know the gains one I re tune at the same boost. Haven't given it full throttle since I gave it a squirt after the install, not easy! Should be getting tuned in about a week. Just getting some suspension parts together so I can get it all done in one hit. Dump is a bit low so raising the front from ssl to sl with Koni reds. Should be sweet to drive after that!

You should see some solid gains. I made 345 @14 psi with xforce 3.5" split dump so after a retune yours should pick up a handful of lost wasps.

nice! what mods you running?

im booked in for a re tune this thursday!