850 custom exhaust question

I was thinking of doing a full custom turbo-back setup. Considering eventual N/A cams, bigger injectors, moving up in turbo from the 15G, and an ECU tune...but will basically stay stock until the money is right.

I've been to 4 shops so far. Threw down the specs of going 3" all the way (downpipe, cat, resonator where the stock muffler is, straight-through muffler at the rear, and all piping in between). I'm looking for CA smog legality and keeping the loud exhaust tickets away from me, not to mention being all set regardless of performance goal. However, after 4 shops and meeting a cat who got his 855T done, conflicts with my idea go as follows:
-2-1/2" will suffice b/c 3" is too big unless I had a huge turbo right off, and I'd probably lose power and torque.
-the stock cat can simply be opened up to whatever size piping I use.
-custom downpipe may not be smog legal.
-turbo cars aren't loud like that to require a resonator in addition to muffler.

So those of you who have already had one done, what is the best compromise?

Also, O2 sensors have thrown a CEL, so I want them to deal with that too. What would I need them to do there?

I've nothing but good things about the iPd exhaust, maybe try and copy that one? (or buy one )

Doesn't OBX make a decent exhaust for the 850?

Go 3" from turbo to tail, ignore the shops saying to go with 2.5".

Yes the stock cat could be opened up but chances are it will not flow as well or last as long as a new cat.

A single oval muffler in the center and small bullet muffler at the rear will kept it fairly quiet but you can also fit a smaller oval muffler at the rear to keep it more on the quiet side. Make sure the exhaust tip sticks out the slightest bit fro. The rear bumper as that will help keep the noise levels down inside of the car.

Mueller said:

I've nothing but good things about the iPd exhaust, maybe try and copy that one? (or buy one )

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Yeah, a grand for an exhaust is just wild, whether I could afford it or not. I'm budgeting 1/3 of that towards this.

Muffler is no object so much as getting the downpipe right, something I'd never have to take off for smog or need to upgrade. IPD charges $900 for that alone....uhhhhh, no.

While $ is a lot if they are still being made by the forum member (VS and TB) the system is so well built it will outlast the car. If I recall he was selling very well built downpipes for sub $500 with cat.

Either way Maybe just get a downpipe from him and then have a shop build up the mufflers and bends.

What they said about the noise level is false, at least on my s70 t5 it was. I had three inch from the turbo back, with a cat and one straight through muffler. That damn thing was stupid loud. Sounded awesome, but christ on a stick that thing was loud.

Move to florida and do whatever you want to your car. I can get 3 inch turbo back with a muffler and cat for $450

red740t said:

Move to florida

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Not gonna happen...

Living in CA is worth the property taxes and a few troublesome car modification rules

Just gotta come up with a mix I can live with.

So say I decided to leave the downpipe stock to avoid the smog risk and just go cat-back. Will there be any power difference or will the car do nothing more than sound kewl?

run two 3" in/out mufflers & 3" pipe & new 3" in/out cat. Would be fairly quiet, flow well. Isn't that what you're after?

Cat back will make it louder and help a little with power, but the downpipe is where the rear power gains, night and day difference.

Personally do the downpipe and out the heat shield back on and as long as it is not super loud and passes the sniffer no one will care. If they give you a hard time about it say you had it installed years ago before the most recent Nazi laws took affect.


Either way myself being from socal as much as I love the weather and beach there is not enough $ to make me go back to socal.

Sorry to do this but quick question I found some nice n/a 240 headers long tube on a site earlier and was condering if they would bolt on and fit properly to an 8 valve head on a b234 block? All joking aside because I cannot locate any n/a 740 headers that are performance styled. I do not enjoy the stock iron moose knuckles.

89volvo740gle8valve said:

Sorry to do this but quick question I found some nice n/a 240 headers long tube on a site earlier and was condering if they would bolt on and fit properly to an 8 valve head on a b234 block? All joking aside because I cannot locate any n/a 740 headers that are performance styled. I do not enjoy the stock iron moose knuckles.

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You'd be better served starting the topic "Will headers for 240 work on a 740?"

Here's an example exhaust: 3" snail-to-tail, 3" I/O cat after downpipe. 3" straight through Magnaflow muffler, and 1 3" I/O 16" length glass pack. It's idling here for the first time under this ECU, so the tune's meh, but you can get an idea...Listen at about 20 seconds onward for actual idle sound.

<iframe width="420" height="315" src="http://www.youtube.com/embed/GrRBXjGAwwk?rel=0" frameborder="0" allowfullscreen></iframe>

After more shop hunting, now looking to probably grip a hi-flow cat, resonator, and muffler off of eBay, as well as possibly a couple of mandrel bends. Found two shops that would do a custom downpipe. Will use that or OBX (if smog legal) and just take it all to a shop to weld the whole thing together.