[B005T3D-G]

Hi all

Winter will be coming to a close soon so getting my wish list together for upgrading the coupe.

As far as breathing is concerned I've already decided on the AFE INTAKE STAGE 2 and AR design Catted DP's but can't find much in the way of options for a DP back system. Plenty available in the States but I hate getting shafted for import duty.

Was thinking the cheapest option is to take a road trip to Turrif and have them make a custom system for me but cheap is not always good so wondered if anyone on here has had a proven system installed and their thoughts on it. Supplier info would be helpful too.

Looking at a budget of around £1k for the system.

Cheers
G

[HeavyRightFoot]

The MV Sport one looks a good bet for £599.

[doughboy]

OP, by 'DP back' do you mean you want to ditch the secondary CATs?

Performance wise, you're better ditching the primary CATs (getting DeCAT DPs) but keeping the secondaries for MOT pass.

The get backboxes for looks / sound.

[335iLondon]

I would recommend you get the DP's installed first.
It is reported this give you a nice change in sound and especially on E92's the catless DP's with standard system give a very nice noise.
Not sure of performance gains with back box but imagine minimal.

[B005T3D-G]

Originally Posted by HeavyRightFoot

The MV Sport one looks a good bet for £599.

Now there's a decent price, your google must work better than mine . Before I contact them do you know if there's any cutting/welding or does it bolt onto the existing system??

Originally Posted by doughboy

OP, by 'DP back' do you mean you want to ditch the secondary CATs?

Performance wise, you're better ditching the primary CATs (getting DeCAT DPs) but keeping the secondaries for MOT pass.

The get backboxes for looks / sound.

Yes I am/was going to delete the secondaries as I figured that any gains from the Primary delete would be cancelled by the restriction in the secondaries. The way i was looking at it was by getting High flow Catted DP's and deleting the secondaries it would give better flow overall and still pass an MOT. Please tell me if I'm wrong, your input is appreciated

Originally Posted by 335iLondon

I would recommend you get the DP's installed first.
It is reported this give you a nice change in sound and especially on E92's the catless DP's with standard system give a very nice noise.
Not sure of performance gains with back box but imagine minimal.

Sounds like a plan. The main reason for replacing the system was for longevity as well as looks and in my experience performance gains from a back box only are minimal as you rightly said.

I love the noise my car makes so really all I want to achieve in that respect is a little more volume.

Thanks to all so far

[doughboy]

OP, agree with others, just fitting DPs really makes the car sound different, you might want to do that first. (DEcat DPs are louder than catted obviously)

Re the CATs, the primaries are the main restriction by miles as they are smaller and right up by the turbo. They are there to heat up quickly and pass the cold start 2 minute emissions type-test (cold start emissions not tested at MOT).

The secondaries are much larger and more high flowing. They will pass an MOT on their own as long as they are warm (as proven on here by Phil200tdi).

Plenty on here running way over 400bhp with secondary CATs on.

[B005T3D-G]

Originally Posted by doughboy

OP, agree with others, just fitting DPs really makes the car sound different, you might want to do that first. (DEcat DPs are louder than catted obviously)

Re the CATs, the primaries are the main restriction by miles as they are smaller and right up by the turbo. They are there to heat up quickly and pass the cold start 2 minute emissions type-test (cold start emissions not tested at MOT).

The secondaries are much larger and more high flowing. They will pass an MOT on their own as long as they are warm (as proven on here by Phil200tdi).

Plenty on here running way over 400bhp with secondary CATs on.

Coolio . Seems like I might be able to save a few more £££'s towards my LSD. Cheers

[335iLondon]

Oh and for an interim fix, have a search for Golf tee mod if you have not done this already.
I have the fuse pulled on mine, and it is a nice easy mod and 100% reversible

[B005T3D-G]

Originally Posted by 335iLondon

Oh and for an interim fix, have a search for Golf tee mod if you have not done this already.
I have the fuse pulled on mine, and it is a nice easy mod and 100% reversible

I tried that before and didn't notice much difference at all. The flap opens up at around 3k anyway so there wasn't any benefit when pinning it. It's ok for cruising I suppose but at this moment in time I'm not fussed. I'll give it another go when I get around to getting the DP's fitted so hopefully it'll make a proper difference then.

Cheers

[Cozy]

Originally Posted by 335iLondon

Oh and for an interim fix, have a search for Golf tee mod if you have not done this already.
I have the fuse pulled on mine, and it is a nice easy mod and 100% reversible

That's just lazy Alex , get under the car and just pop off the vacuum hose .

[doughboy]

...or get a JB4 and do it in the warm and dry via the steering wheel controls....

[m1bjr]

I love the sound of my Bastuck quads.

Having a chat to my Brother in law who runs an MOT test centre and is a tester himself.
The new concerns I raised some time ago regarding catalyser precence checks are very real.
Soon the test centres will be looking to see your 335i has FOUR cats fitted.
If you have any missing, you WILL fail the mot, regardless of emissions.

MOT test centres are quite heavily audited, and the penalties for frigging a test for a customer make it unlikely any will want to do this.

The data the MOT test centres collect is fed into an online system where it is statistically analysed.
Specific trends are identified, unusual amounts of money making 'headlamp alignment' failures are flagged for example.
Likewise if a station flags well below average results for emissions tests, bells ring.

Never realised they did this.

But decats might be an expensive hassle in the very near future. Be warned.

Steve

[B005T3D-G]

Bugger!! Oh well best plan to get the catted DP's, price up a custom center section with race cats and throw a Back Box on. Probably around £1100 worth aft of the DP's.

Think I'll forget it for now until I've got a Diff installed

[phil200tdi]

Originally Posted by m1bjr

I love the sound of my Bastuck quads.

Having a chat to my Brother in law who runs an MOT test centre and is a tester himself.
The new concerns I raised some time ago regarding catalyser precence checks are very real.
Soon the test centres will be looking to see your 335i has FOUR cats fitted.
If you have any missing, you WILL fail the mot, regardless of emissions.

MOT test centres are quite heavily audited, and the penalties for frigging a test for a customer make it unlikely any will want to do this.

The data the MOT test centres collect is fed into an online system where it is statistically analysed.
Specific trends are identified, unusual amounts of money making 'headlamp alignment' failures are flagged for example.
Likewise if a station flags well below average results for emissions tests, bells ring.

Never realised they did this.

But decats might be an expensive hassle in the very near future. Be warned.

Steve

I was about to post a similiar message, i.e. the MOT rules have changed and therefore all bets are off!

I read somewhere that CATS need to meet the spec of OEM, therefore I'd be worried even with race CATS fitted.

I'm likely to keep running mine catless until November (MOT time) and then reassess the options - Revert to stock and sell or keep beyond 100k. I think the risk of being checked at the roadside is minimal.

[B005T3D-G]

Really? Screw it!!! Think I'll put on what I want anyway and just spend the morning the day before putting the old system on for MOT time. It's only once a year after all

[idnan]

Just to reiterate the point, stick with the secondary cats. I've tried the options and find the car drones a bit more when accelerating from low revs without the secondary cats in place. I felt like there might have been a slight increase in performance but it might have been a placebo effect. These new MOT rules are a real PITA for modified cars.

I've got a Borla touring cat back which sounds pretty nice IMO, a bit more throatier than the standard but not overly loud.

Ps there might be a BMW performance exhaust on ebay

[acerboo]

just fit the bmw perf system, superb!

[doughboy]

Originally Posted by phil200tdi

I was about to post a similiar message, i.e. the MOT rules have changed and therefore all bets are off!

I read somewhere that CATS need to meet the spec of OEM, therefore I'd be worried even with race CATS fitted.

minimal.

Worry not, or less anyway...

MOT (or roadside) equipment is not capable of measuring levels accurately much lower than the ones they test for now, thats why the test limits have been roughly the same for 20 years. The OEM factory levels these days are way under the current mot limits.

No car newish car can ever be tested to factory limits outside of a laboratory.

As steve says the new checks are visual inspections for the removal or alteration of emissions equipment.

My father in law runs an MOT garage, he says as far as they're concerned the changes amount to nothing, and knowing of my mods, he says he would never fail it as its obviously not a dodgy car and will still pass the (unchanged) exhaust test, a view taken by most MOTers I hope!

[m1bjr]

Originally Posted by doughboy

he says he would never fail it as its obviously not a dodgy car and will still pass the (unchanged) exhaust test, a view taken by most MOTers I hope!

Naturally.

But what about those who have to rely upon non-family MOT testers?
Or the unsuspecting used car buyer?

He needs to be careful. The test system is smarter than one might imagine.
A 335i with two cats missing will be substantially over the 'norm' emissions albeit below the 'pass' threshold.

Only takes one cross check and he's in bother.

Which is why I'm surprised if any mOT testers will take that chance in todays climate.
We are lucky

[335iLondon]

lol spotted perf exhaust on fleabay
a members?
http://www.ebay.co.uk/itm/3306846055...#ht_500wt_1145

[B005T3D-G]

Originally Posted by 335iLondon

lol spotted perf exhaust on fleabay
a members?
http://www.ebay.co.uk/itm/3306846055...#ht_500wt_1145

Spotted yesterday and watching

If it is a members please get in touch as I'm seriously interested.

[Cozy]

TBH I'd forget the BMW Performance Exhaust and get custom rear boxes, you'd save yourself a load of cash and no doubt it'd sound fantastic .