[turnsignalslol]

I went ahead and installed catless dps on my G87 and all is great but I've ultimately come to the conclusion that I value my warranty over some cool sounds and slightly increased throttle response. Yes, I know that the chances of something going wrong with just DPs is very low but since this is my only car, I don't want to take chances. I was running stock tune with catless dps and a catback exhaust (sounds great tbh lol).

When it's time for service, BMW will definitely know I have catless dps because of the obvious sound and smell, and also because they'll see the catalyst efficiency codes when they plug it in. I'm planning on having my original cats reinstalled and putting the car through its paces afterwards so that the catalyst codes clear themselves from the permanent codes section. (Will BMW be able to see the "permanent" codes even if they clear automatically after the issue causing the codes is fixed, and will they know it's from DPs?)

Another option I could potentially do is go with 400 cel cats which don't throw a CEL and still offer a decent amount of sound increase. The only issue is that they're 10 times the price of regular catless downpipes, which doesn't make them very economical (would cost more than my entire exhaust system lmao). Regardless, some questions I had were:

1. Are they reliable over time? I heard some people saying they will fail within a couple of years of install. Obviously this depends on use case but for me, I plan on keeping the stock tune until warranty is up.

2. Is there a catless smell? I hate how my garage smells like someone dropped a chemical bomb every time I drive my car now.

3. Can you still hear the turbo spool sound like catless dps with 400 cel dps?

and most importantly,

4. If you are an owner of 400 cel DPs (AA, Fabspeed, etc.), are you satisfied with your purchase and do you think it was worth it?

I feel like even though 400 cel DPs can still void your warranty, BMW would be less likely to find it since it doesn't throw a CEL and I assume that the car will still be running at factory parameters since the rear o2 is getting clean enough readings. I didn't go with a o2 spacer with my catless dps because I don't want to feed my car false data and potentially have it run lean or rich.

All responses are appreciated, thanks!

[mike@x-ph.com]

1. Are they reliable over time? I heard some people saying they will fail within a couple of years of install. Obviously this depends on use case but for me, I plan on keeping the stock tune until warranty is up.

they are reliable, tens of thousands have been using them for years

2. Is there a catless smell? I hate how my garage smells like someone dropped a chemical bomb every time I drive my car now.

no smell with the 400 CEL catted downpipes

3. Can you still hear the turbo spool sound like catless dps with 400 cel dps?

Yes you can

and most importantly,

4. If you are an owner of 400 cel DPs (AA, Fabspeed, etc.), are you satisfied with your purchase and do you think it was worth it?

Given how popular this mod is, i'd say yes they are very satisified.


BTW the sale on these downpipes end soon

[Dave07997S]

The Fabspeed DPs are with the HJS cats and they are 200cpi. They are very durable but also very expensive. I believe DPs are a waste of money. I have seen 550rwhp S58s only gain 11rwhp going with catless DPs over the OEm ones.

[kyrix1st]

Go straight DP or don't do it at all. It won't smell either way because the stock exhaust has four more catalytic converters leading to the tail pipes. Stupidly restrictive system.

[turnsignalslol]

Originally Posted by kyrix1st

Go straight DP or don't do it at all. It won't smell either way because the stock exhaust has four more catalytic converters leading to the tail pipes. Stupidly restrictive system.

I have a catback so all of the resonators and cats have been deleted.

[M_Power Rob]

Originally Posted by turnsignalslol

I have a catback so all of the resonators and cats have been deleted.

Mike's responses above are spot on.

To add, I have highflow 200 cell catted downpipes with a catback exhaust...no smell.

[Geighty7]

Originally Posted by M_Power Rob

Mike's responses above are spot on.

To add, I have highflow 200 cell catted downpipes with a catback exhaust...no smell.

Are you throwing a CEL or are you tuned? Do you know if there’s any long term damage to engine with highflow 200cell catted DP’s with no tune?

[mike@x-ph.com]

Originally Posted by Geighty7

Are you throwing a CEL or are you tuned? Do you know if there’s any long term damage to engine with highflow 200cell catted DP’s with no tune?

Fabspeed is 200 CEL and will not trigger the check engine light; that's because they use HJS cats. The less expensive downpipes use regular 200 CEL cats and will trigger the check engine light

There is 0 evidence of damage caused by downpipes. I’m not sure why you’re so concerned, but I’m not aware of anyone on this forum who has made a valid claim about downpipes causing issues.

[M_Power Rob]

Originally Posted by Geighty7

Are you throwing a CEL or are you tuned? Do you know if there’s any long term damage to engine with highflow 200cell catted DP’s with no tune?

I have Evolution Racewerks DPs and yes, I am tuned.

To repeat what Mike stated above, no damage from using them.

[Geighty7]

Originally Posted by mike@x-ph.com

Fabspeed is 200 CEL and will not trigger the check engine light; that's because they use HJS cats. The less expensive downpipes use regular 200 CEL cats and will trigger the check engine light

There is 0 evidence of damage caused by downpipes. I’m not sure why you’re so concerned, but I’m not aware of anyone on this forum who has made a valid claim about downpipes causing issues.

Just triple checking what’s the benefit of having DP’s without a tune? Noise?

[mike@x-ph.com]

Originally Posted by Geighty7

Just triple checking what’s the benefit of having DP’s without a tune? Noise?

better airflow which leads to more power
less backpressure on your turbos
more sound

[Geighty7]

Originally Posted by mike@x-ph.com

better airflow which leads to more power
less backpressure on your turbos
more sound

Would you recommend for someone looking for the most out of the car without resorting to a tune? And if so, which downpipes?

[BroDoze]

Catless DPs definitely allow for quicker spooling.

[mike@x-ph.com]

Originally Posted by Geighty7

Would you recommend for someone looking for the most out of the car without resorting to a tune? And if so, which downpipes?

That depends on what you want to get out of the car; if you want more sound, the downpipe is an excellent option.

If the goal is more power, the tune is the better option.

if the CEL is a concern, i recommend the active autowerke downpipe
if the CEL is not a concern, the MAD one is the best value