Question for downpipes - need help

[aliusa]

I'm new to downpipes and have been reading posts about them and have few questions that I would appreciate if someone can answer:

- how's the performance of Catted DPs? Is the performance gain quite noticeable over factory DPs

- I know labor rates vary so I won't ask the cost but how much time does it typically take to install them?

- what are decent priced brands that have good quality and fitment on '15 M5 CP?

Thanks!

[rickyf10]

-depends on how much more air flow is gained by new DPs. Generally more air flow, better the performance
-mine took 4 hours done by local shop, it would be even shorter if proper instruction is given to mechanic
-mine is vrsf catless DP, fitment is ok and it’s absolutely worth for its price. But if you are looking for high flow catted DP. It would be much more expensive and not many brands offer catted DP.

[Dwaynos]

Smell is a big downside to having catless. I keep toying with the idea myself but the smell puts me off. Although having never witnessed it personally i am only going off what is said on forums.
Don't want to be attracting any sharp nosed police officers.

[aliusa]

Originally Posted by Dwaynos

Smell is a big downside to having catless. I keep toying with the idea myself but the smell puts me off. Although having never witnessed it personally i am only going off what is said on forums.
Don't want to be attracting any sharp nosed police officers.

I have smelled and driven an M5 with catless DP and I did not like it. The smell of fumes get inside the car and even when standing outside you can smell gas. Plus in my state of VA it will not pass the yearly emissions inspection and I don't want to be swapping them every year

[Jonzny]

Catted downpipes cost way too much. That leaves you with catless, the smell isn't awful because youre not standing behind the car most of the time. The issue is emissions, if I could pass with catless i would get them, but not possible afaik

[Ickdeep]

Originally Posted by aliusa

- how's the performance of Catted DPs? Is the performance gain quite noticeable over factory DPs

There is definitly some power gain with going with catted downpipes compared to OEM. OEM are very restrictive. You will get a little smell even with catted downpipes as they are less restrictive. You'll definitly want to get a tune once you install either one.

Originally Posted by aliusa

- I know labor rates vary so I won't ask the cost but how much time does it typically take to install them?

It took my shop 3 hours to install them.

Originally Posted by aliusa

- what are decent priced brands that have good quality and fitment on '15 M5 CP?

I currently have Fabworx catless downpipes. I also had AMS downpipes (they also sell high flow cats but its getting pricey for catted; Catless =$1800 retail vs catted = $3000 retail). https://ind-distribution.com/product...less-downpipes

And seeing talk about emissions, it all depends on each state. You might have to get some research to see if catted downpipes can even pass. If not, its more cost effective to get cattless downpipes and remove/install them when its inspection time.

[Boosted M5]

Roughly 2 to 3 hour install for someone with experience. I have oem gutted cats and the smell is terrible. You just have to either live with it or don't do it at all. As far as performance not sure as I haven't put it on the dyno. That said, stage 1 vs stage 2 tune, I prefer stage 2 as you get more power and the turbo sound is intoxicating.

[aliusa]

Thanks all. Looks like I'll probably just go with Stage 1 tune. Question is DME or BootMod3 tune

[Ickdeep]

Originally Posted by aliusa

Thanks all. Looks like I'll probably just go with Stage 1 tune. Question is DME or BootMod3 tune

Also check out BPMSport . I had their stage one tune for about 6-7 months. Was very happy with it. The only reason why I went to stage two was because my buddies got faster.

[Blaxwil]

Originally Posted by Ickdeep

Also check out bpm sport. I had their stage one tune for about 6-7 months. Was very happy with it

"What he said"

Another vote for Stage 1 BPM. You also get great customer service with Mike. Before doing it I would seriously ask yourself do you truly desire more power. I find the car behaves like a savage even in S1. After several months, I still haven't found enough road in front of me to really get on it. Overall I'm very happy with the tune.

[aliusa]

Originally Posted by Blaxwil

"What he said"

Another vote for Stage 1 BPM. You also get great customer service with Mike. Before doing it I would seriously ask yourself do you truly desire more power. I find the car behaves like a savage even in S1. After several months, I still haven't found enough road in front of me to really get on it. Overall I'm very happy with the tune.

Thanks Ickdeep and Blaxwil for vouching. I went ahead and ordered BPMSport today. Talked to Mike and he was extremely patient in answering my questions and helped me right away. Can't wait to have it tuned.

Ickdeep I don't have any buddies faster than my M, well except for one with Tesla P100D but that doesn't count, so I'm safe with Stage 1 for now 😉