Catless Downpipe Reviews - Tolerability and Performance

[NewDirection]

I recently installed the MMP catless downpipes on my N54 E88 after some debate and wanted to share my impressions. My car has a 5" stepped FMIC, stock intake and exhaust, and runs a Cobb off the shelf tune. Here goes.

1. Tolerability

I was on the fence about catless downpipes as I was not willing to tolerate a lot of smell or noise, regardless of performance gains.

I am happy to report that smell is quite minimal once the car warms up. I was recently stuck in traffic with the roof down and at one point got a slight whiff of gasoline smell. I'm pretty OCD about these things and I can say the smell is NOT an issue.

In terms of noise, there may be a slight increase in exhaust sound but the big change is how much you can now hear turbo spooling. It's a sort of whistle like whoosh sound with a metallic component to it. My friend likes it. I find it annoying as it muddles the previously beautifull exhaust note. I'm mostly indifferent to it after a few days now but definitely don't see it as a plus.

[NewDirection]

2. Performance

Tldr: meh.

I don't know if it's my Cobb tune or I have a leak somewhere but I'm not blown away by the performance. Going from stock to a tune (Cobb Stage 1) wss a huge jump. Then adding the FMIC (Cobb Stage 1+) was pretty solid as well. Now adding downpipes (Cobb 2+) did add some noticeable improvement in acceleration down low nut not much in the midrange. Overall, I was a bit disappointed tbh.

Conclusion

Very tolerable, if you're okay with extra noise, but not a crazy performance boost. What did others think?

[fast1eddy]

I'm considering going back to stock. The smell is not good when I use the climate control. Windows down is fine. I really don't need the extra performance.

[RonnieRobotPants]

Originally Posted by fast1eddy

I'm considering going back to stock. The smell is not good when I use the climate control. Windows down is fine. I really don't need the extra performance.

I get the faintest smell with the windows open sitting idol but I've never heard of the smell coming thru the A/C system. How bad is it?

[fast1eddy]

Originally Posted by RonnieRobotPants

I get the faintest smell with the windows open sitting idol but I've never heard of the smell coming thru the A/C system. How bad is it?

It's bad. Don't know if I've got a leak somewhere. Everything seemed to be buttoned up tight. I'm going to check things over again and if I don't find anything I'll go back to stock.

[Hybrid G]

Well I did it and went catess, it's loud, raspy and the smell is not that bad but, the car has lost its mild manners.


Will report back after I put some miles on her.

[c0bra]

My biggest concern before install was smell, especially since I almost always drive topless. Expecting the smell of rotten eggs, I was pleasantly surprised by the aroma of gasoline. It's not that strong either.

Definitely louder than stock, but not as loud as I had anticipated from watching videos. I do kinda like the tinny whistling spooling sound though. The downside is that I hear less of that sweet vacuum whoosh from the DCI.

As far as performance, there is a noticeable difference, especially low end. Traction control definitely kicks in more often too. Though the real benefit is being able to up the tune and run more boost. Amazing overall gains for the price, highly recommend.