[Veloooo]

I'm thinking about installing a catless downpipe this month, however I have a Dinanflash Stage 1 Handheld tuner on the car. Is running Dinan Stage 1 with a downpipe for a couple of months fine? Also, I would love some recommendations for catless downpipes.

[marcthedark]

It surely is fine. But you will get a CEL and not pass inspection

[Veloooo]

Yeah that's fine, 2 more years till smog. I'll take it off whenever the time comes

[mike@x-ph.com]

the problem with the CEL (other than its annoying), is the fact that if the car ever has an issue, you wont be able to tell since your CEL is on all the time either way

[WolfGTI]

These catless posts make me laugh -the god damn BMW track cars have hi flow cats. 99% of these people can't / won't drive well enough or hard enough to notice the 7 - 18 more hp with catless.

[dradernh]

Originally Posted by WolfGTI

These catless posts make me laugh -the god damn BMW track cars have hi flow cats. 99% of these people can't / won't drive well enough or hard enough to notice the 7 - 18 more hp with catless.

This straight from the horse's mouth (Steve Dinan) at https://carbahn.com/products/stage-1...0i-m340i-m440i:

"A note on down pipes (removing the catalyst). We have run back-to-back dyno runs with the cat on and off and the power gain is much smaller than most people claim usually around 11hp"

Not only will most not be able to take advantage of the extra power on a track, they won't feel it either. By itself, it just doesn't make that much of a difference. I've always assumed it's more about the noise than it is the modest boost in performance.

[Info@mad-us.com]

We have a 5 inch catless which will give you the most horsepower and most sound but if you want something slightly quieter and less smell we also have a 4.5 inch 200 cell catted downpipe. Both are in stock at the moment.