Downpipes VS 200Cell catts.

[manny1424]

Hey everyone,

I got an f10 m5 two months and am starting to collect parts to mod the car soon. I wanted to hear from some people who have no catless downpipes vs 200 cell catts. Is the power difference noticeable and most importantly how bad is the smell for no catts. Reason I am asking because I have a modified e46 m3 as well with race headers and the car smells and I would not be bale to handle it daily since my m5 is my daily driver.

[BinH]

Originally Posted by manny1424

Hey everyone,

I got an f10 m5 two months and am starting to collect parts to mod the car soon. I wanted to hear from some people who have no catless downpipes vs 200 cell catts. Is the power difference noticeable and most importantly how bad is the smell for no catts. Reason I am asking because I have a modified e46 m3 as well with race headers and the car smells and I would not be bale to handle it daily since my m5 is my daily driver.

I have catless and would rather have race cats due to the smell. Its very noticeable!

[manny1424]

Yea I figure the smell would be bad but thought maybe it won't be as back with stock exhaust and resonators. Thnx for the input.

[EnderG60]

Ive been pondering if the 200 CEL DP's are even worth the cost over the stock ones.

[chrisho68]

Originally Posted by BinH

I have catless and would rather have race cats due to the smell. Its very noticeable!

Even while in the car? Or only if outside with the car at a standstill? I've debated whether the smell would get to me too

[Vonhaas]

I really only notice when I'm reversing and my windows are down. Not really a problem other then that.

[manny1424]

I spoke to someone at Fabspeend and they claim you get 10-15 hp gain to the wheels with their 200 cell race cats. I wonder if anyone has actually real data and experiencing with these. Because according to Fabspeed the catless you gain 15-20. Definitely not worth the extra 5-10 horsepower to go catless.

[bgboost]

The smell was noticeable enough for me to swap my factory cats back in after a few days with catless. Everyone has a difference tolerance level, and I'm sure there are many on these boards that aren't bothered one bit by the smell.

My 300ZX twin turbo full catless smelled, but not quite as bad. I suppose being younger and having no kids, it didn't bother me.

In this car, though the sounds were awesome, didn't want to live with the smell that came with it.

That being said, I would go for a catted DP w stage 2 tune down the line.

[manny1424]

Originally Posted by bgboost

The smell was noticeable enough for me to swap my factory cats back in after a few days with catless. Everyone has a difference tolerance level, and I'm sure there are many on these boards that aren't bothered one bit by the smell.

My 300ZX twin turbo full catless smelled, but not quite as bad. I suppose being younger and having no kids, it didn't bother me.

In this car, though the sounds were awesome, didn't want to live with the smell that came with it.

That being said, I would go for a catted DP w stage 2 tune down the line.

Did you dyno your car and see what gains you got without cats?

[bgboost]

Originally Posted by manny1424

Did you dyno your car and see what gains you got without cats?

I didn't, but definitely had more punch in the mid-range and gas pedal was more responsive to touch (quicker turbo response)