LEX99FRC

Hello looking to find out how different the gains are for catted vs catless downpipes

Also all video clips of catted downpipes have resonators still in place does Anyone have catted downpipes with straight pipes instead of resonators?

Amg63-

just reviving this thread. Anybody have any info on this specifically for the 14+ AWD E63S?

gaspam

catted gives almost no gain, catless maybe +10 whp peak gains and maybe 20-30 whp under the curve gains. (non-turbo back style dps)

i felt almost no difference when i put my catless dps on, i even tried really hard to feel a placebo effect to no avail

Wickdwagon

We were lucky enough to snag FairBirds take off Weistec Downpipe and exhaust. We should have a before and after dyno plot here in the next week or so...same exact dyno. With Dave an team at PowerHaus doing the tune!

gaspam

that will be awesome to see as those are true turbo-back downpipes and many members have been looking to see an independent dyno on the true turbo-back style dps for a while on this forum

chiromikey

So he's going to optimize a tune before and after? Or maybe you already have a tune?

gaspam

good point, thought he was tuned... best would be tuned dyno then dyno with tune/dps

Wickdwagon

Yes, we will have three dyno plots. Stock, then just the ecu tune, then the new ecu tune to account turbo back exhaust. So we should have a very scientific comparison of all the different tweets. The only change that we have made is to put on the winter tires but they are the same rolling diameter so I am thinking that will not be an issues.

Amg63-

10whp is nothing much but 20-30whp under the curve is not bad at all. I'm surprised you couldn't feel that.

Im curious to know if catted downpipes add any power under the curve. Would prefer to keep noise at WOT down as much as possible but if it won't give a power gain and barely change the sound I guess it's not worth it. The smell is another concern going catless

From the video i have watched of Rado "street car setup" it seems that catted DP is still good for a solid sound upgrade when car is going WOT but still relatively quiet.

Wickdwagon

This is the first that I am hearing about a smell issue? Can you give some more details? My expectation 10-15 hp a much deeper growl when you lay into it but during highway speeds I am expecting good manners and that we have come to expect from stock.

chiromikey

And you will get fuel smell with windows down at stop lights. It's annoying but livable...

Wickdwagon

Thanks, I am an AC on vs. Windows down kind of guy!

Zod

Yub

Pros:

• You hear turbo witchcraft sounds now in lower gears
• Wakes up the sound
• power gain

Cons:

• Fuel smell when car is stationary, but liveable
• Can at times if in a higher gear, at low speeds sound a bit loud

CarHopper

Looking forward to this.

kponti

Glad to see that. I believe based on my results that the tune needs to be optimized for the turbo back.
I haven't posted my results (from 2 weeks ago) because it had a few confounding issues that came up. So far, while diagnosing, I feel like the turbo backs a quite a bit more bang for buck than we would expect. I post more on my experiences soon.

godrealm06

Just installed Speedriven catless downpipes and their stage 1 ECU flash last week. Will have in depth review and video clips within two weeks. So far so good. Determining whether or not I get a muffler delete as well.

cocobeex

i would keep muffler on.
Without muffler, it drones like crazy.

Wickdwagon

Since, one of my goals is not to destroy a really good thing already. The "smell" with the cat removed is starting to worry me a bit...

Has anyone explored the idea of using the best of the aftermarket exhausts and keeping the cat in place or having another better smaller, etc. cat installed to get rid of this smell? Not a mechanical genius...my right foot and my AMEX are strong though. So sorry if this is a dumb question.

gaspam

honestly the smell on our cars without cats is not near as strong as other cars... on my E55 and C63 it smelled like someone spilled gas all around my car when you were outside of it (inside no smell unless windows rolled down), but on my E63 (and my audi S4) the smell is nothing even close to the E55/ C63....

main difference is the E63/S4 are both twin turbos and a lot of the unburnt fuel gets burnt in the turbos, while the E55/c63 had no turbos so more raw fuel went straight to the exhaust, hence more smell on non-turbo cars.

Pretty much every car i have had has been cattless downpipes and of all of them, the E63 has the least amount of fuel smell.... really only noticeable when standing directly behind the car

Amg63-

If your worried about the smell why not get a high flow catted downpipe setup?

i think those setups are readily available and will still give some small gains in power and sound over stock.

BLKE63

my friend has an e63 with 200 cell cats and when the car is idle the smell is still pretty bad, not sure if all high flow cats are like that but his definitely was.

Zod

See not sure if you know this but the bi turbos have only 1 set of cats, vs the 2 sets we had on our 55k's.

also as mentioned turbo vs NA/ supercharger differ a bit on the smell factor.

My advice to you is this. If you are planing on a turbo back set up, then I would highly advice you find an E/CLS 63 decated and see how you feel about the smell. Reason is turbo back is pricey to install/ remove, where as down-pipe is not.

GL

Ralcbah

Smell isn't bad unless standing outside or with all Windows down. I still roll with sunroof open with no issues. As a courtesy to others, if valeting/etc, just turn it off. Otherwise, no issues here.

Wickdwagon

Thanks for all the feedback...the car is being dropped off for the Wiestec install right after news years. I guess this is why they have the "eco" function .

e65

Adding some methanol to your gas tank you will get rid of that catless smell. It's like a liquid catalytic converter .

E85 will probably work as well.