[orionredwing]

I installed AR Design’s Catless Downpipes about 2 weeks ago, and thought it’d be cool to share my impressions.

Performance Recap:
For those who haven’t been following the catless DP threads, from what I understand (I'm not technical), the advantages of this mod is to reduce restrictions, and to allow the turbos to spool faster. Theoretically, this would translate into more power, as well as better throttle response. Apparently the factory DPs are a major bottleneck in our cars. I apologize for not being hardcore enough to do before/after dyno comparisons, but forum threads indicate a potential 20-30whp gain.

Install:
After researching the market, I went w/ Andrew’s product because it reportedly had the best fit, and he runs a stock oem exhaust like me. The install took about 3 hrs, and was smooth with no issues or difficulty reported by my mechanic, even though it was his first time installing DPs in a 335i.

Sound – is important:
Growing up in SoCal in the 90s when every other car in Alhambra had an aftermarket exhaust (it was really bad back then), I’ve come to dislike a loud exhaust, and the formerly screaming statements have lost its exotic flavor for me. However, I still really enjoy a deep bass rumble, and I like listening to aftermarket exhausts at idle/low RPMs when the dBs are under control.

At around 1500rpms and minimal throttle (windows down), you can hear the high pitched squeal/whine that I think is characteristic of all cars w/ catless DPs installed. This is not a nice sound, but luckily it goes away quickly, and is not present during hard acceleration.

However, once you open up, the sweet rich sound of the catless DPs matched to the OEM exhaust really gets the blood going. At only 5-10db louder than stock, it’s not annoying to those who care, yet totally transforms the sound characteristics of the car. That aggressive rumble really hits the sweet spot for people like me. When I pass cars on the freeway, it gives me a big grin because people can tell my car is fast and ‘modded’, but not annoyingly loud (for those who care).

Driving Impressions – I’m pre-29.2:
For STEP users, you guys know ‘D’ adapts to a driver’s habit. I put a hefty 18K miles per year on my car, and trying to eek out the best gas mileage has made my ‘D’ quite conservative. When my mechanic test drove after a previous install, he was like ‘wow, this car has a lot of turbo lag’. Of course, we 335i owners know better, and I explained the adaptive ‘D’ to him.

So for 2.5 yrs before catless DPs, I ALWAYS shifted into DS or manual mode for hard acceleration, no exceptions.

But one thing I noticed after installing DPs. The car has become super responsive at low RPMs! I step on the gas paddle gently in ‘D’ and the car accelerates immediately. No delayed type of feeling due to my adaptive driving. I can’t express how good it feels to not have to go into DS everytime I want the car to be more responsive. Now, in rush hour traffic, I can do those small 20% throttle, +5-10mph changes effortlessly. It’s really made rush hour driving more bearable w/o sacrificing gas mileage in DS mode.

At WOT, the car is totally transformed. I feel like I’ve added a mini-piggy on top of my piggy. The car feels like it wants to MOVE, and any impressions of turbo lag before have been greatly reduced.

At 4-5K RPMs, you step on the gas it goes. You step on the gas it goes. I feel like a yo-yo sometimes just testing out the awesome throttle response in 2nd or 3rd gear I think ‘crisp’ is the right word to use.

To be fair, I have to mention the AR DPs are matched to the new PROcede 9-9-9 maps (what a catchy name, and cool day to release it on!). The new maps are incredible, but that's for a separate review

Hope you enjoyed my impressions. Cheers.

[john boxter]

any drone associated with it? or is it literaly identical to stock on the highway on cruise control?

[ToadHollow]

Drone is going to depend on the exhaust moreso from the secondary cats back .....

OP:
Wait til you upgrade the FMIC next ...... these two work wonderfully well together.

[vase330]

What stage are you? Waiting on AR catted DPs here. Have FMIC already.

[ToadHollow]

Originally Posted by vase330

What stage are you? Waiting on AR catted DPs here. Have FMIC already.

Same setup I have. Nice .......... stage II Dinan here.

[blisstik]

Shiv should call those maps reverse doomsday.

[orionredwing]

There is no drone (which is a factor in exhausts, not DPs I think).

At cruising speeds, the sound is the same as stock, and I drive w/ my windows down all the time.

Originally Posted by john boxter

any drone associated with it? or is it literaly identical to stock on the highway on cruise control?

[orionredwing]

I guess I'm in a hybrid stage, as all stages assume aftermarket exhaust which I don't plan on upgrading, and my DCI is sitting in a box due to the heatsoak thread by Mr. 5. I'm glad the OEM exhaust is not that restrictive, so I'm only down maybe ~10-12HP from the rest of you guys, but I bet my LSD makes up for that for those of you who don't have it

As for FMIC, I agree. In fact, I ordered the AMS intercooler yesterday

Originally Posted by vase330

What stage are you? Waiting on AR catted DPs here. Have FMIC already.

[Craig@SupremePower]

AR Design FTMFW!!

[dr.roro]

Originally Posted by orionredwing

At around 1500rpms and minimal throttle (windows down), you can hear the high pitched squeal/whine that I think is characteristic of all cars w/ catless DPs installed. This is not a nice sound, but luckily it goes away quickly, and is not present during hard acceleration.

Do you hear this on the highway cruising at low rpm? Or do you mean revving?

Also, do you have an AT or MT?

[orionredwing]

Only during 1st or 2nd gear at slow acceleration and low speeds. Like if you're accelerating from a regular stoplight at regular speeds. Only during acceleration and not during cruise.

You can't hear it on the highways at all (ambient noise too loud), and on the street, you can't really hear it with the windows completely up.

AT as my review said.

Originally Posted by dr.roro

Do you hear this on the highway cruising at low rpm? Or do you mean revving?

Also, do you have an AT or MT?

[vase330]

Originally Posted by ToadHollow

Same setup I have. Nice .......... stage II Dinan here.

Used to have Dinan stage II. Went flashless about 8 months back. If you think the car is fast as is now, try a car with same setup with latest PROCede maps, you will be surprised what these cars are actually capable of.

[letterkills155]

did it add any smell?

[BES335xi]

cant wait for minee to go in!..... Thanks GREAT REVIEW!

[ar design]

Originally Posted by Craig@SupremePower

AR Design FTMFW!!

I'm with stupid.

[ToadHollow]

Originally Posted by ar design

I'm with stupid.

An opportunity missed to use this!! ...........

[ar design]

Originally Posted by ToadHollow

An opportunity missed to use this!! ...........

[Craig@SupremePower]

thats because he's a wise ass who talks before he thinks.... or in this case types before she thinks!

[ar design]

Originally Posted by Craig@SupremePower

thats because he's a wise ass who talks before he thinks.... or in this case types before she thinks!

[Craig@SupremePower]

you know how we do!!!

[ar design]

Originally Posted by Craig@SupremePower

you know how we do!!!

[5soko]

Nice review. I should be going AR catless DP soon