**Riss Racing** 3 inch CATTED downpipes (Prototype)

[JohnnyTT]

Any numbers yet??

[Kris]

Wayne, if you get done in Australia without CATS its MEGA , and I mean MEGA MEGA $$$ for your fine. Its a few thousand, then more for each cylinder over 4 or something...

Anthony, will these pipes fit a RHD Australia/European car?? Exactly like the UK cars..

[WAY]

Kris, there is still another set of cat after the DP as I understand it. Is that right Riss Racing guys?

[WAY]

Originally Posted by WAY

Kris, there is still another set of cat after the DP as I understand it. Is that right Riss Racing guys?

Anyone knows the answer to this? Am I just completely off the wall? Anyone has pic of the exhaust system? Easy to find out by just looking at the pic.

[Kris]

If thats true, I'm up for a set of these puppies !

Issue is, will they fit a RHD car?

[Adam@Riss Racing]

Originally Posted by Kris

If thats true, I'm up for a set of these puppies !

Issue is, will they fit a RHD car?

yup, there are 4 cats on the 135 and 335. Primary and Secondary cats. These downpipes are mandrel bent with 3" flow. Power will go up about 30whp/60whp (tuned) with downpipes and a stock exhaust system. These downpipes fit RHD and LHD vehicles!

Pictures of the exhaust on the 135i.
http://www.1addicts.com/forums/showthread.php?t=5396

[Kris]

Originally Posted by Adam@Riss Racing

yup, there are 4 cats on the 135 and 335. Primary and Secondary cats. These downpipes are mandrel bent with 3" flow. Power will go up about 30whp/60whp (tuned) with downpipes and a stock exhaust system. These downpipes fit RHD and LHD vehicles!

Pictures of the exhaust on the 135i.
http://www.1addicts.com/forums/showthread.php?t=5396

Hi Adam, have they been tested on a RHD car? How do you know they fit? Steering rack is on the other side of the car in a RHD...

Just curious - im very interested. Look forward to the dyno charts, hopefully it doesnt change the power/torque curve. I've had an audi 1.8 turbo motor with a 3" DP and it lost ALOT of bottom end torque... Was horrible. There was also this awful shudder in it...

[professor]

Hi Anthony,

Would I be right in assuming that the catted DPs would not have a CEL issue and therefore no SIM would be needed?

Are these units available with your ceramic coating?

Compared to the catless versions please suggest how much is the "hp sacrificed to number of trees saved
ratio.

[Adam@Riss Racing]

Originally Posted by Kris

Hi Adam, have they been tested on a RHD car? How do you know they fit? Steering rack is on the other side of the car in a RHD...

Just curious - im very interested. Look forward to the dyno charts, hopefully it doesnt change the power/torque curve. I've had an audi 1.8 turbo motor with a 3" DP and it lost ALOT of bottom end torque... Was horrible. There was also this awful shudder in it...

3" downpipes on a 1.8 turbo/4cylinder motor might have worked different. I had a 3" downpipe on my Eclipse GSX (1st gen motor, built, 20G turbo). Worked well when it was built, but didn't work too well when it had just bolt ons. The 3.0 twin turbo I-6 works very well with these downpipes. We are actually guessing on the gains right now, but they might be higher than the dyno we've done on our prototype catless downpipes!

[Adam@Riss Racing]

Originally Posted by professor

Hi Anthony,

Would I be right in assuming that the catted DPs would not have a CEL issue and therefore no SIM would be needed?

Are these units available with your ceramic coating?

Compared to the catless versions please suggest how much is the "hp sacrificed to number of trees saved
ratio.

Catted will not need 02 sims. Ceramic coated will be +$100.00 and will be available. The difference from catless/catted should be around 5-10whp net. On a tuned vehicle, you may see a difference of about 10-20whp.

Adam

[Kris]

Look forward to dynos Adam with/without a tune...

[Adam@Riss Racing]

Originally Posted by Kris

Look forward to dynos Adam with/without a tune...

Very shortly. We have a 335i test car, no tune, currently just has our Catless on there. We'll test out stock/catted/catless to show some runs.

[Riss Racing]

See you at Bimmerfest!

[vivid]

Originally Posted by Adam@Riss Racing

These downpipes are mandrel bent with 3" flow.

Sorry but wanted to make sure this is correct... You are saying your downpipes are completely mandrel bent? Cause I see an awful lot of welds that would mean is NOT mandrel bent.

[Adam@Riss Racing]

Originally Posted by Vivid

Sorry but wanted to make sure this is correct... You are saying your downpipes are completely mandrel bent? Cause I see an awful lot of welds that would mean is NOT mandrel bent.

Mandrel has nothing to do with welds. Mandrel means the diameter is basically the same. Our pipes do not have any crush bends at all. The welds are for the size difference from the taper of 3" to 2.75" to 2.5". This creates a smooth flow through the entire set of downpipes.

[vivid]

Originally Posted by Adam@Riss Racing

Mandrel has nothing to do with welds. Mandrel means the diameter is basically the same. Our pipes do not have any crush bends at all. The welds are for the size difference from the taper of 3" to 2.75" to 2.5". This creates a smooth flow through the entire set of downpipes.

can you explain this thread then?
http://www.e90post.com/forums/showth...4756&highlight

[Adam@Riss Racing]

Originally Posted by Vivid

can you explain this thread then?
http://www.e90post.com/forums/showth...4756&highlight

what is to explain. Please read the definition of MANDREL BENDS. There are no crush bends what so ever. You are also more than welcome to check our welds and compare to others available. Pipes will flow from 3" and taper smoothly. These catted downpipes will create the most power available on a "eco friendly" exhaust system.

[vivid]

A full Mandrel bend pipe has no welds and comes out of the mandrel bender as one solid piece with NO welds... Looks like you have welded togeather several mandrel bend pieces so yours is not a true mandrel bend down pipe...

If you could, please also post pictures of your interior welds so we can see how smooth they are.

[vivid]

Originally Posted by Vivid

A full Mandrel bend pipe has no welds and comes out of the mandrel bender as one solid piece with NO welds... Looks like you have welded togeather several mandrel bend pieces so yours is not a true mandrel bend down pipe...

If you could, please also post pictures of your interior welds so we can see how smooth they are.

any info on the interior pics?

[Riss Racing]

Originally Posted by Vivid

A full Mandrel bend pipe has no welds and comes out of the mandrel bender as one solid piece with NO welds... Looks like you have welded togeather several mandrel bend pieces so yours is not a true mandrel bend down pipe...

If you could, please also post pictures of your interior welds so we can see how smooth they are.

This would be true if the pipe was all one size. Such as 3 inch all the way. However since we have to taper the pipe from 3 - 2.75 - 2.5 You have to weld the mandrel bent sections togeather to make it fit stock/aftermarket exhaust at 2.5. We could do a full 3 inch, and an abrupt taper at the end. However, a slow taper improves preformance. We worked for 7 months making a perfect flowing DP with input from tuners such and Vishnu and many others. These DPs are full 304 stainless steel flange to flange and have the highest HP/TQ reading of any DP with a tune.

Mandrel bend = same diameter throughout the bend.

Also the pics of the catted DP are not final production. They are a first mock up for fitment/testing.

[TunedM2C]

I took out the secondary cats and installed a catback exhaust. Would catted dp's now be the better choice for sound and legal reasons? It's pretty loud as is, am I going to experience an obnoxious setup with the catted dps?

[Riss Racing]

Originally Posted by Tuned1

I took out the secondary cats and installed a catback exhaust. Would catted dp's now be the better choice for sound and legal reasons? It's pretty loud as is, am I going to experience an obnoxious setup with the catted dps?

We just finished our secondary cat delete pipes. I was running this with my catless DPs, and the sound was good. Wasn't raspy just deeper, and you could really hear the turbos spool. If your goal is preformace obviously go with catless DPs. If the only reason you would want catted is sound. I would go with catless since the difference isn't much. Hope this answered your question. Thanks!