jrosa

I finally decided to buy downpipes, but which one to get? Alpha or Weistec?

Alpha has a much better price, but Weistec says it has termal insulation, reducing the engine bay temperature.

In addition, I'm seriously considering to get downpipes without catalytic converters, but smog checks worry me. Does anyone has any thoughts about it?

Last but not least, I will ask again about the noise increase with the new downpipes. Does the car gets to noisy? Can it still be used as a luxury sedan?

Thanks!

chiromikey

Zero noise inside even if you delete the cats. With cat delete you will get a better sound while on the throttle but it's almost stock quiet when cruising. You will have a problem passing smog inspections if you go catless. Don't pay extra. If you think you need heat protection just have them coated yourself for $100-200.

Astolfo

Why in the world would anyone would want to keep exhaust gasses hot? A hot exhaust is entirely contra productive to efficiency in any aspect. If anything you would want to cool the exhaust as soon as possible to facilitate gasses acceleration and volume. This is high school PHY isn't it?

Amg63-

is it that important to get them coated? I just have the regular ones from EC that are made from a high grade stainless steel. I didn't think this would ever be problematic, now I'm concerned.

gaspam

kponti

That is why I run nitrogen blocks between the heads and turbos cool the damn air down, I never understood why you would want exhausts hot???

chiromikey

I don't think the egt theory that people use to justify coatings/wraps is a solid theory but I do think there is benefit in keeping as much heat as possible away from nearby intake components. I personally would try to insulate intake components before trying to keep heat in the exhaust.

chiromikey

Not on stainless steel. I'd consider coating regular steel for aesthetics and possible longevity but not for heat reasons. You have nothing to worry about!

E63 Tony

Ams pipes are very hard to adjust since they're 3 piece. Still a year to this date and I can't get them adjusted right and have them stay from rubbing on the aluminum brace by the ball joint clamps for more than a week after adjusting them. Ive tried countless times. My solution was to use a dish towel and wrap it around the aluminum brace so the pipes lay on that and not make a metal on metal vibration sound. I don not recommend this product.

Emails were not returned as well.
Try to buy a 1 piece pipe. Like rado or speedriven

ajs76

re:exhaust coatings

This may seem like a silly question, but what do race cars do or more dedicated track cars? If you're doing a performance mod seems like you'd want to more or less follow what they do if you're going for max power.

Marketing is a powerful thing though right? The minute someone comes up with a feature or thing you're suddenly like "oh man, do I need that TOO!?"

The exception being the Honda Odyssey with built in vaccuum cleaner in a minivan. I wish my Cayenne had that

chiromikey

Most people can't afford a custom inconel steel system so it's hard to do what real race cars do when it comes to exhaust

Geno51

For what it's worth BMR is working on making downpipes for our cars. My Rado pipes will be for sale once they are done

Astolfo

Nobody will be able to tell you the specs for the alloys used, but they are extremely efficient at radiating heat, year after year (until 2017) the sporting regulations keep decreasing the amount beryllium in the exhaust components and batteries heat sinks.


They are also extremely soft alloys.

it is PHY101, the relationship between temp to volume in a gas is, for the most part, between linear and exponential, clearly this depends in the gas elements.

KLR CLS

Are you rwd or AWD? If RWD, then go full turbo back style like the weistec, but best to get the knock offs from UPD, boost logic or CMS. Great price, fits great and huge torque gains.

Amg63-

do you actually think the BMR pipes will give any power gains over the rado?

from what I've seen they are all pretty much the same thing I don't think it's worth it for you to do that TBH.

Amg63-

does AWD also gain as much as RWD from turbo back pipes or are catless downpipes the same gains on AWD E63?

TMC M5

I have been running Speedriven catted downpipes for a couple thousand miles. Seat of the pants it feels like part throttle responsiveness has increased. I have been busy with work and haven't really had a chance to do vbox testing. There is also a distinct increase in volume, but definitely not obnoxious and it has zero drone (which was very important to me). If you want really loud, you probably should do catless with resonator and/or muffler removed. But for me this was the perfect compromise.

Wickdwagon

Have the weistec down pipes and could not be happier with them. When you are in hooligan mode they have plenty of grunt but when just cruise you would be hard pressed to know the difference. So plenty of area under the curve between the stage I and stage II tunes to justify the cost and expense to have a turbo back system installed properly.

Amg63-

another option is to do catless downpipes and then add 2 extra resonators (3" vibrant straight pipes). I did this and it allows for catless dp power gains and even under full throttle still not too loud, very close to stock but slightly louder that's all, and cruising is actually even quieter than bone stock.

TMC M5

Sounds like an interesting set up, but I also didn't want to deal with CEL (I don't have an ECU tune) and the exhaust smell. I have a 21 month old daughter and didn't want the garage smelling like the drag strip when I put her in the car every morning.

KLR CLS

It's a case of the trouble to install them. Turbo back on RWD can be done relatively easily. AWD you have to drop the motor. Plus you can only get weistec for AWD cause you need shorter engine mounts to be able to route the turbo pipe in a straight shot. Between weistec cost and install cost it's just not worth the difference vs mid pipe style DP s

jrosa

Mine is AWD, and I have a piggyback tune (RaceChip).

CarHopper

You'll have to drop the motor to do true turbo back's such as Weistec. And if you're concerned about emissions, that means each time you need to pass inspections you gotta swap. $$$.

I'm in the same boat and just picked up catless RADO DP's. Much easier to swap.

Also considering a second ECU so I can have one w/ stock maps and one that is tuned so I don't have to keep shipping my ECU back and forth come inspection time.

BlownV8

Hot air flows faster with less resistance than cold air.

gaspam

yep, also know as stack or flue effect ..Greater the inside air temperature is vs outside temperature the faster it will be drafted out as the inside air density will be less than the outside air density and the inside air will flow up and out

cooling exhaust gasses is unwanted since you'll observe greater back pressure. This reduces engine air flow, and thus efficiency

PHY102