[giolanzarin]

I'm looking to getting a catted downpipe and I was wondering if anyone could tell me the difference between these two and what causes the price difference. Thanks!

[Hendo741]

The cats are different. The AA has a GSEI EPA compliant cat that won't throw a CEL. This thread is saying the CTS will throw a CEL:

https://f30.bimmerpost.com/forums/sh....php?t=1754054

[Hendo741]

If you're looking for a good catted DP that will likely pass emissions, mot throw a CEL and want something just a little cheaper than the AA than I'd recommend checking out CG DS1:

https://x-ph.com/cg-precision-ds-1-h...npipe-bmw-b58/

[kumizi206]

At least get the one with GESI cats. Even those aren't great IMO. You'll eventually throw a CEL after some mileage and abuse. I've used them before if I was going to tune the car anyway to get rid of any possible CEL.

The best cats are HJS cats. Downpipes with those cats are probably around $2000.

[giolanzarin]

Originally Posted by Hendo741

If you're looking for a good catted DP that will likely pass emissions, mot throw a CEL and want something just a little cheaper than the AA than I'd recommend checking out CG DS1:

https://x-ph.com/cg-precision-ds-1-h...npipe-bmw-b58/

Could getting a downpipe void my warranty? I know they have to prove that the downpipe caused the issue but how likely is it for a downpipe to break something?

What other modifications to the exhaust do you recommend doing if I wanna get more sound out of the car?

[Hendo741]

Originally Posted by giolanzarin

Could getting a downpipe void my warranty? I know they have to prove that the downpipe caused the issue but how likely is it for a downpipe to break something?

What other modifications to the exhaust do you recommend doing if I wanna get more sound out of the car?

I'd say a DP is unlikely to get a warranty claim denied, but still possible.

If you only want a little more sound and don't plan on ever adding performance upgrades, a cat back exhaust would be the better choice. BMW should be coming out with an M performance exhaust one of these days.

[shaman420]

Originally Posted by Hendo741

I'd say a DP is unlikely to get a warranty claim denied, but still possible.

If you only want a little more sound and don't plan on ever adding performance upgrades, a cat back exhaust would be the better choice. BMW should be coming out with an M performance exhaust one of these days.

there is one for the 340i and it should fit on the 240i, its the M performance exhuast.

[giolanzarin]

Originally Posted by Hendo741

I'd say a DP is unlikely to get a warranty claim denied, but still possible.

If you only want a little more sound and don't plan on ever adding performance upgrades, a cat back exhaust would be the better choice. BMW should be coming out with an M performance exhaust one of these days.

https://x-ph.com/evolution-racewerks...ipe-bmw-supra/


Would this downpipe work for the G42? What determines if the DP is compatible? The diameter of the pipe? (And of course for what engine it is made)

[giolanzarin]

Originally Posted by Hendo741

If you're looking for a good catted DP that will likely pass emissions, mot throw a CEL and want something just a little cheaper than the AA than I'd recommend checking out CG DS1:

https://x-ph.com/cg-precision-ds-1-h...npipe-bmw-b58/

Hey man, I'm buying my downpipe really soon, im just debating on which one to buy. The AA sounds amazing but its pricey, the cg ds1 is cheaper but I'm worried it wont sound as good. What do you think?

[kumizi206]

Downpipes prices are based on the quality of the catalytic converters. Usually the cheaper they are, the shorter amount of time they will last before they are junk. I've seen cheap cats last less than six months. The differentiator in pricing isn't based on the sound. You need to decide how long you want to keep the car and how long you want the cats to last.

There are minute differences in sound between the different cats/downpipes. You wont be able to tell the difference.
OEM cats are usually 600-800 cell. Aftermarket cats are usually 200-400 cell. Catless is obviously straight through. It's a spectrum.

I've gone through all sorts of cats on different cars. The only aftermarket cats that lasted over 25k miles of aggressive driving/tracking are HJS cats. GESI are solid. That's what the AA downpipe has. The CG DS1 or whatever its called doesnt even list which catalytic converter they're using. Likely junk.

[Hendo741]

Originally Posted by giolanzarin

Hey man, I'm buying my downpipe really soon, im just debating on which one to buy. The AA sounds amazing but its pricey, the cg ds1 is cheaper but I'm worried it wont sound as good. What do you think?

If sound is youre only worry, I'd say go cheaper. If ensuring you dont get a CEL and make sure you can pass emissions (depending on state), I'd say spend the money to ensure you get a GESI/EPA cat.

[giolanzarin]

Originally Posted by Hendo741

If sound is youre only worry, I'd say go cheaper. If ensuring you dont get a CEL and make sure you can pass emissions (depending on state), I'd say spend the money to ensure you get a GESI/EPA cat.

I mean I care about the no CEL, thats why I mentioned the CG Precision. I was just asking if there would be any major difference between the two regarding sound. I think I'm going with the AA.

[Dinosoar]

AA is looking good, yes pricey, but looks proper and quality. One question, what is a general % gain in HP for a 300cell cattted DP??

[kumizi206]

Originally Posted by Dinosoar

One question, what is a general % gain in HP for a 300cell cattted DP??

These days...OEM cats are better than they used to be. I wouldn't expect much peak hp from a downpipe...maybe 10-20. Bigger difference with aftermarket downpipes is mid range tq and turbo(s) spooling a little quicker.

A car with more power like the McLaren 720S might get 30-40hp.

[Vudumonkey25]

Just ordered the AA catted downpipe. There's a dealer/performance shop nearby that sells/installs them.

Looking forward to it.

[idontsave]

Originally Posted by Vudumonkey25

Just ordered the AA catted downpipe. There's a dealer/performance shop nearby that sells/installs them.

Looking forward to it.

Mine just arrived as well. Should hopefully have it installed before the end of the week

[TheJerseyDon]

Originally Posted by kumizi206

These days...OEM cats are better than they used to be. I wouldn't expect much peak hp from a downpipe...maybe 10-20. Bigger difference with aftermarket downpipes is mid range tq and turbo(s) spooling a little quicker.

A car with more power like the McLaren 720S might get 30-40hp.

Racechips saw 30hp and 44 twq just from DP.

[613B6]

Is there a difference between the Supra DP vs the G20 one? Some sites have the Supra more expensive. I assume all b58 2020+ would fit/be the same.

[giolanzarin]

Thought I'd post this here as well.

[SupraCooper]

Originally Posted by giolanzarin

Thought I'd post this here as well.

Nice! Did you do a Supra downpipe as well?

[giolanzarin]

Originally Posted by SupraCooper

Nice! Did you do a Supra downpipe as well?

Yes! Bought it from extreme power house!

[Vudumonkey25]

Just got mine installed today. Loving the new sound. I put the Dinan intake on over the weekend and the AA catted Dp this morning.

Nice grumbles when off the acceleration and deeper exhaust note. Turbo spooling and blow off all got huge sound improvements.