[tom @ eas]

Originally Posted by Orange fever

none out there.
You will need to add Mini Cat O2 Sensor ///
If you don't have a tune .

Fabspeed and Milltek catted DPs will not throw CEL, both use HJS cats.

Milltek - Large Bore 200 Cell High-Flow Catted Downpipes - BMW G8X M2/M3/M4
https://europeanautosource.com/produ...w-g8x-m2-m3-m4.

Fabspeed - HJS Sport Cat Downpipes - BMW G8X M2/M3/M4
https://europeanautosource.com/produ...w-g8x-m2-m3-m4

[WhiteRqbbit]

Is there a benefit to changing out the downpipe without an unlocked tune? I guess besides sound, spool, or anything? I have the AA single midpipe already.

[ZPD]

Originally Posted by WhiteRqbbit

Is there a benefit to changing out the downpipe without an unlocked tune? I guess besides sound, spool, or anything? I have the AA single midpipe already.

No benefit other than sound.

[IanH]

Originally Posted by ZPD

No benefit other than sound.

Not true, will improve spool, probably minimal in TT

adds HP and TQ

Adds an impressive 20 WHP and 23 ft/lbs of TQ

From the milltek page.

[ZPD]

Originally Posted by IanH

Not true, will improve spool, probably minimal in TT

adds HP and TQ



From the milltek page.

Do they say that it adds 20 hp without a tune?

[mike@x-ph.com]

Originally Posted by WhiteRqbbit

Is there a benefit to changing out the downpipe without an unlocked tune? I guess besides sound, spool, or anything? I have the AA single midpipe already.

less back pressure
more airflow and power
better sound

[Carefree]

Originally Posted by ZPD

No benefit other than sound.

Wrong

[Info@mad-us.com]

Originally Posted by WhiteRqbbit

Is there a benefit to changing out the downpipe without an unlocked tune? I guess besides sound, spool, or anything? I have the AA single midpipe already.

Faster turbo spool/ response and more sound are what we noticed without a tune. The ecu does a good job at harnessing that extra power and reducing boost to keep oem targets.

[IanH]

Originally Posted by ZPD

Do they say that it adds 20 hp without a tune?

I mean, milltek doesnt make a tune so, yeah thats "stock" although chances are the car they A-B tested wasnt fully stock coulda had other mods.

It has always been the case, on almost any platform you can think of, that a downpipe alone adds around this amount of power. The difference that I see in BMW is that you can actually run the downpipe without software and have no issues, which is not the case for any other car I have owned (and modified)

[ZPD]

Originally Posted by IanH

I mean, milltek doesnt make a tune so, yeah thats "stock" although chances are the car they A-B tested wasnt fully stock coulda had other mods.

It has always been the case, on almost any platform you can think of, that a downpipe alone adds around this amount of power. The difference that I see in BMW is that you can actually run the downpipe without software and have no issues, which is not the case for any other car I have owned (and modified)

Every manufacturer that I have seen says something to the effect of "makes xx more horsepower with a tune." This statement exists with MAD, IRL, CTS, and Project Gamma. As I understand it, with catless DP, the turbos can spin easier and create less turbo lag, but the engine reduces the boost to compensate. You really don't have extra power unless you use a tune to override the reduced boost. I am willing to be proven wrong if someone has a dyno or draggy comparison of an S58 with stock downpipes and catless downpipes as the only change. Every video I have seen so far where someone puts on DP without a tune results in some guy saying "Bruh it sounds so sick"

[WhiteRqbbit]

I do have the Race chip piggyback tuner so I wonder if that would be enough to actually get the benefit. The only thing holding me back even if true is the cost of a catted downpipe that doesn't throw a CEL, pretty spendy for a little more sound and few potential ponies.

[IanH]

Originally Posted by WhiteRqbbit

I do have the Race chip piggyback tuner so I wonder if that would be enough to actually get the benefit. The only thing holding me back even if true is the cost of a catted downpipe that doesn't throw a CEL, pretty spendy for a little more sound and few potential ponies.

Why do you think people are running around with angle grinders and hack saws carving up random cars?

[WhiteRqbbit]

Originally Posted by IanH

Why do you think people are running around with angle grinders and hack saws carving up random cars?

hahaha its true, I should sell my secondary cats from replacing the midpipe to help fund the downpipe ones.

[Carefree]

There is a difference in performance above 5,000 RPM since I added Fabspeed downpipes and BMC air filters.

Is it substantial? No. However, there is a noticeable power boost and deeper growl when I don’t act my age.

[Info@mad-us.com]

Originally Posted by ZPD

Every manufacturer that I have seen says something to the effect of "makes xx more horsepower with a tune." This statement exists with MAD, IRL, CTS, and Project Gamma. As I understand it, with catless DP, the turbos can spin easier and create less turbo lag, but the engine reduces the boost to compensate. You really don't have extra power unless you use a tune to override the reduced boost. I am willing to be proven wrong if someone has a dyno or draggy comparison of an S58 with stock downpipes and catless downpipes as the only change. Every video I have seen so far where someone puts on DP without a tune results in some guy saying "Bruh it sounds so sick"

This is a very accurate statement.

[BSM2]

Any one have sound clips of just catted downpipes with stock exhaust?

[mike@x-ph.com]

Originally Posted by BSM2

Any one have sound clips of just catted downpipes with stock exhaust?

not the same car but close

[Info@mad-us.com]

Mad 200 cell catted completely stock vehicle.