m5 downpipe gains?

[combatbmw]

hey guys, seems like im the only 550i with catless downpipes on this board.

So wanted to ask if any of the m5 guys with stock exhaust and catless dps are seeing gains?

Here is my dyno stock and with a tune. BMS tune.
Good gains but if you look at 5k range. dips down and i lose about 50-60 hp
Both stock and tuned.

only mod is catless dps.



Boost graphs tuned and untuned:




here is my friends car same year same dyno same miles same day..
Just totally stock:

[gmd2003]

Originally Posted by combatbmw

hey guys, seems like im the only 550i with catless downpipes on this board.

So wanted to ask if any of the m5 guys with stock exhaust and catless dps are seeing gains?

Here is my dyno stock and with a tune. BMS tune.
Good gains but if you look at 5k range. dips down and i lose about 50-60 hp
Both stock and tuned.

only mod is catless dps.



Boost graphs tuned and untuned:




here is my friends car same year same dyno same miles same day..
Just totally stock:

Totally different motor and ECU . You're ECU is pulling its boost target back with the DP's , the S63tu does not do that . Multiple cars have shown significant gains with both catted and catless DP's on the S63 TU, both tuned and untuned .

[greentrbo95gst]

Your transmission could be a limitation as well. Is it Auto?

[combatbmw]

Originally Posted by greentrbo95gst

Your transmission could be a limitation as well. Is it Auto?

Thanks for the input. I think I have eliminated that as a possibility because my friend has the same car and not seeing the drops that my car is, I posted his graph in the original post.

here are the recent dyno from last week.

drops same spot every run.


Im thinking 550s ecus just dump the boost, unlike the m5 which adapts and gets really good gains.
I mean I wouldnt have a problem gaining nothing or a little bit, sound alone makes it worthwhile.. lol

but lossing 60+hp from 5k-6500 is unreal.

thoughts?

[combatbmw]

another solution is I need an exhaust system

catless dp to stock full system .. like hitting a wall. vs free flow.

That may resolve it who knows.

or put stock downpipes back on and dyno to see if it does it with stock dps.

but the consistency of the hp curve hitting a wall and dropping on 4 straight pulls .. looks to be ecu related.

[gmd2003]

Originally Posted by combatbmw

another solution is I need an exhaust system

catless dp to stock full system .. like hitting a wall. vs free flow.

That may resolve it who knows.

or put stock downpipes back on and dyno to see if it does it with stock dps.

but the consistency of the hp curve hitting a wall and dropping on 4 straight pulls .. looks to be ecu related.

Honestly that's almost 100% ECU . A piggyback will not be able to solve that , not even a full JB4 . You'll need a JB4/ flash tune combo . Honestly I'd just go back to stock DP's .

[combatbmw]

Originally Posted by gmd2003

Honestly that's almost 100% ECU . A piggyback will not be able to solve that , not even a full JB4 . You'll need a JB4/ flash tune combo . Honestly I'd just go back to stock DP's .

I totally agree with you. The way each pull does the same thing.. makes me believe this.

The stock restricted exhaust is a good guess also. But the ECU, is the best answer and makes most sense.
What made you guess this? Boost graph?

I also just found out from BMW that my car has a software recall.

[gmd2003]

Originally Posted by combatbmw

I totally agree with you. The way each pull does the same thing.. makes me believe this.

The stock restricted exhaust is a good guess also. But the ECU, is the best answer and makes most sense.
What made you guess this? Boost graph?

I also just found out from BMW that my car has a software recall.

Yes the boost graph , and the stock exhaust is a very minimal contributor .

[mwlmd]

Have you asked Terry at Burger Tuning? He seems to know a lot about FI BMW engines.

[combatbmw]

Originally Posted by mwlmd

Have you asked Terry at Burger Tuning? He seems to know a lot about FI BMW engines.

Yes i was the 1st n63tu car out there. I was the pilot.
But the tune isnt a full length one like the ones for the 3 series. so he wasnt able to really dig deep into the ecus.
im banking on the software update that i have right now, since my friend who dyno'd higher already had the update and I didnt, maybe bmw fixed some issues with the ecu who knows.

[greentrbo95gst]

Wait, you have a MY2014. Is your friend with the other 550 also a 2014 or 2013. They did change some things and when I was there I was talking to Terry about this and we were discussing your issue as well.
They did buy a MY2014 and I know Terry was working on it.

[combatbmw]

Originally Posted by greentrbo95gst

Wait, you have a MY2014. Is your friend with the other 550 also a 2014 or 2013. They did change some things and when I was there I was talking to Terry about this and we were discussing your issue as well.
They did buy a MY2014 and I know Terry was working on it.

Yes im the guy, funny small world.

My friends car is the stock 2014 with just carbon filter removed. I have the 2014 with the catless dps.

There was some changes between the 2011-13 vs 2014, the 14 is totally different.
more boost factory, valvetronics, Launch control and various other things like duel dms vs single with the older f10s. pre 14.

[combatbmw]

by the way green, did you give terry the code for the catless dp in the Can Tool?
He told me he got it form a m5, thats how my check light turned off lol if so Thanks

[greentrbo95gst]

Originally Posted by combatbmw

by the way green, did you give terry the code for the catless dp in the Can Tool?
He told me he got it form a m5, thats how my check light turned off lol if so Thanks

Lol, yea he pulled it from my car.

[Timberwolf]

It could also be the stock turbos being maxed out or unable to move air fast enough... That car was deisgned to have the low end grunt so smaller faster spooling turbos. Im sure dps and a real tune with meth would help but larger snails would give you that m5-esque power curve.. I could be wrong

[combatbmw]

Originally Posted by Timberwolf

It could also be the stock turbos being maxed out or unable to move air fast enough... That car was deisgned to have the low end grunt so smaller faster spooling turbos. Im sure dps and a real tune with meth would help but larger snails would give you that m5-esque power curve.. I could be wrong

Good point, but keep in mind stock car without catless downpipes made more power with the same amount of boost. And didnt lose any after my plummeting spot at around 5100rpms.

[scott135i]

It's the ecu pulling timing and or boost likely due to some values it's seeing. My best guess is intake, then exhaust, if not both of them.

That or you have an exhaust leak which comes to light only with significant back pressure hut that's unlikely.