do we know if the car loses power with valves closed?

8600RPM · 02-11-2015, 12:04 AM

Has anyone tested the car on dyno keeping the valves closed with one of the available methods? I'm planning on getting downpipes but thinking I csn keep the valves closed with my MPE to get a nice sound that's not too loud. However I certainly am not willing to lose power

6speeds · 02-11-2015, 03:39 AM

My experience on other cars More flow = more power but ... You loose a lil torque down low and gain upper rpm HP where u don't need or use on the street.. that's why I'm keeping my stock exhust..

ARMASPEED · 02-11-2015, 03:58 AM

do you know that ARMA has exhaust valve product? it links to OBD2 system so you can set RPM to open/close the valve.

GOLFFRR · 02-11-2015, 06:52 AM

I have not experienced any noticeable change in power when I have my valves closed. Its basically just night and day in sound change. then again I have yet to really get on the car with valves closed to feel the difference between the two.

I drive mostly with valves closed 80/20

MasterC17 · 02-11-2015, 06:58 AM

My guess is you would see a few horsepower on a dyno but never actually feel it.

mshab356 · 02-11-2015, 07:54 AM

The power difference will be negligible at best. I've owned a few valve controlled exhaust cars and never noticed a power difference.

dmk08 · 02-11-2015, 08:16 AM

Not to mention you're adding downpipes. So you should always have more then you have right now. Valves open or closed.

nbennettksu · 02-11-2015, 09:01 AM

probably do not lose power from them opening; if so, then why would they open under WOT?

8600RPM · 02-11-2015, 10:13 AM

I'm asking if they lose power closed.

Thanks for the input. I just feel since they still open in efficiency mode tells me closed valves have some effect otherwise why not keep closed

FC4 · 02-11-2015, 09:34 PM

Quote:

Originally Posted by 6speeds

My experience on other cars More flow = more power but ... You loose a lil torque down low and gain upper rpm HP where u don't need or use on the street.. that's why I'm keeping my stock exhust..

Why do people think that a reduction in back pressure on a turbocharged car results in less low-end torque? You see this in every other thread related to exhaust and it's beyond me why people believe this.

FC4 · 02-11-2015, 09:40 PM

OP, you're not going to get a quantitative answer. Any difference in power between exhaust flap modes will be within standard variance of two separate dyno pulls. Data will be inconclusive.

Any reduction or increase in exhaust flow will effect power simply by definition. I'd guess the flap is good for 1 to 2 RWHP at most.

MatthewDavid · 03-09-2015, 12:03 AM

Does anyone know if having the valves closed most of the time has a negative impact on the engines longevity? Guessing no, but...

MasterC17 · 03-09-2015, 06:04 AM

Quote:

Originally Posted by MatthewDavid

Does anyone know if having the valves closed most of the time has a negative impact on the engines longevity? Guessing no, but...

No, not at all. Never.

Vectors2final · 03-09-2015, 07:12 AM

Nope, the hot side is going to force that air out one way or another.

shortseller · 03-09-2015, 07:24 AM

Quote:

Originally Posted by 6speeds

My experience on other cars More flow = more power but ... You loose a lil torque down low and gain upper rpm HP where u don't need or use on the street.. that's why I'm keeping my stock exhust..

This was the consensus back on the N54 back when it was debated to death over on the 335i E9x forums.

MatthewDavid · 03-09-2015, 07:27 AM

Quote:

Originally Posted by MasterC17

Quote:

Originally Posted by MatthewDavid

Does anyone know if having the valves closed most of the time has a negative impact on the engines longevity? Guessing no, but...

No, not at all. Never.

Ha what're you pulling your hair out for? It's a reasonable question. You just said it may incrementally reduce horsepower, which seems to logically indicate some additional load on the engine. Unless you can definitively state it doesn't impact the engine using some real facts then put your hair back in.

Vectors2final · 03-09-2015, 07:31 AM

Doesn't necessarily put more load on the engine as much as it restricts the airflow of the turbo.

Stage1 · 03-09-2015, 03:31 PM

Valves open all day for me. It seems from diagrams the flaps just change what chambers the exhaust gas flows through. So open of closed, it is still flowing pretty good, but not through the muffler

Drive4Fun · 03-09-2015, 07:22 PM

I made a pull on efficient mode and then realized and switched over to sport plus and made another pull 30sec later and made another 2whp. Could mean something but my baseline varied by 3whp so...

Ranoz · 03-09-2015, 10:32 PM

Quote:

Originally Posted by info@ARMA

do you know that ARMA has exhaust valve product? it links to OBD2 system so you can set RPM to open/close the valve.

stock car is already open/close with throttle response?

8600RPM · 03-10-2015, 12:57 AM

Quote:

Originally Posted by Drive4Fun

I made a pull on efficient mode and then realized and switched over to sport plus and made another pull 30sec later and made another 2whp. Could mean something but my baseline varied by 3whp so...

Efficient mode opens valves too as rpms raise so all three modes ultimately open valves so unless you have a device that can control valves we can't test it

jackkk · 03-10-2015, 05:10 AM

May be it will get you +1hp)
The power is about cats, not about valves.

02-11-2015, 12:04 AM	#1
8600RPM Lieutenant Colonel 657 Rep 1,749 Posts Drives: e92 m3 Join Date: Oct 2014 Location: AZ iTrader: (0)	do we know if the car loses power with valves closed? Has anyone tested the car on dyno keeping the valves closed with one of the available methods? I'm planning on getting downpipes but thinking I csn keep the valves closed with my MPE to get a nice sound that's not too loud. However I certainly am not willing to lose power
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02-11-2015, 03:39 AM	#2
6speeds Private First Class 34 Rep 155 Posts Drives: M3 Join Date: Feb 2015 Location: Manual RWD iTrader: (0)	My experience on other cars More flow = more power but ... You loose a lil torque down low and gain upper rpm HP where u don't need or use on the street.. that's why I'm keeping my stock exhust..
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02-11-2015, 03:58 AM	#3
ARMASPEED BimmerPost Supporting Vendor 80 Rep 440 Posts Drives: G20 M340i Join Date: Aug 2011 Location: Taiwan iTrader: (0)	do you know that ARMA has exhaust valve product? it links to OBD2 system so you can set RPM to open/close the valve. __________________ info@armaspeed.com \| www.armaspeed.com
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02-11-2015, 06:52 AM	#4
GOLFFRR 10817 Rep 27,600 Posts Drives: GOLFFRR cart Join Date: Mar 2009 Location: we sell BMWs to "ALL" US states iTrader: (4)	I have not experienced any noticeable change in power when I have my valves closed. Its basically just night and day in sound change. then again I have yet to really get on the car with valves closed to feel the difference between the two. I drive mostly with valves closed 80/20 __________________ BEFORE YOU BUY YOUR NEXT BMW, EMAIL OUR GUY KOTE FIRST! Kote M Sales:Kotem@bmwofcamarillo.com Cell:805-368-9101 vipfinance@bmwofcamarillo.com for warranties!
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02-11-2015, 06:58 AM	#5
MasterC17 Captain 329 Rep 984 Posts Drives: 2015 BMW M3 Join Date: Aug 2014 Location: Massachusetts iTrader: (3)	My guess is you would see a few horsepower on a dyno but never actually feel it. __________________ 2009 X5d \| 2007 E90 Track \| 2002 M3 Track \| 1991 535i Track
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02-11-2015, 07:54 AM	#6
mshab356 Go ///M or go home 276 Rep 1,280 Posts Drives: 2015 F80 M3 6MT Join Date: Jan 2007 Location: Los Angeles, CA iTrader: (5)	The power difference will be negligible at best. I've owned a few valve controlled exhaust cars and never noticed a power difference. __________________ 2015 AB/SO F80 M3 6MT \| 19" Black M437 \| KW H.A.S. \| AutoTechnik Black Front Grills \| BMW Performance Side Grills \| Painted Front Bumper Reflectors \| Gloss Black Exhaust Tips GONE 2011 SG/Blk E92 M3 CS 6MT
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02-11-2015, 08:16 AM	#7
dmk08 Gone Fishin’ 7318 Rep 12,125 Posts Drives: Walks Join Date: Jul 2012 Location: Atlanta iTrader: (19)	Not to mention you're adding downpipes. So you should always have more then you have right now. Valves open or closed.
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02-11-2015, 10:13 AM	#9
8600RPM Lieutenant Colonel 657 Rep 1,749 Posts Drives: e92 m3 Join Date: Oct 2014 Location: AZ iTrader: (0)	I'm asking if they lose power closed. Thanks for the input. I just feel since they still open in efficiency mode tells me closed valves have some effect otherwise why not keep closed
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02-11-2015, 09:40 PM	#11
FC4 Brigadier General 2680 Rep 3,406 Posts Drives: Yes Join Date: May 2014 Location: US iTrader: (0)	OP, you're not going to get a quantitative answer. Any difference in power between exhaust flap modes will be within standard variance of two separate dyno pulls. Data will be inconclusive. Any reduction or increase in exhaust flow will effect power simply by definition. I'd guess the flap is good for 1 to 2 RWHP at most.
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03-09-2015, 12:03 AM	#12
MatthewDavid Captain 148 Rep 774 Posts Drives: 21 X5 M50i Join Date: Oct 2008 Location: San Francisco, CA iTrader: (0) Garage List 2015 F82 M4 [0.00] 2012 E92 M3 ZCP [0.00] 2008 E92 M3 [9.00]	Does anyone know if having the valves closed most of the time has a negative impact on the engines longevity? Guessing no, but...
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03-09-2015, 07:12 AM	#14
Vectors2final Brigadier General 1357 Rep 3,349 Posts Drives: 2018 F80 YMB/SS ZCP Join Date: May 2011 Location: Austin, Tx iTrader: (0)	Nope, the hot side is going to force that air out one way or another. __________________ 2019 Ruby GT350 - Gen 5 Whipple on corn making 855RWHP. Sold: 2018 F80 Part Deux /DCT /YMB /Full SS /CF Trim /ZCP /ZEC w/Black 666M Sold: 2015 F80 /DCT /YMB /Full SS /CF Trim /ZEC /ZLP /HK /S&TVC- 18''///M
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03-09-2015, 07:31 AM	#17
Vectors2final Brigadier General 1357 Rep 3,349 Posts Drives: 2018 F80 YMB/SS ZCP Join Date: May 2011 Location: Austin, Tx iTrader: (0)	Doesn't necessarily put more load on the engine as much as it restricts the airflow of the turbo. __________________ 2019 Ruby GT350 - Gen 5 Whipple on corn making 855RWHP. Sold: 2018 F80 Part Deux /DCT /YMB /Full SS /CF Trim /ZCP /ZEC w/Black 666M Sold: 2015 F80 /DCT /YMB /Full SS /CF Trim /ZEC /ZLP /HK /S&TVC- 18''///M
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03-09-2015, 03:31 PM	#18
Stage1 Curiosity Killed the Cat 241 Rep 822 Posts Drives: M4 GTS Join Date: Jan 2015 Location: PA iTrader: (2) Garage List 2021 BMW M4 [0.00] 2016 M4 GTS [8.00] 2016 Cayman GT4 [0.00] 2016 Wrangler [0.00]	Valves open all day for me. It seems from diagrams the flaps just change what chambers the exhaust gas flows through. So open of closed, it is still flowing pretty good, but not through the muffler __________________ SOLD - 2015 /// F82 M4 / AY-SO "AY-BRAVE" I'M BACK - 2016 M4 GTS I'M BACK AGAIN - 2021 M4 COMP FPB
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03-09-2015, 07:22 PM	#19
Drive4Fun Private First Class 57 Rep 146 Posts Drives: MW BMW M4 Join Date: Dec 2014 Location: Southeast Louisiana iTrader: (0)	I made a pull on efficient mode and then realized and switched over to sport plus and made another pull 30sec later and made another 2whp. Could mean something but my baseline varied by 3whp so...
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03-10-2015, 05:10 AM	#22
jackkk Lieutenant 73 Rep 549 Posts Drives: M3 F80 Join Date: Nov 2012 Location: Moscow iTrader: (0)	May be it will get you +1hp) The power is about cats, not about valves. __________________ F80 M3 SO/SO \|BM3 St.1 91 oct.\|Cattless DPs\|Tractive P'n'P\|Brembo 6pot\|Rays G25 with CUP2 tires\|GTS coding\| 1M VO FBO (KW DDC) PTF st.2+ sold e90 335i FBO jb4 sold
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