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Read the WELCOME ALL BMWFANATICS post.
Benefits of a Downpipe
- Thread starter Junz
- Start date
gavsadler
///Member
I did some research on N55s a while back, someone in the states put together a comparison.
Power gains ranged between 8-16kw and 20-50nm - that’s at the wheels on a RWD car.
The most benefits will be had if the cat is blocked. Less resistance will help spool up time slightly and reduced back pressure will have some benefit.
But I also concur- sound is arguably the biggest benefit
Power gains ranged between 8-16kw and 20-50nm - that’s at the wheels on a RWD car.
The most benefits will be had if the cat is blocked. Less resistance will help spool up time slightly and reduced back pressure will have some benefit.
But I also concur- sound is arguably the biggest benefit
zubz.parker10
Member
what bmw are you driving ?
on my 330d my fuel consumption dropped , throttle response improved and theres definitely a few more horses now
on my 330d my fuel consumption dropped , throttle response improved and theres definitely a few more horses now
Bazza
Active member
Interesting read, I always thought fitting a DP was a no-brainer if you wanted big power, but I think most people, like me, look at the final output after DP plus software which gives a misconception of the DP being the biggest contributer because it's hardware.
Either way... I'm just waiting for my MP to expire on my 640d and I'm doing DP and software.:smilebounce:
Not to thread-jack but if anyone knows if there's any advantage/disadvantage to straight-piping a 640d in addition to DP and software, please drop me a PM, also something I'm considering. Thanks all!!
Either way... I'm just waiting for my MP to expire on my 640d and I'm doing DP and software.:smilebounce:
Not to thread-jack but if anyone knows if there's any advantage/disadvantage to straight-piping a 640d in addition to DP and software, please drop me a PM, also something I'm considering. Thanks all!!
osiris
///Member
I bought my car with down pipes on. I then put stock software back on the car, stock inter cooler, stock charge pipe and basically converted the car back to stock but kept the down pipes. I then drove another E89 Z4 that was 100% stock and felt a marked improvement in drive-ability in town driving scenarios, allot more punchier. So I decided to look for a nice set of stock down pipes and had them fitted to my car and my car felt allot better to drive, felt exactly the same as the 100% stock E89 z4.
Upon doing allot of research I found that their is a common misconception about down pipes in that people believe they make your turbos spool faster! This is not true, it is in fact the opposite, The back pressure caused by cats actually cause the turbos to build pressure faster and thus spool faster, if you hook up MHD or JB4 or any other monitoring software to your car you you will see that boost builds quicker as you touch the accelerator, there is a definite lag with catless down pipes on a stock car.
However, this is not to say that you wont get more performance from fitting catless down pipes because you 100% will get more performance but it will be slightly later in the rev range AND installing software to the car will take advantage of the better flow. Also due to less back pressure and slower spool of the turbos there is a definite improvement with regards to the turbos running slightly cooler equating to longer life. Also you will see allot more benefits high up in the rev range when you are aiming to run higher boost, you will have less higher rpm boost drop off.
I have since installed my downpipes again due to other hardware mods like higher flowing turbos and inlets etc so to have a stock downpipe would cause a bottleneck in the system.
My 2c
Upon doing allot of research I found that their is a common misconception about down pipes in that people believe they make your turbos spool faster! This is not true, it is in fact the opposite, The back pressure caused by cats actually cause the turbos to build pressure faster and thus spool faster, if you hook up MHD or JB4 or any other monitoring software to your car you you will see that boost builds quicker as you touch the accelerator, there is a definite lag with catless down pipes on a stock car.
However, this is not to say that you wont get more performance from fitting catless down pipes because you 100% will get more performance but it will be slightly later in the rev range AND installing software to the car will take advantage of the better flow. Also due to less back pressure and slower spool of the turbos there is a definite improvement with regards to the turbos running slightly cooler equating to longer life. Also you will see allot more benefits high up in the rev range when you are aiming to run higher boost, you will have less higher rpm boost drop off.
I have since installed my downpipes again due to other hardware mods like higher flowing turbos and inlets etc so to have a stock downpipe would cause a bottleneck in the system.
My 2c
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