4 min read

Nobody likes to spend their hard-earned money on things you don't need for your build, and the S55 charge pipes often get questioned if they're worth upgrading.  This article is intended to shed some light on the topic of upgraded S55 Charge Pipes.

S55 Charge Pipes

While upgraded charge pipes on the S55 engine aren't proven to increase power directly, they are a critical component in the charged air system.  The S55 charge pipes are responsible for delivering the charged air from the turbos to the intercooler which sits on top of your S55 engine.

There are two distinct components which comprise the charge air piping on the S55.  The first is the pair of pipes connected to the turbos and the intercooler, we'll refer to this as the Hot-Side Charge Pipes.  The other component of the charge piping is the pipe connected between the intercooler and the throttle body, we'll refer to this as the J-Pipe.

S55 Charge Pipes OEM

In short, yes.  The Hot-Side OEM S55 charge pipes are known for cracking, especially near the plastic mounting brackets and at the connections to the turbos.  Many times the charge pipes will only develop hairline cracks that are not visible to the naked eye.  If this happens, the charge pipe will pass a quick visual inspection, but under boost the crack will spread open further, allowing the charge air to escape before it gets to the intercooler.

It is unlikely that the charge pipes will fail on a stock S55, but the odds increase substantially for S55's even with only a Stage 1 tune.  For the S55 owners out there who are not aware that this is an issue, it can cause a lot of frustration, time and money troubleshooting the source of the leak.  



Our project F80 M3 developed one of these hairline cracks during development.  The way we found out we had a hairline crack in our charge pipe was during a dyno session.  We had our F80 strapped to the dyno, and as we were making pulls and checking the datalogs, we noticed that our WGDC was at 100%, even though we were only targeting 24psi. 
S55 Charge Pipe failure WGDC datalog

For reference, a healthy S55 should be around 90% when targeting this boost pressure.  With WGDC at 100% while targeting only 24psi we knew there was a leak somewhere, and after some research indicating that this has been an issue for numerous other S55 owners, we had strong reason to believe the OEM hot-side charge pipes were the culprit.

S55 Silicone Charge Pipes

With the ARM Silicone S55 Charge Pipes finishing up production, we installed them onto our project F80 with high hopes that this would resolve our leak.  
S55 Charge Pipes WGDC improvements

Sure enough, the leak was fixed this was confirmed by the new datalogs we took which showed that the WGDC was back down to an appropriate 92% while targeting same 24psi.  We could now resume tuning our F80 which then went on to make a respectable 558whp/564wtq.

S55 Charge Pipes


If you decide that you do want to upgrade your S55's hot-side charge pipes to prevent boost leaks, you have two primary options, a hard pipe or silicone pipe.  The hard pipe options are mainly going to be comprised of aluminum, although there are some titanium and steel options available as well. The benefit of a hard pipe setup is that the charge pipes are, of course, rigid, therefore there are minimal disruptions in airflow as the pipe does not distort. 

S55 Charge Pipes Aluminum ARM

The ARM Aluminum S55 Charge Pipes allow for methanol injection pre-intercooler.  The ARM S55 Aluminum Charge Pipes have a methanol port on each pipe, located discreetly towards the rear of the charge pipe allowing them to be concealed.

S55 Charge Pipes Silicone ARM
The silicone charge pipes for the S55 are beneficial as they provide some extra insulation for the charge air.  Also, if you decide to run port injection on your S55 the ARM Silicone S55 Charge Pipes will reach the intercooler even though it has been pushed slightly further away from the charge pipes.  Aluminum charge pipes will require a longer coupler for this to work.  


The cold-side charge pipe, also referred to as the J-Pipe because of it's shape, transfers the charge air from the intercooler to the throttle body.  This component is not typically failure point on most S55's.  One of the main reasons S55 owners upgrade their J-Pipe is that it allows for methanol injection post-intercooler, which is often the preferred location for many tunes. 

S55 J Pipe OEM ARM

The ARM S55 J-Pipe incorporates 2x methanol bungs to allow for adequate meth flow, while many J-Pipes only have 1x meth bung which is often not adequate enough to flow the amount of meth the tune requires.  This is a great component to upgrade while you have the intercooler removed as it is easy to access.  With the intercooler on your S55 removed the installation of the J-Pipe is only about 15 minutes.  Considering that the cost of the J-Pipe is low and installation is easy, you may want to consider upgrading it for peace of mind in knowing that your entire charge air system is now bulletproof.  

S55 J Pipe ARM

In conclusion, if your S55 is tuned or if you plan on tuning it, a Hot-Side charge pipe upgrade should be on your to-do list.  While the J-Pipe is often not going to be an issue as far as failure goes, due to it's low cost and ease of installation you may want to consider it for peace of mind, or if you plan on injecting meth post-intercooler.

We hope you found this information helpful.  If you have any questions on how to set up your S55 fee free to reach out to us!

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