My Evolve Airbox Failure
The Evolve CSL Airbox Install
In 2019 I purchased a used Evolve CSL style carbon fibre airbox for my Z4M radster from a reputable seller. My airbox was an early production model being #150. I had it installed and had an Alpha N Tune from Epic Motorsports applied to the car. I had done a pre-dyno, but not got around to a post dyno. I drove the car as my daily, and for several track days with the airbox installed.
I no longer do business with the shop that did the original installation due to a couple of bad experiences with them. I asked that shop to service the air filter on the airbox and provided them with a kit. They did not service the air filter, so they never removed the air filter and, as a result, I don’t know if there were issues with the airbox internals at the time it was installed.
Detecting a problem
Near the end of the 2020 track season, on the last session of the day, my car developed a really rough idle. I took it to The Speed Syndicate, my favourite local indy shop, and had them take a look. It turns out the rough idle issues were related to the VANOS solenoid failing.
A different shop had serviced the VANOS, the aforementioned shop I no longer do business with. The VANOS timing had not been properly set. They did not replace the internal VANOS bolts - something I am told you do whenever you open the VANOS. I was disappointed in the quality of service from that shop and left a Google Review reflecting that.
Curtis, the owner of The Speed Syndicate, still felt that something was wrong beyond the VANOS issue. They opened up the airbox to investigate and this is what they found:
What my shop found when they opened the airbox
What caused the failure?
It seems like the glue used to hold in the trumpets gets brittle with age. This causes it to crumble and lose strength. It fails and, eventually, pieces start flying around inside the airbox, likely contributing to more failures. My shop owner said the type of glue was not even a strong epoxy, it appeared to just be regular glue of some sort.
A piece of the glue, and one of the reinforcement struts from inside the airbox.
The loose pieces that had been bouncing around inside the airbox
Loose parts cleaned out, the glue can still be seen where the trumpets are supposed to be
What was the impact of the failure?
At first, my mechanic sent me some leak-down test results with a typo in them that made it look like there was engine damage. I was rather panicked by this. However, they redid the tests and the results were fine for an engine of this age. There was no significant damage to the engine. Ultimately it seems that the damage was limited to the airbox.
I considered reinstalling the stock airbox and then reflashing the ECU to stock configuration. That would have been costly because I would have had to undo all that again as I wanted to keep a CSL style airbox. Thankfully Curtis from The Speed Syndicate was awesome about it and they agreed to let me keep the car there while waiting for replacement parts from Evolve.
The reason I brought the car into the shop was ultimately a VANOS issue. It’s not known how long the airbox internals had been damaged. It could have been like this for months. I was very lucky not to have suffered any significant engine damage. I am certain pieces of the glue, or even some small pieces of carbon fibre got into my engine and were burned up in combustion.
How did Evolve respond?
I wrote to Evolve and sent them pictures of the failure. The airbox was out of warranty. Evolve was very good about it and committed to sending me a replacement airbox free of charge. However, they were waiting on stock to arrive, so it was going to be 6 to 8 weeks before they would ship a replacement airbox out of England.
And the replacement needed to be replaced…
The replacement airbox arrived from Evolve and my shop inspected it thoroughly. They identified a defect that made them concerned. Ultimately after some back and forth Evolve shipped out another airbox, which they did very apologetically. The replacement airbox was without issue; we installed Evolve airbox #527.
This now meant that the car was down for almost three months! While this is my daily driver, with the COVID pandemic, I am hardly driving at all, so the downtime was not too big of an impact.
I was very pleased with how Evolve handled this. However, this is a premium-priced product and should not be suffering from this kind of failure. The need to replace the replacement airbox is indicative of some quality control concerns.
Inspecting the replacement Evolve airbox and finding a defect
Has anybody else had a similar failure?
Why yes, there has been…
I posted to the Zpost forums about my failure. A forum user who operates a high-performance shop had the same issue. They want to remain anonymous to avoid being perceived as “bashing” another vendor. Their Airbox is #330. Their pictures are much better than mine.
What I recommend you do if you have an Evolve intake
If you have an Evolve intake on the S54 in your E36, E85, E86 or E46 (or other cars) you should inspect this for weaknesses or failures in the glue that holds the internal parts in place. This is a bit of a hassle as it means taking off part of the intake and removing the air filter.
I don’t know if it’s possible to inspect this properly without completely removing the airbox. I think it’s very worth it because if a piece gets into the engine, it will lead to engine damage possibly catastrophic.
You can also check the thread on zpost to see if there is any new information on these issues.
If you are in the market for a CSL style carbon fibre intake…
While I was very happy with how Evolve supported their products, I cannot recommend this intake due to the premium price and the issues with the construction and quality control. There are other alternatives from Turner Motorsports, Bimmerworld (which is actually an EPIC Motorsports airbox sold by Bimmerworld) or from Karbonius.
From what I have researched, and if I was doing this again, I would choose the Karbonius airbox even though it is slightly premium priced compared to the Turner or other alternatives.
Am I still using the intake?
I am still using the Evolve airbox and plan to stick with it. I will have it inspected with some regularity, preferably when some other work is going on that would necessitate the removal of the airbox.
I am addicted to the sound of the CSL style carbon fibre airbox and individual throttle bodies on the S54. I think this is one of the nicest sounds in motorsports. Check out the video below that captures the airbox sounds and a little moment I had in my Z4M.
Listen to that airbox, those ITBs and check out that save!
It’s a little dirty, but I love all the carbon fibre in the engine bay!
In conclusion
I hope this post is findable by other S54 owners with an Evolve CSL style carbon fibre intake. I hope other enthusiasts can avoid catastrophic failures or unnecessary expense by inspecting their airboxes. I also hope it helps inform purchase decisions for people in the market for an intake.