Maximum PSI F8X Front Mount Intakes dyno test


We did some back to back testing with stock airboxes and then with our front mount intakes to see the actual gains on our shop M3.  Same day, same conditions, same car.

Test conditions:
Hood closed.  3 runs each, tested with engine and components at operating temperature with brief cooldown between runs.  DCT trans, 5th gear. Runs 0-2 are stock airboxes/filters/ducting.  Runs 4-6 are Maximum PSI intakes without socks

Test Vehicle:
2016 F80 M3
JB4 on Map 2 – 93 octane fuel
Maximum PSI catless downpipes
Stock exhaust

We were expecting 10-15whp at best at this power level, and possibly larger gains on E85, meth, etc.   Upon reviewing the results we immediately noticed a trend.   If you compare runs 0-2 vs 4-6 you can see significant gains above 5700rpm even with a JB4 and downpipes.  The gains will likely be better with higher power output cars(upgraded turbos, full exhaust, race fuel/e85, etc.).  We normally post all of our results with SAE correction, however the N54/N55/S55 community seems to use STD or uncorrected, smoothing 5.

STD corrected:




Here is a graph of the best run from the stock airboxes(blue) vs the best run from the Maximum PSI intakes(red).  You can see a notable gain in the upper rpm of over 30whp:






Why did our intakes make more power than stock (and other aftermarket ones)?  This is where I get to speculate a bit:

  • The oem system (and several aftermarket systems) use the factory ducting that basically draws air from the same place.  The oem system is completely sealed, and has a charcoal filter plus a paper one(restriction#1).  It then draws ALL of the air through the kidney ducts (restriction #2).
  • Aftermarket intakes that use the lower halves of the oem airbox and oem ducting have larger filter elements, however they are now drawing a blend of hot air from the engine bay and the air coming through the ducts.  That results in an unrestricted pipe, however AIT’s are higher, resulting in hotter charge air temps.  The intercooler is only as efficient as the air entering the system.
  • If you decide to try a drop-in filter like BMC or K&N you may eliminate some of the restriction, however it is still using a torturous path with rectangular passages and various less-than-smooth transitions.  Our system is 3″mandrel bent piping throughout.


We wanted to address a few customers questions and concerns:

We plan on making significant power with this platform, and took that into account when designing the intakes. We chose the filter size and location for performance and aesthetics. The filters are large, however BMW did an excellent job of ducting all airflow through the kidneys and into the heat exchanger and radiator, regardless of what is in front of the ducts. If it is needed, a slightly smaller filter length can be used. Until that point, this is the route that we prefer. There is plenty of airflow to go above and below the filters and into the ther cooling components. The filters simply get first prority.

We have obviously took into account driving these cars in the rain with exposed filter elements. I have done extended driving through heavy rainfall with no issues. The ratio of airflow going through the filters vs the amount of rain that will contact and be ingested through the filters is not enough to have any concern. People pay good money for water injection to allow for charge air cooling. Look at the M4 GTS that comes with water injection from the factory! I’m not saying we are intentionally trying to have water enter the system, only to say the small amount contacting the filter elements will dissipate long before there is any concern for water ingestion. Someone equated driving in the rain similar to spraying a power washer at the air filters. That is certainly NOT the case. A power washer directed at the filters.

Hot air:
Regarding hot air being drawn from the radiator to the filter, the only situation that would exist is sitting at idle, where it does not matter.  As soon as there is forward motion the car gets forced air into the kidneys. The airflow will be past the filters, and through the radiator.  There will not be enough time to have any heat radiating forward towards the filters.  We easily confirmed this on the dyno with relatively poor airflow.

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Maximum PSI stage 2 E46 runs a 9.74@145.99 in the 1/4 mile!

We took the shop E46 M3 to MIR for a track rental and we were able to make multiple passes and chip away at a 9 second pass.  The end result was a 9.7@145.99mph, making it the fastest E46 in the US and the first in the 9’s.  We plan on continuing to push the car with the stock motor for now, and eventually we will install the built motor and larger turbo with our sights on an 8 second run.

MPACT Motorsports Festival 2015


Maximum PSI was an event sponsor for the second year in a row at MPACT Motorsports Festival at Pocono International Raceway.

We brought out our Stage 2 Turbocharged E46 M3 shop car along with several customer turbo cars.  We had a great time checking out the cars, hanging out with like-minded enthusiasts, and most importantly, thrashing on the cars!  We participated in the roll races, put on a respectable performance in the burnout competition, and enjoyed a lap in the Sarli Motorsports Drift Taxi.  We look forward to MPACT 2016!

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Videos – Make sure to click HD in the settings!

Roll racing:

Sarli Drift Taxi:



User reviews are always nice!

One of our Stage 1 E46 M3 turbo kit customers posted up a review on one of the BMW forums.  The original review can be seen here:

What I bought:

MaxPsi E46 M3 Turbo Kit (91 and 100oct)
MaxPsi 3″ Exhaust system (used)

Customer Service:
As everyone already knows Mikes reputation is top notch. I was bugging him at his most busy times and he still found the time to sit down and deal with my questions. You can really see the pride he has in this kit and will do whatever it takes to solve any issues.

Shipping and Quality:
First off, the freight shipping got from NJ or AZ in 3-4 days! Everything was packed perfectly and everything was there. Being that i am an aerospace welder/machinist for a living the first thing i look for in any part is the quality. All of the welding on this kit is awesome and is up to my high standards. I was very impressed with the intake manifold, the 6 runners are all CNC machined to perfection.

Install and Fitmet:
I have done 7+ E46 M3 Turbo installs so the install was fairly easy for me to tackle. Even if this is your first install Mike provides everything you could possibly need to handle it, the instructions are very detailed. Anytime you design something on another car and fixture it you can expect a little variance on fitmet, NOPE, this kit fit PERFECT.

I had expected on first start up to have to solve some issues, but everything fired right up and idles perfectly. On the first drive i was over boosting a little bit, but after a few adjustments it now holds right at 9psi every single time. Since then i have been beating on the car and everything is flawless. This is my daily and i drive it 50 miles a day.

All in all i am extremely pleased!! Everyone should own one of these kits, Mike dialed these in to perfection!!

Winter update – 2.22.15


We have been busy cranking out turbo BMW’s. We have over 35 E46 M3 kits out there, and we are currently assembling and finalizing two Stage 4 cars at the shop, along with our first S54 Z3 kit. A stage 3 car is down at Technique Tuning in Florida for calibration development with larger ID1000 injectors. We ran an 8 second 1/4 mile with my E36 M3 at the end of last year, and I sold the car to a customer that will continue to push it further. This will allow us to focus on pushing the E46 development further rather than getting distracted between the two cars. It was a long, rewarding road with the e36. First in the 9’s, first in the 8’s! Sad to see her go, but it was a necessary progression.

8 second compilation video, 1/2 mile roll race and other media:

If you follow us on Facebook or Instagram, some of you have already seen the transformation of my E46 M3. Last year we installed a bimmerdiffs upgraded differential, along with all new poly bushings all around. We also performed the subframe reinforcement before buttoning it up. The car currently has the entire interior removed to begin the NHRA roll cage fabrication (complete with parachute and window net). The car is also getting a driveshaft loop and battery cutoff per the rulebook. While the cage is doing in, I am also installing a carbon trunk, carbon diffuser, and carbon roof. We also fabricated a larger 3.5″ single exhaust (that can be used with any of our different kit levels, and it has options for a single exit using a carbon diffuser, or quad exit using an oem style diffuser).

We suffered numerous 6 speed transmission failures with the e36 running an e46 M3 getrag box. They don’t stand a chance when the car makes almost 900 ft/lbs of torque!

I have a 6 speed dog box getting built by Samsonas Motorsport for my car. It uses an OEM ZF E36 transmission case with all new gears and internals, along with a CNC’d spacer to make the case the correct length for the additional gears.I also have a new twin disc clutch from Comp Clutch to try out in the car. We will have feedback shortly. I have had it for a while, however I am waiting for the new transmission to arrive so I can install it at the same time. I also have a Tilton carbon triple disc clutch for when things get serious and the built motor goes in later on this year.

We are going to keep the stock motor in the car and race it as-is with our current Stage 2 hardware, however it will be using our flex fuel system(Yes, we are still working on it!) running E85. My car has over 30k miles with our kit, and I have no issue driving it anywhere. We drove the car ~1400 miles to PRI and back this year and I have been to florida a few times with it. We also thrashed on it when we went to Bimmerfest, Willow springs track day, and MFEST. Still running strong!

At the same time, we are also assembling a built motor for my car, so that once the flex fuel development is completed, we can swap in the built motor and Stage 4 components. Exciting times for sure!!!


There have been some bumps in the road with our kits, but nothing that hasn’t been remedied. We had a few of our first intake plenums split at one of the welded seams. The first four cars were the only ones to have that issue, and they have all been repaired by now.

The major issue that we are still dealing with is cracking of the earlier tubular headers. We have always tried to do as much of the fabrication for our kits in-house, however the tubular headers take so much time to fabricate that we have other people fabricate them for us. There have been multiple failures with the first batch of tubular headers. The failures are caused by incomplete weld penetration. Over time some of the cars have had multiple cracks develop at various locations. We tried repairing the first few manifolds, however the time needed to strip the coating, blast the inside and outside clean, grind the cracked sections, and re-weld the entire header is too labor intensive. I will say that any of the later kits with non-ceramic coated headers do not need to worry about the issue since they were welded by another shop. Unfortunately we do not have the resources to replace all of the headers, so we came up with another plan.

We have used cast headers from SPA turbo on numerous E36’s over the years. With multiple tubular header failures, I decided to work with SPA turbo to duplicate our tubular headers into an identical cast manifold. After shipping them our tubular manifold, we soon had a sample that I ended up installing on my own car. The flow path and flange location is identical, however we were able to make more clearance for the rear cam sensor and A/C line. We also increased the inside diameter of the runners to account for some flow disturbances caused by the bolt hole recesses. I have the second revision on my car now, and I can say that the manifold performs as good or better than the previous tubular manifolds. We should be receiving our first batch of manifolds any day now, and the current round of kits are now shipping with them.

To anyone with a previous tubular manifold that has developed a crack: We will be selling the cast headers at a discount to help offset replacement cost. We apologize for the inconvenience, however it is not possible for us to cover the replacement expenses. If you have had the kit less than one year then the replacement header will be covered under warranty. Please email me at and we can go over the details.

THE GOOD(again):

We raised the Stage 1 kit price! How is that good? We actually lowered the kit price to account for the cost difference of the cast header. We are now including an eBoost 2 EBC and AEM wideband, and gauge pod($850 in components) since we use them in every kit besides the first few cars that we did.

That’s all for now. 2015 should be a good year for turbo E46’s!

-Mike and the Maximum PSI crew