On 3 Performance BMW N55 335i Top Mount Single Turbo System - V-Band

Over the last two years we have been developing an N55 Big Single Turbo system. We love the support the N54 community has shown us and wanted to continue providing for BMW guys by moving our knowledge to the N55 platform.  There are not a lot of options and those that are would generally require you to take out a small loan.  We have set out to change the market and design an affordable, top mounted, single turbo system.  From a design standpoint, this application is a challenge with the tight engine bay and a lot of tubing to fit in a small space.

Our system starts with a completely custom designed manifold.  We have designed it from an extremely thick schedule 40 tubing and only use 304ss for the construction.  Our manifold is designed to use our On 3 Performance 44mm v-banded wastegate to control boost.  Out of the box your kit will be setup to make around 7.5psi on wastegate pressure, with options available to increase up to 15psi and anywhere in between.  Coming out of the wastegate, we have it setup to atmosphere. Let me tell you personally, this car has factory exhaust and sounds pretty much like any other 335 driving around….until it rolls into boost.  We build a lot of cars around here and this N55 engine rolling into boost sounds like nothing else we have worked with.  The exhaust note is amazing and just right for for this caliber car that has all the comfort and now the power to back it up.  The 304ss dump tube routes down from the wastegate and terminates right at the factory exhaust connection.

Turbocharger

Our turbo system was designed around a few of our already popular turbochargers.  The first option is going to be the On 3 55mm GT30 turbocharger.  If you are looking for the quickest spooling option and sticking to around 400-450hp max range, this will be the option for you.  Although spool time will be almost identical(~300rpm slower), the On 3 Performance 61mm GT35 is a great upgrade for the guys looking to make 450-550hp. This is a decent step up in power potential over the GT30. We then have our Billet Wheel GTX67mm, 6466, and 6766 that have capabilities to take your N55 engine to 700+hp, these will be slower to spool but the power potential enormously different. You will be able to select which turbo option you want when ordering your system. If you arent sure which turbo option best suits you, please feel free to call in and get assistance from us. We also carry options for selection as journal bearing turbos or ceramic ball bearing turbos, these are offered for a small fee. All Turbo options will use our v-banded inlet and outlet.  With any tight engine bay, this is key to allow for endless adjustments.  This will not only look great but when the install time comes, it will make life that much easier.

Moving the air out of the turbocharger, we designed a 3″ downpipes from 304ss.  This will take the gases back to the factory exhaust location and splits into duals.  With each kit we also include the necessary stainless steel v-band clamps to secure the turbo in place, downpipes as well as the needed clamp for the turbo manifold.  To make our kit that much easier to install and to keep it a direct bolt on, we also include a set of billet fittings to help with a number of complications.  When removing the factory turbo, draining as well as water passages used for cooling the stock units wide open.  We had custom machined billet fittings made to do the following:

• Billet Plugs Factory Water Ports
• Billet Plugs For Turbo Water Drain
• Custom Billet Oil Supply Fitting for New On 3 GT Series Turbo
• Custom Turbo Oil Restrictor Fitting
• Custom Billet Turbo Oil Drain (Into Engine Block)

Cold Side

To address the cold side, coming out of the turbo we designed a short 2.5″ charge pipe out of the turbo to the massive 7″ core On 3 Performance air to air intercooler upgrade.  In order to maximize power to redline, the IAT’s with the factory intercooler will become a problem.  Airflow surpasses what the factory air to air will handle and start delivering hot air to the engine.  As that warms up, the computer starts pulling timing and that will become a power loss.  Cool the air with the new 7″ On 3 Intercooler and your not pulling timing, air temps drop and everything is good.  Although that is all that is required to get the car running, we didn’t want to stop there.  We wanted to improve upon what most see or already on the market.  So we also designed a custom throttle body charge pipe to include with each turbo system standard at no additional cost.  This is a 3″ polished aluminum charge pipe and also intergraded in our 50mm On 3 Performance blow off valve flange.  Each system will come with the 50mm On 3 blow off valve, this will not only sound good but fight compressor surge.  Most will look at this feature and like it for the sound but its a very crucial piece to a turbo system to keep the turbo alive.  Also hard to see but we do have the map sensor bung welded in so its ready for a plug and play install.