On3 Top Mount Single Turbo System
Over the past year On 3 Performance has been developing one of their newest turbo system options. On 3 has 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.
This turbo system starts with a completely custom designed manifold that is a 2pc design. On 3 has designed it from an extremely thick schedule 40 tubing and only use 304ss for the construction. By making this unique manifold, it allows for a much easier install. Most of the single top mount kits also require you to modify the factory coolant line as its routed through the same area where the factory turbos sit. They took serious attention to detail and built around it so it retains the hard aluminum tubing. This is not a good area to run rubber hose like some systems do. Sure it would be easier but in the long run, but they have a better design. The On 3 Performance manifold is designed to use their 44mm v-banded wastegate to control boost. Out of the box your kit will be setup to make around 14psi on wastegate pressure. Coming out of the wastegate, it is setup to vent to the atmosphere. They build a lot of cars around there and this 335 engine rolling into boost sounds like nothing else they 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.
This turbo system was designed around 2 of their 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 450-500hp 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 the top shelf and will yield the highest HP that they can offer. The kit options will allow you to select either turbo dependant upon your HP expectations. The standard option included is their journal bearing turbo, and the dual ceramic ball bearing is offered as an upgrade for a small fee. We had this exhaust housing cast from stainless steel and best of all it is v-banded inlet and outlet. With a very 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 turbochargers, they designed a set of 3″ downpipes from 304ss. This will take the gases back to the factory exhaust location and splits into duals. With each kit they also include the necessary stainless steel v-band clamps to secure the turbos and downpipes in place as well as the needed clamps for the turbo manifold. To make their kit that much easier to install and to keep it a direct bolt on, they also include a set of billet fittings to help with a number of complications. When removing the factory twin turbos, that will leave oil ports for supply, draining as well as water passages used for cooling the stock units wide open. They had custom machined billet fittings made to do the following:
Billet Plugs Factory Water Ports
Billet Plugs For Factory Oil Supply Ports
Billet Plugs For Turbo Water Drain
Billet Plugs For Factory Turbo Oil 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 Technical
To address the cold side, coming out of the turbo they 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, they didn’t want to stop there. On 3 wanted to improve upon what most see already on the market, so they 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 the 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. Additionally there is a MAP sensor bung welded in so its ready for a plug and play install. Another touch which was not required was the power steering reservoir. They built a custom billet aluminum fabricated reservoir which contains a custom washable filter element. This is simply a nice dress up item to the engine bay, clearly not required but looks sleek and how BMW should of produced the car. They just forgot to call and ask us for our opinion
Dyno / Boost Details
All customers looking are going to be focused on power potential with this turbo system upgrade. Right now if you have a factory stock 335, you can compare the numbers simply to what you would/can make without other supporting fuel, trans, etc mods. The On 3 test car is sitting at just shy of 17psi right now and its starting to lean out so the factory low pressure pump is only going to support roughly 480rwhp. They had to bow out at this point although they are more than pleased with the power and the level of boost currently running. We hope to work with a new tuning software company, upgrade the fueling and go back for more testing. Our target for this car is going to be around 525-550 wheel as thats going to bring us to the limit of the factory transmission(automatic).
Intercooler Technical DATA:
On 3 initially base lined their test car with the factory intercooler at ~17psi of boost. Since then, they upgraded the car to their new 7″ Core 335i Intercooler and went back to the dyno for a few more pulls. Not surprised, the IAT’s were down and from the start of the pull till the end they are only getting about a 10 degree rise. The pull was starting at ~100 degrees F and ends right at 110 degrees F. This is a HUGE gain and by simply keeping the temps cool going into the engine. they were down 1psi at 16psi of boost and making 40 MORE HP to the tires at 6100rpm. So if you are pushing the stock turbos, or on an upgraded turbo setup, this is a must have. On 3 does sell the intercooler upgrade by itself so check out the BMW section for that specific upgrade if you are interested. Serious power potential and keeps the IAT’s in check. This is included with your turbo system purchase so your going to have the most efficient setup and coolest air charge temps possible
Keep in mind with this car, its a completely stock 335i they started with. There is zero upgrades, and it is an AUTOMATIC transmission, so the numbers will be a little lower than a manual car(still making killer power). As the vehicle is running out of fuel, it is apparent the stock low pressure pump needs to be upgraded if making anymore power than this. They are more than satisfied with the system and easily going to crack 500rwhp after the pump upgrade. That is the only thing holding them back right now and this is on pump 93 oct fuel, 7 degrees total timing!
Coolant Overflow Tank Relocation Info: On 3 gets calls on the coolant tank and what needs to be done very often. It cannot stay in the factory location as it interferes with the tubing and the way they have it routed. It simply is relocated to the firewall, if you need photos, please let us know and we can send you exactly how they have theirs mounted. It doesn’t require any brackets or anything special, you can simply drill a few holes and bolt it right to the firewall on the Driver side. Then a new coolant hose is run to make the connection for the extended area and your good to go!
Will fit AWD w- Modifications
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