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aflatau aflatau is offline
Junior Member
Posts: 75
Join Date: Apr 2012
Car: 335i
Default My Custom Single PT6466 Build Thread - 08-27-2013, 06:00 PM


I thought I would start my own custom single turbo build thread. The car(e90 335i) will be going into the shop soon to start the process..

When I first start doing research I had quite a few questions I had for my self that I went out and found the answers to share with you guys:
  • What turbo should I go with?

This was my first issue I needed to over come, I originally wanted todo a custom twin setup - such as GT2832rs but my fabricator said it would be a lot more costly to go that route and a pain in the ass and suggested a single setup.

From there I was concerned about boost lag, I am so use to the powerband of the current OEM twins. So I did some research and found the following turbos:
  • Garret GTX3582r
  • Comp CT4 6465 Billet
  • PT6466

While looking trough all these options I found that the best bang for buck would be the PT6466 for the power goals I want to go with. Problem with this turbo is that it is the most lagy out of the three. But at the end of the day I decided to purchase this option. I purchased the Vband inlet and outlet housings to make a simple install and remove process.
  • Do I run an external or internal wastegate?

I was concerned about which wastegate to run, due to the fact that our OEM system is an internally wastegated setup. I dug around and sent some emails to Terry and found out that an external wastegate is not an issue and to go that route.
  • Upgrade the boost solenoid?

This option here is still up in the air, I was concerned about running the OEM boost solenoid due to the fact that they some times fail in open state to cause over boost. So I decided to shell out and purchase a MAC boost solenoid I got from ebay for less then $40 shipped. This here will be a trial and error process and won't know more till I get to that point in the process.
  • Upgrading the BAR Map Sensor?

Since the OEM Bar Map sensor is only a 2.0 bar, and I plan on running more then 20 PSI on this single turbo, I had to find a suitable Bar map sensor. Luckly
BMS offers a plug and play harness for the N20 3.5 bar map sensor. I purchased the map sensor from ECS Tunning and ordered the harness from BMS.
  • O2 Sensor Placement pre-turbo?

So with going single I have learned that you have to place the O2 sensors before the turbo, when typically you would do post placement. The reason for this is that our OEM ECU reads two separate banks, 1-3 and 4-6 for A/F ratios. If you put the O2 sensors post turbo with a single turbo it mixes the gases and throws off the A/F ratios which will cause a tuning night mare.
  • What fueling am I going to run?

Well since I have an upgrade LPFP with the Walbro Intake option, I will be running a big e85 mix of atleast 70/30 and move up from there if the system can take it. I want to see what I can do with just e85 around. Hoping to reach 25-26 PSI on E85 alone, but at this point its all hopes and dreams.

  • What tuning platform?

Well with the new option of open flashing, I will be running the JB4 G5 with the open flash to tune this project. This is where I will see needing the most help from Terry, I will be making a new thread on this alone about this topic.

Those are the questions of what I could think of now, I am sure during this process I will have more, and have more answers to share with you guys.

The parts I have purchased so far are
  1. Exhuast head flange from RB Turbo
  2. Tial MVR Wastegate
  3. 3.5 Bar N20 Map Sensor
  4. Plug and play harness for bar map sensor from BMS
  5. PT6466 Turbo with Vband housings
  6. MAC Boost Solenoid

Right now I am also currently sourcing up the raw materials for the manifold and etc.

We will be designing a top mount manifold for this turbo, which leads me to ask some questions maybe you guys can help me answer.

Air filter placement, Where do you think the best option is to place the air filter?

What do you think the best placement is for the o2 sensors with out burning them out?

I will update this thread as I go, the car should be going under the knife this weekend if I get all my parts in time.

Please if you have any questions or comments, please feel free to share.
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