N54 $5 boost controller

Mook

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BMW owners are snobs, so I'm not surprised.
 

Mr_Roboto

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At expense of asking a stupid question wouldn't that short the MAP input to ground if it's a DPTD switch?

Reminds me of the Zener circuits that the Chrysler guys would use on the Turbo cars to prevent boost overcut.
 

Ron Vogel

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It’s a simple voltage divider. So the 0-5v sends out a lower output. I’m getting throttle closures because reported boost is too high. So in my case I’m just recovering lost boost
 

Mr_Roboto

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My question is how you're adding fuel to not blow the engine up going lean. The diode setups back in the day were crude at best and not without their dangers. Fuel was usually added separately after boost cutout. Not hating on your solution, just trying to provide some input.
 

Ron Vogel

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It’s already too rich, I monitor it. I have supplemental fuel for if need be also
 

Ron Vogel

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Just fooling the computer by scaling down the 0-5v map output. I’m seeing throttle closures because my reported boost is to high vs commanded. I just came up with this to allow the boost without the BMW nannies shutting down the fun. It’s a down and dirty little deal, but it’s more of a tuning/experimenting aid
 

1quick

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That’s cool, I read the thread title the last couple days and never clicked because I thought it was a video game controller for some reason lol
 

Pressure Ratio

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The new v8 maps with the throttle closures helping control the boost isn't an uncommon strategy. But seems to have really confused N54 owners. MHD went that route on these maps to keep the turbos spooling for better response. But with you doing this you keep the response and take advantage of the extra boost/airflow. lol

With this you are saying you are seeing +2 & +4 pounds over the Boost set limits?
 

Ron Vogel

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My set limit is 18.5, but I’m seeing 20-22. So I’m seeing 75-80% throttle. I have a custom e30 map that works fine, but the car runs like shit with it. I like the stage 2+ map, but I think it needs a bit more. The MHD maps are ultra conservative. I’ve got all the MHD maps, and a few custom ones. I don’t want to start custom tuning on the car until I do inlets/outlets, but it will be getting a custom tune eventually.

Other thing that bothers me is part throttle diverter bleed off, it may be normal but it makes the car feel weak unless it’s WOT.

What I’m doing here is nothing new though, it’s just a more basic JB+.
 

Pressure Ratio

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Oh for sure. I have seen the same thing done with fancier packaging on different cars. Just wanted to confirm that was the case.

I think the v7 maps were pretty good. But v8 maps seem smoother for sure. I think v8 makes more torque and recovers quicker. A lot of people think v7 has more torque/power and I think that is because it was more violent when it did finally come into torque.

I have seen people with like 80% closures on v8 maps. I typically will see about 20-30%. Slightly more in very cool weather. But I have inlets, upgraded intercooler, cold side piping, and down pipes. So it isn't surprising to see closures on my set up. But because I have that stuff the turbos could be pushed harder than the v8 maps allow. I have not done any custom maps yet because I have the flexfuel sensor to install still. Once I do that I plan on doing a customer 93 octane, e85, and flexfuel tune.


Did I read in another thread you have a BMW wagon? N54 converted?
 

Ron Vogel

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It’s not converted, it’s a 535xi. Appears previous owner barely drove it, only 60k on it when I bought it and the motor is very strong. Turbos/hpfp look to have been replaced, but other basic maintenance was neglected. Still had original plugs in it when I got it. I spent the first few months going through the car doing all the preventative stuff and getting everything to 100% before modding it. Only thing that still needs to be addressed is one of the positions of the comfort seats is not working, and I suspect I will have to cut back the cables from the motor to the gear.

I’ve got the “big Tom” IC and meth, my IATs rarely get 5f above ambient. Not worried about pushing it. I’ve run as high as an e40 mix, and the lpfp is well within the safe zone so far.
Long term is to be high 400’s to the wheels on stock turbos, then go to upgraded turbos when these fail.
 

Pressure Ratio

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ahhhh ok. I assumed 3 series wagon. lol

Sounds like a nice setup. These motors have their issues with leaks and coils. But if you took care of all that you should be good to go. I am shooting for the same kind of power with my 335i xdrive. But since it is my daily driver I hope I can stay away from upgrading the turbos. But my car has 120k+ miles on it now. I think these are the original turbos. So we will see what happens. haha


Who did your custom tunes?
 

Ron Vogel

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ahhhh ok. I assumed 3 series wagon. lol

Sounds like a nice setup. These motors have their issues with leaks and coils. But if you took care of all that you should be good to go. I am shooting for the same kind of power with my 335i xdrive. But since it is my daily driver I hope I can stay away from upgrading the turbos. But my car has 120k+ miles on it now. I think these are the original turbos. So we will see what happens. haha


Who did your custom tunes?
The custom tunes are not specific to the car. Once you have MHD m-boost option you can DL custom tunes off the internet or from other users. MHD tunes are locked, but you can tune from a custom bin. I’m still learning this platform, so I’m holding off for now...but the actual tuning software is free.

I’m hoping I can hit my goals without secondary injection, but it’s not off the table yet. The “BMW tax” is slowing me down, so I’m planning on making a lot of what I can myself
 

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