[HiRide]

Well, I had hoped to build and sell my o2 simulator but I cant guarantee that it will last forever and making the whole box for the simulator and the super hot resistors is just not something I want to spend time on. The resistors on my setup have burnt out after 7 months and although I can increase their capacity, I can never guarantee this product and charge for it. The actual simulator is still working fine and I just replaced my resistors and I'm fine.

I have decided to give away my secret. I have more lucrative ventures to worry about and I think there are some people who could use this information.

To those who asked about my sims for so long, I am sorry that I did not make this information available earlier.

So here we go.

What is included in this DIY will be the parts and sources and a general install.

Parts:

O2 Simulator
(1) Universal Dual Output O2 Simulator from (www.o2sim.com) - $40.00

Heater Circuit Simulator
(2) Aluminum Housed Wirewound Axial Resistors [ 5ohm ; 50 Watt ; 1% tolerance] Part # 850F5R0E-ND - $6.25 (ea.)
(www.digikey.com)

The Install is very basic.
(0) Turn car off...
(1) Remove plastic engine cover and disconnect Post-Cat O2 Sensors
(2) Remove Post-Cat O2 Sensors from headers
(3) Cut the sensors off of the wires
(4)Install the o2 simulator and resistors using these directions
http://www.o2simulator.com/doc/o2sim...ion_manual.pdf

Color Code for factory o2 wiring:

Black - O2 Signal Wire
Grey - O2 Signal Ground
White (1) - Heater Circuit (+)
White (2) - Heater Circuit (-)

- You will have to use a volt meter to determine which white wire is the power and which is ground. You will need to know this because even though it wont matter for the actual resistor on the heater circuit, the power wire is used to run the simulator.

Before you actually start this project there are a few things you will need to consider.

1st. You do not need the resistors in order to make this work. The resistors only replace the factory heater circuit located within the o2 sensors. While the resistors get just as hot as the o2 sensors, they are much smaller and can be put into a metal project box for mounting. If you have no problem keeping your o2 sensors plugged into the headers, you can skip the resistors and just keep the heater circuits from the stock o2's working. You will still need to splice into the (+) heater wire in order to power the simulator and trick the ECU.

2nd. If you decide you would rather remove the o2's completely (and say use the extra bungs for a wideband sensor and guage) then use the resistors and completely cut off the sensors. However if you do this, you will need to find a safe place to mount the setup. The resistors get very very hot. More than likely you will want to find a small aluminum project box that you can mount all the parts in. You can then mount that box somewhere it does not have direct contact with plastic or anything important that could melt or be damaged by intense heat.

3rd. I put all my parts under the engine cover as a temp setup, Do Not Do This. You risk melting your ignition wires. Also, having an aluminum heat sink for the resistors will dissipate heat better and increase the life of the resistors. I never did all that, and perhaps that is why mine burnt out in less than a year.

4th. If you prefer a little more from your o2 sim. You can instead buy (4) 2.5 ohm resistors (50 Watts each) and run two in series for each o2 heater circuit. By doing this you will have the same resistance (5 ohms) but you will have a higher wattage rating of (100 Watts). The only downside to this is a lower tolerance which could lead to more fluctuation in resistance but that should not cause any problems and would not be enough to throw any SES lights to my knowledge. This should also run cooler than a single (5 ohm) resistor on each heater circuit.

( off road use only... I have never tampered with my emissions systems ... and I dont condone anyone using this on public roads or tampering with their emissions systems on road vehicles, I dont even use this on my car since it has to run on the street)

Obioban... if you wan to write this up with pictures and make a proper DIY, go ahead. That goes for anyone else as well.

Hope this helps!

Rich

[Jumbosock]

Ha ha you said somewhere in Mexico.

[Fissionx]

I looked at these for the e36 and these would not work. The problem was that these o2 sims were designed to work on 0-5V o2 sensors (typical domestic) and would not work with the bosch 0-1V o2 sensor (or visa versa it was a while ago). Did you find this true or are these different?

I'll save you the environmental discussion, however I will say that you can buy high-flow cats that will still function and will not significantly reduce power on almost any street driven bmw, N/A or turbo. I think this is the best option and your car will still be legal. Depending on where you live the penalties can be very harsh, ie impound your car; its happened to someone i know.

[doublearon20]

Originally Posted by Fissionx

I looked at these for the e36 and these would not work. The problem was that these o2 sims were designed to work on 0-5V o2 sensors (typical domestic) and would not work with the bosch 0-1V o2 sensor (or visa versa it was a while ago). Did you find this true or are these different?

I'll save you the environmental discussion, however I will say that you can buy high-flow cats that will still function and will not significantly reduce power on almost any street driven bmw, N/A or turbo. I think this is the best option and your car will still be legal. Depending on where you live the penalties can be very harsh, ie impound your car; its happened to someone i know.

True the penalties are quite steep, but in places that don't do yearly emission check, like Michigan, the chances of you getting caught are slim to none.

[///M-thrizle]

Thanks for the write up! Will be making this for myself this winter.

Minnesota FTW! no inspections what-so-ever.. Good bye kitties...

[HiRide]

I am just covering myself.

Yes high-flow cats are pretty much the same as running catless. But they also add another $800 to your exhaust setup. Unless you can weld in your own 100 cell high flow cats, the retail options are ridiculously priced. Many people with headers find themselves without cats and with an SES light.

These sims will not work on the e36... they will work with the E46. So far I only know they work on the E46 M3.. I havent tried them on an E46 non-M.

[Romad]

If anyone needs some of these O2 sims I have two dual outputs for sale. Just PM if you are interested.

[nuc1]

Originally Posted by HiRide

4th. If you prefer a little more from your o2 sim. You can instead buy (4) 2.5 ohm resistors (50 Watts each) and run two in parallel for each o2 heater circuit. By doing this you will have the same resistance (5 ohms) but you will have a higher wattage rating of (100 Watts).

Rich

Believe you meant in series? Two 2.5 ohm resistors in parallel will give you an equivalent resistance of 1.25 ohms; series equivalent resistance is 5 ohms.

Mike

[SammyXp]

Originally Posted by HiRide

You do not need the resistors in order to make this work. The resistors only replace the factory heater circuit located within the o2 sensors. If you have no problem keeping your o2 simulators plugged into the headers, you can skip the resistors and just keep the heater circuits from the stock o2's working. You will still need to splice into the (+) heater wire in order to power the simulator and trick the ECU.

I like this solution. Can't think of a better place for a resistor that hot.
Thanks for confirming these O2 sims work, Rich!

[tonggi]

nice, if only i knew what you were talking about with these ohms stuff