I decided to compile a lot of questions I see into one big n00b FAQ. So here it is!
The N00B FAQ to an engine swap.
Q: What engine? M50? M52? S50? S52? Whats the difference?
A: There are 4 typical engines that people swap in, (said above) I will talk a bit about each one with pros and cons.
M50: Found in the e36 325i and the e34 525i, this engine puts out about 189 HP and is OBDI (I’ll talk about that later), this is probably the most done swap, “cheapest” to do, and has potential for power. From what I have read and been told by people who have swapped to a m50, they are not entirely satisfied. Although it is probably the cheapest of the bunch it lacks the most HP, a m20 with a few mods will have as much if not surpass the m50 engine.
M52: I don’t know a great deal about this engine, but I know it has an aluminum block to save weight. Most of the people who go for this engine plan on stripping the whole thing down and build it up block up with a collage of parts. Pretty similar to the m50 and what mods can be done to that. (I believe its OBDII? Someone correct me if I am wrong)
S50: Found in the 93-~96 m3. This is a 3.0 liter engine with OBDI, stock is 240 HP, probably the best “bang for the buck” engine you can get. There are tons of aftermarket parts and mods you can bolt on to get a few more HP.
S52: Found in the ~96-99 m3 This is pretty much the same as the s50, but it is 3.2 liters and OBDII. It also puts out 240 HP stock.
Q: Ok, so whats OBDI and OBDII? What do people mean when they “convert” from OBDII to OBDI?
A: OBDI and OBDII are two forms of engine management. In the middle of 96 IIRC car makers switched from their almost proprietary OBDI system to a universal OBDII system. Whats this mean for you? Nothing really unless you are trying to swap an OBDII engine into an e30. The OBDII system cannot work in an e30 because of the EWS anti-theft system, there is not an easy way to disable it. You have a couple options, 1 would be to retrofit the EWS system into an e30, from what I have read and have been told it costs just about as much as an OBDI conversion and you don’t really gain anything. 2 convert to OBDI it will free up a couple extra HP.
Here is one of many threads on the topic
What it comes down to, is you will have to replace the engine wiring harness, ECU, all the sensors, throttle body, fuel rail, and intake manifold from an OBDI car. My conversion cost around $1500 to do it with used parts.
One thing that frequently comes up in the conversion is the dual temp sensor on the head of the engine. The s50 engine has two sensors, one goes to the ECU, and one goes to the gauge on your cluster. The s52 however uses a dual temp sensor, it has 4 wires coming off it, in an e36 two would goto the ECU and two would goto the cluster. However, in an e30 the e30 cluster CANNOT read the dual temp sensor. You have 4 options to choose from
1. Retrofit an e36 water temp gauge in the e30 cluster (in theory it should work although I have not tried it, its almost impossible to track one of these gauges down)
2. Tap the head and thread in the e30 gauge temp sensor.
3. Tap the head and go for a VDO unit
4. Tap the thermostat (wont be as accurate) but its less to f*&k up and a lot easier to do if you already have the motor back together. Better than not knowing the temps anyways.
There are two ECU’s you can do with. The silver 413 or the Red 413. The red 412 does not have EWS, which means you can just plug that ECU in and god. The Silver 413 (more common) has EWS, you will need to get a chip from someone to disable the EWS system. I am running a Jim Confori chip that I got here
This will disable EWS, have the same effect as just chipping the car, and can be tuned for any mods you have.
Q: I have heard something about an oilpan, whats this about?
A: The oilpan from any 3 series (including m3) engine will not work in an e30. You will need to get an oilpan from the m50 on an e34 525i, don’t forget the oilpickup too! If you pulled an m50 from an e34 525i you don’t even have to worry about this step, you already have the correct pan.
One thing that tricked me was the oil sump bracket on the engine after pulling the old pan off. It will hang down too low and prevent the new pan from going on. The easiest way to fix this is just to dremel it off
Heres a thread about it
Q: What do I do about wiring the engine in?
A: You can search around for wiring diagrams, but a lot of them are incorrect. If you have the cash goto www.treehouseraching.com and pickup one of their converters, its spendy but it comes with free support If you are not electronically skilled I would highly recommend this.
Q:What do I do about the brake booster?
A: http://www.r3vlimited.com/board/showthread.php?t=64988 check it.
Q:Can I use my old m20 tranny?
A: Yes, but I don’t know anything about that…. Sorry, Search a bit people do it.
Q: Do adding stickers give me HP?
A: Only if they say “equate kicks ass” and you pay me $50 then they might.
Q: Whats the engine speed wiring about?
A:If you car is pre 88 (IIRC) there is a 4 plug wire by the ECU in the glove box. The wire colors are
Pin #1 Black Wire-Engine speed
Pin #2 green wire-OBC Fuel cut function
Pin #3 Yellow/White wire-Fuel rate
ONLY if you have this connector and your car is throwing a speed sensor code, you will need to hook a wire on the green plug on the back of the cluster (the blue/yellow wire) to pin 42 on the ECU. Also your tach probably wont work either. You will have to hook the black wire on the c104 (the 4 pin connector) to the correct wire on the ECU. do some searching if you come across this.
Notes
Lots of parts can be found here
Make sure you get the e24/e28 M30 3.5L Engine mounts and the e36 throttle cable.
The N00B FAQ to an engine swap.
Q: What engine? M50? M52? S50? S52? Whats the difference?
A: There are 4 typical engines that people swap in, (said above) I will talk a bit about each one with pros and cons.
M50: Found in the e36 325i and the e34 525i, this engine puts out about 189 HP and is OBDI (I’ll talk about that later), this is probably the most done swap, “cheapest” to do, and has potential for power. From what I have read and been told by people who have swapped to a m50, they are not entirely satisfied. Although it is probably the cheapest of the bunch it lacks the most HP, a m20 with a few mods will have as much if not surpass the m50 engine.
M52: I don’t know a great deal about this engine, but I know it has an aluminum block to save weight. Most of the people who go for this engine plan on stripping the whole thing down and build it up block up with a collage of parts. Pretty similar to the m50 and what mods can be done to that. (I believe its OBDII? Someone correct me if I am wrong)
S50: Found in the 93-~96 m3. This is a 3.0 liter engine with OBDI, stock is 240 HP, probably the best “bang for the buck” engine you can get. There are tons of aftermarket parts and mods you can bolt on to get a few more HP.
S52: Found in the ~96-99 m3 This is pretty much the same as the s50, but it is 3.2 liters and OBDII. It also puts out 240 HP stock.
Q: Ok, so whats OBDI and OBDII? What do people mean when they “convert” from OBDII to OBDI?
A: OBDI and OBDII are two forms of engine management. In the middle of 96 IIRC car makers switched from their almost proprietary OBDI system to a universal OBDII system. Whats this mean for you? Nothing really unless you are trying to swap an OBDII engine into an e30. The OBDII system cannot work in an e30 because of the EWS anti-theft system, there is not an easy way to disable it. You have a couple options, 1 would be to retrofit the EWS system into an e30, from what I have read and have been told it costs just about as much as an OBDI conversion and you don’t really gain anything. 2 convert to OBDI it will free up a couple extra HP.
Here is one of many threads on the topic
What it comes down to, is you will have to replace the engine wiring harness, ECU, all the sensors, throttle body, fuel rail, and intake manifold from an OBDI car. My conversion cost around $1500 to do it with used parts.
One thing that frequently comes up in the conversion is the dual temp sensor on the head of the engine. The s50 engine has two sensors, one goes to the ECU, and one goes to the gauge on your cluster. The s52 however uses a dual temp sensor, it has 4 wires coming off it, in an e36 two would goto the ECU and two would goto the cluster. However, in an e30 the e30 cluster CANNOT read the dual temp sensor. You have 4 options to choose from
1. Retrofit an e36 water temp gauge in the e30 cluster (in theory it should work although I have not tried it, its almost impossible to track one of these gauges down)
2. Tap the head and thread in the e30 gauge temp sensor.
3. Tap the head and go for a VDO unit
4. Tap the thermostat (wont be as accurate) but its less to f*&k up and a lot easier to do if you already have the motor back together. Better than not knowing the temps anyways.
There are two ECU’s you can do with. The silver 413 or the Red 413. The red 412 does not have EWS, which means you can just plug that ECU in and god. The Silver 413 (more common) has EWS, you will need to get a chip from someone to disable the EWS system. I am running a Jim Confori chip that I got here
This will disable EWS, have the same effect as just chipping the car, and can be tuned for any mods you have.
Q: I have heard something about an oilpan, whats this about?
A: The oilpan from any 3 series (including m3) engine will not work in an e30. You will need to get an oilpan from the m50 on an e34 525i, don’t forget the oilpickup too! If you pulled an m50 from an e34 525i you don’t even have to worry about this step, you already have the correct pan.
One thing that tricked me was the oil sump bracket on the engine after pulling the old pan off. It will hang down too low and prevent the new pan from going on. The easiest way to fix this is just to dremel it off
Heres a thread about it
Q: What do I do about wiring the engine in?
A: You can search around for wiring diagrams, but a lot of them are incorrect. If you have the cash goto www.treehouseraching.com and pickup one of their converters, its spendy but it comes with free support If you are not electronically skilled I would highly recommend this.
Q:What do I do about the brake booster?
A: http://www.r3vlimited.com/board/showthread.php?t=64988 check it.
Q:Can I use my old m20 tranny?
A: Yes, but I don’t know anything about that…. Sorry, Search a bit people do it.
Q: Do adding stickers give me HP?
A: Only if they say “equate kicks ass” and you pay me $50 then they might.
Q: Whats the engine speed wiring about?
A:If you car is pre 88 (IIRC) there is a 4 plug wire by the ECU in the glove box. The wire colors are
Pin #1 Black Wire-Engine speed
Pin #2 green wire-OBC Fuel cut function
Pin #3 Yellow/White wire-Fuel rate
ONLY if you have this connector and your car is throwing a speed sensor code, you will need to hook a wire on the green plug on the back of the cluster (the blue/yellow wire) to pin 42 on the ECU. Also your tach probably wont work either. You will have to hook the black wire on the c104 (the 4 pin connector) to the correct wire on the ECU. do some searching if you come across this.
Notes
Lots of parts can be found here
Make sure you get the e24/e28 M30 3.5L Engine mounts and the e36 throttle cable.
Comment