Turbo E21 help

[Justinfewster]

I finally figured out how to post. I follow josh’s threads and try to follow as many other posts as I can but get lost. I’m planning on boosting my e21 1983 320is m10b18 but I have no Idea where to start when it comes to the fuel system. I’m familiar with the cis injection but I definitely don’t want a lean engine under boost. I only want about 250whp on around 10-15psi. But I would love to have a parts list and some direction on what to do. I’m putting a lot of money into my car comin up soon including air suspension, forged internals, redone interior, paint, new seals, and a Getrag 245 sport od trans. I just can’t figure out what to do with the fuel, just someone to point me in the right direction or a parts list or anything really. I’ve been on bimmerforums for a few years now and I’ve come to see there aren’t a lot of young guys like me modifying these cars around anymore so it’s nice to finally be able to communicate with you all now.

[someguy2800]

If it was my car I would get a manifold off an E30 318i intake manifold and fuel rail and convert it to EFI. The CIS is neat, I used to have an E21, but its not what I would try to run a turbo car on. Actually scratch that, I would put an M20 in it and turbo that with a megasquirt.

[Justinfewster]

Would I have to get the harness as well. And im really tryin to avoid swapping. I wanna keep the factory motor in it with the factor a/c if it’s possible. But please tell me more about this efi conversion sounds like the way I wanna go

[hotdish]

Would I have to get the harness as well. And im really tryin to avoid swapping. I wanna keep the factory motor in it with the factor a/c if it’s possible. But please tell me more about this efi conversion sounds like the way I wanna go

There used to be a link in the E21 section FAQ/DIY sticky, but looks like it's broken. I found a 2002 thread on the topic, should be quite a few differences but enough to get you started. I would make a post in the e21 section if you're looking into an L-jetronic or megasquirt conversion since a few "active" members have converted.

[Justinfewster]

There used to be a link in the E21 section FAQ/DIY sticky, but looks like it's broken. I found a 2002 thread on the topic, should be quite a few differences but enough to get you started. I would make a post in the e21 section if you're looking into an L-jetronic or megasquirt conversion since a few "active" members have converted.

Thank tou you that’s helps a lot. I’m just debating on wether to keep the stock motor and put forged intervals on it and push the hell out of it or efi swapping or just getting an entire e30 parts car and swapping the whole motor and ecu and harnesses over. I don’t know which is cheapest but also gets to where I wanna be. I want around 250-300whp and so far to my understanding if I built the motor at trans and pushed 14psi on my stock rebuilt cis injection. Please correct me if I’m wrong.

[hotdish]

Thank tou you that’s helps a lot. I’m just debating on wether to keep the stock motor and put forged intervals on it and push the hell out of it or efi swapping or just getting an entire e30 parts car and swapping the whole motor and ecu and harnesses over. I don’t know which is cheapest but also gets to where I wanna be. I want around 250-300whp and so far to my understanding if I built the motor at trans and pushed 14psi on my stock rebuilt cis injection. Please correct me if I’m wrong.

The 84-85 318i is the least desirable e30 sold in the US so getting a whole parts car might be pretty cheap if you can't find the engine or parts you need in a junkyard. Trying to buy everything individually online sounds like it would be more expensive to me. I've never owned a 4cyl e21 or e30, but trying to track down parts for a k-jet turbo build sounds more time consuming and expensive from what I've read, especially if you're not starting with an old school turbo e21 kit. The e21 forum or the BMW E21 Legion facebook page probably have more people who can answer e21-specific questions.

[Justinfewster]

I’ll check it out. But I’m just gonna throw a turbo on the rebuilt motor and push around 14 psi and be happy with the hp at that point.

[someguy2800]

That’s not going to happen without an aftermarket efi system to control it. The K jet system thats in their now was not meant to have boost going through it.

[Justinfewster]

I literally just got done reading post about the mechanical cis injection holding 14psi. I just need a pressure regulator somewhere in the system. Josh has the cis injection in his and so do many other people. It might need some upgrades but it can definitely handle some boost ��

[PowerKraut]

swap m42b18 in. boost it. never look back.

[PowerKraut]

srsly, i would never ever swap a m50 or other sixbanger in it anymore, after i did my m20 to m50 conversion. i just could not live with pulling a 6 cylinder out and throwing a 4 cylinder in it, but i am very sure a m42 with proper internals can put out more power than the e21 can handle while having a nice weight distribution and a lot of space in the bay.

but wasting time and nerves on a crappy injection system under boost is the worst you can do. you will spend more time on fiddling with bullshit to get it sorted out than swapping the m42 in plus stand alone ecu...

just my 2 cents.

[Justinfewster]

srsly, i would never ever swap a m50 or other sixbanger in it anymore, after i did my m20 to m50 conversion. i just could not live with pulling a 6 cylinder out and throwing a 4 cylinder in it, but i am very sure a m42 with proper internals can put out more power than the e21 can handle while having a nice weight distribution and a lot of space in the bay.

but wasting time and nerves on a crappy injection system under boost is the worst you can do. you will spend more time on fiddling with bullshit to get it sorted out than swapping the m42 in plus stand alone ecu...

just my 2 cents.

I definetly see your point. But my next option would be swapping in an e30 318i motor into it and putting a MegaSquirt in it then building that motor so I have the best of both worlds. A light efi engine that I can tune with a good turbo build and I’ll be on my way. I would rather swap a motor that bolts in rather then a m42 that I’m sure you had to fabricate every mount for (I could be wrong not familiar with the motor swap) but just not my cup of tea.

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doesn’t that motor bolt in?