Should I swap?

[McGyver]

Here's my take on it, having done an m30 swap, an m5x swap, and currently building a turbo car:

First, the best thing you can do for resale value is reseal the outside of the m20, clean it, and paint it. Unless you have bad compression, don't even open it. Just fix all the leaks and make it pretty. Selling a swapped car can be difficult and you'll never get as much back as you put into it. Any power upgrades (other than a chip tune) will either take $$$ to buy pre-made parts, $$$ to buy equipment to make your own parts, and the time you put into researching/fabricating/building is also worth $$$.

Second, changing things will have unanticipated consequences. Lowering the car may look good and handle better, but you may be disappointed by a harsh ride and other problems. Without rear subframe mods and camber plate, you're going to chew through 60k mile tires in 15k miles. Your ball-joints and bushings may need to be changed more often. Other components will rattle loose or break (maybe a solder joint on your tach? Maybe your exhaust hangers tear all the time?) Now think about modifying the car for a new engine.

Third, once you start power upgrades, you will either loose reliability or spend $$$ to make the modifications work correctly. It's also likely that you will loose creature comforts (AC, working econo gauge, ABS, power steering, temp-controlled aux fan, stock brake booster, etc.) You've also got to remember what you did to make the modifications work. (how did I rewire something? what hose did I use to make the radiator fit?)

Fourth, what legal requirements do you need to deal with? (emissions, safety, etc.)

If you need to tear down the engine (and it looks like you already opened yours up) my suggestion would be to do some sort of stroker than can run off of the stock ECU with a chip. Introducing standalone is a massive project. Going too big with your stoker will mean a shorter engine life. Going crazy with power goals means spending a lot of time trying to prevent things from braking, figuring out what broke, and fixing broken stuff. All of that is time you aren't driving. It's nice to be able to just get in and drive instead of worrying about some half-finished mod.

FYI, here's a thread I started on building MegaSquirt (I'm still not done):
https://www.r3vlimited.com/board/for...ild-and-wiring

[GarbageCanE30]

The Dinan turbo kit would be baller. On top of that I still think you should do the 81mm stroker because it's simple and effective for how much it costs, probably best if you can source the forged 524 diesel crank. Then you just need to decide what pistons you want, but I think it's better go with the option that utilizes the longer 135mm b25 rods (or upgrade to the lighter s5x, m52, m54 rods). I guess I don't know a lot about turbo m20s and what the best cam upgrade, valve size, etc, would be, though. You say cost isn't an issue, but I bet by the time it's ready to drop in you'd still be below the cost of a proper turn-key s54 swap but have something just as powerful with a unique OG throwback.

Ultimately I think I've decided that's what I'm after. The kit comes with modern engine management in the form of a MS2 as well as the original engine management provided by dinan. The Ms already has a tune in place for the b25 tho apparently 2 owners back it was reported to be running rather lean. I will like upgrade/rebuild the dinan turbo (more likely a rebuild to keep it original) as well as the dinan injectors that come along with it. Like you said, I think this may actually be a surprisingly cost effective method, though the extended maintenance worries me just a bit being that if something brakes, it cannot be replaced and will have to be repaired if I wish to keep it in its original state. Either way, I'm sitting here with a completely disassembled m20b25 with low-ish mileage, and all the parts for a total rebuild essentially. Would kinda be a shame to return them all and go a different route at this point. Definitely going to investigate some stroker add ons as well. Thanks again everyone for the suggestions and guidance.

[E30 Wagen]

The Dinan turbo kit would be baller. On top of that I still think you should do the 81mm stroker because it's simple and effective for how much it costs, probably best if you can source the forged 524 diesel crank. Then you just need to decide what pistons you want, but I think it's better go with the option that utilizes the longer 135mm b25 rods (or upgrade to the lighter s5x, m52, m54 rods). I guess I don't know a lot about turbo m20s and what the best cam upgrade, valve size, etc, would be, though. You say cost isn't an issue, but I bet by the time it's ready to drop in you'd still be below the cost of a proper turn-key s54 swap but have something just as powerful with a unique OG throwback.

[e30austin]

having done at least 25-30 24v conversions in the last decade, i actually am going to vote against that, and say to leave the m20 in the car. you will enjoy the car a lot more, for what it is, than trying to make it something it isn't. a healthy b25 makes lovely noises and is plenty of fun for the car. if you decide you want more power, you can always build a 2.7 liter pretty easily, or if you really want to go crazy, a 2.9 or 3.0 isn't out of the question.

either way, it's your car - go have fun, whatever route you pick.

[GarbageCanE30]

whatever it is you need to turbo it.
m20 is sweet.
m30 is nice too. The thing i really like about the m30 is that 100% stock it can handle 500tq all day.
m50 is also nice because the aftermarket for those is huge.

When you say show worthy do u mean like with judges or like impressing parking lot guys?
m30/m20 for sure m50 just looks like a plastic box.

When I say show quality I genuinely mean to take it as far as appearance goes as near to fresh from the dealership as i can. I definitely understand the level of investment that requires and have quotes from several extremely capable shops. Luckily I already have an extremely clean interior in my car but there's an enormous journey ahead of me that I'm prepared to take. Not only have I loved these cars for over a decade, but I also firmly believe excellent examples will soon be regarded in a similar light to 911s of the same era.

[GarbageCanE30]

Tracking and show ready are opposing goals imo. Tracking a relatively uncommon car that has a lot of money dumped into restoration and show quality paint is kinda dumb, the hard use with chunks of rubber and rocks bouncing off your car is the opposite of what you want for a squeaky clean show ready car. If you want to track the car, don't bother making it any nicer than a 20' car. If you want to do regular tracking, get a cheap E36 and strip it down to the bare essentials. They're still common, cheap, and have a better chassis to boot.

Yeah I guess I didn't make that clear my apologies, I have no intent on tracking the car, but want it to be a track-worthy preformer with suspension upgrades and other drivetrain upgrades. Not talking about weight saving and throwing a cage in it. Definitely want to be a car that can be enjoyed spiritedly in a street setting

[varg]

Tracking and show ready are opposing goals imo. Tracking a relatively uncommon car that has a lot of money dumped into restoration and show quality paint is kinda dumb, the hard use with chunks of rubber and rocks bouncing off your car is the opposite of what you want for a squeaky clean show ready car. If you want to track the car, don't bother making it any nicer than a 20' car. If you want to do regular tracking, get a cheap E36 and strip it down to the bare essentials. They're still common, cheap, and have a better chassis to boot.

[KI4UJO]

My goal isn't a track car, but a car that could be tracked and is built to withstand some abuse. I honestly really like the idea of keeping the m20 and turboing it as I think keeping things period correct for show purposes is an interesting notion. I also just stumbled across and extremely rare dinan turbo kit from the early 90s made for m20s and it's got me thinking... Although it's not particularly competitive or likely even ideal turbo charging technology by today's standards, mannnn would it be cool to have a period correct full dinan kit on the og motor that came in the car. Just a thought.. Another reason I'm beginning to lean away from a swap is this is something I hope to accomplish fairly quickly, which can be difficult when hunting for individual parts to complete the build.

If being period correct is an issue, the majority of swaps (outside of an m30, s14 or s38) are out of the question then. You may have answered your own question w/the Dinan turbo kit - running that on modern engine management would satisfy essentially all of your goals.

[LowR3V'in]

whatever it is you need to turbo it.
m20 is sweet.
m30 is nice too. The thing i really like about the m30 is that 100% stock it can handle 500tq all day.
m50 is also nice because the aftermarket for those is huge.

When you say show worthy do u mean like with judges or like impressing parking lot guys?
m30/m20 for sure m50 just looks like a plastic box.

[GarbageCanE30]

I personally would recommend an m54 - it is the newest of the (mostly) bolt in 24v options. m/s50s are approaching 25-30yrs old at this point, the majority of them would benefit from an overhaul. As noted above, doing a "normal" m50 swap really isn't worth it vs building an m20 (with that in mind, I have had an m50 in mine for 5 years at this point and love it - though the car started out w/a m10)

You mentioned show-worthy and tracking it, what is your end goal?

My goal isn't a track car, but a car that could be tracked and is built to withstand some abuse. I honestly really like the idea of keeping the m20 and turboing it as I think keeping things period correct for show purposes is an interesting notion. I also just stumbled across and extremely rare dinan turbo kit from the early 90s made for m20s and it's got me thinking... Although it's not particularly competitive or likely even ideal turbo charging technology by today's standards, mannnn would it be cool to have a period correct full dinan kit on the og motor that came in the car. Just a thought.. Another reason I'm beginning to lean away from a swap is this is something I hope to accomplish fairly quickly, which can be difficult when hunting for individual parts to complete the build.

[KI4UJO]

I personally would recommend an m54 - it is the newest of the (mostly) bolt in 24v options. m/s50s are approaching 25-30yrs old at this point, the majority of them would benefit from an overhaul. As noted above, doing a "normal" m50 swap really isn't worth it vs building an m20 (with that in mind, I have had an m50 in mine for 5 years at this point and love it - though the car started out w/a m10)

You mentioned show-worthy and tracking it, what is your end goal?

[varg]

Thank you for the fantastic response!! Gave me a lot of good points to think about... One question tho. When you said turboing is a good idea for more power in the show car category as tracking it is too risky, what exactly did you mean? I honestly really like the idea of a turbo m20 and don't need to make crazy power but would like to be in the mid 200s at least. Any resources for turbo m20 builds on here? I was under the impression the 2.7s were better for turbo builds as the lower compression suits them better.

Tracking a show ready car is too risky. Just the rocks getting flung up by the car in front of you will ruin your show ready paint unless you tape it, and if you don't lose it yourself there's a good possibility that someone else losing it or dumping coolant or something could end your car for you. Additionally, a turbo M20 needs other upgrades to be track worthy. A cooling system and oil cooler upgrade, and the car will need bigger brakes unless you turn the boost down. When it's easily making twice stock wheel horsepower it's going to be 30mph faster than the spec E30 guys go on the same straights. M20 turbo builds are common, the parts are available to make it pretty much a bolt on affair from header to plug and play MS ECU, and build threads are numerous addressing most questions you would have. The more you read the more you'll learn about the nuances of these options and that will help guide your decision. A used M20 will make twice stock power indefinitely, let alone a refreshed one. The only way to kill it at the power output you're talking about is a bad tune or serious neglect. 8.8:1 is the stock M20B25 compression ratio, it's nearly perfect for turbocharging and would be even better at 9:1. I wouldn't want a lower compression ratio than that, the car will be a dog off boost.

[Slybeanx]

Hey guys, new to the forum and e30 world. I recently acquired an 89' 325is in zinno and am trying to refresh it and take it to show-worthy condition. I currently have the m20 out and was on the fence as to how to proceed. I'm definitely wanting to make more power over stock whether that means stroking the m20, turboing it, or doing a m50/52 or s50/52 swap. What would you do and why? Obviously this is a matter of opinion, but I'm having a hard time deciding what direction to go in. Id probably take into account the difficulty of the build as I'm new to auto projects of this magnitude but tend to get comfortable and learn quickly. Thanks for reading and looking forward to hearing your opinions.

M30 swap is the easiest if your new to swaps and want to start with something simple with a 50hp gain and tons of torque

[GarbageCanE30]

Depends on what you want out of it performance wise. If the car is being brought to show quality it makes the most sense to have a squeaky clean M20 under the hood, whether stock looking, ITB equipped or turbocharged. The only M5X swaps that makes sense are the aluminum 2.8 or an M54B30. Everything else is extra weight gain for nothing since it's downright easy to make the meager M50/52 power with an M20 build. Plus M5Xs are so ugly... I suppose a case could be made for an M50 swap if you want to make big turbo power, but people have done that on M20s too (Nisse Järnet making like 700whp with an M20 comes to mind).

A 2.8 Stroker M20 is M52B28 crank, 130mm M20 rods (eta or aftermarket), M20B25 pistons, deck brought down to suit and give a good compression ratio, and a spacer on the crank snout. There's some machine work involved, taking the skirts on the pistons and the weights on the crankshaft down, but it's an easy recipe for 200hp+ depending on how much you want to spend on a head, cam and induction system. It's a tried and true recipe and it keeps the handsome M20 under your hood instead of those awful plastic valve covers on M5X and S50/52. If you want some fast a turbo M20 is the way to go, especially since you aren't going to be tracking a show ready car; it's too risky.
2.8 examples: https://www.r3vlimited.com/board/for...i-reincarnated

http://www.msportster.co.uk/question/m20b28-build-in-full/

https://www.r3vlimited.com/board/forum/e30-technical-forums/engine-drivetrain/m20/210196-bullet-ride-s-2-8l-stroker-project-updated-dyno-plot-pg-6

There are lots of them and it's easy to find them if you search with google by using the site:r3vlimited.com in your search, vs the forum's search engine.

Whoops didn't realize your search suggestions. My bad

[GarbageCanE30]

Depends on what you want out of it performance wise. If the car is being brought to show quality it makes the most sense to have a squeaky clean M20 under the hood, whether stock looking, ITB equipped or turbocharged. The only M5X swaps that makes sense are the aluminum 2.8 or an M54B30. Everything else is extra weight gain for nothing since it's downright easy to make the meager M50/52 power with an M20 build. Plus M5Xs are so ugly... I suppose a case could be made for an M50 swap if you want to make big turbo power, but people have done that on M20s too (Nisse Järnet making like 700whp with an M20 comes to mind).

A 2.8 Stroker M20 is M52B28 crank, 130mm M20 rods (eta or aftermarket), M20B25 pistons, deck brought down to suit and give a good compression ratio, and a spacer on the crank snout. There's some machine work involved, taking the skirts on the pistons and the weights on the crankshaft down, but it's an easy recipe for 200hp+ depending on how much you want to spend on a head, cam and induction system. It's a tried and true recipe and it keeps the handsome M20 under your hood instead of those awful plastic valve covers on M5X and S50/52. If you want some fast a turbo M20 is the way to go, especially since you aren't going to be tracking a show ready car; it's too risky.
2.8 examples: https://www.r3vlimited.com/board/for...i-reincarnated

http://www.msportster.co.uk/question/m20b28-build-in-full/

https://www.r3vlimited.com/board/forum/e30-technical-forums/engine-drivetrain/m20/210196-bullet-ride-s-2-8l-stroker-project-updated-dyno-plot-pg-6

There are lots of them and it's easy to find them if you search with google by using the site:r3vlimited.com in your search, vs the forum's search engine.

Thank you for the fantastic response!! Gave me a lot of good points to think about... One question tho. When you said turboing is a good idea for more power in the show car category as tracking it is too risky, what exactly did you mean? I honestly really like the idea of a turbo m20 and don't need to make crazy power but would like to be in the mid 200s at least. Any resources for turbo m20 builds on here? I was under the impression the 2.7s were better for turbo builds as the lower compression suits them better.