M20 2.5L performance build

[E30_corey]

Hi I have a 1987 325is that I’m trying to build some more power with. I want to do this without stroking the motor(yes I know for max power I need to stroke it not doing it with the m20 tho). I have already bought a 272 cam and 18lb injectors. I planned on getting the following parts:

IE long tube headers and full exhaust
Heavy duty valve springs and rockers
itb kit
port and polish head
nuke performance fuel system
Upgraded radiator
New ecu?
miller chip?

I’ve also been thinking about going with a turbo but I must keep the ac it would be low boost. I saw some eBay turbo kits for $800-1800. What do you guys think about that?

please help with any feedback or links to parts /threads

[Reichart12]

What are your power goals? ITBs on a stock motor with standalone ecu have been reported to give a nice bump in power. If you want something into the 200s, that won't do it with just that and your idea to go turbo would make more sense.

The cam, ITBs, ecu, and full exhaust with maintenance parts will probably put you close to $4k if you install and tune yourself.

[digger]

comes down to $$$ and how many shetlands you want

[Slybeanx]

Dont get the miller maf. Get a megasquirt and get it tuned that way.

I vote turbo, I wouldnt go with an Ebay setup though.

Manifold, wastegate and turbo should be quality products imho.

[ADEN]

Dont get the miller maf. Get a megasquirt and get it tuned that way.

I vote turbo, I wouldnt go with an Ebay setup though.

Manifold, wastegate and turbo should be quality products imho.

Since you mentioned miller maf new maf solution came up. Tunable maf signal. It will be possible to go turbo with it and keep the stock ecu .right?

https://sssquid.com/v3/ssshop/pre-release-maf-conversion-kit/

[e30davie]

Throw the stock ecu and the Maf in the bin. Once you go map sensor and standalone ecu you'll never go back.

There is some advantages to be had on a standalone even if you don't make any changes, proper TPS with acceleration enrichment for one. You can also convert to distributor-less ignition fairly easily, can use modern injectors, engine diagnostics, data logging, wideband 02 afr targeting, lots of good stuff....

[ADEN]

I think you are right e30davie stock ecu lack important sensors i believe you also gain more mpg by running standalone. Right?

Waiting for my pcb to start assembling my speeduino.

[e30davie]

Only if you tune it properly.

[E30_corey]

What are your power goals? ITBs on a stock motor with standalone ecu have been reported to give a nice bump in power. If you want something into the 200s, that won't do it with just that and your idea to go turbo would make more sense.

The cam, ITBs, ecu, and full exhaust with maintenance parts will probably put you close to $4k if you install and tune yourself.

I’m definitely trying to get 220+ so I guess I’ll have to go with a low boost set up do you know any cheap kits or will I be better off piecing it together

[E30_corey]

Dont get the miller maf. Get a megasquirt and get it tuned that way.

I vote turbo, I wouldnt go with an Ebay setup though.

Manifold, wastegate and turbo should be quality products imho.

Do you know anything about the cxracing turbo kit it’s $2500 I’ve seen people use them on other cars and they say they hold up decent

[Reichart12]

You could check out KaMotors. Not sure if he's still doing it or what brands were sued but he sold turbo kits for the e30.

[Slybeanx]

Do you know anything about the cxracing turbo kit it’s $2500 I’ve seen people use them on other cars and they say they hold up decent

Some people run CXracing here and havnt had issues. They crack like crazy on NA Miata setups (only mentioned because QC is a factor).

I think only KAmotors is the only other one making kits atm besides the ebay specials.

[E30_corey]

Cool I think I’ll give the kit a shot this will be the first turbo I’ve installed.

[TobyB]

Throw the stock ecu and the AFM in the bin. Once you go MAF and standalone ecu you'll never go back.

MAP being suitable for 80's Ford pickups, certainly...

Turbos are... not trivial.

t
tried one once.

[dvallis]

You either do an optimized NA build with the headers etc. or do a turbo build. Not both.

If you're a reasonably proficient Wrench, piecing together a turbo setup is not hard. Lots of examples on here. Otherwise, a kit is the way to go. Don't use a huge turbo. Smaller is better. Check the turbo map and size it to M20 flow.

We had a lot of success with Megasquirt plus MAP.