State of the M20 stroker in 2021

[lefthookz]

I have an iX and engine swaps are a pain, so I've been looking at stroker builds. I have found a lot of different information but it seems like there's been a huge progression over the years in power output, especially with the RHD ITB kits. What is the current state of the M20 stroker game? Seems like the cheapest route for me is rebuilding the motor with my stock 885 head, while using an ETA crank and ETA rods and my regular 325i pistons, with an adjustable cam gear. The classic 2.7 budget stroker. The car is already chipped and has an exhaust on it. It's got to keep passing CA SMOG so I was going to leave the cam, headers, and cat alone. I'm guessing 180whp if I'm very lucky, 200whp if I go with ITBs and standalone and just swap my regular intake and ECU back in for smog testing time every two years. Does that sound realistic? Is there anything easy that I'm leaving on the table?

[reelizmpro]

Have you considered not having an iX? 325iX in CA is...uncommon =]. Everything depends on your resources. ITB's and standalone are a few thousand dollars and changing the ITB's every 2 years is going to be a hassle. Besides, are ITB's really worth the investment on a mild engine with stock cam, exhaust, etc? I don't think so. I do think a pnp standalone would be worth it to uncork the engine and get the most out of it.

[Reichart12]

Fairly certain that the e/i stroker combo won't be better than a chipped i. Since you're starting with the i engine, I wouldnt go through the trouble.

[digger]

Fairly certain that the e/i stroker combo won't be better than a chipped i. Since you're starting with the i engine, I wouldnt go through the trouble.

it sure would be better, we aren't talking "I" head onto an eta

other option would be a 2.8L with M52B28 crank, eta rods and b25 slugs, its a bit more work but not having to deck block 2mm (0.5 instead) might be advantageous on a block that is much rarer

I'm sure a mild cam would still pass SMOG properly tuned

[Reichart12]

Ah, I misread it then. Was thinking just eta block with i head.

[lefthookz]

it sure would be better, we aren't talking "I" head onto an eta

other option would be a 2.8L with M52B28 crank, eta rods and b25 slugs, its a bit more work but not having to deck block 2mm (0.5 instead) might be advantageous on a block that is much rarer

I'm sure a mild cam would still pass SMOG properly tuned

Great info, thank you all. I should have mentioned that I was told this engine was rebuilt at some point in its life and supposedly already has a mild cam. It's just that plus the Turner Motorsports chip and a scorpion exhaust. I've honestly always thought the car felt pretty lively, but could use more torque more than anything else. Maybe I should have it dyno'd first before I make any changes.

To the guy who said "maybe not have an ix", lol :) The thing is, I've already got the car, I've already done a bunch of work on it, and red two-door 5-speed 325ixs (as you point out) do not grow on trees here in CA so it's not that easy to replace. I know a RWD E30 would be much, much easier to mod, but I always seem to have to touch the hot stove even when told not to. I like the ix. It IS weird. There aren't a lot of clean ones running around. It's true that unlocking more power in an ix takes dedication, but this whole drivetrain from the transfer case forward ultimately needs the reseal anyways, so... here we are.

[lefthookz]

Basically, if the low-buck stroker route can't get me at least another 40-50hp over what I have, I probably won't bother - just reseal everything with new gaskets and drive. This car just did an 11 hour drive today including interstates and the PCH for some spirited driving, and it didn't miss a beat. Plenty of power for a windy road if you keep it above 3k. I guess that's the ethos behind this engine!

[digger]

Not going to get an extra 50 numbers tbh with a mild build

[ADEN]

It seems that m20 doesn't enjoy the mods...only boost will give you what you are asking.

I still love my m20 and won't do m5x i believe that after my speeduino project finished it will be ready for some little boost lol

[digger]

It seems that m20 doesn't enjoy the mods...only boost will give you what you are asking.

I still love my m20 and won't do m5x i believe that after my speeduino project finished it will be ready for some little boost lol

the mods to get good power gains are the cylinder head, intake manifold and camshaft. A build that doesn’t address all of those properly will be limited to mild peak power gains at best

[lefthookz]

the mods to get good power gains are the cylinder head, intake manifold and camshaft. A build that doesn’t address all of those properly will be limited to mild peak power gains at best

And it sounds like you'd need a standalone ECU to get the best possible tuning out of all that, too.

It's almost like the 325ix isn't a great choice for CA-legal big power builds?! /sarcasm

Thanks for the input everyone!

[digger]

And it sounds like you'd need a standalone ECU to get the best possible tuning out of all that, too.

It's almost like the 325ix isn't a great choice for CA-legal big power builds?! /sarcasm

Thanks for the input everyone!

The more power you make the more you benefit from an ECU upgrade.

CA is a buzz kill for modified cars. You aren't getting big power gains from a nice green M20 as that's an oxymoron.
If a swap can be done legal with the same emission equipment as on the donor its probably best to go down that path to get more power from an E30

[McGyver]

And it sounds like you'd need a standalone ECU to get the best possible tuning out of all that, too.

It's almost like the 325ix isn't a great choice for CA-legal big power builds?! /sarcasm

Thanks for the input everyone!

How big are you trying to go with an ix? How much can the transfer case deal with? Getting 180+whp in an m20 e30 sounds like a lot of fun. Swapping for more power sounds difficult to keep the 4wd, so at that point, why not get a rwd e30?

As far as engine builds (from my research, not practical knowledge)

They're not going to plug into your car for a CA smog check on an M20, it's only going to be a sniff test. Most shops don't have the equipment to test a 4wd car, so you're only getting tested at idle (which is a HUGE advantage). You're going to have to pass a visual inspection, so you can't change the look of anything between the AFM and the cat. That means you're stuck with the stock intake (no ITBs) stock exhaust (no headers), stock looking ignition system (no wasted spark), stock looking fuel system, and a cat.

That being said, as long as it LOOKS stock, you can make changes. 3L stroker with big injectors, big cam, and oversized valves will all pass the visual. A standalone that uses the stock ignition system and keeps a gutted AFM in place will pass visual. That means that it's down to getting a good tune that idles clean to make the car pass. Sure, it may sound funny, but they can't fail you for it sounding weird.