Which engine would you choose for a swap?

[Andrew325is]

Yes, fuel efficiency for me, but this thread isn't just for myself. I know other people would prefer to have a more powerful engine. M54 is great. I have one sitting in the Landy, but that vehicle is larger/heavier and needs the extra power.

[djjerme]

I’d double check those weights though, the M54 is pretty light for a 6 (all aluminum) and even in my big ass X3 and my heavy right foot, I still manage a 16mpg. That swap is still on my radar for either the Touring or the racecar at some point.


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[varg]

So this whole time you've been after fuel efficiency and not 200hp? M44 and done it's basically an economy engine, will yield great MPG. Handling? You may not notice a difference in handling there. AFAIK the M54 is lighter than the M20, and the M20/G260 package is 70lbs heavier than the M42/G260 package. CG would be a little further forward, probably a couple percentage points on the F/R balance if you weigh it.

Which would make you smile the most behind the wheel? All 3 produce similar peak power (200+ HP), but each has a little different characteristics and they have their own pros and cons.

Is what I've been operating on, minus the going off track talking about the pros and cons of various motors.

[Andrew325is]

If your ok with being down on power and just want a fuel efficient car to zip around and have fun with a M44/M42 with bolt on's should do you good. Cant justify the cost building them when the M54 is a option. I've had my 318is for almost 2 years and Its perfect for around town. I'm sure a shaved 325i flywheel, exhaust, intake and tune would make it even more fun. anything past that seems financially foolish, but to each there own.

I think so too. With so much traffic and stop lights around here I can't get it up to speed much anyways, so more power doesn't really make sense.

Worrying about lack of fuel efficiency and dumping $10,000 on a MM engine does not compute. It's not like you're going to any better gas mileage with a high strung I4 than you will with a stock M54B30, you certainly won't be getting stock 318is gas mileage with a 205hp M42 and an M54 swap's relative cost will take a very long time to make up with a couple extra MPG.

I'm sorry that you got confused. The poll option is for a stroker because I wanted to give people options of engines that are somewhat close in power output, but I would select a stock M44. Upgrades like building a stroker could come later if I wanted. So with a cheap parts car the swap could basically be free. Same as M54, but the M44 still gets a little better MPG and a little better handling. Someone who has both a Z3 1.9 and a 3.0i said they get about 5 mpg better on average with the 1.9. Plus with M54 you need a CAN controller for A/C and things like the OBC and MPG gauge won't work. I can get an M42 coding plug for the OBC (edit: NLA, unless I could find one used.)

[nando]

The point is I have sequential injection on my M20 and it made no difference in fuel efficiency that I can tell. It ended up just being a fun project - the biggest benefit is I haven't had to touch the ignition system in almost 10 years.

BTW, my E30 has run some form of Megasquirt since 2007 - I was likely the first to do MS3 on the M20. :)

[varg]

A small one in efficiency

And that's what is being discussed in my post... I am fully aware of the benefits, requirements and implications of sequential fuel injection, having been playing around with and tuning megasquirt systems that varied from basic MS1 in the 200Xs to MS3 and MS2 units addon injector and ignition sequencing boards.

[nando]

Sequential fuel injection doesn't make a big difference. A small one in efficiency, and none for power. I can switch mine on the fly between batch and sequential - you can't tell any difference in how the engine runs.

If you want fuel economy I'm not sure an E30 is the right vehicle, and the difference between the M54 and M20 is probably not as big as you'd think. But yeah, a $10k M42 build is probably not a great investment - other than doing it because you can and just enjoying the process.

[varg]

on the contrary my MM stroker got way better fuel economy than what it did stock b25 (atleast while cruising), but thats because the cam was specced that way unbeknown to me at the time and the upped CR really helps. they claim their ST is repsonsible for that and being able to run high compression on pump fuel buts its just the cam(s) they use. Their engines are no where near highly strung they also dont perform anywhere near as well as youd expect for the work they do.

Good info. How about some numbers? And how does that stock M20B25 you're comparing the MM build to compare to an M54B30? Crude 2 bank semi-sequential/part time batch fire fuel injection with limited trim capability vs arguably modern fully sequential fuel injection setup with VVT. E46s get better fuel economy than E30s, they're more aerodynamic but they're also heavier and have more rolling resistance, a few of the factors at play. However, I'm willing to bet an M54B30 swap with stock EMS beats a stock E30 325i in the fuel economy department hands down but someone out there probably can speak from experience on the numbers. If fuel economy is the deciding factor between a $10,000 M42 and an M54 swap which will cost what, half that? You're just not going to recoup that cost in a timely manner.

[digger]

Worrying about lack of fuel efficiency and dumping $10,000 on a MM engine does not compute. It's not like you're going to any better gas mileage with a high strung I4 than you will with a stock M54B30, you certainly won't be getting stock 318is gas mileage with a 205hp M42 and an M54 swap's relative cost will take a very long time to make up with a couple extra MPG.

on the contrary my MM stroker got way better fuel economy than what it did stock b25 (atleast while cruising), but thats because the cam was specced that way unbeknown to me at the time and the upped CR really helps. they claim their ST is repsonsible for that and being able to run high compression on pump fuel buts its just the cam(s) they use. Their engines are no where near highly strung they also dont perform anywhere near as well as youd expect for the work they do.

[varg]

Worrying about lack of fuel efficiency and dumping $10,000 on a MM engine does not compute. It's not like you're going to any better gas mileage with a high strung I4 than you will with a stock M54B30, you certainly won't be getting stock 318is gas mileage with a 205hp M42 and an M54 swap's relative cost will take a very long time to make up with a couple extra MPG.

[Motheye99]

The only V8 I'd consider for an E30 would be the S65, but V8s are not fuel efficient and I don't need that much power myself so I wouldn't want it. IMO M30 belongs in a E32 or E24. Simple and reliable, but it's not fuel efficient and too big and heavy for an E30. Most people do a swap because they want more power, like I did before with S54. My E30 is a daily driver that I use for running errands around town, so if I swap an engine into it I want one that is inexpensive, fairly reliable, and provides better fuel economy. I would also want something more modern with OBD2. So an M44 fits the bill for me. I think it would be neat to have a high-spec 318is (with the 325is options).

If your ok with being down on power and just want a fuel efficient car to zip around and have fun with a M44/M42 with bolt on's should do you good. Cant justify the cost building them when the M54 is a option. I've had my 318is for almost 2 years and Its perfect for around town. I'm sure a shaved 325i flywheel, exhaust, intake and tune would make it even more fun. anything past that seems financially foolish, but to each there own.

[Danny]

wworm will your friend sell me the s52?

[Andrew325is]

The only V8 I'd consider for an E30 would be the S65, but V8s are not fuel efficient and I don't need that much power myself so I wouldn't want it. IMO M30 belongs in a E32 or E24. Simple and reliable, but it's not fuel efficient and too big and heavy for an E30. Most people do a swap because they want more power, like I did before with S54. My E30 is a daily driver that I use for running errands around town, so if I swap an engine into it I want one that is inexpensive, fairly reliable, and provides better fuel economy. I would also want something more modern with OBD2. So an M44 fits the bill for me. I think it would be neat to have a high-spec 318is (with the 325is options).

[Andrew325is]

We had similar issues with my wife's Element. That engine started burning oil bad at highway speeds as well. The single vtec k24 in the CR-V & Element seem much more prone to these issues. As well a burned exhaust valves & transmission problems. It may be that these are more likely to be neglected, I think my wife's car was not treated well it's first 60k by a previous owner.

We sold it & got her the e30 325i. We are both much happier now.

Good decision. We found Mom a E46 325xi Touring. She likes it much better. It's had some issues due to neglect by the previous owner, but at least they are fairly straightforward to resolve. Plus the wrecking yards are completely littered with E46s so parts are cheap and plentiful.

[Motheye99]

There's an M42 pattern G240 as well. Not sure how an M10/M30 pattern compares to an M20 pattern or M42 pattern, but I know the M20 G260 bolts to the M42 with a bit of an improper tilt.

bolting a E30 G260 to a M42 is the same as bolting it to a M5x, it sits 10 deg off. If you bolt a ZF or a G250 from a M5x to a M20 it will also sit 10 deg off. Flywheels is even more complicated.