Help me decide which engine to build.

[Al Canuck]

Hey Guys,

I've got a 90 325is. Nothing at all wrong with the original engine, still runs great, makes decent power, etc. But I'm a mechanic, shop owner, car collector, and a driver's driver! In other words, I want more! More power, more torque, just more.

I can't decide which route to go, and I have a few options.

1) M30B35 with 265 gearbox. I already have ALL the parts needed to do this swap. Simlle, cheap, and fast, but I'm afraid it will upset the balance of the E30, as well as comsuming much more fuel.

2) M20B25 with rebuilt head, oversize valves, 272 cam. This one is appealing because it's very very simple, and I've driven cars with similar setups. Fast, rev happy, and fun.

3) M20B27eta with custom pistons, i head, 272 cam, larger valves. I have a 2.7 bottom end in great shape already, just need the pistons, and have a head built.

4) M20B25 with IE 3.1 stroker kit. This will also include an appropriately built head. Most expensive option, but should net some serious power, sound great, very unique, and best of all, everything will be NEW!

I'm leaning towards.....oh fuck, I don't know. Thats why I made this thread.

Anyone have similar setups, pros and cons of each?

Thanks,

Al

ps - Yes, I've also consider M50/52, S50/52 swaps as well, but I don't have any of those motors, and franky, I'm a bit old school, and enjoy the single cammers.

[Charlie]

ps - Yes, I've also consider M50/52, S50/52 swaps as well, but I don't have any of those motors, and franky, I'm a bit old school, and enjoy the single cammers.

Yes, curse those 17 year old DOHC "new" motors!

-Charlie

[kenika65]

Good keep it old school.
I would prefer just getting a bigger differential to start, maby a big case 4.10.
A performance chip,7000+ rpm's.

Because you are looking for more torque I am going to highly suggest finding some 88 2.7 super eta pistons or custom high comp. 2.7 pistons.

The super eta bottom end with all of your 2.5i parts will make a torque monster... well let me just say I drive a 318is M42 and it is fast but when you get in to the 2.7 you can pop clutch and never stop doing donuts if you dont want to the torque is amazing for the size of the car.

Here are some links.

BMW M20 - Wikipedia, the free encyclopedia

http://www.r3vlimited.com/board/showthread.php?t=100939

http://www.r3vlimited.com/board/showthread.php?t=102799&highlight=2.7

Google Image Result for http://www.strictlyeta.net/images/suspension1.jpg

[jlevie]

The buckets of torque an M30B35 engine makes would more than offset the weight that you have to add to the rear of the car to restore the balance. It would not result in great mileage, but if you are leaning towards more performance that has to be low on the list. A stroker motor has the advantage of increased performance, good fuel economy, and the reliability of the M20.

Having an M30B35 & transmission on hand would make me seriously consider that option. I still remember the punch that engine produced in a 735i and it should really make an E30 go.

[Al Canuck]

Yes, curse those 17 year old DOHC "new" motors!

-Charlie

I don't curse them at all, they're great engines. If I had one laying around, it would be on my list. An M52B28 aluminum mill would be a great choice. But I don't have one, and I've shipped enough engines in my day, to realise I don't enjoy dealing with the logistics of it. I simply want to work with what I've already got. Plus, I'm a long time 2002 guy, and a big proponent of period correct mods. M20/M30 suits me just fine.

Cheers,

Al

[Al Canuck]

The buckets of torque an M30B35 engine makes would more than offset the weight that you have to add to the rear of the car to restore the balance. It would not result in great mileage, but if you are leaning towards more performance that has to be low on the list. A stroker motor has the advantage of increased performance, good fuel economy, and the reliability of the M20.

Having an M30B35 & transmission on hand would make me seriously consider that option. I still remember the punch that engine produced in a 735i and it should really make an E30 go.

I've owned half a dozen E28's, several E24's, and just sold a 90 735iL. Suffice to say, I LOVE the M30. My apprentice at my shop has an 87 325is. Sitting on a stand in the showroom is his M30B35 we're bolting into it next weekend. He's installed a hotter cam, cleaned up the head, and powder coated everything in site. I can't wait to see how it all turns out in his car. Due to the fact that I have everything I need to make the swap, it is very very high on the list.

That said, friend of mine has an 89 325i with 272 cam, chip, and a little headwork. The car simply screams to 7000rpm, sounds wonderful, and is a total gas to drive.

[george graves]

1) M30B35 with 265 gearbox.........but I'm afraid it will upset the balance of the E30, as well as comsuming much more fuel.

Do some research on the actual weight of the motor versus a m20, and m50...then report back.

As far as gas mileage - I was worried about it too - It's maybe 10-15 bucks more a month IF that...

[digger]

when in doubt go for CC's

[george graves]

when in doubt go for CC's

Wrong - pick the motor that you think will make you happy....

[digger]

Wrong - pick the motor that you think will make you happy....

.......given he wants to swap a motor for more power and torque its logical that the one with more cc's will fulfil both those requirements

[nando]

IE stroker kit? blech! you can put a better kit together yourself for $1000 less, and not have to deal with their shitty service. if you're going to pay $3000 + labor and all the parts it doesn't come with (like a built head, for one) you may as well just buy an off the shelf metric mechanic motor.

it sounds like you want an M30 - since you drive a cabby, realistically the balance of the car has already been compromised. adding 40lbs to the front isn't going to make a big difference - and you could always spend the savings on a CF hood to make up for it (a real CF hood, not the junk most people buy).

as far as the M50 guys, don't worry about them. the furthest most of them have been inside a motor is opening the valve cover to change the gasket ;)

[FredK]

as far as the M50 guys, don't worry about them. the furthest most of them have been inside a motor is opening the valve cover to change the gasket ;)

YA DUDE IT IS TUFF TO CHG THE M50 VC GASKET!!! TOOK ME LIEK 2 HRS!

HERE IS DYNO INFOZ ON M20 ENGINES.



MUSTANG DYNOS ARE A LIL WORSE ON THE NUMBERS I HERD.

[nando]

lol

[Garageaholic]

I said it once, and i'll say it again, Go M30 dude.

Just relocate the battery to the rear of the car and when you have the top down, you should have relatively stock weight distribution (assuming you push the M30 back far enough to have about 1" of space between the E28 radiator and the distributor)

Hope this helps.

[Al Canuck]

I don't drive a cabrio, I have an is. Hmmm, M30, eh? Well, I'm building one next weekend, so we'll see how it turns out. It's an 87 325is with a cammed M30B35.

Al