rb25 beemer

[Guest fourwheeldemon]

hey guys i was wondering is it possible to fit a rb25det into a 1986 bmw 318i? if so how much would it cost to fit? i have $8,000 to spend on just mods for the motor what sort of mods should i do? what sort of power?

[slip]

The first thing to do would be measure the engine, and your engine bay.

[Belly_up]

I've seen a RB25 in an E30, it was being done by Rollins Imports on the Gold Coast (ads in zoom if you want a no.), the actual engine fitted ok (remebering that the BMW engine bay is already designed for a straight 6 engine, but they did have issues fitting in a radiator and intercooler, so you might want to see if you can ask them about that. I've just put and RB20DET (which is the same dimensions as the 25) into my '77 520i, and it fits beautifully, looks like it was factory, but i've probably got a bit bigger engine bay. I also have no room for a FMIC, i'm running a top mount water-to-air jobbie. Thats more related to the front bar design on my car though, so you might be ok.

I notice you're in toowoomba, if you want to come and check my car out sometime (not that it's verry impressive atm), even just to compare the size of the engine bay, let me know and we can arrange something.

Hope that helps in some small way,

Cheers

Belly_up

Hope that helps in some way

[rb25]

A client of ours has an older 318 with a turbo motor in it - I'll ask him whats in it next time I see him. Sounds like a 4 tho...

[Ronin 09]

Forget it, too expensive. I had a E30 ('85) 323i rebuilt as as 2.8L. The thing is if you want a RB, you'll have to change the tranny and diff too - i popped 4 diffs. Get a 3 series inline 6 second hand, drop it in with the box and diff and turbo it. It wil boogie.

Heres some links for you:

http://www.bmauto.iinet.net.au/

http://www.bavariacars.com.au/

http://www.kormanfastbmw.com/

http://www.bmwe30.net/

I miss my E30 beemer

and heres a pic

[Zahos]

Why don't you try putting an SR20 in it? I've heared of people putting them in mid eighties 3 series BMW's, so it has all been done before. The only BM I've seen with an RB25 was a 5 series....

[Belly_up]

the other thing to look out for is that the BMW motors are intake on the the passenger side, exhaust on the drivers side, whereas the nissans are the other way around. So you'll have manifolding in different places from normal. for me this was a good thing, as it gave me more clearance for exhaust manifolding (my beamer has a huge steering gbox on the drivers side, i think the e30 i saw was much better in that respect), but it might be different for you.

[Ronin 09]

just thought of something, drop an M50 or M52 engine in it - twin cams from the later E36 models - bolt right in and you get instant power... get your hands on a M3 engine and unleash hell!

[Belly_up]

yeah, about 6 months after i started my RB20 conversion, i found out that if i'd looked in the right place, i could have done the BMW motor for much cheaper than what i originally thought. Although if you want to go the turbo route, you're up for a turbo, custom exhaust manifold, intercooler, possibly injectors, possibly decompression of the engine, and definately aftermarket ecu, all straight away, whereas the RB25 already comes with most, if not all of that stuff.

[meggala]

sr 20 is the engine of choice or the 1gzgte from toyota

cheers

meggala

[Zensoku]

I can vouch for Belly_up seeing Rolin Imports dropping the RB25DET into the E30 Beemer. It was a black car by memory. The stage i saw it in (this was well over 18 months ago) was when they just lowered the engine & tranny into it with the fabricated mounts. they were struggling for engine bay real estate, that's for sure. they had to actually cut a piece of the Rb25 timing cover to clear one of the intercooler pipes which crossed over. very tight fit. the car sat very low (stock springs?) with this engine. the guys there doubted its weight bias front to rear. i doubt it would have handled well being front heavy. i'd go down the SR20DET path if it was me and i wanted a great handling chassis. but if straight line stuff is more the go, then by all means, the RB is still a great choice.

[b2barker]

Try a google search for "bmw 335i". Check out this one also http://www.autospeed.com/cms/A_1735/article.html . Stick with BMW engines I reckon.

[Ronin 09]

The 'big block' 3.5 straight six is more of an effort to fit compared to a 2.5 twin cam or 2.3-3L from a later E46. The block of the 'small block' inline 6 hasn't really changed in the last 20 years (virtually the same external dimensions), so it is much easier to drop in with minor crossmember mods etc. By memory all that is needed is a sump modification - it wil fit with stock engine mounts.

The 3.5 is also a fair bit heavier, whereas the twin cams from the later E36 on are only marginally heavier and will not disrupt the balance as much. They will more or less match the older big block single cam straight sixes for power, but less torque.

I would seriously stick to the small block twin cam six from a later car. Make sure you check out the BM Auto Engineering website i posted above - they have done E36 M3 engine / gearbox transplants into E30s and they fly...