M30 vs. M90

this might help...

The length of the rod into the master cylinder may be more important than you think. The M/C has to completely "relax" to allow fluid it has pumped out to the calipers to return completely, otherwise you are just pushing more and more fluid out there.

Check to see if the M/C piston is in the rest position when you release the pedal.

HTH
 
Hey Gazzo..Take a hike...

You want to pick a fight.. you picked the wrong guy..

I was speaking from actual driving experience with two versions of the M30 based engine (M90 and B35).

I am sure you know how to tune an engine, as does BMW, but the plain facts are than 90% of those with these cars are basing modification decisions on engines that have no performance baseline. Trying to get more power from an angine that is not properly tuned is a waste of time.. Maybe YOU know this, but insulting me doesn't make others wiser, it just makes you look like an A$$.

I have not had my engine on a dyno, but I have driven the crap out of the car. Perhaps the peak is at 5500, but if it is, it is not much of a peak, since the car still pulls hard at redline...By contrast (and this was my point), the B35 DOES drop off in torque right at about 5500 RPM..so whatever the numbers say, actual experience says that the stock M90 pulls harder higher into the band than the B35.

I am not sure what you were trying to do with your post, other than wow everyone with how smart you are, but the fact is that your attitude is not what I would expect from this board. Please just go take your bile and go somewhere else..

S
 
Hello all,

So I to am about to start the engine rebuild track, and after some research on m90 v m35b I am still a little unsure on a few bits, can you guys help?

So far I know from what i've read

M90 93.4 bore x 84 stroke 218 hp @5200, 224 ft/lb @4000

M35b 92 bore x 86 stoke 218hp @5500, 224 ft/lb @4000
valves in 47mm ex 38mm

So what I want to know is the following

What are M90 valve sizes?
Do both motors besides the stroke have the same bottom end?
(is one better than the other? stronger (high revs,better suited to NZ roads))
Cam specs for both motors, Duration, lift etc

Is the M30 cam the "wildest" of the standard cams? and will it fit into either the M90 or M35b?

Steve
 
Valves:
http://www.realoem.com/bmw/showparts.do?model=5331&mospid=47199&btnr=11_0388&hg=11&fg=25

shows M90 valves are intake: 46mm / exhaust: 38mm

Motors have different blocks, but can swap many, many parts, like crankshafts.

This whole thread has been about which one is better. Lots of opinions and information on the subject now.

Cam, I have no idea, but I think the B35's is a 264, which makes it second highest to the Euro E9 coupe's 272 stock. I could be mistaken, however.

The kind of cam you can fit depends more on what kind of fuel system you will be running. The Motronic 1.3 on the M30B35 requires dropping the distributor, so take the conversion cost in mind. The M90 never came in a "distributorless" Motronic flavor, so I think the guys running Motronic on their M90s modify their cams to support the distributorless system like most others to make it work.

A nice amalgam is to combine the B35 head with a M90 block using a B35 crank, which gives you a ~10:1 CR, bigger valved, 3.65L engine which uses Motronic 1.3. You'd probably need to get a custom tune done, however.
 
The hottest cam that was fitted by the factory was indeed to the CSi which was quoted as 272 although it was actually a little more as the figures BMW quoted were at a valve clearance of 15 thou and not 10 thou which is the figure at which they are set for normal running.
 
cool, thanks guys, I'm thinking now from a money point of veiw I might just freahen the 3.0l, balance the bottom end, tidy up the rods and shot peen, ARP? rod bolts, get the compresion up as far as poss with a 3 angle valve job and a little port work, I'm going to fit an after market ECU that will take care of ign as well and I'll have to make a set of headers myself as I'm RHD ( any body got info on pipe diameters and lenghts?)
I think it may be a good idea to fit later injectors also
All of the above should be good for about 210-215 crank HP?
I'll do a before and after dyno test for intrest
 
From a money point of view, why not put in a M30B35 and use Motronic 1.3? I was able to do a 5 speed swap, get a M30B35, and the complete Motronic 1.3 system for about 1500$, after shipping. That would get you to your power point and be much cheaper than all the work you suggested.
 
I'm a bit anal with my motors and don't really like buying used, you don't know the history and it may be a pig that craps out in 6 months, besides m35b motor only (no ECU) second hand from auto dismantler down here is $1800-$2000 ECU about another$500 and I think I would like it to look as origanal as poss under the hood so later model inj set up not an option
How ever I will keep thinking about it and see if I can pick up a moter somewere for maybe$500-$800 Hmmmmm?
 
I'm a bit anal with my motors and don't really like buying used, you don't know the history and it may be a pig that craps out in 6 months, besides m35b motor only (no ECU) second hand from auto dismantler down here is $1800-$2000 ECU about another$500 and I think I would like it to look as origanal as poss under the hood so later model inj set up not an option
How ever I will keep thinking about it and see if I can pick up a moter somewere for maybe$500-$800 Hmmmmm?
Click to expand...

Hm, I see. finding parts cars on the island may prove to be kinda difficult. Instead of looking for a complete engine, then, why not rebuild your current one with a B35 crank, pistons, and head? You can still bolt up the L-jet manifold to the B35 head, so it looks stock. Takes a bit more wiring, though. I have seen a B35 crank on ebay for <100$ US, B35 heads for ~200$ US, and it would likely be cheaper to get aftermarket pistons than to try and get BMW pistons. There are several parts yards in the US that will ship to other countries, and a Motronic 1.3 DME will usually run ~100-150$ US. Even with shipping, that is way less than your local guy wants. You could probably pull this job off for ~2k complete, depending on how much somebody wants to bore out your block.
 
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