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Jorge
11-30-2012, 08:13 AM
I've been toying with keeping the M30B34 out of the red E24, and rebuilding it. As at University we have been tearing down little K series Rover engines and it makes me want to give it a proper go.

In the process, I may as well look into further work.. turbo, pistons, camshafts, etc.

What do people think about that, I've read that the B35 in the grey 88 E24 is slightly different, with a higher compression ratio, though. Couple of threads said to use the B35 top end, due to the camshaft and valves being a cheap way to more power on the B34.

I'm just starting to look into this, if you were in my place, what would you do?

I don't want to rip the engine out of the grey car without a semi-working replacement standing by. Shall I just sell the B34 and work on the B35 when I can, or shall I work on the B34 and play around with additional power from it. Does anyone know what would happen just using the B35 head on the B34 bottom end, would it see any potential increases?

Vague open ended question, I hope I can pick the other BMW fanatics brains for discussion.

BenKoflach
11-30-2012, 11:03 AM
No need to bother with pistons etc, just whack a turbo at 9-10psi and job done. I know a guy who's run his at that since 1996, and that's on an un-opened engine that had 238,000 miles when he did it, and on only 91 octane fuel.

Byron
11-30-2012, 11:43 AM
Putting the b35 head on the b34 will lower compression slightly and negate the benefits of the larger valves. People will say the lower compression makes it better for boost, but the m30 is such a low compression engine to start that it doesn't really matter.

If you were to keep the b34 head, you would need to change around the cooling system. I think there are some differences in the wiring around the head too but I may be thinking of a different motor- it's been so long since I had an m30.

If it were me, I would sell the b34 and find a b35 to rebuild. They have slight differences that make them better, and it will be a direct swap into your car without having to change anything around. When you rebuild it, use the stock pistons/rods/cam/etc but convert it to head studs and get a better headgasket. The rest of the engine will be fine unless you're looking to get something like 600hp.

b34's and b35's have different mounting holes for the passengers side motor mount arms cast into the blocks. e28's had the holes further back and e34's had them further forward. e24's were weird in that sense because they came with both sets of mounting holes. I'm not sure which ones your 88 would have used, but if it uses the rear ones you would need to make a new mount arm if you were to get a b35 from an e34.

Zic
12-01-2012, 07:31 PM
Putting the b35 head on the b34 will lower compression slightly and negate the benefits of the larger valves. People will say the lower compression makes it better for boost, but the m30 is such a low compression engine to start that it doesn't really matter.


This x100000

I have bin thinking about putting a set, and my thoughts so far on the subject is that.

I personally would go with a m30b35 from a e32 or e34, from the first three years they made them. (those blocks have dual mounting points, so they are direct fits (mechanically) in the e24's and e28's) But the main reason i would go with them, is the motronic 1.3. Ecu ending with the three last digest of 179.
I don't know if the b35 in your car has the 179 ecu. But you can convert the engine to it, requires some soldering of the wires.

The main reason for me to go 179, is that in my opinion that you can get the best tuning package available for the m30b35. It converts the car from a AFM to a draw-thru MAF, and you get full adjust ability of the ecu with all of the OEM perks, such as cold start and etc etc. MAF is a way better than a AFM (if you don't know, there are allot of good sites describing why its better)

The tuning package is pricey tho, here is a link to it. Click here (https://www.millerperformancecars.com/catalogue.html?page=shop.product_details&flypage=flypage.tpl&product_id=67&category_id=10) with this set, you get injectors, a MAF, the chip and all the software that is needed also you get the full support from them.

my setup would be something in the lines of, (this is pricey and would push out some decent whp)
ppf twin scroll mainfold
pt 6262 twin scroll (undecided of the AR atm)
millers turbo tuning package
sachs 765 pressure plate with a oem clutch disk.
bosch 044 fuel pump
and all the supporting hardware, such as intercooler, wastegates and blow of valve.
all this on a m30b35 with a 179 ECU.

All of those parts are available on http://pure-pf.com/wp_new/ except the millers tuning package.

*edit, i don't know how much money you are willing to spend, but there are some other sits that have cheaper stuff, such as cast mainfolds over the tubular, etc etc. I'm just very picky when it comes to engine parts.
also this plan has bin postponed for a long time, due to recent events.

Brian.
12-13-2012, 11:36 AM
B35 head, ARP bolts, HX35 65lb injectors, MSII, and you're pretty much golden.

Willie
12-13-2012, 01:55 PM
Is the e24 your daily? If you can afford it, I'd buy a complete b35 and build it on a stand and get as much of it done out of the car as possible, then swap it all in over a weekend or so, then sell the b34 to minimise time off the road if that's an issue. I personally have no experience with m30's though, and if it were me I'd turbo m50 it but that's getting needlessly complicated.

Just out of interest, what are you studying at Derby Uni?

j work
12-18-2012, 03:33 PM
keep b34. get a whole 745i. Swap on a weekend when you got time. Then mod from there. Able to maintain a daily driver too.

Jorge
06-07-2013, 12:14 PM
Bumping this up as I found it in my additional research. I was reading into this again, and found more people using the 34 bottom end with a b35 head, leaving a 9.1:1 compression ratio. Then bolting on an Eaton M90 S/C at around 9-12psi.

However, after a quick discussion with 'Fritz', BMW tuners, their opinion is:

If you want to get to 300bhp, you will need to plan the situation carefully. It is possible with a good B34, but to get there on the standard 10:1 compression, you need a much better fuel injection system. The B35 (post 87) has a better flowing head, but is a rubbish compression ratio. Here is what I would do: I have an Alpina B9 bottom end here with 1 damaged piston crown. Take the forged crank and rods, balance them, stick it together with some new 10.5:1 pistons - use the B35 head with one of my copy Alpina B10 cams, cut the inlet valves to a 30deg seat, E12 535i inlet manifold and if you can stretch to it Stand a alone management - 330- 350bhp 300+ ftlbs. You'll never break it, just need to change the oil now and again.

j work
06-10-2013, 01:34 AM
Jorge Bumping this up as I found it in my additional research. I was reading into this again, and found more people using the 34 bottom end with a b35 head, leaving a 9.1:1 compression ratio. Then bolting on an Eaton M90 S/C at around 9-12psi.

However, after a quick discussion with 'Fritz', BMW tuners, their opinion is:

If you want to get to 300bhp, you will need to plan the situation carefully. It is possible with a good B34, but to get there on the standard 10:1 compression, you need a much better fuel injection system. The B35 (post 87) has a better flowing head, but is a rubbish compression ratio. Here is what I would do: I have an Alpina B9 bottom end here with 1 damaged piston crown. Take the forged crank and rods, balance them, stick it together with some new 10.5:1 pistons - use the B35 head with one of my copy Alpina B10 cams, cut the inlet valves to a 30deg seat, E12 535i inlet manifold and if you can stretch to it Stand a alone management - 330- 350bhp 300+ ftlbs. You'll never break it, just need to change the oil now and again.

supercharger would be awesome! :eyebrows Sounds like you got a good parts connection. You would be able to make made power with that motor build. Saw a 535i b34 turbo charged with tcd exhaust mani and 745i parts on standalone. (forget what system though, not MS) and was making high 300's on stock internals and no problems.

6inarow
06-12-2013, 01:05 PM
This x100000

But the main reason i would go with them, is the motronic 1.3. Ecu ending with the three last digest of 179.
I don't know if the b35 in your car has the 179 ecu. But you can convert the engine to it, requires some soldering of the wires.

The main reason for me to go 179, is that in my opinion that you can get the best tuning package available for the m30b35. It converts the car from a AFM to a draw-thru MAF, and you get full adjust ability of the ecu


The m30b35 never came with a maf. It has always had a barn door afm. People convert it to maf with a unit from miller. Tere is no real gain. Some say you get more power, but unless you have higher compression, better cam, and better flowing head with headers, you're wasting your money.

Motronic 1.3 is the adaptive type and makes for a better running m30. I have 1.0 in my 6 right now, and I'm going to do the 1.3 conversion. Smoother idle, more power, and the ability to use chips. Also you don't need an idle control module cause its now taken care of through the ecu.

Back on topic with the turbo. Just a factory rebuild would do the trick. These motors are so strong, internally, they can take boost all day long. It just makes sense to use the b34. Better cooling jackets, and lower compression. The motor is not the issue with a turbo, its the transmission, driveline, that worries me. You have to get a g265/6. Strongest one. Also good to get a stronger driveshaft, as you'll be breaking them all day with a turbo.





Jon