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• downforce22 No R3VLimiter
  • Join Date: Aug 2009
  • Posts: 3191
  #16 02-07-2015, 10:25 AM Very nice, m90 is better than your average m30! Originally posted by Good & Tight 93.5mm bore 84mm stroke. M90 is basically the M88 (engine from the m1) just with single timing chain, 2 valves per cylinder, and wet sump. It was derived from the M88 with the same engine dimensions(bore and stroke). You can think of it as the precursor to the s38 Quoted from BF.c Quote Originally Posted by BoldUlysses View Post AFAIK, an M90 is an earlier variant of the M30, with, as Bert mentioned, a larger bore and shorter stroke. Rumor has it the M90 bottom end is more or less identical to the M88's, but I haven't double-checked the bore/stroke measurements to be sure. The consensus is that the M90's bore/stroke combo makes it more playful and willing to rev compared to the "regular" M30, hence its desirability. THe M90 IS an M30. The M30 engine design came out in the E9, and was based on the M10. Production lasted through to the M30B35 seen in some E24's and E34's. The M90 was used as a test platform for the daring overbore modifications going from the standard 92 x 86 (8:1, 180bhp@5400 214ftlbs@4000) to the 93.4 x 84 (9.3:1, 218bhp@5200 224ftlbs@4000). The engine is known to rev more readily than any typical M30, and a large part of this is the torque down low-- rumor is that it makes 191 ftlb at only 2000rpm. I always thought they had a lightweight flywheel or something! You have to remember the context of the engine. It was offered initially in E24's in 1978. As I understand, it was the test horse while they were working on engine variants. They overbored the standard M30 3.5 and shortened the stroke (many people point to Paul Rosche). Later were additional modifactions such as the M88/1, M88/3 (dohc with the M90 block). The street M1 came out in 1978 as well, but has a difference, wet sump vs dry sump (along with dohc). So in 1978, the hottest car you could buy from BMW besides the M1, was the 635 with the M90. They went ahead and stuck the M90 in the E12 M535i with the same dogleg gearbox, brakes, 3.07 LSD to get the first front engined M car-- the E12 M535i. All this power offered on L-jet injection, not even motronic! Remember, i wasn't until 1979 that the E23 745i turbo was offered, but it's also 3600lbs. Furthermore, the M635CSi wasn't offered until 1984. Somebody could have had a hot sport coupe (M90) for 5-6 years by that point! The head is similar to a M30B34 head, and the cam is the same as a M30B35 (but the part number is different). Also the standard 135mm rods as I understand. The M90 is a bored/stroked M30 that gets different running characteristics. The block is the same as the M88, however an M88 uses different pistons and then obviously the different head. During the beginning stages of the development of the M1 the idea was to have a company other than BMW develop and produce the engine. There were plans for 8 and even 10 cylinder engines. It was relatively late in the development process that the decision was made to use a BMW straight 6 power plant. The starting point for the development of the M1 engine (internally designated as the M88) was the motor of the 635 CSi. At that point in time this unit (the M90) was the most powerful engine available within BWM. The M90 had been around for about 10 years but BMW’s engine guru Paul Rosche had a lot of work to do before the motor was ready to be used in the M1. In the end the commonality of the M90 and M88 engines was very small. The M90 was the first road going BMW engine with 3.5 litre displacement. Originally this engine was used to test if the M88 engine was reliable with the narrow web spacing of 6.6mm. This means that this engine has exactly the same bore and stroke as the M88 and is directly related. However instead of a DOHC cylinder head with 24 valves, BMW used the SOHC cylinder head with 12 valves. The use of an electronically controlled fuel management system (Bosch LE-Jetronic) allowed a slightly higher compression of 9.3:1. Strictly, the M90 engine is not an M production engine although the E12 ///M535I in which it is used is a real M car. Until 1981, the M90 engine was used for the early 635CSI and the very rare and delectable E12 ///M535I from 1980. In 1981 and 1982, Alpina used the last batch of the M90 engine to power the last versions of the B7 turbo versions of the E12 sedan and E24 coupe. For the B7S turbo, the M90 has been modified extensively to allow the use of a turbocharger. The B7S delivered 330hp @ 5800RPM and 500nm @3000RPM. During 1981 and 1982, Alpina only made 60 E12 sedans and 30 E24 coupe's in the B7S version. Engines HP RPM Torq. RPM Bore Stroke C/R 530i 176* 5500 188 4500 89 80 8.3* 528i 169 5500 166 4500 86 80 8.2 2500 150 6000 155 3700 86 71.6 9 2800 170 6000 174 3700 86 80 9 3.0 carb 170 5800 188 3700 89 80 8.3 3.3, 78/79 173 5500 192 4000 89 86 8 3.3 80/81 174 5200 184 4200 89 86 8 3.3 82-84 181 6000 195 4200 89 86 8.8 3.5 85-88 182 5400 214 4000 92 86 8 3.5 88-93 211 5700 225 4000 92 86 9 Euro M30's 3.0 carb 180 6000 188 3700 89 80 9 3.0 D-jet 195 5500 200 4300 89 80 9.5 3.0 L-jet 190 5500 188 3500 89 80 9 3.3 carb, 3299cc 190 5500 217 3500 89 88.4 9 3.3i 200 5500 210 4250 89 86 9 2.8i to 81 177 5800 86 80 9 2.8i 82 on 184 86 80 9.3 3.5, thru 82 218 93.4 84 9.3 3.5, 83-87 218 92 86 10 3.5, w cat 185 92 86 8 Turbos M102, 3.3 252 89 86 7 M106, 3.5 252 5200 279 2200 92 86 8 M88/S38 E28 euro 3.5 286 6500 251 4500 93.4 84 10.5 E28 US 3.5 256 6500 243 4500 93.4 84 9.8 E34 euro 3.8 340 6900 295 4750 94.6 90 10.5 E34 US 3.6 311 6900 265 4750 93.4 86 10 These are as "Official" of ratings as I can find. E12 US spec 530i's are a little confusing, my BMW manual lists compression ratio as either 8.1 or 8.3:1 depending on weather Mahle or Kobenschmidt manufactured the pistons, yet listed all other spec's the same. I'm also skeptical of the 176HP rating on the same 530i, given that 528i's were always regarded as quicker, yet rated at only 169HP, also 3.3's of the era were only rated at 173 with the same engine management, though a slightly lower compression ratio of 8.0:1, or 174HP with the later Lambda FI. Something doesn't make sense there. The magazines raved about the increase in power when early E24's went from 3.0 to 3.3, yet they were rated at lower power? There is also some confusion about 3.0 Bavaria's. Some literature lists them at 9:1, but they were rated at the same power as 2800 Bav's with 9:1 compression. Even more confusing is 2800 Bav's were actually rated at 192HP, but that was a SAE gross number, DIN on the euro engines was 170, and BMW kind of made a point about power being "unchanged" when they went from 2.8 to 3.0 and listed the 3.0 carb Bavaria at 170. I've also seen as assortment of different ratings for euro 3.3's, seeming to depend of what car it came in perhaps. 190, 194, 197 and 200. High compression euro 3.5's were rated the same early and late at 218, but the late one had significantly higher compression though missing 23CC's, but the early one is the "L" block that is regarded as ultra desirable. Makes no sense to me, but I haven't driven one of the early ones either. Starting in about 85 there was a "green" euro 3.5 with a cat that was basically a US spec smog engine, although rated at a miniscule 3HP more. Getting into the very late M30B35 engines that came in E32/E34's, even though it was a "World" engine, with common spec's everywhere, there is some talk that there was a slightly higher compression version with an added 2 or 4 Horsepower more. That's a "maybe," don't take it as fact, just as a possibility. Also remeber as outlined in the table, there is such a s thing as a US M30B34 (8:1- 182hp), M30B35 (9:1 - 204hp), Euro M30B34 (10:1- 218hp), and then the M90 (9.3:1 - 218hp)which is technically still an M30. These are all fuel injected. I hope this helps. I have only good things to say about mine! 318iS Track Rat :nice: www.drive4corners.com '86 325iX 3.1 Stroker Turbo '86 S38B36 325 No one makes this car anymore. The government won't allow them, normal people won't buy them. So it's up to us: the freaks, the weirdos, the informed. To buy them, to appreciate them, and most importantly, to drive them.

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• BMW335i Noobie
  • Join Date: Jan 2015
  • Posts: 34
  #17 02-07-2015, 01:07 PM Originally posted by downforce22 Very nice, m90 is better than your average m30! M90 is basically the M88 (engine from the m1) just with single timing chain, 2 valves per cylinder, and wet sump. It was derived from the M88 with the same engine dimensions(bore and stroke). You can think of it as the precursor to the s38 Quoted from BF.c Indeed, the M90 is the more responsive and aggressive engine compared to the M30 i.m.o. The fact that it delivers around 200(?)lb ft. @ around 2k rpm is insane. The M30 comes alive after 3k - 3.5k rpm, which is still an amazing machine. Still haven't decided what diff I will match the close ratio dogleg gearbox with. Any ideas?

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• LJ851 R3V OG
  • Join Date: Nov 2010
  • Posts: 7918
  #18 02-07-2015, 01:12 PM Originally posted by BMW335i Indeed, the M90 is the more responsive and aggressive engine compared to the M30 i.m.o. The fact that it delivers around 200(?)lb ft. @ around 2k rpm is insane. The M30 comes alive after 3k - 3.5k rpm, which is still an amazing machine. Still haven't decided what diff I will match the close ratio dogleg gearbox with. Any ideas? What kind of driving do you do? Something in the low 3's is a good starting point. Lorin Originally posted by slammin.e28 The M30 is God's engine.

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• BMW335i Noobie
  • Join Date: Jan 2015
  • Posts: 34
  #19 02-07-2015, 03:10 PM Originally posted by LJ851 What kind of driving do you do? Something in the low 3's is a good starting point. An s3.25 diff would be perfect I'm guessing? The torque this thing delivers will peel the rubber of the tires like peeling a potato.

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• Bearmw E30 Fanatic
  • Join Date: Aug 2010
  • Posts: 1323
  #20 02-07-2015, 03:11 PM That may be a better intake for an M90 but doesnt the B35 intake have better flow potential? Never argue with stupid people, they will drag you down to their level and beat you with experience. -Mark Twain

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• BMW335i Noobie
  • Join Date: Jan 2015
  • Posts: 34
  #21 02-07-2015, 03:19 PM Originally posted by Bearmw That may be a better intake for an M90 but doesnt the B35 intake have better flow potential? I did look it up on the internet but no one has ever been able to prove that. What I do know is that the valves are bigger on the B35. Perhaps an idea. First imma get this thing fit into the engine bay.

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• Bearmw E30 Fanatic
  • Join Date: Aug 2010
  • Posts: 1323
  #22 02-07-2015, 10:03 PM Whatever it flows I think your intake looks better than the later ones. Never argue with stupid people, they will drag you down to their level and beat you with experience. -Mark Twain

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• BMW335i Noobie
  • Join Date: Jan 2015
  • Posts: 34
  #23 02-08-2015, 01:52 AM Originally posted by Bearmw Whatever it flows I think your intake looks better than the later ones. Was about to say that !!

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• BMW335i Noobie
  • Join Date: Jan 2015
  • Posts: 34
  #24 02-08-2015, 12:37 PM Does the E34/E32 oil pan bolt up on the m90?

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• Van Westervelt R3V OG
  • Join Date: May 2006
  • Posts: 9365
  #25 02-12-2015, 02:17 AM Yes. As far as accessories go, the m90 is an m30. Lots of little variances though. You will need the e34/e32 oil pump as well. I picked up a severely neglected m90 and I am tearing it down for a complete rebuild. I also have a couple m30b35s I'm toying with for the other car. sigpic

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• BMW335i Noobie
  • Join Date: Jan 2015
  • Posts: 34
  #26 02-12-2015, 03:39 AM Originally posted by Van Westervelt Yes. As far as accessories go, the m90 is an m30. Lots of little variances though. You will need the e34/e32 oil pump as well. I picked up a severely neglected m90 and I am tearing it down for a complete rebuild. I also have a couple m30b35s I'm toying with for the other car. Ah, so I'll be needing the oil pan and the oil pump of the e32/e34. Post some pictures of your M90 and the M30, and let us know which one is the better engine =)!

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• BMW335i Noobie
  • Join Date: Jan 2015
  • Posts: 34
  #27 03-07-2015, 12:15 PM Mounts from E30.de Oil pan from a E34.

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• navytapaul Mod Crazy
  • Join Date: Oct 2011
  • Posts: 615
  #28 03-08-2015, 09:22 AM the m30b35 has the biggest valves between the two heads

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• Van Westervelt R3V OG
  • Join Date: May 2006
  • Posts: 9365
  #29 03-08-2015, 12:21 PM The intake ports dont match up well from m30b35 to m90. And the combustion chambers are not compatible without some work either. sigpic

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• ThatOneEuroE30 R3V OG
  • Join Date: Dec 2013
  • Posts: 8626
  #30 03-08-2015, 05:48 PM Those mounts are shiny. Your getting there this will be great when done. Are you going to boost it? I mean it is a m90... 1989 325is l 1984 euro 320i l 1970 2002 Racecar 1991 318i 4dr slick top Euro spec 320i/Alpina B6 3.5 project(the never ending saga) Vintage race car revival (2002 content) Mtech 2 turbo restoration Brilliantrot slick top "build"

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