BMW 635 CSi M30 engine questions
Discussion
it is possible to get the head to flow around 260CFM which is as good as even the best inline 6 4V head from BMW (standard form) so lots of potential, there are also stroker cranks for upto 4.2L M30 which would be fun.
there are not as many off the shelf cam options as with some other engines and the rocker ratio is quite low. the aftermarket tuners Alpina, Hartge etc had good results by simply upping the CR, cam, free flowing exhaust and tune....the US guys get good gains from a simple chip and MAF conversion but this might be exaggerated because of the slight differences between the engine specs of the US and rest of world.
there are not as many off the shelf cam options as with some other engines and the rocker ratio is quite low. the aftermarket tuners Alpina, Hartge etc had good results by simply upping the CR, cam, free flowing exhaust and tune....the US guys get good gains from a simple chip and MAF conversion but this might be exaggerated because of the slight differences between the engine specs of the US and rest of world.
I'm working on the M30B34 in my E28 race car. So far I've had the head done including the bigger inlet valves from a B35, fitted an Alpina-spec cam and a Fritz Bits supplied Alpina spec ECU chip.
I dyno'd the car before and it came out bang on factory power (220bhp). I'l dyno it again now the work is done and see what it's giving now - I'm expect in the region of 235bhp.
It's booked in with Paul Shepherd of Circuit Motors for the end of the month to have a Dastek Unichip piggyback ECU fitted, which allows for the AFM to be deleted, and then a couple of days of live mapping on his rollers. He said he's done a few M30s before and just the AFM delete and mapping can give 25bhp on an otherwise standard car - we shall see.
I'm hoping that all together these mods will see me somewhere in the 250-260bhp area, but it'll have cost near on £3k to get there.
I dyno'd the car before and it came out bang on factory power (220bhp). I'l dyno it again now the work is done and see what it's giving now - I'm expect in the region of 235bhp.
It's booked in with Paul Shepherd of Circuit Motors for the end of the month to have a Dastek Unichip piggyback ECU fitted, which allows for the AFM to be deleted, and then a couple of days of live mapping on his rollers. He said he's done a few M30s before and just the AFM delete and mapping can give 25bhp on an otherwise standard car - we shall see.
I'm hoping that all together these mods will see me somewhere in the 250-260bhp area, but it'll have cost near on £3k to get there.
Output Flange said:
I'm working on the M30B34 in my E28 race car. So far I've had the head done including the bigger inlet valves from a B35, fitted an Alpina-spec cam and a Fritz Bits supplied Alpina spec ECU chip.
I dyno'd the car before and it came out bang on factory power (220bhp). I'l dyno it again now the work is done and see what it's giving now - I'm expect in the region of 235bhp.
It's booked in with Paul Shepherd of Circuit Motors for the end of the month to have a Dastek Unichip piggyback ECU fitted, which allows for the AFM to be deleted, and then a couple of days of live mapping on his rollers. He said he's done a few M30s before and just the AFM delete and mapping can give 25bhp on an otherwise standard car - we shall see.
I'm hoping that all together these mods will see me somewhere in the 250-260bhp area, but it'll have cost near on £3k to get there.
Interested to know how you got on with the unichip?I dyno'd the car before and it came out bang on factory power (220bhp). I'l dyno it again now the work is done and see what it's giving now - I'm expect in the region of 235bhp.
It's booked in with Paul Shepherd of Circuit Motors for the end of the month to have a Dastek Unichip piggyback ECU fitted, which allows for the AFM to be deleted, and then a couple of days of live mapping on his rollers. He said he's done a few M30s before and just the AFM delete and mapping can give 25bhp on an otherwise standard car - we shall see.
I'm hoping that all together these mods will see me somewhere in the 250-260bhp area, but it'll have cost near on £3k to get there.
I've just been to pick it up this afternoon, funnily enough. Which means I've not driven it other than onto the trailer (it's a track-only car) so I can't give you the results of my arse dyno, but I can tell you what the graphs say.
The spec of the engine is that it's an M30B34 that has the larger exhaust valves from an M30B35, an Alpina B10 spec cam and the head has been ported/polished/flowed. It was using an Alpina-spec ECU chip to go with that.
The aim was to bin the AFM and get a few more horses.
With the engine totally stock it made 178bhp at the wheels on Charlie's dyno at Surrey Rolling Road (220bhp @ fly).
I didn't get a chance to dyno it with the head work but before the chip on the same dyno, however on Circuit Motors' dyno it gave 182.5bhp at the wheels (214.5 @ fly).
Paul wasn't able to get it to run without the AFM. He usually uses a TPS, but got sent a duff one and couldn't get a working one in time for me to collect the car today, so he tried to use a MAP sensor instead - he hadn't tried it on this engine before. In the end he gave up on trying to delete the AFM and left it in situ, and after mapping got it to 206.2bhp at the wheels (232.7bhp @ fly). He reckons there's another 5-6bhp available if the AFM can go.
More than just the BHP gains are the increase in torque too - again, only from the graphs but it looks good. On top of that, my car has been running very rich, which the Alpina-spec chip was supposed to address, but didn't. In fact it was running so rich that the ECU reported it as running lean instead, as it was so far outside of the expected range. That's now sorted, which is useful for my purposes (race car) as it means I can carry less fuel, so less weight.
So, in short, I won't know for sure until I drive it, but it's not a bad result for a N/A car. I may go back and get the TPS fitted so the AFM can go, or I may swap the engine out for an M88 instead - I've not decided yet.
The spec of the engine is that it's an M30B34 that has the larger exhaust valves from an M30B35, an Alpina B10 spec cam and the head has been ported/polished/flowed. It was using an Alpina-spec ECU chip to go with that.
The aim was to bin the AFM and get a few more horses.
With the engine totally stock it made 178bhp at the wheels on Charlie's dyno at Surrey Rolling Road (220bhp @ fly).
I didn't get a chance to dyno it with the head work but before the chip on the same dyno, however on Circuit Motors' dyno it gave 182.5bhp at the wheels (214.5 @ fly).
Paul wasn't able to get it to run without the AFM. He usually uses a TPS, but got sent a duff one and couldn't get a working one in time for me to collect the car today, so he tried to use a MAP sensor instead - he hadn't tried it on this engine before. In the end he gave up on trying to delete the AFM and left it in situ, and after mapping got it to 206.2bhp at the wheels (232.7bhp @ fly). He reckons there's another 5-6bhp available if the AFM can go.
More than just the BHP gains are the increase in torque too - again, only from the graphs but it looks good. On top of that, my car has been running very rich, which the Alpina-spec chip was supposed to address, but didn't. In fact it was running so rich that the ECU reported it as running lean instead, as it was so far outside of the expected range. That's now sorted, which is useful for my purposes (race car) as it means I can carry less fuel, so less weight.
So, in short, I won't know for sure until I drive it, but it's not a bad result for a N/A car. I may go back and get the TPS fitted so the AFM can go, or I may swap the engine out for an M88 instead - I've not decided yet.
Appreciate the response Dan many thanks.
Does look interesting. That increase in torque lower down the range really appeals.
I'd be considering this for my E24 highline, which is a 100% road car and I believe runs at a lower compression than yours, so wondering if the gains would be as impressive.
Can I ask how much the setup cost - email if needed
Does look interesting. That increase in torque lower down the range really appeals.
I'd be considering this for my E24 highline, which is a 100% road car and I believe runs at a lower compression than yours, so wondering if the gains would be as impressive.
Can I ask how much the setup cost - email if needed
I've been running my 1985 manual 635csi for 15 years now and am keen to refresh the engine like you. Over that time I have become somewhat of an expert on them.
Bit of info, Alpina did a b9 m30 that was good for 245bhp which had mahl pistons a slightly higher compression ratio 10.5.1 I believe and a cam of around 268 degrees along with a different ECU.
When the later bigger valves headed M30's came out which are easily spotted as the intake manifold reads 3.5 and not 3.2/3.5 on the earlier ones. This engine gave the same power, but with a lower compression ratio, but bigger valves and a freer flowing intake and exhaust manifold. This engine was designed to totally run on unleaded and was catalytic converter prepared. Alpina then developed the b10 m30 which was identical to the B6 in the e30. This gave 260bhp (254bhp with cat) doing basically the same as the b9 conversion, but making use of the better flow and having a slightly different exhaust manifold.
The m30 was also the engine of choice for the E3 CSL's and later 635's and in race tune they would give 280bhp in endurance tune and up to 330bhp in sprint touring car spec. Some CSL's of a very late vintage had turbo charged m30's that were reputed to give as much as 700bhp.
Alpina also did the B7 turbo 3.0 m30 which had 300bhp all the way up to the later cars that gave 330bhp.
I used to organise events for the BMW CAR CLUB as I was coupe chairman and once run a rolling road day just for 635's and most were making around 200- 205bhp. Mine was 207bhp. I always felt the intake was a poor design so designed my own moving to having a filter at the back of the headlight with a nice cold air feed and doing away with the OEM air box. My design had it all insulated and shielded from the heat of the engine. I was hoping for a few BHP and was staggered when it gave a 17bhp uplift to 222bhp from the same rolling road on another day, but with the same ambient temperature.
Other things that will transform the acceleration is to address the gearing. With the standard 3.07 differential the car has a theoretical top speed of 200mph if it has 600bhp and the gearing is very tall. By fitting a higher ratio diff. I am currently fitting a 3.46 this will gain significant time. Interestingly in the production of the e24 early series one cars had much higher gearings and were a second quicker to 60 then the series 2 cars post 84 as the performance was a little too close for BMW's liking to their new flagship the M635. An auto will be around 8.5 to 60 an early manual was 7.0. The m635 being 6.0. Out of interest American spec cars had much lower. Power due to emissions law and that is why there is such a large tuning scene for the e24 as they wanted the same performance as their European cousins. Consequently BMW fitted them with much higher 3.64 or even 3.91 ratio differentials.
Another big area that can be improved is fitting the flywheel from the M635. This is massively lighter and makes the engine feel less heavy under throttle. Less power will be lost and this will have an affect on the power to the road being increased.
In return to your dilemma. If you used the pistons from an early 1982-1987 engine with the head a inlet manifold from a later high line engine you would be looking at around 230bhp+_5. Add a camshaft from Shrick, Piper or Cat cams 272 and you have 240bhp. A Fritz manifold might give you 5bhp and a different set of pistons from JE or Mahl and 260bhp would be easily feasible, but now costs would be rising quickly. Add a stand alone ECU and no AFM and 280bhp is possible at another £2000 or so of costs and add individual throttle bodies from Jenvey and 300bhp is possible. The question is how much money do you want to spend. You could easily spend £5,000 and get towards £10,000.
Hope this helps
J
Bit of info, Alpina did a b9 m30 that was good for 245bhp which had mahl pistons a slightly higher compression ratio 10.5.1 I believe and a cam of around 268 degrees along with a different ECU.
When the later bigger valves headed M30's came out which are easily spotted as the intake manifold reads 3.5 and not 3.2/3.5 on the earlier ones. This engine gave the same power, but with a lower compression ratio, but bigger valves and a freer flowing intake and exhaust manifold. This engine was designed to totally run on unleaded and was catalytic converter prepared. Alpina then developed the b10 m30 which was identical to the B6 in the e30. This gave 260bhp (254bhp with cat) doing basically the same as the b9 conversion, but making use of the better flow and having a slightly different exhaust manifold.
The m30 was also the engine of choice for the E3 CSL's and later 635's and in race tune they would give 280bhp in endurance tune and up to 330bhp in sprint touring car spec. Some CSL's of a very late vintage had turbo charged m30's that were reputed to give as much as 700bhp.
Alpina also did the B7 turbo 3.0 m30 which had 300bhp all the way up to the later cars that gave 330bhp.
I used to organise events for the BMW CAR CLUB as I was coupe chairman and once run a rolling road day just for 635's and most were making around 200- 205bhp. Mine was 207bhp. I always felt the intake was a poor design so designed my own moving to having a filter at the back of the headlight with a nice cold air feed and doing away with the OEM air box. My design had it all insulated and shielded from the heat of the engine. I was hoping for a few BHP and was staggered when it gave a 17bhp uplift to 222bhp from the same rolling road on another day, but with the same ambient temperature.
Other things that will transform the acceleration is to address the gearing. With the standard 3.07 differential the car has a theoretical top speed of 200mph if it has 600bhp and the gearing is very tall. By fitting a higher ratio diff. I am currently fitting a 3.46 this will gain significant time. Interestingly in the production of the e24 early series one cars had much higher gearings and were a second quicker to 60 then the series 2 cars post 84 as the performance was a little too close for BMW's liking to their new flagship the M635. An auto will be around 8.5 to 60 an early manual was 7.0. The m635 being 6.0. Out of interest American spec cars had much lower. Power due to emissions law and that is why there is such a large tuning scene for the e24 as they wanted the same performance as their European cousins. Consequently BMW fitted them with much higher 3.64 or even 3.91 ratio differentials.
Another big area that can be improved is fitting the flywheel from the M635. This is massively lighter and makes the engine feel less heavy under throttle. Less power will be lost and this will have an affect on the power to the road being increased.
In return to your dilemma. If you used the pistons from an early 1982-1987 engine with the head a inlet manifold from a later high line engine you would be looking at around 230bhp+_5. Add a camshaft from Shrick, Piper or Cat cams 272 and you have 240bhp. A Fritz manifold might give you 5bhp and a different set of pistons from JE or Mahl and 260bhp would be easily feasible, but now costs would be rising quickly. Add a stand alone ECU and no AFM and 280bhp is possible at another £2000 or so of costs and add individual throttle bodies from Jenvey and 300bhp is possible. The question is how much money do you want to spend. You could easily spend £5,000 and get towards £10,000.
Hope this helps
J
e28525e said:
Thanks for the information, some really useful stuff there
Interesting thread! Would love to know where you are at now with the project? My own E28 is due for some engine work now, the mileage is huge! Would like to do a sprint with it in October, then pull it out for a major sort out. Having owned M535s in both E12 and E28 shape, and driven plenty of others, in standard form the earlier engine is just a livelier, revvier thing than the later one, much more fun, despite same quoted power overall. So the option is available to go early crank with early big bore block, later crank in early block, or tune later engine, which seems on the face of it to be starting with something of a disadvantage? Thoughts?
Output Flange said:
C) None of the above.
Buy the engine on eBay that has already had all the work done to it, and save yourself £2500.
Fabulous if that's possible, but i'd be surprised. I have an early crank, ground with bearings but not knife-edged yet, possibly an early block, definitely a later block and crank, at least four new steel rods... and nobody elses dodgy work in there, no spurious go-faster bitz...Buy the engine on eBay that has already had all the work done to it, and save yourself £2500.
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