High Rev M20B25

[jebc125]

Hello guys,

In this moment I am fixing my e30 and my engine will need a rebuilt/refreshment, but I want to throw some money on it. The car is not my daily driver.

I am looking for some info/knowledge from the community for info about compability and parts info.

I know for making a high rev engine, the parts needs to be lightweight. I am looking for rev up to 7500rpms. Why I am looking for this... I love my revy K20Z3 engine on my daily driver. I dont want turbo or supercharger or swap and I love N/A engines.

I am thinking in the following parts:

• Internals:

S50/S52 rods from:

http://www.enjoytechnica.com/products-page/rods/e36-rods/

or

http://www.iemotorsport.com/bmw/item/m20hrod.html

• Pistons:

A new set of M20B25 pistons, mahle or something from IE:

http://www.iemotorsport.com/bmw/item/M20B25cstpstn.html

Or going full retard:
https://store.vacmotorsports.com/je-...b25-p3559.aspx (really not necessary because I dont want a turbo or a supercharger... mmmmm :money: )

• Flywheel from RHD:

http://racehead.com.au/products-page...ng-flywheel-2/

• Damper:

A new one from BMW.

• Crank, reuse and balance the actual one.

• Bearings for crank and rods (What brand or OEM ones?)

• Head from bimmerheads:

https://bimmerheads.com/collections/...=8357904744490 With everything new using a camshaft of 274/280

• Waterpump, belts, pulleys (from ECS) and crank scraper everything new.

https://www.crank-scrapers.com/bmw_m20.html

• Oil Pump ? Options?
• Engine Management (chip or MS2)
• ITBs: RHD or Dbilas
• AFM conversion from Miller or standard flow sensor.
• Headers (ebay LOL)

Thanks




For reference I am using this 2 threads:

https://www.r3vlimited.com/board/showthread.php?t=274394

https://www.r3vlimited.com/board/showthread.php?t=346310

[nando]

People still buy the Miller Maf crap?

For an engine like this - standalone is the only viable choice.

[ForcedFirebird]

That cam will run out of steam with ITB's and anything over about 2.8l in the neighborhood of about 6700rpm. If you want something to rev high and make power up there (not noise), you will want to be in the neighborhood of 11:1 compression and at least a Schrick 288.

How much power/torque are you looking to make? IMO, I think that's more important than what RPM's you would like to turn.

[e30davie]

People still buy the Miller Maf crap?

For an engine like this - standalone is the only viable choice.

Is a miller maf just like an interceptor type thing to trick the ecu into giving more fuel?

[ForcedFirebird]

Is a miller maf just like an interceptor type thing to trick the ecu into giving more fuel?

It's an emulator of sorts with a user interface. If you are handy with software, the Moates Ostrich does a very similar function. It doesn't "trick" the ECU, you are really editing maps.

[digger]

7500rpm is not high rpm if you want a high rpm engine then start with a smaller crank and do it properly if youre going to spend all that money....lol

[zaq123]

7500rpm is not high rpm if you want a high rpm engine then start with a smaller crank and do it properly if youre going to spend all that money....lol

7.5k is pretty high for M20 IMO. 9.5k with forged aluminium pistons, forged ti con rods and solid ti valves? That would be cool to see. I think custom Ti rods are close to $1k/ea or so :)

[jebc125]

People still buy the Miller Maf crap?

For an engine like this - standalone is the only viable choice.

Actually forexhaust fumes regulation the standalone is the only way to have a car of these in Costa Rica. Almost all the e30s I know, that were imported after 2011 all of them are having problems with the exhausts fumes regulation.

7500rpm is not high rpm if you want a high rpm engine then start with a smaller crank and do it properly if youre going to spend all that money....lol

I know is not high, I know high rev engine will be something reving over 8000 rpms like a Honda Engine, but taking in consideration this is for a road car, that probably will see the track at least 1 time per year, it can be considered a revy engine :P on the E30. Also, I want something reliable.

It's an emulator of sorts with a user interface. If you are handy with software, the Moates Ostrich does a very similar function. It doesn't "trick" the ECU, you are really editing maps.

Didnt know that.

Is a miller maf just like an interceptor type thing to trick the ecu into giving more fuel?

Can you explain me?

That cam will run out of steam with ITB's and anything over about 2.8l in the neighborhood of about 6700rpm. If you want something to rev high and make power up there (not noise), you will want to be in the neighborhood of 11:1 compression and at least a Schrick 288.

How much power/torque are you looking to make? IMO, I think that's more important than what RPM's you would like to turn.

Man I am looking for 200~210 to the crank and ~170 to the wheels (like 40hp increase). Also that is something I need to investigate for raise the compresion on the engine (Pistons from other BMW engine? What kind of head gasket?). One of the things that worries me more is the Oil pump, some pumps suffer of cavitation at high RPMS

potstir

[jebc125]

7.5k is pretty high for M20 IMO. 9.5k with forged aluminium pistons, forged ti con rods and solid ti valves? That would be cool to see. I think custom Ti rods are close to $1k/ea or so :)

You got my point man! I see 7.5K barrier doesnt looks expensive using some aftermarket hardware with OEM stuff and upgrading the normal things that everybody uses.

:D

[zaq123]

You got my point man! I see 7.5K barrier doesnt looks expensive using some aftermarket hardware with OEM stuff and upgrading the normal things that everybody uses.

:D

Reliable 7.5k M20 that actually makes any power at that range won't be cheap. Can probably get away with forged 4340 rods but the rest will still be expensive.

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[nando]

You don't need crazy rods for 7500rpm. I did that years ago with an eta crank and S52 rods. Stock rods are already forged anyway - it's more a matter of weight.

[ForcedFirebird]

7.5k is pretty high for M20 IMO. 9.5k with forged aluminium pistons, forged ti con rods and solid ti valves? That would be cool to see. I think custom Ti rods are close to $1k/ea or so :)

I put my stock e30 rev limiter to 7800 just to see what would happen. Went to Sebring raceway and banged it off the limiter a bunch of times. Nothing happened, that was 5 years ago and the engine is now in the race car lol.

Man I am looking for 200~210 to the crank and ~170 to the wheels (like 40hp increase). Also that is something I need to investigate for raise the compresion on the engine (Pistons from other BMW engine? What kind of head gasket?). One of the things that worries me more is the Oil pump, some pumps suffer of cavitation at high RPMS

potstir

170whp, no sweat (I get close to that with stock cam .5mm over b25's). An m52b28 crank, 130mm rods, +.5mm stock pistons, 272 cam and stock inlet manifold made 178whp in a locals' car. That engine was not built by us, so he never shaved the block .5mm it could have made more power

I built a 2.8 last year that made 217whp. b28 crank, stock +.5mm pistons, .25mm shaved block, 130mm rods, 272 cam, +1mm valves, headers, RHD ITB's and proper exhaust on Megasquirt.

If you use the b28 crank, b25 pistons, 130mm rods and shave the block .5mm you will be near 9.5:1 compression. Leave everything else stock and you will meet your goal if the engine is built and balanced proper.

[zaq123]

They are all forget, that's right. I think m20 are wrought forging monsters that are too heavy for proper high rev setup unlike S52 ones

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[nando]

^wat?

[MrBurgundy]

They are all forget, that's right. I think m20 are wrought forging monsters that are too heavy for proper high rev setup unlike S52 ones

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