how much power from 2.9 stroker?

[digger]

IMO you can't really make decent power unless you run standalone. Once you start adding cam, bumping CR up and adding other high perf. mods you really need standalone to get the power up close to 100hp/liter

Depends what you mean by decent but given that you won't get 100hp/L from a NA M20 unless its a M20B20 (i.e. small displacment but with the same head that a 2.7L-3.1L stroker uses) i would disagree about standalone. For NA full standalone is not a must, a 3L can make >200whp using a plug in chip for motronic, AFM, standard intake manifold and standard airbox (obviously more possible) and i would say that 200whp is more than decent when on road performance is looked at.

[Hadrian]

I have an E21. It comes with CIS, not EFI. The manifold is made up of part of an E30 323i manifold which has L-jetronic, not Motronic. I will be using Dellorto carburettors (better than Webber DCOE IMO).
I'll be using the standard E21 323i distributor which uses vacuum ot controll advance and retard.

[winstontj]

Standalone

My manifold is made up of the first few inches of the stock manifold so it still has the oil return thingy.
You guys are lucky you don't have vacuum dependant distributors.

If you are going to run a car like that (an m20 with ITB's etc.) than you'll be able to make much better power running a standalone system and chucking the stock motronic in the garbage. Something like MegaSquirt is perfect and has a provision to control spark... so just run distributorless ignition.... For example EDIS-6 (wasted spark) and totally delete the cap & rotor... run whatever cam you want, clean up the engine bay by putting the coil & wires under the dash... yada yada....

IMO you can't really make decent power unless you run standalone. Once you start adding cam, bumping CR up and adding other high perf. mods you really need standalone to get the power up close to 100hp/liter

[Hadrian]

My manifold is made up of the first few inches of the stock manifold so it still has the oil return thingy.
You guys are lucky you don't have vacuum dependant distributors.

[der affe]

What problems? Do you mean the brake booster & fittment issues of the ITB's? I'd love to build a 3.0L motor but dont know where to get the crank from.

Do you guys have a source for billet cranks?

my Dbilas ITB's don't have any fitment problems with the brake booster.

[Andreas]

What problems? Do you mean the brake booster & fittment issues of the ITB's? I'd love to build a 3.0L motor but dont know where to get the crank from.

Do you guys have a source for billet cranks?

If you want to retain the brake booster, then ITBs will create some work for. Maybe you can leave the brake booster where it is if you angle the TBs up quite high and compromise the shape of your airbox. However, most likely you will have to move it. Your new handmade manifold must also provide a vacuum to the booster.

Another option would be to convert to hydraulic brakes like on the very old 7 series BMWs. You'd have to make up some brackets (similar to power steering) to mount the pump.

Another option, and the one that I am using, is to install competition brake master cylinders that do not need a brake booster. Supposedly they give you much better feedback when you apply brakes. Tilton and AP Racing are two companies where you can obtain this.


Although I haven't confirmed it yet, the thermostat housing may be a bit difficult to work around. It depends on your design I suppose. Most guys build the manifold to let the air come to the head at 90 degrees. I prefer to mount the ITBs so that air goes straight into the port - about 30 deg.


When building your own manifold, also consider the oil return from cylinder head to bottom of the block.


328i cranks can be found used without too much difficulty. I bought a forged steel one for R6,500 (incl. machining work for front pulley). The 330i cranks are very difficult to obtain and I bought mine at the BMW dealer brand new for R11,500 (E46 330i with 89.6mm stroke ; the E90 330i crank has less stroke and the chain sprocket is mounted elsewhere - don't buy this one).

[Andreas]

I recall seeing one 3.6 liter M30 running 11:1 compression, very kick ass headers, tripple Weber 45 DCOEs and like a 300 degree cam making about 330rwhp.

That is awesome. It must have sounded absolutely wicked. Was that engine in an E30 ?

[winstontj]

I will pick on every single NA E30 that I can find and hopefully even some turbo guys. I will especially look for your Budler built 2.9 liter :)

Are you hinting at an all-out 2.9 NA M20 for your track car ? With throttle bodies - will be interesting to see how you solve the problems involved with that setup.

What problems? Do you mean the brake booster & fittment issues of the ITB's? I'd love to build a 3.0L motor but dont know where to get the crank from.

Do you guys have a source for billet cranks?

[euroshark]

3.6 liter M30 strokers can make ~90hp/liter if they are built pretty hot. You'd have to have megasquirt or at least tripple carbs (or a cool ITB setup) to achieve 100hp/liter from an M20 or M30 I bet.

I recall seeing one 3.6 liter M30 running 11:1 compression, very kick ass headers, tripple Weber 45 DCOEs and like a 300 degree cam making about 330rwhp.

[Andreas]

I hope u not coming to pick on me :P

but, I would like to see what a 2.9lt with similar specs to what your 3.1lt would do compared to the 3.1 ... only time will tell :D

I will pick on every single NA E30 that I can find and hopefully even some turbo guys. I will especially look for your Budler built 2.9 liter :)

Are you hinting at an all-out 2.9 NA M20 for your track car ? With throttle bodies - will be interesting to see how you solve the problems involved with that setup.

[winstontj]

I dont get why a smooth idle is good for a DD ? I can understand emissions, but thats the only reason I can come up with.

Cams cause a "lumpy" idle. It's rough and it's not a problem at all once the car is warm (engine up to full operating temp) - - - BUT - - - when it's cold outside or if you live in new england (like me in Boston) a lumpy or non smooth idle is a major PITA in the winter. It's like having an old carbureted car without a choke in the winter. You have to keep your foot on the gas to keep the idle up so the motor doesn't stall until it's warm. It makes it a little harder to just get in and drive the car whenever.... only a minor issue but still a big issue because drivability goes down a bunch IMO.

[SA E30]

I dont get why a smooth idle is good for a DD ? I can understand emissions, but thats the only reason I can come up with.

[nando]

We'll see. Money is all relative. I have an opportunity to buy a totally unknown past race s38 and I'm going to pass it up because of the expense. m20 looks cheap once you start looking at BMW multivalve motors :-)

I'm looking (passively) for a motor now to use as a build platform. I may go 3.0L but probably will stay 2.9. I'm still learning (as if you didn't know) so there will be many more questions. Megan and I chose this e30 because I want an e30 as my DD until we have kids and need two 4-doors. Until then I'll be building my 71 2002 and will start an m20 build ASAP.

I am quite confident that a 2.9L with the right amount of work (hopefully in the $8,000 range) and a modern engine management system can come VERY close to 200whp with a single plenum intake manifold (single TB). As you say though... there is only one way to find out.

Things I need to learn more about is exactly what cams produce what power bands, what size valves do you guys run (+1 for both intake and exhaust??), do you guys knife edge your cranks, run windage trays, dry sumps????, distributorless ignition systems, convert to manual steering racks, etc.

I'll figure it out and find a suitable motor shortly....

IMO all that extra crap costs a lot more money and isn't going to get you much. maybe a crank scraper (just because it'll help with potential oiling problems on a track), but the rest isn't going to make any difference that you'll be able to notice.

I think with an 86mm bore and 84mm stroke, you should easily be able to break 200whp. I've said it before but jordan had a pretty mild cam (272) and he had the base stroker dimensions - 81x85. also because of his piston design (I think they were IE) he had to retard the timing a whole bunch just to get it to run. he did have the car fully dyno tuned with long tube headers though which is probably why he made more power than almost everyone else who has done this.

spend your money on a good bottom end build using the lightest parts you can afford (the 84mm crank is forged and it's already lighter than the stock one, so that's a start). The rest is in the headwork - arguably the most important part, especially for us 12v guys. I still think that wanting to make power at 7500rpm is a waste of time - I usually don't rev past 6500, it doesn't make much power past anyway there and the meat of the torque curve is between 2000 and 6000rpm. Focusing on a broad torque curve and smooth revs will probably be much more satisfying than an elusive and ultimately useless peak #..

FYI I think my motor cost about $8k. I don't think I have 200rwhp tho :p

oh yeah, I'm really a believer in the schrick 284/272 cam.. I originally put it in my car stock, and I actually *gained* low end torque (butt dyno), plus in the high end it just screams. the idle is still smooth enough for a DD as well.

[SA E30]

Hi winstontj

I am glad that someone is willing to spend some serious money on a M20 motor just to see what can come of it. It will be very interesting to see how your project turns out.

A lot of people on E30 forums like to debate about what is possible with the M20 if you did this ... or what if you did that. Hardly anyone ever tries to do anything serious. The guys that do have some spare cash usually chicken out and install a modern multivalve motor.

So please, stay unreasonable and stay on track with the M20 buildup. I was going to build a high revving 2.8 but was convinced to go 3.1 instead. Hope to still rev it 7,500 rpm though. I would love to compare what can be done with 2.9 vs a 3.1

I hope u not coming to pick on me :P

but, I would like to see what a 2.9lt with similar specs to what your 3.1lt would do compared to the 3.1 ... only time will tell :D

[winstontj]

the cam is one of the most critical parts to consider, too much cam will kill bottom end for little gain up top. The cam used should compliment the CR so a high CR can use a big cam but low CR (read alot less 10) with a high duration cam will anihilate bottomend its mostly to do with dynaimc compression ratio opposed to the static compression ratio normally quoted. Also there is more to a cam than duration so all 272 are not equal.

+1 valves intake will gain some but exhaust is a waste really you'll never feel it except in the wallet and gains from this will be all mid to topend.

There are many many more important things to do/purchase before knife edging or windage trays are considered.

Don't chase rwhp it doesn't really give a true indiation of how a car will perform.

The thing is the car is already done - suspension... shocks, springs, bushings, sways, strut bars

I'm not out for 300000rwhp I simply want to be at a certain power to weight ratio so whether its' a bhp or whp number it's only a small increase that I'm after. This car will will take me to many driver's education courses and I'm going to start racing an itb/c prepped 2002 this season so I don't need a race car - just a little fun off the track. dodging cones isn't for me so it is simply just to have a little fun. I'm after low end power more than peak HP. I think when I'm done (12months) you'll be suprised at the power curve I end up with. Ideally it'll go straight up to 200whp, stay there from 2,000 up to 7,000 and then who cares from there - LOL... we can dream right???