the m20 developement thread. Some progress and a new lump.

[morerevsm3]

259.1kW equates to 347.5bhp! Remarkable, from a carb'd M20.

...and NOT corrected to flywheel, that is ~ 400bhp

[Speedtouch]

How is this feasibly possible, given that an E36 M3 3.0-litre 'only' gave around 300bhp, using sophisticated fuel injection.

[morerevsm3]

2,8 crank and rods, custom 14.5:1 pistons, E85 fuel, .550" valve lift, lots of duration, VERY modified head etc...

[morerevsm3]

I am in the long slow process of building an S50B30 race engine that should make ~ 450BHP@8700rpm injection does not give any more peak power than carbs, it improves driveability, the 2.8 M20 won't take full throttle below 5000rpm, or it just pops and bangs back through carbs due to reversion of gas from so much overlap, but all hell breaks loose over 5000rpm, and it is a race car motor, not a street car

[reggid]

i would have though spec for spec (same fuel and CR) with the S50 head being able to go 300+CFM vs 230-240CFM for M20 that you'd make alot more than 450bhp from the 3L

[morerevsm3]

flow is only part of the story, 2 valve engines have a lot of swirl, which gives a faster, more complete burn and resists detonation better than 4 valve, 4 valve comes into it's own above 8000rpm where curtain area of the valves on 2 valver stops efficiency above that

[HairyScreech]

I would like to believe this, however I am an incurable skeptic.

The main parts seem to be there but not for 124hp/l at the wheels or about 150hp/l at the flywheel.

Is there any more info on this engine? A build thread or anything?

[reggid]

http://speedtalk.com/forum/viewtopic.ph ... 2&start=15

[HairyScreech]

^^ hmm, well I guess that's what I get for slacking on my reading material.

I will take a long steady read of that but one thing that strikes me instantly is the pistons.

[Speedtouch]

And the very high 14:1 compression ratio!

[HairyScreech]

Its on E85, I have been hearing some interesting things about viable compression on E85. It would appear that 13:1-15:1 is just fine on E85, it would seem what is possible with E85 is still not fully understood.

I will admit i have been thinking for a little while that although the stock piston shape is good in terms of squish and chamber geometry, perhaps the squish is not being directed to effectively.
That piston is pretty much a high compression version of what I was thinking of doing with the m52 piston and creating a central chamber with concentric squish designed to use both the squish band and the far side of the chamber.

The math says the numbers are theoretically possible.
I can believe 360 at the fly but having trouble with 360 at the wheels, any possibility the dyno number is at the fly?

Either way it is something to think about, I have been saying for a while there is a lot more to come from the m20 it just needs to be found.

[morerevsm3]

the guy that owns the car also owns the dyno, his previous race car, a 4.4litre Chrysler Charger group Nc (historic) car made 260.2 rwkw the day he sold the car, the new owner had the engine out and on an engine dyno for a baseline run a few days later (he lives 4 hour drive away, so made sense to use a more local dyno) engine made 403.6BHP, the numbers on this engine are definitely at the wheels. it is not a streetable engine, you can't give full throttle below 5000rpm or it spits back through the carbs due to the amount of overlap, but hit 5000rpm and stick your boot into it, all hell breaks loose

[tomislav]

My good god!!!! That engine must have had lots of money spent on it!!!!!

[HairyScreech]

Not really. $25k Aus. Including labor by all accounts.
Seems most of the work is in the head and it is still not the most drastic of heads. Beyond what I have the tooling to do at home but could certainly be done for under £1K with labor.

The whole build is nothing that could be done by someone at home with a bit of learning and a lot of care and attention.
Even the guy that built it seems surprised at the output.

The real key points are the head and inlet valve size, the angle of the pistons (no flat pistons with an 885 here), tunedilet and exhaust via pipemax and replicating components to hold 8krpm.
Its clear proof of what can be done with these motors when all the right bits are put together.

[kimbo]

^^ hmm, well I guess that's what I get for slacking on my reading material.

I will take a long steady read of that but one thing that strikes me instantly is the pistons.

Those pistons look a lot like ours - I've tried to cut and paste the picture but it wont have it - refer back to page 5 for the image.
The head looks a lot like ours, too insofar as the chamber shape is concerned, although ours I think has std size valves.
btw just to avoid confusion, you're also talking to my son about the same motor (on E30Tech, I think) his normal login is taylorspug.

Kim

eta We were told that ours was a Griffin Motorsport motor, but can't prove it either way.

[tomislav]

Not really. $25k Aus. Including labor by all accounts.
Seems most of the work is in the head and it is still not the most drastic of heads. Beyond what I have the tooling to do at home but could certainly be done for under £1K with labor.

The whole build is nothing that could be done by someone at home with a bit of learning and a lot of care and attention.
Even the guy that built it seems surprised at the output.

The real key points are the head and inlet valve size, the angle of the pistons (no flat pistons with an 885 here), tunedilet and exhaust via pipemax and replicating components to hold 8krpm.
Its clear proof of what can be done with these motors when all the right bits are put together.

Cool, does that mean you could build me one?

[morerevsm3]

just to clear a couple of things up, Knight Engines did the head, and pipemax calculations, the owner (who also owns the dyno) and myself did the rest, there are a lot of little attention to detail things that all match up to make it all happen

[reggid]

and head is not happening for £1K (1450AUD) me thinks.

[HairyScreech]

and head is not happening for £1K (1450AUD) me thinks.

Just to be clear I meant if you were to reproduce something similar for yourself at home, it would need a bit of paid machining. Never meant to imply that one could be bought for that, I am sure the guys time is worth a lot more than that.

[reggid]

and head is not happening for £1K (1450AUD) me thinks.

Just to be clear I meant if you were to reproduce something similar for yourself at home, it would need a bit of paid machining. Never meant to imply that one could be bought for that, I am sure the guys time is worth a lot more than that.

few could even do it at home and most workshops would have the know how, the techniques used are nothing new but it is all in the execution and combining them all into something that works on the head infront of you, and knowing when you have something that will work. you seem to be implying that it is pretty easy when there is a very good reason why we haven't seen anything come close to this....

[e21jps]

I will bet my left testicle the valve train wont last a season with 14mm valve lift! I have done a lot of work with m20 rocker geometry and at that sort of lift you are into some very harsh rocker ratio's the loading over the nose of the lobe will be massive, but i guess in its favor with big 280 odd 050 duration the velocities will be ok. Sounds more like a drag racing engine than circuit racing, what gearbox does he have? it will be very hard to keep it in its power band without some very close ratios.

sorry dont mean to rain on an impressive build..... im excited to see but also cut because its blown my previously proud (pump fuel) effort out of the water by some 60Kw!

[morerevsm3]

has strong, useable power from 5000rpm to 8500rpm, and at it's first race meeting at Phillip Island last weekend, it performed very well for its first hitout, still currently has stock 260 getrag, now looking into samsonas close ratio dog box, or E36 M3 box, was dropping below cam range at siberia, no problems elsewhere, hit 9000rpm a couple of times, and just over 250kmh on the straight, and 1:48.0 in it's first race. it is getting too much oil to the top end, so will have restictor fitted before next race meeting, pressure over the nose isn't too bad now, it did chew a cam very quickly at the first attempt, some out of square rocker pads, combined with silly spring pressure made for very short lived cam, but the result of that was going back and doing other things better too.

[HairyScreech]

Just curious as to what the bottom end set up is?

I have heard it both ways, firstly that the m52 crank and rods are ok with the stock piston weights to 8000.
Have also heard that there are harmonic damping issues over ~5700prm.

I am sure this is a situation you have either encountered or will encounter at some point so your experience on this front would be much appreciated.

[morerevsm3]

stock M52 rods and crank, JE pistons are lighter than stock, engine note changes above 8500 indicating some bad harmonics ~ 8700rpm

[Steven320]

Simon, i cant really find in this topic the most simple rull of porting.

What the moste people are doing after they port the intake ports is polishing, and thats wrong cause. if you make the walls of the intake poort 2 smooth the laminaire air can't stik on the walls and will create even more turbulence. The laminaire air is a layer that creats less friction between the high flow air and the poort wall.
and i read that if you use grid 40 till 200 sandpapper you get the best result. maby you can explain it better cause of my englisch pretty sucks.

(and polishing also doesnt work on the exhaust.)

but if have a little theory.
What if you do it also on your multi angle seats but with out the vlave contact aera. i think same story??

[e21jps]

has strong, useable power from 5000rpm to 8500rpm, and at it's first race meeting at Phillip Island last weekend, it performed very well for its first hitout, still currently has stock 260 getrag, now looking into samsonas close ratio dog box, or E36 M3 box, was dropping below cam range at siberia, no problems elsewhere, hit 9000rpm a couple of times, and just over 250kmh on the straight, and 1:48.0 in it's first race. it is getting too much oil to the top end, so will have restictor fitted before next race meeting, pressure over the nose isn't too bad now, it did chew a cam very quickly at the first attempt, some out of square rocker pads, combined with silly spring pressure made for very short lived cam, but the result of that was going back and doing other things better too.

I have had many years experience with reving the crap out of m20's and the valve train just doesnt cope. You guys need one of my roller cams! proven to be strong enough to survive 50 plus laps of valve piston contact after we fatally tried too much advanc so cant pass a much tougher test than that!

Im about to get a bunch ground and I can get any profile done but there is about a $300 fee for designing a new profile. Curently the one i have is 313 @seat, 257 @050, 0.502 lift @ 106 LSA Cams are made in sweden so takes a few weeks cost is around $850 if i get at least 6 at a time, rockers are $1450 set, I can also source eibach 300#@14mm springs $250/set, Ti retainers $200/set. I put nothing on the cams and only a little on the others

theres a big thread following the development on e30tech http://www.e30tech.com/forum/showthread.php?t=108906

[morerevsm3]

due to a broken oil pump drive shaft, new bottom end under way, top end still perfect, no sign of cam wear yet, after new bottom end goes in, Samsonas dog box is next ( I am Australian agent for them)

here is a video from a 650bhp LS1 powered commodore of the E30's first race with this engine, car was very loose, costing ~ 2 seconds a lap...

[reggid]

was this a new oil pump drive shaft?

what spring pressures were used on the original one that chewed out?

[morerevsm3]

no, was not a new shaft, and 60 weight oil was the main cause, it will now run a 30 weight oil, and a tool steel shaft, I have forgotten spring pressure on old setup, but was spiking a lot going over the nose, now has stock springs

[e21jps]

[quote="morerevsm3"]due to a broken oil pump drive shaft, new bottom end under way, top end still perfect, no sign of cam wear yet, after new bottom end goes in, Samsonas dog box is next ( I am Australian agent for them) /quote]


Thats unusual to break an oil pump drive ive never heard of an m20 doing that!

So what are the ratios and cost of a samsonas gear set??
I have a nissan 71c and albins CR syncro gear set ready to go together sometime, the bell housing adaption is done i still have to do the rest. I have used a dog box before and they really are a mixed blessing.

[morerevsm3]

ratios all listed here-
http://samsonas.com/?page_id=234

easiest option is E36 328i/3 litre M3 Zf case
price depends on current exchange rate, but cheaper than PPG/Holinger/Albins

[e21jps]

ratios all listed here-
http://samsonas.com/?page_id=234

easiest option is E36 328i/3 litre M3 Zf case
price depends on current exchange rate, but cheaper than PPG/Holinger/Albins

the listed ratios for m20... etc look like they are from a front wheel drive they are very odd?? are they for a gettrag box?? surely that would be easier, or does the zf box bolt straight up??

the e36 zf case are all 1:1 5th which is ok with maybe a 3.65 diff, 4th to 5th is very close!

still if the price is right its another option available, so what sort of price are we looking at?

[morerevsm3]

the M20 ratios are for a 320i rally class, not much good for big hp, zf bolts straight up to motor, crossmember needs slight mod for slight angle change, and you have option of 4, 5 or 6 speed with ZF also, RRP is 4000euro for 5 speed, 4800 for 6 speed, then there is optional shifter, GST etc, I can do a better price than that though...

[reggid]

i wonder if the high rpm harmonic issues at high rpm are responsible for oil pump shaft breakage? ive heard of them breaking before and even the auxiliary shaft !

[morerevsm3]

it twisted 180* before it snapped, the 60 weight oil, cold winter morning and cold temps that E85 keeps engine at all combined to snap it