Most Powerful N/A M20's

[digger]

Thanks for this Info Digger, Very Helpful, Ill get the head of my 'new' engine flow tested and see how results compare with the above, based on this you can almost correlate the power to the flow of the heads on the three engines!

roughly hp potential = 1.65 x cfm (for a 6 cyl based on 2.2hp per cfm for a v8)

so stock head taps out at 275bhp (220-230whp) and ported 355bhp (293 to 302whp) assuming 15-17.5% drivertrain.

its no suprise there are many m20 around that 200-230whp range as most have a stock or ineffectually ported head

Rob's 2.8 is a bit of an outlier. i did read in a magazine some years ago that subsequent incarnation made 240rwkw which is 322rwhp which makes sense with e85 and abunch more compression worth 20-25rwhp.

[downforce22]

e30tech isn't dead, you're welcome, only problem is the search function and those type of features don't work

http://e30techarchive.com/

[moatilliatta]

https://racecarsdirect.com/Advert/Details/133372/bmw-e30-325i-m20-29-engine

[AntParker]

This is the head that TK did for mine but with a better valve shape than what they were when TK flowed it. i never really liked the valves i got from VAC that i supplied to Tony so i changed them out sometime later for some with a different shape so i could add a nice backcut and reflowed it and it picked up 10-12CFM over the other valves (back to back tested) without touching anything else. In my build thread this is why the numbers below are higher.



Robs 2.8 flows a little bit more than this and Rama's 2.9 a little less as a point of reference

I would get the head flow test by a reputable place

Thanks for this Info Digger, Very Helpful, Ill get the head of my 'new' engine flow tested and see how results compare with the above, based on this you can almost correlate the power to the flow of the heads on the three engines!

[AntParker]

AntParker, one possibility is to contact Atrex Automotive in Belgium, not in U.K but at least this side of the ball. Their 2.8 race engines perform around 320bhp, and measured with devices and standards we use here.

Oh perfect, ill take a look, thank you !

[digger]

Thanks Digger, Really interesting, So the head which is on my engine now was ported and matched to the intake (RHD ITBs) but id be interested to get it on a flow bench and see what she actually flows.

I'm based in the UK, there was an engine built here last year which made 298BHP, I have now bought that engine (albeit in bits) so I'm tempted to bolt that back together and in theory should make good power, however looking at the head and how worked it looks in comparison to some of these others I'm sceptical of it making the numbers. Maybe i'll contact one of the guys above and see if they can do me a head so i know its good for the figures.

Without getting too geeky, I don't suppose you have flow figures for heads on any of these big power builds. If so much focus is on the head, is it safe to say that a conventional(ish) stroker bottom end (M52 Crank, rods (Either H Beam or normal) and mahle forged pistons are about all thats needed for the bottom end to be reliable (of course normal stuff like decent bearings, ARP Bolts etc))

thanks again

This is the head that TK did for mine but with a better valve shape than what they were when TK flowed it. i never really liked the valves i got from VAC that i supplied to Tony so i changed them out sometime later for some with a different shape so i could add a nice backcut and reflowed it and it picked up 10-12CFM over the other valves (back to back tested) without touching anything else. In my build thread this is why the numbers below are higher.



Robs 2.8 flows a little bit more than this and Rama's 2.9 a little less as a point of reference

i would get the head flow test by a reputable place

[hasa]

AntParker, one possibility is to contact Atrex Automotive in Belgium, not in U.K but at least this side of the ball. Their 2.8 race engines perform around 320bhp, and measured with devices and standards we use here.

[AntParker]

TK (Tony Knight) Knight Engines is in South Australia so even for me like 1,000km. Rama (RHD) has a digitised port that is very good (need to ship a good checked core) and Grooty also does porting and knows his stuff. Lots of options if youre down under. Forcedfirebird doesn't post much but also has done a big valve head that flows the goods but he's in USA. Stay away from the "namebrand" shops for portwork IMO

Thanks Digger, Really interesting, So the head which is on my engine now was ported and matched to the intake (RHD ITBs) but id be interested to get it on a flow bench and see what she actually flows.

I'm based in the UK, there was an engine built here last year which made 298BHP, I have now bought that engine (albeit in bits) so I'm tempted to bolt that back together and in theory should make good power, however looking at the head and how worked it looks in comparison to some of these others I'm sceptical of it making the numbers. Maybe i'll contact one of the guys above and see if they can do me a head so i know its good for the figures.

Without getting too geeky, I don't suppose you have flow figures for heads on any of these big power builds. If so much focus is on the head, is it safe to say that a conventional(ish) stroker bottom end (M52 Crank, rods (Either H Beam or normal) and mahle forged pistons are about all thats needed for the bottom end to be reliable (of course normal stuff like decent bearings, ARP Bolts etc))

thanks again

[digger]

Gotcha, Sounds like i need to find this guy and ship him the head for my new build! after watching some more of grooty's videos yesterday it looks like the head is key!

Sadly i don't have a build thread no, I didn't build it myself, i made a thread of the spec before i had it built, but now I'm sceptical in if it contains all the bits i sent them. I will build the 3.0 myself over the winter and see whats what - although I'm almost tempted to pull apart both motors and take all the best bits from each - or even to bolt a really good head onto my existing bottom end.

Is the guy that did your head in the states or australia mate?

TK (Tony Knight) Knight Engines is in South Australia so even for me like 1,000km. Rama (RHD) has a digitised port that is very good (need to ship a good checked core) and Grooty also does porting and knows his stuff. Lots of options if youre down under. Forcedfirebird doesnt post much but also has done a big valve head that flows the goods but hes in USA. Stay away from the "namebrand" shops for portwork IMO

[digger]

I found some old images

Rob 2.8 348 whp




A 2.8 with 306whp (tk head)




Rama 2.9L 294whp


Rama 2.7L 731 head 247whp (288 cam) 266whp (catcams 304)



2.7L 265bhp (from this site?)


3L 276bhp (288 cam iirc)


Seen a few other 2.8/2.7/2.9 about same power level

Grooty has atleast a few > 200rwkw

only the first few had full on port work 885's (tk) and ramas 2.9 was a 731 (rama). Rama's original 2.7 had a ported 731 head (by someone lese) but didnt have near the same work as the others but still better than stock

[AntParker]

I would do +2mm 44mm Inlet stock 36 exhaust. There is no need for +1 exhaust valve

do you have a build thread.? Most ported heads are no better than stock. I bought one from a well known place and flowed it independently and it didn’t match upto the claims hence mine doesn’t make anymore than what a stock headed stroker with itb does.

That’s why I found someone who knows what they are doing and that’s what’s in my build thread. The same guy that build the e85 engine did my head and the finishing touches to Grooty’s 2.9 head If I’m not mistaken

Gotcha, Sounds like i need to find this guy and ship him the head for my new build! after watching some more of grooty's videos yesterday it looks like the head is key!

Sadly i don't have a build thread no, I didn't build it myself, i made a thread of the spec before i had it built, but now I'm sceptical in if it contains all the bits i sent them. I will build the 3.0 myself over the winter and see whats what - although I'm almost tempted to pull apart both motors and take all the best bits from each - or even to bolt a really good head onto my existing bottom end.

Is the guy that did your head in the states or australia mate?

[digger]

The Comments for the engine on youtube above - 'robs 2.8E30' Says it has 4mm Larger valves if thats right that must be a considerable re work of the entire head surely.
Do you think 1mm oversize valves with decent head work and say 288 or similar cam would be enough to see 300bhp?

Its a shame the E30 tech forum dies, i guess the number of people doing these sorts of buils has decreased massively over the years in favour of cheap power elsewhere.

I will take a look at your build thread digger as well as those others linked above.

I have a decent Stroker build with ITB's, ported head etc which isn't making the power i feel it should and trying to work out why/ what i need to do with the next build to ensure i make the power I'm after (Ideally 280/300bhp)

:)

I would do +2mm 44mm Inlet stock 36 exhaust. There is no need for +1 exhaust valve

do you have a build thread.? Most ported heads are no better than stock. I bought one from a well known place and flowed it independently and it didn’t match upto the claims hence mine doesn’t make anymore than what a stock headed stroker with itb does.

That’s why I found someone who knows what they are doing and that’s what’s in my build thread. The same guy that build the e85 engine did my head and the finishing touches to Grooty’s 2.9 head If I’m not mistaken

[AntParker]

Yeah it’s pointless using bigger valves without machining the throat to suit and also blending to the bowl and reprofiling the short side etc

you don’t need a roller rocker setup as the highest hp numbers were without one. You will likely end up needing slightly more duration though.

build sheets were on e30tech forum which died. There is Grooty’s YT channel. My build has some head stuff iirc but I’m not using a big camshaft but should easily do 300bhp but not 300whp

knightengines built the big ho e85 2.8 discussed here but only some snippets

https://www.speed-talk.com/forum/viewtopic.php?t=31132&sid=6093a3ea87a73288a26108ec758c7597&start=15

comparing power at the crank is a variable itself as every dyno does it differently and deducing it in some respects flawed as the drivetrain inertias are not known and the losses are not measured under load they are done under coastdown

The Comments for the engine on youtube above - 'robs 2.8E30' Says it has 4mm Larger valves if thats right that must be a considerable re work of the entire head surely.
Do you think 1mm oversize valves with decent head work and say 288 or similar cam would be enough to see 300bhp?

Its a shame the E30 tech forum dies, i guess the number of people doing these sorts of buils has decreased massively over the years in favour of cheap power elsewhere.

I will take a look at your build thread digger as well as those others linked above.

I have a decent Stroker build with ITB's, ported head etc which isn't making the power i feel it should and trying to work out why/ what i need to do with the next build to ensure i make the power I'm after (Ideally 280/300bhp)

:)

[digger]

Other way around. Regardless of typo, do you really think 50hp is going to be lost going from engine dyno to chassis in an E30 at this level? That's almost over 3x what is lost in a stock car, which will typically dyno in the low 150s in good health from what I've seen. Unless the engine dynos you're thinking of are measuring old school gross hp without even a water pump belt, like what is commonly seen in american V8 engine shops. Anyway I was would say yes, I would refer to a streetable M20 in asking if anyone has ever actually made 300hp with an M20, just about anything can make power on race gas with a no holds barred race build. I still have yet to see any documented instances of M20s making 100hp/L or more at all let alone more than that, like 100whp/L.

I’m going by dyno dynamics (most common around these parts) 250rwhp vs 300bhp which is 17%

haven’t directly seen a 300bhp dyno but I will dig out records and by extension its very doable. Mine will easily do it when I get around to it with a pretty tame cam

I should still have a couple of pump fuel dyno charts 290rwhp (2.9L) and 305whp(2.8) not really street engines. I have some mild street engines with 270-280bhp 2.8-3L. I will see if I can dig out details and collate

[varg]

300bhp is probably 350rwhp depending on dyno in question.

Other way around. Regardless of typo, do you really think 50hp is going to be lost going from engine dyno to chassis in an E30 at this level? That's almost over 3x what is lost in a stock car, which will typically dyno in the low 150s in good health from what I've seen. Unless the engine dynos you're thinking of are measuring old school gross hp without even a water pump belt, like what is commonly seen in american V8 engine shops. Anyway I was would say yes, I would refer to a streetable M20 in asking if anyone has ever actually made 300hp with an M20, just about anything can make power on race gas with a no holds barred race build. I still have yet to see any documented instances of M20s making 100hp/L or more at all let alone more than that, like 100whp/L.