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Reynard38
02-04-2007, 09:23 AM
OK, trying to make a final decision. The car will be a DD as well as trackdays, time trials and hill climbs. I prefer the response from a NA engine, but obviously the power of FI is intoxicating.
I have a 2.7 ETA block, and a 524td crank. If I go the NA route, keeping the car emmisions legal, how much HP and torque could I make?
I don't mind doing it right- MAF conversion, head work,Schrick cam, headers, hi-flo cat, extrude hone etc.
I read in the E30 resto book that Alpina made 210hp and good torque with their 2.7's so I would thing with modern equipment this should be exceedable.
Ideas?

e30_325es
02-04-2007, 10:46 AM
I don't think you could do much in terms of modifications and still keep your car emmisions legal, unless you go stand-alone and get 2 tunes, one for power the other for emmisions.

Reynard38
02-04-2007, 12:54 PM
I should have clarfied just what "emmisions legal" means here in GA. It's a sniff test, and they roll a mirror under the car to see if there is a cat (or something that looks like a car) installed.
There is no under hood inspection at all.
FWIW my friend has a 325is race car with a 288 cam, bigger injectors, AFPR and a chip and it passes no problem.

chris325ix
02-04-2007, 01:51 PM
don't bother with the TD crank on an N/A M20.

Reynard38
02-04-2007, 02:23 PM
don't bother with the TD crank on an N/A M20.

Too late, its already being lightened, polished and balanced. Besides for what I paid it's cheap piece of mind as the revs creep up to 7000. :thumright:

e30_325es
02-04-2007, 03:19 PM
I should have clarfied just what "emmisions legal" means here in GA. It's a sniff test, and they roll a mirror under the car to see if there is a cat (or something that looks like a car) installed.
There is no under hood inspection at all.
FWIW my friend has a 325is race car with a 288 cam, bigger injectors, AFPR and a chip and it passes no problem.


Well....There's your answer. Have him put that on a dyno.

Reynard38
02-04-2007, 03:20 PM
I should have clarfied just what "emmisions legal" means here in GA. It's a sniff test, and they roll a mirror under the car to see if there is a cat (or something that looks like a car) installed.
There is no under hood inspection at all.
FWIW my friend has a 325is race car with a 288 cam, bigger injectors, AFPR and a chip and it passes no problem.

192 RWHP from a 2.5 liter

Well....There's your answer. Have him put that on a dyno.

Dominic49
02-04-2007, 04:21 PM
where in marietta are you? i'm over off shallowford and sandyplains and have been looking for more e30s to play with....



and if you decide to go all out NA monster i have an emissions hook up........

Reynard38
02-04-2007, 05:23 PM
where in marietta are you? i'm over off shallowford and sandyplains and have been looking for more e30s to play with....

Just off of Johnson Ferry, Little Willeo Rd.



and if you decide to go all out NA monster i have an emissions hook up........

Thanks. I may need that. Oh and on the subject of hook ups, about your signature... :twisted:

digger
02-04-2007, 09:27 PM
180 whp 180 rwtq is realistically achievable.

klrskies
02-05-2007, 11:45 AM
If you focus on the top end, good results should be obtainable in N/A state. IPerhaps 210 ~ 220 Crank HP.

I would go with a 264 cam w/ 11 mm lift. this will increase flow due to increased valve lift and a hight valve lift acceleration rate, yet maintain low overlap to control emmissions.

You could bore your valve seats 2mm to increase port flow without hurting the seat or head.

Look at metric mechanics web site for some porting tips and Port match yourt intake.

Our long "i" Intake is great for torque, useing the second reflection, but if you could cut the plenum off, and shorten the runners 2 inches, then add two plenums of the correct volume, you'd see some dramatic improvements in breathing and HP output at about 1000 higher RPM than stock. It would require the correct header to make it all work together.

While the head is off, consider having it milled to take compression up a point. You'll need to re-time the cam.

Upgrade to the improved rocker arms to take the RPM's.


You might want to go to a rising rate regulator to provide the fuel you'll be needing when the header and intake start to work at about 5500 rpm up to 6800 RPM, Or consider stand alone engine management to do it right.

stylngle2003
02-05-2007, 03:05 PM
it really isn't a good idea to skim the head to increase compression because it reduces your squish area, which messes with flame propagation and combustion efficiency. skim the head only as much as necessary to make a flat mating surface.

reynard, are you thinking of going with an I head/intake? that would help get top end breathing up toward where you need it.

if you want increased compression and combustion efficiency, skim the block. i dont know what the compressed thickness of your headgaskets are for m20s, but in the volvo community, having a squish clearance (that is compressed HG thickness minus piston protrusion) of .035" or less is good for promoting fastburn and tight squish.

with headwork and a nice cam, i dont see why you couldnt attain your goals easily with standalone ems, be it MS, VEMS, whatever. make everything light and balance it all, so it revs smoothly. give it some more compression and a meaty cam, work the head/intake/exhaust for more flow, and rev the crap out of it. RPMs make big HP, so you'll probably want to focus on 3000+ rpm as your powerband. but torque is ultimately more important, especially for a DD, so give it a good tune and have whoever is working your head focus on low-lift flow numbers also.

klrskies
02-05-2007, 04:03 PM
I'd go with "i" top end componets. Eta was never designed to go where your wanting to go. You need RPM's to make HP.

If your uncomfortable skimming the head the whole amount to raise compression up, you might consider applying thermal barrier coatings to your head, and possibly pistons tops. Compression will come up some and gas speed and cylinder pressures will be higher. The stock pistons will be stronger in the top ring land area, and will resist detonation damage better when coated. ETA pistons are known to collapse the skirts so be aware af that possibility.

As for cam choice, I'd stay light on the duration to pass emmissions 270~275 degrees is nice for a DD. A free breathing top end with a good scavenging header will raise the RPM range signifigantly without the diminishing idle / low-end torque qualities of increased duration cam profiles. You really don't need alot of duration if the ports flow well and the intake and exhaust are designed for the job. The right header will be signifigant in making better top end HP.

G2
02-05-2007, 04:07 PM
hey, guys I'm just over the county line in fulton off johnson ferry and abernthy. We need to get an e30 gathering together. I have a red 325i set up for DE's...

digger
02-05-2007, 08:10 PM
If you focus on the top end, good results should be obtainable in N/A state. IPerhaps 210 ~ 220 Crank HP.

I would go with a 264 cam w/ 11 mm lift. this will increase flow due to increased valve lift and a hight valve lift acceleration rate, yet maintain low overlap to control emmissions.

You could bore your valve seats 2mm to increase port flow without hurting the seat or head.

Look at metric mechanics web site for some porting tips and Port match yourt intake.

Our long "i" Intake is great for torque, useing the second reflection, but if you could cut the plenum off, and shorten the runners 2 inches, then add two plenums of the correct volume, you'd see some dramatic improvements in breathing and HP output at about 1000 higher RPM than stock. It would require the correct header to make it all work together.

While the head is off, consider having it milled to take compression up a point. You'll need to re-time the cam.

Upgrade to the improved rocker arms to take the RPM's.


You might want to go to a rising rate regulator to provide the fuel you'll be needing when the header and intake start to work at about 5500 rpm up to 6800 RPM, Or consider stand alone engine management to do it right.

it is interesting to note that MM use standard valves and don't port match the exhaust to the gasket as alot of people do( it prevents reversion of exhaust gases into the combustion chamber) A light clean to the ports (particularily the exhaust) and some work to move the air flow around the valve guide and more focus around the valves is where any gains are to be had but headwork should always be accompanied by a suitable cam and don't be confused into thinking that the duration and lift tell the whole story (lift off the seat durign overlap will strongly influence idle and emmsions and duration doesn't indicate this). Jordan used a shrick 274 IIRC with good results. One think to note is the peak power band will be between 5500-6500rpm at best, the bigger the capacity the lower the rpm where the peak occurs will be.

mormonmopedmafia
02-05-2007, 09:07 PM
sorry for off topic but what would you guys say the best "bang for buck" buy is for an N/A eta? becuase most of the usual honda boy things dont work... i hear intakes are almost always worse, and have not really seen real improvements with exhuast (save turbo applications) ...

right now im thinkin ill stay n/a till im out of school so im thinkin i might do

-- chip ( ebay)
-- 3.73 rear diff
-- lowered "1-"1 1/2

and besides that i cant think of a good really good n/a improvement

imsotyerred
02-05-2007, 09:38 PM
3.15 (if you can find one) or a 3.25 LSD and a TMS chip

don't go with a 3.73

mormonmopedmafia
02-05-2007, 10:07 PM
where might i obtain one of these ... what kinda car can i find one in

bottlecape30
02-05-2007, 11:45 PM
search a little and you can find all that info.
You can find the 3.25 in a e28 535i
you must swap the output flanges to fit.
the best for performance is the 3.46 from a e24 635i
or have korman re-build you one with any gear you want.
I run a 3.33 lsd and it made the car real quick.

klrskies
02-06-2007, 12:21 AM
I think were a little anxious to throw in the towel on N/A M20 tuneing techniques!

N/A M20's can be built in various states of tune to accomodate a broad spectrum of enthusists. Check out Korman's stuff, he's been at it for quite a while, and certainly has built some world class BMW racing engines... including M20's. Metric Mechanic has done alot of development, and has publicized much of it for we laymen to see. When someone in business decides to market a product such as a ported cylinder head, he's faced with a few hurdles...Waranty issues, parts costs, machine time, labor, liablility risks, r/d costs, materials, advertising costs,etc... A business has to turn a profit to survive. That's no surprise, and it's not because they wouldn't like to offer a more impressive product, but because the product has to make the necessry compromises to generate enough profit to remain afloat, it's not quite the state of the art product it's marketed as.

Can Metric Mechanic build a more agressively ported, high flow volume, big valve head? sure they can! Will the market support it? No, it's not cost effective for their market sector. Can Korman offer a 300 HP race engine? Sure, but it's for the select few who can justify the expense. We don't have the aftermarket strength of Honda, but realize that our pistons go up and down too, and respond to all kinds of tuning techniques. Study those other engines to see why they perform well and apply what will work to your engine. The M20 was never provided the kind of High-performance development of the S14, S38, S50, S52 but what would have BMW Motorsport done if they'd focused on the M20? You would have seen it grow into a 225 HP screamer. With displacement increases, it would easily have been a streetable 250 HP.

Could a person build a streetable 225~250 HP N/A M20 today? Without a doubt. It would be a great engine for our e-30's! light and un-complicated.

Reynard38
02-06-2007, 09:35 AM
I think were a little anxious to throw in the towel on N/A M20 tuneing techniques!

N/A M20's can be built in various states of tune to accomodate a broad spectrum of enthusists. Check out Korman's stuff, he's been at it for quite a while, and certainly has built some world class BMW racing engines... including M20's. Metric Mechanic has done alot of development, and has publicized much of it for we laymen to see. When someone in business decides to market a product such as a ported cylinder head, he's faced with a few hurdles...Waranty issues, parts costs, machine time, labor, liablility risks, r/d costs, materials, advertising costs,etc... A business has to turn a profit to survive. That's no surprise, and it's not because they wouldn't like to offer a more impressive product, but because the product has to make the necessry compromises to generate enough profit to remain afloat, it's not quite the state of the art product it's marketed as.

Can Metric Mechanic build a more agressively ported, high flow volume, big valve head? sure they can! Will the market support it? No, it's not cost effective for their market sector. Can Korman offer a 300 HP race engine? Sure, but it's for the select few who can justify the expense. We don't have the aftermarket strength of Honda, but realize that our pistons go up and down too, and respond to all kinds of tuning techniques. Study those other engines to see why they perform well and apply what will work to your engine. The M20 was never provided the kind of High-performance development of the S14, S38, S50, S52 but what would have BMW Motorsport done if they'd focused on the M20? You would have seen it grow into a 225 HP screamer. With displacement increases, it would easily have been a streetable 250 HP.

Could a person build a streetable 225~250 HP N/A M20 today? Without a doubt. It would be a great engine for our e-30's! light and un-complicated.

This is what I wanted to hear! I love those two words "light and un-complicated"
So a 2.7 ETA with a forged crank and I head. Where do I go now to achive 225-250 NA horsepower? I am ready to build this thing.

klrskies
02-06-2007, 12:57 PM
It's best to get a realistic budget set up before you begin.

How much do you have to spend?

Reynard38
02-06-2007, 02:33 PM
It's best to get a realistic budget set up before you begin.

How much do you have to spend?

$7500 for parts and machining, though obviously I wouldn't mind some change back out of that.
I already have the 2.7 ETA motor sitting in a stand, and the forged crank is at a machine shop being lightened, balanced and polished. I also have a spare I head and intake.

Thing-90ix
02-06-2007, 02:48 PM
1. ECU, preferably autronic. Cheaper options: VEMS, MS

2. fabricate a exhaust manifold to match your camshaft and intended rpm range.

3. cam shaft

4. headwork, and NONE of that p&p or "gasket matching" bullshit

5. higher compression 11:1 should be in the ballpark

klrskies
02-06-2007, 03:04 PM
How much of the work are you comfortable doing yourself? Do you have the time and space to do it?

Reynard38
02-06-2007, 03:15 PM
How much of the work are you comfortable doing yourself? Do you have the time and space to do it?

All of the work, and yes I have a shop to do the work in. FWIW I have build 2 engines. A 2 liter OHC Ford for an F2000, and a very modified 914 type 4 motor.
I also have a very good race machine shop close by. If I get stuck the shop that works on my 911 has offered to help. He says he makes plenty of $$ off of my 911 and doesn't mind helping out with a fun project.

klrskies
02-06-2007, 03:22 PM
OK, Good.

I've built a few AIr cooled VW's myself. It's nice that everything is so modular on them isn't it? What engine does your 911 have? I hope to have a 911 some day O:)

Might as well start with the block, what shape is it in? are you committed to using your eta pistons?

Reynard38
02-06-2007, 05:54 PM
OK, Good.

I've built a few AIr cooled VW's myself. It's nice that everything is so modular on them isn't it? What engine does your 911 have? I hope to have a 911 some day O:)

Might as well start with the block, what shape is it in? are you committed to using your eta pistons?

My 911 has the 3.6 liter varioram engine (last of the aircooled 911's). I've always wanted one. Finally was able to swing it 3 years ago.

I'm going to start pulling the ETA down tomorrow night, and no, aside from the block and 524td crank I'm not commited to using any parts from it.

wiglaf
02-06-2007, 07:51 PM
so.. is it realistic to take a regular 325 bottom end and shave it down to get 12.5:1 compression or will i be looking at some wierd special pistons and stuff?

I know that 12.5:1 isn't too high because my sportbike pulls it off fine.. just gotta use midgrade or premium gas.

chris325ix
02-06-2007, 09:17 PM
12.5:1 using stock cast pistons would be a pretty bad idea. I belt they would melt sooner rather than later.. plus stock pistons are heavy, not what you want if you intend to rev.

digger
02-06-2007, 09:39 PM
1. ECU, preferably autronic. Cheaper options: VEMS, MS

2. fabricate a exhaust manifold to match your camshaft and intended rpm range.

3. cam shaft

4. headwork, and NONE of that p&p or "gasket matching" bullshit

5. higher compression 11:1 should be in the ballpark

port work is good. As can be polishing the exhaust ports to prevent carbon build up but its not essential and the $$$ usually make it not worthwhile.

peerless
02-07-2007, 12:06 AM
M20 block, bore to 86mm. 524TD crank, 135mm rods, custom pistons forged 11.5:1 domed, 885 head with a very aggressive cam, quality set of headers (Stahl, etc.), either ITB's or 3 sidedraft carbs (saves the hassle of standalone electronics)

Make sure to use quality components throughout. Build a solid stout shortblock, but really work the hell out of the head as thats whats making your power.

Good Luck with it. You have a perfect budget to build some serious M20 HP.

=D>

Stevin
02-07-2007, 03:26 AM
M20 block, bore to 86mm. 524TD crank, 135mm rods, custom pistons forged 11.5:1 domed, 885 head with a very aggressive cam, quality set of headers (Stahl, etc.), either ITB's or 3 sidedraft carbs (saves the hassle of standalone electronics)

Make sure to use quality components throughout. Build a solid stout shortblock, but really work the hell out of the head as thats whats making your power.

Good Luck with it. You have a perfect budget to build some serious M20 HP.

=D>

I like this setup, except... I would go witha M52B28 crank...

klrskies
02-07-2007, 03:26 PM
As for the bottom end, you like the TD crank, so you could design the engine to obtain peak HP around 6500 ~ 7000 RPM without worrying about the crank. Rods could be 130 or 135 mm length. The 130's will generate a slightly stronger impulse for your tuned intake and exhaust, will put more demand on your the intake and exhaust tracts, and probably make a little more power than the longer rod. They will also put more stress on the pistons and crank and themselves with the steeper rod angle. the 135's will be a little easier on things and make a little less power. I don't know the weight difference yet but I have both so I'll try to weigh them and see.

The rods should be new or thoroughly inspected and high grade fasteners installed. They could be lightened slightly ( 5~8%), shot-peened, polished on the beams, and balanced as a set and end to end. You can do alot of this yourself if your inclined for a little expenditure and some time.

stylngle2003
02-07-2007, 03:55 PM
N/A, you'll find your power in the head and by upping the compression. Having programmable timing control will make huge gains also.

Work the I head, get bigger valves, with the needed work to make them do their thing properly.

Up the compression with lighter, forged pistons. 11:1 should be the low end of what you should run for that kind of power.

Lighten and balance everything...flywheel, crank (which you are already doing, cool!) rods, pistons, everything.

Get a big cam. 272 or bigger

Megasquirt at the very least

I think you could do it on the I intake, as long as you make sure it flows well and gets nice cold air.

Bigger injectors and a beefy fuel system is a must also

Likely a 6:1 header, but shorties could probably work also.

should be a hoot, keep us up on it!

bigjake
06-19-2008, 02:36 PM
awhile back there was a guy at heartland park with a 88 325 that had a built n/a m20 with itbs, and alot of other stuff done to it, i think it had like 263 hp naturally aspirated, but he had to run it on 100 octane, and i think he rebuilt like once every 29k, i am taking a similiar route but im not buying the 3.2 metric mechanic motor like he did, im just doing a 2.7 stroker with itbs, i expect 220 range on pump gas

BMW BUM
06-19-2008, 05:06 PM
awhile back there was a guy at heartland park with a 88 325 that had a built n/a m20 with itbs, and alot of other stuff done to it, i think it had like 263 hp naturally aspirated, but he had to run it on 100 octane, and i think he rebuilt like once every 29k, i am taking a similiar route but im not buying the 3.2 metric mechanic motor like he did, im just doing a 2.7 stroker with itbs, i expect 220 range on pump gas

220 range at the wheels on pump gas on a 2.7? I'd say maybe about 200 on a decent build, no?

j9fd3s
06-19-2008, 08:21 PM
idea!

since bmw basically took an m20, and has upgraded it into an m50/m52/??? you can kinda follow their lead...

i know they raised the redline, but how? lighter pistons? longer rods? shorter rods?

higher compression....

basic difference is that you're sticking with the m20 head, so getting that right is mucho importante.