Why does everyone seem to think 320i's a rubbish

[Brianmoooore]

They're biting well again!

[StuBeeDoo]

They're biting well again!

Not biting Brian, just making a point. You are a guy who is known and respected for your opinion and expertise,:thumb: can you disprove any of the above? I'm always willing to learn and if you can prove me wrong, I'll accept graciously.

On a general note, certain members have a habit of greeting newbies with "nice looking car, now bin the engine and put a 325i in"! (or something similar) Not very welcoming, is it?
Stuart.

[Borderbmw]

I think maybe we should put it down to and keep it as friendly rivalry,just a bit of fun......i cant afford anything bigger(yet! )

Lets keep it fun boys as i dont want to see anything get out of hand,be cool

[tomstickland]

I've been down various engine tuning routes before. Tuning engines for large gains is not cost effective if there's a bigger engine already out there that's suitable. It can be fun though, which often is reason enough.

I don't see a chip and a throttle body change lifting the 320 engine up to 150BHP though. That and a tidy exhaust system might change the character of the 320 though, to an engine that's more satisfying.

But there is no really good argument for doing expensive tuning to a 320 when the 325 engine is already making 170BHP ish out of the box.

[StuBeeDoo]

It can be fun though, which often is reason enough.

Indubitably(sp?)!!

I don't see a chip and a throttle body change lifting the 320 engine up to 150BHP though.

Been done more than once! Cam and exhaust in addition take it over 160.

[tomstickland]

Ah, I doubt most power claims from tuning/rolling roads. 90% of them are not plausible. I'd have to see the testing back to back on a decent rolling road. Or using 1/4 mile times which are more reliable.

Actually the at wheel power of these 150BHP 320s would be nice to know before commenting any further.

At what rpm do these engines make 150/160BHP?

[Brianmoooore]

Ah, I doubt most power claims from tuning/rolling roads. 90% of them are not plausible. I'd have to see the testing back to back on a decent rolling road.

Totally agree. Most rolling roads are OK for before and after testing, but the actual figures are next to meaningless.
HP can be calculated from acceleration times with a bit of simple maths, though.

[Andy_magic]

Widge, in your opinion, why is the 325i combustion chamber more effiecient.?

If you look at the power output/litre the 320 isn't far behind the 325.

I think the killer for 320s fuel consumption is the gearing. 80mph/4krpm is silly for a car.

If they had built the 320i engine with more stroke and less bore it would have been torquier and more capable with higher final drive ratio's

I liken driving my 320 to riding an RD125LC, peaky, gutless when off the boil (Not as smoky though - lol:) and a nice machine when wound up. But not as quick as a 250!

I'm hoping to get some work done on my 2.7 conversion this week.

Apart from the engine, box, diff, front struts what are the other differences between a 20 and a 25.

[Widge]

IMO the combustion chamber is more efficient - it's this which comtributes to the poor fuel economy, it's not just the gearing because you have to consider that the smaller engine produces less power for the same amout of fuel. Look at the diags below.

The bowl/dome on thew 2.5 piston, which matches the head increases the swil and mixing of the fuel air mix throught out the chamber which gives a more even burn. And it also helps in the exhausting of hot gasses.

Other differances are Valve sizes, Port sizes, Inlet manifold, TB, and I think the exhaust manifold is smaller.

Mate I'm not here to junk the 320 it's just with our petrol prices who can blame people for saying the 2.0ltr is crap, when there is a larger more powerful and almost more economical lump avalible.

What spec is your 2.7 going to be mate?

[Andy_magic]

my postings probably sound much more serious than they really are, I'm just gauging peoples interests and views (and to a certain extent if people know as much as they let on )

I know where your coming from on the fuel consumption front.

My 2.7 is a poverty spec build, due to a couple of reasons, 1, I'm too poor to fork out for machining costs, 2 I've got 2 bike projects on the go (Silly 125's from the 80's) and 3 is my lack of workshop facilites. I have access to a workshop (and know what to do in there) but it's an 80 mile trip and 80 back again. Which makes things difficult.

It will be ETA bottom end, 320i re-con head, mildly ported by myself, 325i injectors, TB AFM etc and a Zone 2.7 chip.

This car is my daily driver so anything I do to it has to be done in 2 days or less due to the workshop hassles.

I'd be very interested in the comparison between this method and the 325i way of things...

And maybe a bang per buck ratio!

[Widge]

No cam then? Just the 256 i cam? I was gonna do that till I got a steal
I know what you mean about the 2 days thing, thats why I'm gonna get a spare engine and build it all up then drop it in over a week end.
Mine will be poverty spec too (student) but I think at this rate it may cost abit and just take a long time I'm in no hurry.

[Andyboy1]

Sorry Brian old boy, but the M50 conversion is nothing new, very 2003 to be honest. A mate in Germany and I are doing a 3 litre M52 at the moment on a 1990 325i Touring, M50 head with Schrick cams and E36 engine loom - expecting about 245 bhp from that one. We went that route after experimenting with a 2.8 litre M20 (modded M50 crank) that's in Adam's car, but after a certain BMW specialist made a complete bollocks of the management (a Unichip for f*ck's sake - can you believe it??!) we decided to go 3 litre. In theory you could even use a 3.2 M3 short engine with an M50 head.

BTW if you want to know what a fast car is, pack the rice rocket away and have a go in my old man's 911. 1994 992 C2 with modded varioram 3.8 twin plug motor, 350 bhp - reasonably brisk.

[Brianmoooore]

My 2.7 is a poverty spec build

It will be ETA bottom end, 320i re-con head, mildly ported by myself, 325i injectors, TB AFM etc and a Zone 2.7 chip.
!

[Widge]

My 2.7 is a poverty spec build

It will be ETA bottom end, 320i re-con head, mildly ported by myself, 325i injectors, TB AFM etc and a Zone 2.7 chip.
!

And?????

Comments appreciated, ing someones post is not really constructive

[Andyboy1]

Slightly but what's the difference between a 2.0 ---> 2.7 and a 2.5 ---> 2.7?

Have wondered for a while now...

Easy - the 2.7 conversion on the 320i is the easiest. Although the 2.7 525e used a 200 casting head (from the E21 320 and 323i), the chamber volume is exactly the same as the 731 head used on the E30 320i and 323i. Therefore the head goes straight on without skimming and you can take advantage of the Eta's high compression. Cars up until around Aug/Sept 1985 had the 11:1 compression which is a little high and would require 98 fuel. later cars used a 10:1 compression which is fine. The 320i inlet manifold is okay and in fact, the 320i ports aren't much smaller than those of the 325i. All screwed together with the 325i throttle body, it makes for a very responsive and torquey engine with around 180 bhp.

The 325i conversion to a 2.7 is more involved, requiring block machining (after taking it all apart) to use the 325i pistons. You CAN screw a 325i head straight onto a stock Eta bottom end and it will work - just not quite as well as doing the job right.

[Brianmoooore]

My 2.7 is a poverty spec build

It will be ETA bottom end, 320i re-con head, mildly ported by myself, 325i injectors, TB AFM etc and a Zone 2.7 chip.
!

Interesting! I have all these bits lying around doing nothing, except the ETA bottom end, and I know where there's one of them for Ԛ£15 (E28 525e)
I'm not into forking out for machining work or special bits either. Skint - wife, three kids and too many BMWs, so will all these bits just bolt together with no mods.
What's the best cam to use? standard 320 or 325?

[Brianmoooore]

My 2.7 is a poverty spec build

It will be ETA bottom end, 320i re-con head, mildly ported by myself, 325i injectors, TB AFM etc and a Zone 2.7 chip.
!

And?????

Comments appreciated, ing someones post is not really constructive

Think I may have pushed the wrong button!

[Andyboy1]

That's a nice build spec Widge, ideal really. Properly set up you should have an easy 180 bhp but it would be daft not to fit a better cam (if you can spare the Ԛ£Ã”šÃ‚£Ãƒ”šÃ‚£ of course) as the standard cam is just wank - they are 252 degrees which is like something out of a lawnmower. Ideally smoething like a 270 degree stick would liven it up. The 320i head won't need much - if anything - in the way of gasflowing. part of the rerason the 320i and 323i were so gutless at low RPM is that the ports were really a bit too big. For example, Ford tuners found out years ago that fitting a 1600 Pinto cylinder herad to a 2 litre gave marginally more power and a lot more low down torque. In much the same vein, an E21 323i with the 200 head with the 'crap' small ports was a lot more lively than the E30 version. Leave your head well alone!
With the standard 4.1 diff she'll be an animal!!

Alpina made a catalyst version of the C2 2.7 which used the standard 325i cam for emissions yet they were still quoting 200 bhp. Hmmm - I've not seen a C2 2.7 yet that does over 200 bhp WITH the Alpina (268 degree) cam. It must have been an exceptionally good one that did 210 bhp.
Using the early (chrome bumper 325i) type plugs also gives more power - on the last C2 that was on the rollers a set of Bosch W7 DCR plugs gave it about 4 bhp over the W8 LCR's.

My good mates up at Parkside just built a 320i Convertible with a 2.7 to much the same spec as you're suggesting - and it's superb. All for a few quid and a gasket set. Lovely.

[320Touring]

Widge is building his 2.7 from a 2.5 block and head, iirc
and he also has a alpina spec cam for it...he thinks the 320 head aint worth the effort

andy-magic is building his 2.7 from a 320 head...

we're awaiting a 'bangs per buck' shootout

[Andyboy1]

Not being able to host pictures here is a pain in the arse. I have a superb picture of all three M60/M20 heads together.

[Andyboy1]

Widge is building his 2.7 from a 2.5 block and head, i
andy-magic is building his 2.7 from a 320 head...

You're not wrong!!

Alpina don't sell their cam any more, no longer in stock and with a list price of about Ԛ£600, they'll stay that way. The Alpina cam was nothing special anyway - you can do better in this day and age.

[E30BeemerLad]

I'm sure Cabrio327i said the 2.5 head was crap on his when he did the 2.7 conversion, that's why he was selling a 2.5 head with 284 cam in it, think he must have put 320 head on, but worth checking with him.

[320Touring]

dont worry dude-i was confused for a while too

think widge's cam is a cam made to alpina spec (268 ish) as opposed to a genuine 'pina cam

[cabrio327i]

Hi Folks, Like Lee says i tried the 2.5 head on my 2.7 bottom end and found it would not run properly, main reason being the wrong shape combustion chamber in the 2.5 head compared to the flat top pistons of the ETA bottom end, no contact problems here with piston and head, like you would have with what somebody on the zone did the other day by fitting a 2.0 head on a 2.5 but the reason it does not work properly is because the compression is too low, you can see this when you compare the combustion chambers of the 2.0 and the 2.5, if you use the standard 2.7 ETA head, to use a decent cam say 2.5 or better still a 282/272 etc then you have to drill the extra oil feeds for the cam lobes in the head journals, but for very little money bit of your time and gasket sets you can have like Andyboy says a good 180+ motor without special pistons decking the block vernier pulleys etc etc, Cheers Dave

[Widge]

Yep my cam is reprofiled to Alpina C2 spec which as far as I can gather is 268 deg, if this is the same on the ex and Inlet sides I don't know.
The thing is I don't want a lumpy idle and I don't want a cam where all the power comes in at 4000rpm or somthing, so I think the Alpina is a good compromise which should reap some mid range power gians.And yes I'm building a 2.7 with 2.5 block head and pistons, which will require some machining but will be a good basis for an awesomely powerful 2.7 when I have some cash for serious tuning later down the line.

Off topic, does anyone have any photos of an M30 piston?? I'm trying to decide weather to go with an M20 2.8 using M30 2.8 pistons.

[Andyboy1]

Off topic, does anyone have any photos of an M30 piston?? I'm trying to decide weather to go with an M20 2.8 using M30 2.8 pistons.

You wouldn't get the buggers in! They're an 86mm bore (84mm on a 325i) plus the gudgeon pin to piston crown height is all wrong (by about 4mm) plus the M30 gudgeon pin is bigger.

There's only one way to build a 2.8 M20 - use an M52 crank with 320i/323i/Eta conrods and the bottom of the piston skirts shaved. The block doesn't have to be machined at all because the (325i) pistons come right to the top of the block.

[Widge]

Oh well bugger, it was only an idle idea on a hot summers day
I'll just have to make some ITB's for the 2.7

[M5pilot]

Nothing wrong with 320i's!

Much smoother to drive around town and they sound very nice.

At the end of the day for some people the insurance difference is huge as was the case with my wife. Therefore, rathern go down the route of 4 pot wrongness I prefered to get her a nice smooth 320i.

Even better, to make a half decent 2.7 all you do is change the block to an ETA one and suddenly your pissing on 325i sports due to 4.10 diff and 320 gearbox + wedge of torque everywhere.


HAHHAHAHHA!!!

[E30BeemerLad]

M5Pilot - the 320 you have just bought looks a cracker

[Andy_magic]

Brian, after lots of looking around and daft question asking on my behalf I've found the 320i > 2.7 doable.

I had read lots of posts about 2.7 engined cars and originally thought the only way was to stroke a 325i motor with an ETA crank etc etc. This method would have been out of the question for me due to the costs of the machining etc.

Then, due to the good ole zone I found the 320i version. I've got a head off my breaker, a gasket set off eBay for Ԛ£9 delivered and a bag 'o' shite 525e also off ebay for Ԛ£100

[Zayyan]

Slightly but what's the difference between a 2.0 ---> 2.7 and a 2.5 ---> 2.7?

Have wondered for a while now...

Easy - the 2.7 conversion on the 320i is the easiest. Although the 2.7 525e used a 200 casting head (from the E21 320 and 323i), the chamber volume is exactly the same as the 731 head used on the E30 320i and 323i. Therefore the head goes straight on without skimming and you can take advantage of the Eta's high compression. Cars up until around Aug/Sept 1985 had the 11:1 compression which is a little high and would require 98 fuel. later cars used a 10:1 compression which is fine. The 320i inlet manifold is okay and in fact, the 320i ports aren't much smaller than those of the 325i. All screwed together with the 325i throttle body, it makes for a very responsive and torquey engine with around 180 bhp.

The 325i conversion to a 2.7 is more involved, requiring block machining (after taking it all apart) to use the 325i pistons. You CAN screw a 325i head straight onto a stock Eta bottom end and it will work - just not quite as well as doing the job right.

That's a good explanation, I'm a bit more in the know now

Cheers for that

[M5pilot]

M5Pilot - the 320 you have just bought looks a cracker

Thanks dude for the compliment! Lets hope the car stays in this condition.

Looks like im going to have to wash it atleast 3 times a week and hoover it that many times too.

[Gunni]

But what about it when you have a free 2.0 and already own all the 2.5 bits and are rebuilding your S50B30 motor??????????

Yebb thats the situation IԚ´m in,,

IԚ´m only doing the mods so that 2.0 owners know what they are getting and loosing by doing them,

I for one would not be able to stick with a stock motor, no matter what the power level, thats why I donԚ´t go FI on my S50

[Gunni]

just checked the 320i tb again and itԚ´s only 55mm , then the 325i one should be about 65mm,
donԚ´t know how I messed up that reading

[StuBeeDoo]

IԚ´m only doing the mods so that 2.0 owners know what they are getting and loosing by doing them

Go for it Gunni!! There will be a few people interested in your results. Hopefully there will be a few who "see the light" too.
Stuart.