M20B27 Engine Modifications

[Rickbmw1984]

I am looking at doing some engine mods to up the power on my M20B27 engine. What would people suggest as some cheap but effective mods? So far im looking at a chipped ecu, forced induction, possibly some fast road cams (regrinds possibly) and some bigger injectors.

Im going to start with the best and easiest mod of them all”¦.a damn good engine service!

Will be nice to know what you think.

Thanks

[HartgeH27]

BBTB, lightened flywheel, port/flow head, squirt, cams, remap

[Rickbmw1984]

that would certainly give me more power and better response. I have megasquirt on my kit car and wouldnt want to do it on another car.

Cams, remap and BBTB is definitely an option.

arent lightened flywheels hard to fit? suppose it would give me the chance to change my clutch whilst im there.

[oakey]

Got any build spec for your engine?

[Rickbmw1984]

not at all. I had a few queries when i bought it as the guy who i bought it off didnt have a clue. I was buying a bmw e30 325i with heated seats 5 months tax 3 months mot. what i got was a 2.7 none heated seats e30 with not mot and 1 months tax. but i thought the fact he didnt know it had lsd, uprated gearbox or the 2.7 was a bonus.

All i know is the engine has 2.5/2.7 on the head and is totally standard.

Just noticed though that my ECU is 0 261 200 172 which by all accounts appears to be the standard m20b20 ecu that would of been on the car prior to the engine transplant. should i buy a m20b25 one? could this be where my power has been lost?

Thanks

[oakey]

How can you be sure it has a 2.7 engine?
I know feck all about ecu's and their numbers but a b20 ecu won't be correct. Unless the b20 ecu only needs a "chip" swap to run a b25/27 engine.

2.5/2.7 on the head doesn't reveal that it is a 2.5, 2.7, 2.8 etc etc. I think That is stamped on most b25 cyl heads.

[Rickbmw1984]

it is wrote in the service history what engine was put in.

The car had a lot of work done on it all at once. Engine swap, gearbox, lsd, full leather recaro and alpina wheels. Plus my mate who has a 2.7 has checked it over and it is exactly the same as his. to be honest everything is so up in the air with the car it would be nice to know for sure.

[oakey]

Plus my mate who has a 2.7 has checked it over and it is exactly the same as his.

Apart from it not being as fast??

Get it to a dyno for a quick power run. This will let you know for sure and it may also give a rough indication to the build spec. Shouldn't cost any more than £50.

[Rickbmw1984]

well yea its nowhere near as fast.....saying that though it is still pretty quick and his is running 250bhp. He sells rolling roads for a living so hopefully get in somewhere even cheaper.

[daimlerman]

A 2.7 will require a custom chip to run properly,so just opening the ECU to check the chip should give more clues.

[Rickbmw1984]

ah ok ill have to check that tonight then. problem after problem with this car.....still love it though

[DanThe]

Another 250bhp 2.7 eh

Love to see some engine pics/specs

I think you should be checking the crank stroke first, you can measure it with a length of stiff wire down the plug hole

[Rickbmw1984]

yea his build spec is pretty good. cams, injectors, lexus v8 afm, chipped plus lots more. he also has a 500bhp supra which is nice.

what sort of stroke am i looking for?

[DanThe]

2.7 uses an 81mm stroke as opposed to the 2.5 75mm

[Rickbmw1984]

ok well ill check the stroke. Thinking as a matter of course ill book it in for a rolling road session and look in to getting another ecu. does anyone know where i could get a 2.7 ecu from?

[DanThe]

As daimlerman said, you just swap the chip, I think speedtouch has some for sale in the F/S forum

[m_jermyn]

You need to post a pic of the motor so we can tell you what it is...

We need to know what inlet manifold is on the car but most importantly what head is on the motor... On the exhaust side of the head it will have cast into it (eta 2.7) or (2.5) and on the inlet side of the head it will have some numbers stamped (***** 200) or (**** 885) or (**** 731) The numbers on the inlet side are hard to see as you have to look between the runners on the inlet manifold to see. the numbers are located between piston 3 and 4, it is hard to see but they are there..

We need to know what the car revs to aswell.. Not the redline on the tacho but what it revs to when you rev it... Does it only go up to 5000rpm or does it go higher?

Also has it been chipped?

If you can tell us this we can identify what engine you have and if it has some mods...

I have just been through all this and if your lucky you might have a modified 2.7 eta... witch is better the a 325i Or you might have a standard 2.7 eta motor witch isnt as good as a 325i.... My opinion is a standard eta is the best motor as it has heaps of room for modification that is relativly cheap to do. Basically you can place the top end of a 325i 2.5ltr motor on the bottom end of a eta 2.7ltr motor and have a e30 that will hose all.. This combo gives you a 327i

Mike

[m_jermyn]

You can check the stroke first if you want but its far easier to check what head you have on it... Check the numbers I supplied above first mate...

[Rickbmw1984]

cheers mike very helpful indeed, i will psot back all the numbers later on tonight and hopefully ill have a good one!

The car revs way past 5000 ive had it to 6500 easily.

[Simon13]

it is wrote in the service history what engine was put in.

The car had a lot of work done on it all at once. Engine swap, gearbox, lsd, full leather recaro and alpina wheels. Plus my mate who has a 2.7 has checked it over and it is exactly the same as his. to be honest everything is so up in the air with the car it would be nice to know for sure.

sorry mate but you won't know what type of 2.7 it is until you strip the engine to bits. Theres a 1000 ways of building them

[tomson]

So it has a 320i ECU, looks the same as your mates 250bhp 2.7 but is much slower. Are you sure the engine that was swapped in isnt a 2litre ? There are plenty of 320i's with leather and burger kings, check ebay ! !

[stonesie]

Is the inlet all smooth and flowing, or do the outer branches have a slight kink to them?

Revs to 6500 dosent mean that much if im honest, my 320 does that and sounds damn nice doing it too

[B7]

it is wrote in the service history what engine was put in.

The car had a lot of work done on it all at once. Engine swap, gearbox, lsd, full leather recaro and alpina wheels. Plus my mate who has a 2.7 has checked it over and it is exactly the same as his. to be honest everything is so up in the air with the car it would be nice to know for sure.

sorry mate but you won't know what type of 2.7 it is until you strip the engine to bits. Theres a 1000 ways of building them

Spot on. I've seen standard 325's with an 885 head which has cast 2.5/2.7 on the head. That casting bares no resemblance to the fact the engine is a 2.7!

What does the service history state? You're being a bit vague to be honest. Does it state:

"2.7 bottom end supplied with eta crank, 130 rods with early 325i high comp pistons. Block skimmed by 3mm. 731 head fitted including xxx cam and vernier pulley etc. etc etc.

or does it state:

"Replacement engine fitted" and you're taking it to be a 2.7 off the stamp on the head?

As Si says, there are a lot of ways to build a 2.7 and whithout stripping it and looking at the crank, you'll never know.

I could be wrong but a 172 ecu is a 325 one is it not?

[m_jermyn]

Regardless a 885 has 885 written on it..... Given that it revs past 5500 means if it is a 2.7 it has had some modifications to it... as the eta will only rev to 5500rpm unless its been chipped... A super eta will rev to 6000rpm.. But they are U.S only cars....

Time to pull of the sump maybe

[Simon13]

facelift cast heads have 2.5/2.7 cast into them possibly because of the super eta which used this head instead of the 731 jobbie.

Early chrome bumper 325's have just 2.5 cast into the head if* they are on the original head still that is

Thats about the only difference on post and pre facelift cylinder heads on 325's