2.7 question

[Quaser]

Hiya

Im looking to do a budget 2.7 coversion on my cab but cant decide which route to go down.

The choice is either 2.7 block with my 320i head and 325i cam, inlet, injectors etc - or just a 2.7 block with a 325i head etc.

The question is - what are the charcteristic differences between the 2? What bhp/torque would i expect from each one and what are the differences in driveability?

Cheers

Q

[daimlerman]

Piston choice will determine head choice!

Using the eta flat topped pistons is the easiest/cheapest way,just drop the 320/731 head on with your choice of cam inserted.

If you use the 325/885 head,you really should be using the matching 325 pistons,to take proper advantage of the combustion chamber design on this head.This then sends you down the route of modifying the block,as the 325 pistons sit too low on the longer eta con-rods.

Just plonking the 885 head onto the eta bottom will run,but the larger valves of this head will just waste fuel and lose you low down torque.

My 2.7 has now been built for more than 5 years....

Eta crank/rods/pistons
84mm block
731 head
325 stock cam
325 inlet/injectors/FPR
hottuning exhaust manifold
Miller MAF
2.7 chip supplied by Ant,modified by Miller.

Two years back,when the engine was swapping cars,I fitted an ex E21 323 cam.This lost me a little low down torque,but the gains above 3000rpm more than compansate.Car ran even better after Gunni had live mapped it for me.

There is no 'right way' or 'wrong way' to build a 2.7,just the way that you want for your needs.

[Quaser]

so what bhp/torque output do you have?

[daimlerman]

Currently,after Gunni's work last springtime,just under 180ft/lb torque at 4500rpm and just less than 175bhp at 5800rpm.Usable torque(150ft/lb)starts much lower down,though,at about 2000rpm!
This wide spread of torque is what a 2.7 is all about,less need to use the gearbox to get good acceleration for quick overtaking.

[Quaser]

hmm - i was hoping for more like 190bhp!

[daimlerman]

hmm - i was hoping for more like 190bhp!

For that,you will need to go the 885 head route!

Dummy build one cylinder and measure just how for down the bore the 325 piston sits,then get the top of the blokck 'decked' by this amount.
Then,because the camshaft will sit closer to the crank than usual,you will need a vernier cam pulley....you will also need an after market cam and a decent BTB exhaust manifold.
This will all add between £1k and £1.5k to your build cost.Tuning M20 is not for those with short arms and long pockets.....

[Quaser]

Yep - I know - I have a 'proper' build putting out 225bhp

This was supposed to be a budget build instead of swapping my 2.0 for a 2.5

I can't decide whether to use the 2.0 head with 325 stuff or just have a 325 head complete!!

What's the 325i head + 2.7 block bhp output?? Does it use that much more fuel??
Or should I just put in a complete 325 engine?? Car is a cab auto!

[daimlerman]

Look at it this way,you are starting with a 320i....129bhp?
So a budget build similar to mine nets you 175bhp,a gain of 46bhp,or better than 35%!

WTF do you want?

[Quaser]

or another way - drop in a 325i and get 170bhp for a lot less!

i just dont want a 320 in there basically! Ive already got the 2.7 bottom end - just wanted to know differences between the 2.5 and 2.0 head characteristics.

[Ajsingh]

I used a 2.5 head and there is plently of torque and power! Has peed all over an e36 328i, apprently it had a rebuilt head with race cams and so on.. Also pee on e46 330s all day long too

[Quaser]

whats your bhp AJ? have you had it rolling roaded? where abouts in west london are you?

[e301988325i]

hmm - i was hoping for more like 190bhp!

2.7's are a worthwhile upgrade. Don't fret about the bhp, different dyno's read very different, upping the capacity will not result in disappointment.

[Ajsingh]

Im just outside of southall

Bhp wise i have no idea, its never been on the rollers mate

[ross2009]

if you want it quick its not bhp you wanna worry about its torque
you seem to be worrying alot about bhp figures, natually the bigger the engine the more torque you will have the 2.7 is a torquey motor like aj mentoned, has pissed over alot of others which aint slow in there own right

[Ajsingh]

if you want it quick its not bhp you wanna worry about its torque
you seem to be worrying alot about bhp figures, natually the bigger the engine the more torque you will have the 2.7 is a torquey motor like aj mentoned, has pissed over alot of others which aint slow in there own right

+1

Bhp is pub talk, torque is where the men come into it lollll

[fowler]

Q you cheap Git lol! Just bang a "Good" 2.5 in it and few tweeks and you will be up near the eta based 2.7 power, if you are gonna do it proper just build one its been clearly documented how to build a good 2.7 on here loads of times...
I could get one built for you if you so require but it don't come cheap...

[Eddie25]

Q you cheap Git lol! Just bang a "Good" 2.5 in it and few tweeks and you will be up near the eta based 2.7 power, if you are gonna do it proper just build one its been clearly documented how to build a good 2.7 on here loads of times...
I could get one built for you if you so require but it don't come cheap...

+1 My B25 was put together following advice from Ben and Ant and i can vouch a B25 with a cam and its breathing sorted is a very different animal to a standard B25.

[Quaser]

OK - so i got all the bits, put the engine on my shiney new engine stand, tried to turn the crank and.... nothing - its seized!

I knew it turned before! If the bottem end goosed or what will i need to do to repair it?

Q

[ross2009]

OK - so i got all the bits, put the engine on my shiney new engine stand, tried to turn the crank and.... nothing - its seized!

I knew it turned before! If the bottem end goosed or what will i need to do to repair it?

Q

which engine is this ? the 2.7 or you got a 2.5 now ?
how long has it been standing it wouldnt have siezed that quick

[Quaser]

its a 525e bottom end - i know it was turning before, but i have a leaky roof in my car port and i think some might have got into the block and rusted it up a bit inside!

I havent taken the sump of yet though to have a look - but i cant even turn it with a breaker bar on it!

Q

[ross2009]

well in that case sounds like the rings have rusted in the bores get loads of wd40 or penetrating oil in the bore and let it soak then try again be careful tho as you could snap a ring

[Quaser]

cool - will it be ok as it is or will i need to change something before i use it??

[ross2009]

if you can un seize it , it should be ok the rings should clean the bore up but really it needs looking at to see how bad the bores are

[fowler]

Q rebuild it to tight sod !

[Andyboy]

Run a glazebuster down the bores and reassemble it with new rod bolts. Use an 885 head - after a quick clean up skim the CR will be okay and it will go well enough.