M20: More power.....ADVISE & DEBATE

[ZedOne]

Right guys - I am looking for some more power for my beloved Zed...

Here are the rules:

I would like around 220-240bhp from a currently standard M20 engine (M20B25).
I would rather keep the M20 engine than go for a different engine if possible.
I know f**k all about rebuilding engines, so don't go impressing me with fancy talk! Keep it simple for me to understand.
I'd like to use 'tried and tested' techniques fro tuning these engines, not wild and crazy concepts.
I'd like to keep the conversion as German as possible (i.e. not using cams/turbos from a Skyline etc..)
I'd prefer to keep the cost down. I don't mean cut corners, but if I can get the results from easy to source, affordable parts - then this makes more sense than paying through the nose for a specialist job.

What I want to avoid:

Stupid horsepower that will be wasted on me or end up in my death!
Parts that mean I have to re-mortgage my house or sell a kidney to afford!
Parts that are hard to source! I want to enjoy this conversion, not become the new Lara Croft for rare BMW parts!
I'm sure there will be more to add - but my brain has dried up, so this will have to do for now!

Here's the crunch!

The 'conversion' I choose may well end up with some of you helping me out in some way if that is OK? Sourcing parts, getting your hands dirty, giving advice......I have a lovely girlfriend who makes some killer food as part payment for any mechanical help on a fairly unique project! A constant supply of top quality tea is also guaranteed!

Advice is the main thing, but anyone willing to physically help out will not go unappreciated!

All advice welcome if it fits within these rules.....please feel free to dicuss and debate the virtues of turbo VS displacement - but ultimately, please have in your mind the end result - a rare BMW in need of some more power in an appropriate form!

Many thanks and let the debate begin.....

Bruce.

P.S. I have an engine stand and access to an engine crane. Pretty good range of tools, double garage, lots of jacks and stands etc.....and a partridge in a pear tree......

[Jhonno]

if you dont want to spend alot, then turbo is the way forward.. N/A Setup producing 240bhp is gonna cost you £Â£Ã‚£Ã‚£Ã‚£!

[ZedOne]

if you dont want to spend alot, then turbo is the way forward.. N/A Setup producing 240bhp is gonna cost you £Â£Ã‚£Ã‚£Ã‚£!

Please tell me more?

I thought a turbo system would be the big bucks compared to increasing CC's....

I'm often wrong though and always willing to listen....

Pro's - con's - costs....all will be helpful....

(oh - and someone good with a spanner! )

Regards,

Bruce.

[Ant]

very little room to play in the Z1 engine bay limits options dude

TBH, given the raricty and novelty value a well worked stroker 2.7/2.8 would provide a good, cost effective solotuin.

the build is easily DIYable, there are a few tricks to gaining the best from this setup but most are well documented.

Turbo/S-charger also an option,but due to space limitations and lack of frontal area for cooling perhaps would have an impact.

whatever you decide 220HP is a very real possibilty.

[Simon13]

2.7 mate, the engine bay will stick look identical to how it is, so no one will even know, apart from it goes well!

Nice gains to be had that won't put you in the ditch, it won't set the world on fire but will be no slouch!

2.7 engines can come in 100 different flavours depending on what you want from the engine and which route you choose to do it. Either with a 325i engine as the base or 320i engine as the base. These can be built in many different ways from just the BMW parts bin.

[ZedOne]

Hi Ant,

When you say 'stroker' I assume you are talking about the M20 engine? What is involved in making this into a 2.7 or 2.8? Any links to what's involved? (parts used, how it's done?)

You say there are tricks to get more Hp - again...any links etc....

I know this sort of question has probably been asked a million times and I know some of you are tempted to type "SEARCH" but if I could at least have some pointers it would be great.

I have used the search function, but the sheer volume of returned responses is quite overwhelming, especially as most of them don't cover what is actually involved.

Pro's & cons of Turbo vs CC's would be good. I know I can get a good cold air source from the front, but what else is involved? Would N/A be a more suitable way to go?

SO many questions (sorry!) and I know that collectively, you guys have the answer....

Thanks again for the quick responses.....keep 'em coming

Bruce.

[oldroydsr4]

Your really looking at close to 4K for a reliable turbo set up, however your target power would be easily obtainable.

IMO due to the car in question i would also go stroker.

[daimlerman]

Way to go is 2.7/8.You already have a 2.5?Obtain a 2.8 crank,set of 2.0 conrods,have a spacer machined to suit the crank/block,cam and chip from Ant and put it all together.Best guess is £1500 for parts.You should see your target power.Look carefully at cams,though,this conversion gives lots of bottom end torque with the standard cam, a lumpier one gives more absolute power but much futher up the rev range,great for a track day but IMO not much use on the road.

[Ant]

good point......

What is the proposed budget for this ??

as for pro's and con's, N/A is cheaper @ the beginning but ultimately limited in growth potential, FI will be more outlay for defo, but has almost limitless potential...................

experience has show that everyone wants more, but when they get more, they want more still, hence the growing numbers of boost-junkies on here.

Decide on available funds, then the options will be clearer imo.

[Gunni]

Try and locate a used Z1 or M20 Mosselman kit,
used on a completely stock M20, and fits the Z1 engine bay.
uses nothing fancy at all and provides the horsepower you noted at the 6-7psi level

[ZedOne]

What is the proposed budget for this ??

Hmm - that is an interesting one!

Being out of work with NO income, the budget is as cheap as I can make it without using nasty or unreliable parts.

I'm not one of these people that always crave more and more and more power....too much power comes at the expense of driveability, economy and reliability (in my small and narrow minded world anyway! )

I'm liking the idea of the 2.7/2.8 at the moment because it sounds more in keeping with the character of the car in the way the Alpina, Hartge, Schnitzer and Hamann Z1's all had 2.7 conversion It also sounds like it will be more manageable a project with less pitfalls from the feedback so far and also sounds like it will be more reasonable on my empty wallet!

I really don't desire huge horsepower - if I did I'd be looking for another car to use for this purpose (my G/friend would go spare if I bought another car!) - but I would like a useable increase in HP over the standard 170hp.

I have had the car for nearly 8 years and always enjoy driving it. I'm not 'desperate' for the extra power because it is such a lovely car to drive regardless, but I do, however, feel that more power will enhance the experience.

If people can let me know approximate figures of what it has cost them to do this work to their engine, then that will certainly help me?

I'm sorry if I sound vague, but I don't have a budget in mind because I have no idea what is involved. If I get some realistic figures from people (DIY installation), then I can work out how soon I can do the job.....if that makes sense?

I'm not afraid to do the work if you guys can offer the advice and expertise along the way. I've never done an engine job like this before, but I'm not afraid to try either.

Not only will it be more rewarding that I did some/all of it myslef, I will also know what was involved and will also keep the costs lower than paying someone else to do it.

The theory is I get my hands on a 'donor' engine that I can work on at my own pace without having to take the car off the road until the 'swap' occurs.

With this in mind, the 2.7/2.8 conversion sounds even more suited than the turbo option....

Please keep the comments coming....

Regards,

Bruce.

[oakey]

if you want a powerful NA m20 you will be looking at spending the same amount as fitting a turbo. It is not impossible to get 250hp from a m20 but it will cost! and after building a very powerful NA engine it will be very unsuited for a turbo if you want more power.
If you are not going to do the work yourself and you want 220hp I would estimate it costing anywhere from £2500 to £4000. But if your doing it yourself the costs will be significantly lower.
Bang for buck- turbo
but if you want to retain the originality and do things stage by stage and if you dont fancy a turbo then 2.7 or 2.8 conversion seems best for you.

all parts for 2.7 conversion- £1000 as a rough guide maybe? depending on whether you buy custom pistons etc.- there are a couple of different ways of doing this conversion and alot of different parts that can be used.

[maxfield]

scoot (player6) on here is running 260hp from a 2.8 n/a but it would make your eyes water to how much it would cost

[oakey]

scoot (player6) on here is running 260hp from a 2.8 n/a but it would make your eyes water to how much it would cost

as far as i know he has not done the majority of work. therefore half of that sum will be labour

[maxfield]

Yes but building an engine isn't easy.

Neither is the machinning to be done.

Well head anyway.

[ed325i]

If I was you I would build a 2.8

Or 2.7 >> http://www.e30zone.net/modules.php?name ... highlight=

[oakey]

Yes but building an engine isn't easy.

Neither is the machinning to be done.

Well head anyway.

^very true^ i was just pointing that out as zedone says he would like to tackle the work himself

[ZedOne]

If I was you I would build a 2.8

Or 2.7 >> http://www.e30zone.net/modules.php?name ... highlight=

Thanks to EVERYONE for the comments and feedback. I am certainly swinging more towards the 2.7/2.8 camp right now for a number of reasons....

Thanks for the link too Ed, will try and make a hot date with it to absorb all the info and drool over the photos.

I guess now I need to source a 'donor' 2.5 and get advice from you clever ba5tards as to where to get the parts.....and more importantly.....how the frig I do it!

I might have the engine out of Simon's silver touring that is about to go to the great BMW resting place 'up there'.

2.7 or 2.8 - that should be my next question I guess?

Regards for now,

Bruce.

P.S. You guys sick of the questions yet?

[Simon13]

with a good powered 2.7 200-210bhp it will actually be alot better on fuel too on average!

everyone says 2.8 but we only have 2 real examples of them! Adams which is a good spe but makes no more power than 2.7's of the same spec and Scotts 2.8 which is a 10k Bexleys engine

If we talk about various 2.7's there are too many to list, in terms of build spec and the money it cost.

My advice would be to go the 325i head route (you can use 2.0 head also) This route will cost a little more money than a 2.0 head route but......you already have a 2.5 engine! The 325i head will also leave you with the best power output ultimately.

Imagine your 325i with 30 more bhp and a sh!t load more torque low down, 3rd gear 1500rpm put your foot down and it won't labour. A nice 2.7 is a get up and go engine if you get me. Whats a Z1's wieght? can't be more than a E30

[Dan318-is]

can't be more than a E30

125 kilos more apparently!

[Simon13]

P.S. You guys sick of the questions yet?

you are special as you have a Z1! It's majorly different from the norm,but it's not!

[daimlerman]

Just a little niggle zedone,your car is certainly a classic in the best sense,you may devalue it in some peoples eyes by doing a high power engine job...I am not saying do not do it,just bear it in mind.Whilst the under bonnet view with no turbo will be just the same,you may just spend £1500 and end up with a car worth less than you started with This is something that does not concern the average E30 owner,as only the M3 version and realy tidy UNMOLESTED 325i sports ones are worth more than a few quid,bet I get a blast for saying this

[ZedOne]

with a good powered 2.7 200-210bhp it will actually be alot better on fuel too on average!

Hi Simon,

Many thanks for the insight into the 2.7 vs 2.8 thing. This is exactly the sort of info I was after....i.e. 2.8 not a well known quantity, so not for me!

2.7 is sounding like the daddy right now and I'd be quite happy with 200-210hp (220-240 was an ideal, not an absolute )

Other than Ed's link to oguz327's conversion, is there any other useful 'bibles' that you could set me off with for research/homework?

It sounds like there are a lot of variables, so any pointers as to a set-up that you would personally recommend would be appreciated. Here is what my mind is thinking right now....

You mention using a 325i head - but what about the rest?
How do I get to 2.7 from 2.5?
What can I do and more importantly, what can I not do (i.e. specialist machining!)
Are there other things that can enhance the power along the way? (i.e. AFM, cam etc..) or are these all part of the 200bhp 2.7?
Are any of these parts hard to source?

Thanks again for all the input.....I know where I want to go now (2.7) but I think you guys are gonna have to hold my hand a little in my quest to get there!

Be patient with me.....

Regards,

Bruce.

[oakey]

You mention using a 325i head - but what about the rest?
How do I get to 2.7 from 2.5?
What can I do and more importantly, what can I not do (i.e. specialist machining!)

You will need the head and block skimmed.

Are there other things that can enhance the power along the way? (i.e. AFM, cam etc..) or are these all part of the 200bhp 2.7?
Are any of these parts hard to source?

A camshaft will give you more peak power higher in the rev range but it may not pull as well at low revs. Also, depending on what duration/lift cam you use, you may need to fit better valve springs, machine the pistons etc.
If you use standalone management (such as MS) then you can get rid of the AFM which apparently give a good power increase, and run the car of a coil pack rather than the distributor which is also supposedly better.
The car will also need to me mapped on a rolling road for it to run its best- which isnt cheap.

I dont think any parts are particuarly hard to source.

dave

[oakey]

You can use your 325i head and block. I dont know the exact method of doing it. but im sure my 2.7 was built with a 325i block and head. but with custom pistons and crankshaft- i think

but i think people also build 2.7s with the block from a 525e or 325e (eta M20 2.7) and the cyl head from a 325i. + a bit of machine work.

Dont hold me to this though- hopefully someone will come and correct me and tell you more of what you need to know

[DaveD]

do a search on the zone there has been lots of threads on this...or you can run this through a translator program

http://www.327i.com/

[daimlerman]

The basis of the 2.7 is the crank from an early 80s 525e(not525i)this has a long throw to give more stroke and there fore more capacity.It also raises the c/r.there are two con rod lengths available,you need the shorter ones as used in the 320/520/525e,not the longer ones used in the 325i.the 525e pistons have a scallop in the sides to clear the rods/crank web at BDC.You can use 325i pistons(your existing ones)but they will need this scallop machining in.Also,the 325 piston is lower from the crown to the gudgeon pin,this means that the piston fails to reach the top of the bore(by about 2mm I belive)To get round this,you have the top of the block machined,we call it decking.The snag to this is that the crank is now closer to the cam....to get the valve timing correct again you need a vernier pulley.When I built my 2.7 I used the 525e pistons and the small valve 320 head to avoid the above problems.The 325i head that you already have may not clear the 525e pistons when the valves are open.There again,I did run a 325i head for a few weeks(until it cracked)on mine.If I was starting from a 320,I would go the same route again.But if starting from a 325,the improved head/piston issue changes things.I belive (I have NOT done this myself)that the 2.8 crank/short conrod/325i piston combination puts the piston in the correct place at TDC,but the piston will still require the 525e style scallop to clear at BDC.This is why I suggested the 2.8 route was the way to go.IMO it will be cheaper overall.Also,525e short motors in usable condition are now hard to find,I had to have my crank reground(£85) and new piston rings(£98).

[ed325i]

This is why I suggested the 2.8 route was the way to go.IMO it will be cheaper overall.

This is why I am building a 2.8 but its still not going to be cheap but is easyer.

[daimlerman]

To be honest,I did not expect to spend as much as I did...but once started I was determined to get a result

[appletree]

Have you thought about how you want the power to come in/be avalible? do you want it more torquey or realy peaky? might be another thing worth considering, although i supose if you spec things right you could make it so the turbo gave a more linear power deliverly but it might be a bit more difficult to build a peaky 2.7/8.

[ZedOne]

This is why I suggested the 2.8 route was the way to go.IMO it will be cheaper overall.

This is why I am building a 2.8 but its still not going to be cheap but is easyer.

Thanks for the insight guys - very helpful! Certainly up for the capacity increase over the turbo. (sorry all you boost boys! )

Excellent info there Daimlerman & Oakey....Cheers for that! Exactly the sort of detail I was after.

So Ed & Daimlerdude, what is involved/different for the 2.8 Vs 2.7?? Totally different build, I'm confused? (go easy with me guys! )

2.7 sounds pretty good, but if 2.8 is a more suited package, then please let me know what is involved?

Thanks again,

Bruce.

[ZedOne]

Have you thought about how you want the power to come in/be avalible? do you want it more torquey or realy peaky?

Hi Appletree,

I'm probably looking more for low-mid torque rather than a screamer! The Z1 is a bit flat low down, good power from 3.5-5k, but flattens out again after that.

If I could gain a nice fat wallop of torque that works well from low down and doesn't die out as the revs build then I'b be happy.

My old Mk1 Mr2 was a fantastic screamer and to get the most I had to live with it at 5k-8k which was hugely entertaining but very draining!

The Zed is not really a screamer - so if the power deliver was smoother rather than peaky then I'd be very pleased....

Regards,

Bruce.

[daimlerman]

The 2.8 is the new kid on the block. You need an M52 crank.The best info is onpage 135/6 of andyboys book,BMW E30 3Series Restoraton Bible.(Brookland Books ISBN 1-855-20678-1)available from that on line bookshop whose name eludes me at the moment due to my great age.You will also need the short (320/525e) conrods as already posted.Some machine shop work is required,but I would expect that this is less than the cost of a crank regrind.So for the cost of a s/hand crank and a set of rods,you gain 300cc.You will need a modified chip for the ECU,but Ant can probably sort that out.Looks like ed325 is doing this build at the moment,he may share his highs and lows and perhaps his costs if we ask him properly?

[daimlerman]

Futher to above,Ed has a thread in this forum called 2.8 crank spacer....

[ed325i]

I have only just started the build but its a

M52 2.8 crank which cost me £100.
Having a spacer made for the front of the crank.
323 conrods. (But can use 320/525e ones)
Early 325 high compression pistons.
323 block bored out to fit the 325 pistons.
325 head skimed 0.5mm plus fitted with 1mm bigger valves.
Cat cam (not sure of spec yet)
custom chip.
6 branch exhaust manifold.
Looking to get a e34 535 Throttle body fitted to a modded m20 inlet manifold but I am not sure about this yet.
And on top of this you have got gaskets/seals/bolts/nuts/water pump/oil pump etc.