To stroke or not to stroke.....

[Gio_SA]

Thanks for all the inout fellas.....

You all make very valid points and have good reason for your preferances when it comes to either of the options.

So where are we at currently:

1) Stroker... keep the original m20 look in the engine bay but with more grunt, power delivery at high rpm (if I understand correctly), fuel consumption is through the roof (incomparison), will take quite some time to have it done (will be without wheels for that time), need to find a reliable mechanic to do the business (almost impossible task) or do the business myself (which will take longer than usual as I'm no mechanic) and last but not least will cost alot of cash to do.

2) M52B28 swap... Not the original m20 look in the engine bay but a BMW motor none the less and a beautiful motor at that with power to match, smooth power delivery throughout the gears (if I understand correctly), fuel consumption that may be even better than a stock M20B25, will not take that long to have done (will be without a car but not for too long), I should be able to manage a simple motor swap and just get someone to sort out the electrical parts of the swap and last but not least should/ will cost far less than the stroker...

Do I have it about right???

[Gio_SA]

Guys.... and gals I thought you guys would like to read how the same discussion is going on the South African forum and maybe even comment.

You may have to register to read it first (I'm not too sure)

http://www.e30clubsa.co.za/forum/index. ... e-rebuilt/

[MillRat]

I have just found this thread, and find that Ade has already done a wonderful job of introducing my project.

I have already chatted with Gio-SA via PM so he has the general jist of the motor already, but for anyone else interested;

The IE 2.9L kit uses the US M3 3L crank, M20 rods and ROSS racing pistons. We over bored the cylinders 1mm (OEM head gasket still) and combined with the extra stroke of the crank makes up the 2.9L. No extra block work was required. We chose to fit an IE M20 crank scrapper which needed alittle modification to accomodate the bigger crank, but nothing else.

The head was worked and fitted with an IE 272 cam, and 1mm oversized valves. Apart from all that, we used OEM seals, bearings, head bolts, etc and have had no worries.

Besides the engine, the car is fitted with a Miller MAF, a Miller WAR chip, Hottuning extractors and free flowing exhaust. Big bore throttle body and matched phelum.

The last dyno run the car made 143rwkw on a generic Miller MAP, that is, the car hasn't yet been properly tuned. With a proper tune to sort out fuelling we expect about 150rwkw with this engine configuration (more once we get a bigger cam and modify the intake more).

I read and have read lots about stroker engines and choose the IE kit because it was complete and uses OEM parts for everyting but the valves and pistons/rings. The most important part however is the car tuning to reveal all the potential power available. I so often see builds where lots of money has been thrown at a 2.7, 2.9, 3.1 etc BUT none has been spend on a proper engine tune. As you all know, to tune an M20 properly you must get a write/rewrite ECU like the Miller WAR chip (which is the route I went), or stand alone like Megasquirt (which is very popular). In summary, a big engine with all the biz will always be let down if not properly tuned.

I will load up a video of the car in my driveway and post up a link (it is easily the toughest E30 I have ever heard.... Not many "good" E30's in Adelaide though).

My thoughts are good luck and stroke away.

[daimlerman]

That's a goodlooking motor,Millrat,what sort of airbox are you using?
Strokers can be built to give power just where you want it,for road use in the UK I find that my 2.7 with a stock 731 head and 325 cam gives good torque from 2000rpm.Using a lumpier cam just moves the power further up the rev range.
My current project is fitted with a 3.45 diff,I am interested to see if the torque can pull this very high ratio and still return the 'smile factor' and improved fuel economy...

[N00b]

As a continuation of this, are there any options to increase the stroke of the M52?

[daimlerman]

As a continuation of this, are there any options to increase the stroke of the M52?

'Dezzy' is building a beast of an M52 at the moment,may be worthwile PM'ing him for details!

[N00b]

As a continuation of this, are there any options to increase the stroke of the M52?

'Dezzy' is building a beast of an M52 at the moment,may be worthwile PM'ing him for details!

After I asked the question, I thought the answer would be no. The IE kit seems to use an OEM crank, and I couldn't think of another OEM crank that would fit into the M52 and increase its displacement.
I'm still undecided which way to go with my car, either the IE M20 stroker or an M52. When I saw Lees car (a top fella, by the way) the M52 just looks like it belongs there, but for the same rough cost I could have an IE stroked M20.

Hmm.

[doc323]

Ive been reading this with great interest as im sort of in the same position.

I have just got a very clean 316 because my old 325 had rust issues and i have the major parts to stroke the M20, but im now considering selling the parts and going for a M52!
But have been offered a set of throttle bodies and aftermarket ecu, so it would be a bit more work but can’t decide which way to go. Seem to change my mind on a daily basis

[N00b]

1) Stroker... fuel consumption is through the roof (incomparison)

Any more detail on this part of the conversion?
What are the 2.7 M20's like on fuel?

[dazleeds]

if she's cute then yeh have a good stroke
if its a bit of a minger then lights out and quick tap should suffice

oh and if shes a ginger, send her straight to fuzzy

[reggid]

1) Stroker... fuel consumption is through the roof (incomparison)

Any more detail on this part of the conversion?
What are the 2.7 M20's like on fuel?

when i was running a 3.1L on motronic with my MM cam i was getting 7L/100km on the freeway at 110km/h which is better than a stock M20B25 so a stroker does not always mean bad economy. Now with different cam etc i get about 8L but goes to shit easily enough

[N00b]

1) Stroker... fuel consumption is through the roof (incomparison)

Any more detail on this part of the conversion?
What are the 2.7 M20's like on fuel?

when i was running a 3.1L on motronic with my MM cam i was getting 7L/100km on the freeway at 110km/h

Jesus, isn't that about 40mpg?
The way our SA friend described it I was expecting fuel costs to be unliveable as a daily driver.

[reggid]

Any more detail on this part of the conversion?
What are the 2.7 M20's like on fuel?

when i was running a 3.1L on motronic with my MM cam i was getting 7L/100km on the freeway at 110km/h

Jesus, isn't that about 40mpg?
The way our SA friend described it I was expecting fuel costs to be unliveable as a daily driver.

there is no real reason why it would be through the roof unless your driving habits change.

It takes certain amount of power to move an E30 on the road and that means a certain amount of fuel. Whether the engine is a 2.5L or 2.9L or whatever the rolling resistance and drag have barely changed so it still requires the same power (fuel).

The only thing changing is the combustion efficiency and to some extent the larger throttling losses brought about from the smaller throttle position required for the same power compared to the smaller engine. So unless you build a cheap low compression dog of an M20 with a poorly chosen camshaft you should not be much worse off. Must be properly tuned of course Drive it hard then things are different.

[MillRat]

That's a goodlooking motor,Millrat,what sort of airbox are you using?
Strokers can be built to give power just where you want it,for road use in the UK I find that my 2.7 with a stock 731 head and 325 cam gives good torque from 2000rpm.Using a lumpier cam just moves the power further up the rev range.
My current project is fitted with a 3.45 diff,I am interested to see if the torque can pull this very high ratio and still return the 'smile factor' and improved fuel economy...

Thanks.

The airbox is a home job made out of alloy. The matching box on the other side is for symetry more than anything else. It does channel air over the extractors though.

We run a 3.60 LSD and that matches the engine to our local track very well. We also have a 4.10 but I think that will be a little to high for this engine.