m40 tuning

[ejoeyward]

got a few questions about tuning the m40, so i know already what people are going to say and thats just do a conversion. but what i cant get people to understand is i like to do things diffrently.

my first question what parts could i use to stroke a m40?

can i use individual coil packs like whats on the m42 or the style thats on the m44?

does any one make a carb manifold for the m40?

would you regring the cams or buy new?

what good double valve springs are out there?

is it true that m43 rockers fit the m40?

[maxfield]

There is doing things differnt but trying to tune an M40 is like trying to wank with your left hand*.


*I'm right handed

[ejoeyward]

yeah il give you that but a clean well detailed engine bay is more important to me than the numbers or the amount of c*m in your case

[maxfield]

So what have cams and double valve springs got to do with a detailed engine bay?

[ejoeyward]

alot! the cylinder head is in the engine bay therefore it has alot to do with detailing

[broadie]

Bogg Bros will make you an inlet manifold.
Diesel cranks are used for stroking but they run chains.

[maxfield]

alot! the cylinder head is in the engine bay therefore it has alot to do with detailing

A detailed engine bay to me is a nice clean engine bay.

Cams and valve springs are inside the engine, you do realise this?

[ejoeyward]

yes i do but whats the point of having a nice detailed engine with out have just a little bit of performance to go with it

[maxfield]

yes i do but whats the point of having a nice detailed engine with out have just a little bit of performance to go with it

If you want performance bin the M40. Get something with Atleast 6 cylinders in there.

[ejoeyward]

but 4 cylinder is less weight over the front wheels so there for better handling and yes a 6 pot gives more power but also cost more to buy, to run and to insure

[maxfield]

There ain't much difference between a 4 pot and 6 pot in terms of handling IMO. But then I'm not a racing driver....

By the time you've bought a cam and some valve springs.

You could have put a M20B25 in....

[broadie]

K20 it.

[ejoeyward]

y does every one go for the same engines are people not aloud to be different cuz we dont live in a fascist state.
if i was going to do an engine swap i would try and shoe horn a 440 magnum or 572 chevy with a blower on top and why not 40 litres of nos while im at it.

[maxfield]

Rather than spending a few hundred quid and lots of man hours trying to squeeze power out of an M40, which you might gain 10hp....

A couple of hundred quid and a days work will get you 170hp with lots of potential.

[jmc330i]

No problem with sticking with a 4 pot and no problem with being different. But if you really have a hard on for the M40 donk, go for a turbo or supercharger.

The reason people go with the same old 6 pots is because its a simple, reliable and cheaper way of getting the performance gains an M40 could only dream of.

A stock M40 can be boosted to around 160-170bhp for maybe £1500, a lot of man hours and less reliability.... or as Max says, a few hundred quid for a B25 and a day or two work will get you 170bhp while still being reliable.


As for handling, an M40 may feel nimbler through the twistys, but a 325i will approach the bend quicker, go through the bend just as quick, and then f uck off in to the distance.

[broadie]

Wouldn't bother with a 12valve.
I must say for shear corner speed the m40 touring is the most balanced car I've ever come across. I think a K20 could well be even better.

[ajay]

An M42 swap is simple, its still a 4pot so handling won't be affected, more economical than an M40 revs and pulls way better its 24v and forged bottom end too and just incase you get bored of the superior 136bhp much more easily tuneable too. IMO,tuning an M40 will never come close to a decent M42 so thats why the M40 is a piontless exercise.
Win win win! And looks way better than an M40 too'

[broadie]

Until it pisses oil out of the camchain box due to being a bodged m40

[NoTurbo]

An M42 swap is simple, its still a 4pot so handling won't be affected, more economical than an M40 revs and pulls way better its 24v and forged bottom end too and just incase you get bored of the superior 136bhp much more easily tuneable too. IMO,tuning an M40 will never come close to a decent M42 so thats why the M40 is a piontless exercise.
Win win win! And looks way better than an M40 too'

+1 to that

[ejoeyward]

well my plan is to bolt twin 40 webbers to the side, port polish the tits out of it with ribbed floor on intake and slightly raise the roof on both sides,a 3 angle valve job and some nice medium grind cams about 270ish and MAYBE some hemi pistons with valve cut outs.

and dont say its a waste of money cuz it relatively cheap cuz iv cannibalized a m40 intake manifold for the carb manifold, the valve job is being done by a friend in the industry, the carbs are already sitting in my shed. so the only thing that will cost money are the hemi pistons if i go that far

so all in including buying the engine im looking about £175 plus hiring an engine hoiste for a day and then plus pistons if i go that far. (would love them just to say iv got a hemi but not sure if they would give me any more performance)

[ejoeyward]

btw already worked out that the port spacing is perfect for 40 dcoe webers

[pacerpete]

well my plan is to bolt twin 40 webbers to the side, port polish the tits out of it with ribbed floor on intake and slightly raise the roof on both sides,a 3 angle valve job and some nice medium grind cams about 270ish and MAYBE some hemi pistons with valve cut outs.

and dont say its a waste of money cuz it relatively cheap cuz iv cannibalized a m40 intake manifold for the carb manifold, the valve job is being done by a friend in the industry, the carbs are already sitting in my shed. so the only thing that will cost money are the hemi pistons if i go that far

so all in including buying the engine im looking about £175 plus hiring an engine hoiste for a day and then plus pistons if i go that far. (would love them just to say iv got a hemi but not sure if they would give me any more performance)

Are you Ed Balls ? You obviously had the same maths teacher !

[Jon_Bmw]

Buying two cams would be a waste of money.

[broadie]

Result that will be the 400hp you wanted then.

[NoTurbo]

Let us know how you get on.

[ejoeyward]

well my plan is to bolt twin 40 webbers to the side, port polish the tits out of it with ribbed floor on intake and slightly raise the roof on both sides,a 3 angle valve job and some nice medium grind cams about 270ish and MAYBE some hemi pistons with valve cut outs.

and dont say its a waste of money cuz it relatively cheap cuz iv cannibalized a m40 intake manifold for the carb manifold, the valve job is being done by a friend in the industry, the carbs are already sitting in my shed. so the only thing that will cost money are the hemi pistons if i go that far

so all in including buying the engine im looking about £175 plus hiring an engine hoiste for a day and then plus pistons if i go that far. (would love them just to say iv got a hemi but not sure if they would give me any more performance)

Are you Ed Balls ? You obviously had the same maths teacher !

no im not ed balls we dont have the same maths teacher. i have all the parts in my shed so there for it wont cost me anything

and i will keep you up to date and post some pics of the head when its done and im hoping to go santa pod on the 28th of september

[NoTurbo]

You should definitely look at the Valve guides and throughts these heads can be quite restricted on the intake side. Also look at fitting bigger valves and angling the valve seats.
If you are going to spend your money then it will be good to see what difference a bit of tuning can male to these engines. If you can raise the level of torque available under 4k then it could be a fun project to blast about in.

[ejoeyward]

im just a bit weary of inlarging valves cuz a friend done it and he lost all bottom end power.
could you explain why this happened because although i work on cars as a bit of a hobby i am by no means and engineer

plus i got a mates rates quote on custom exhaust today with headers and im thinking 4 to 2 to minimise how much the gases clash in the manifold

if you had to guess: would i gain any performance from hemi pistons with valve cut out
what kinda power output would i be looking at with and with out the custom pistons (id be really happy if i managed 160bhp but would settle for anything around the figures of a stock m44 so about 140-145)

[Speedtouch]

Probably something to do with Venturi effect:

http://en.wikipedia.org/wiki/Venturi_effect

Smaller intake tracts actually speed up the air flow and create more torque.

I would imagine custom pistons will only create more power if they give a subsequent increase in the compression ratio (CR).

[maxfield]

well my plan is to bolt twin 40 webbers to the side, port polish the tits out of it with ribbed floor on intake and slightly raise the roof on both sides,a 3 angle valve job and some nice medium grind cams about 270ish and MAYBE some hemi pistons with valve cut outs.

and dont say its a waste of money cuz it relatively cheap cuz iv cannibalized a m40 intake manifold for the carb manifold, the valve job is being done by a friend in the industry, the carbs are already sitting in my shed. so the only thing that will cost money are the hemi pistons if i go that far

so all in including buying the engine im looking about £175 plus hiring an engine hoiste for a day and then plus pistons if i go that far. (would love them just to say iv got a hemi but not sure if they would give me any more performance)

Where do you get £175 from.

That wouldn't even cover the cost of a cam.

[ejoeyward]

well my plan is to bolt twin 40 webbers to the side, port polish the tits out of it with ribbed floor on intake and slightly raise the roof on both sides,a 3 angle valve job and some nice medium grind cams about 270ish and MAYBE some hemi pistons with valve cut outs.

and dont say its a waste of money cuz it relatively cheap cuz iv cannibalized a m40 intake manifold for the carb manifold, the valve job is being done by a friend in the industry, the carbs are already sitting in my shed. so the only thing that will cost money are the hemi pistons if i go that far

so all in including buying the engine im looking about £175 plus hiring an engine hoiste for a day and then plus pistons if i go that far. (would love them just to say iv got a hemi but not sure if they would give me any more performance)

Where do you get £175 from.

That wouldn't even cover the cost of a cam.

if i use a reground cam the it will cuz me and a friend will do it at his engineering work shop

[ejoeyward]

Probably something to do with Venturi effect:

http://en.wikipedia.org/wiki/Venturi_effect

Smaller intake tracts actually speed up the air flow and create more torque.

I would imagine custom pistons will only create more power if they give a subsequent increase in the compression ratio (CR).

that why i was thinking about forged hemi's but what could i raise the cr to without putting to much stress on the block

[Speedtouch]

A fairly high level; Ant and others have fitted a turbocharger to an M40 engine, so it's obviously capable of withstanding a reasonable level of boost and pressure.

http://www.e30zone.net/modules.php?name ... =m40+turbo

[ejoeyward]

i am interested in a chip. what you recommend

[Speedtouch]

PM sent.