4 or 6 cyls ?????

[tickle]

been reading through a few posts and seen how much 318's are slated, i think that this is a bit false all in all.

all that keeps coming into my head when it boils down to it is power to weight ratio.
as best my understanding goes and have recently been re-assured that the scale for power to weight ratio is as follows-

if you double the weight you need to * weight by a multiple of 4, that equates to a ratio of 2/1 power/weight,

so:

enigine specs

m10 318i = 105bhp

m20 320i = 129bhp

m20 325i = 170bhp

as a rough guide as i have no weights (will amend if supplied) i will assume that a 6yl is to have an extra 40% in total weight (ENGINE + BOX).

as standard this means that the m20 will need 42bhp extra just to meet the m10, and anything extra it has is halved,

so if the m20 needs a total of 147 bhp to match m10 the actual gain once power to weight has been considered is,


m20 320i = -36bhp

m20 325i = 11.5bhp


SHOCKING EH???

although it does need to be considered that all spesc are not using the same box and diff, so i expect that there is a margin of around 30% error on my calculations (yet again will ammend if flywheel bhp can be supplied)
m10 and m20 ebgines where only chosen as rough comparison aswell

so really the square headed germans where spot on by making the m3 a 4cyl, and also for making f1 cars with 4cyls, and considering that this car ran 1400bhp and was basically an m10

you can't meet the sound of 6cyl with 4 cyl's though

[Simon]

you can't meet the sound of 6cyl with 4 cyl's though

An S14 with carbon airbox and supersprint race system can though!

[jonbuoy]

I to do have a qeurie(sp) about this as i did a 1/4 mile run at Donington in my M40 318i for the fun of it and was disapointed to see just over 17 sec's. I had 17" wheel's on and a 4.10 open diff on at the time and now have 15" BBS's with a 4.27 open diff on and reckon i could get a bit better on the 1/4 mile stretch as the car feel's alot better in accelleration.

To my surprise most of the 325i's on here can only do a 15-16 sec 1/4 mile What does that say for it then?
I am going to change to an M20 as i need the torque for my drifting hobbie but it does make you think

[tickle]

i bet it can! how does your car come up against 3.5's +3.7's in race situations??

[tickle]

with diff change and wheel change should be far better

hail 4 cyl

[Si316]

4 pots are far better!

[tickle]

SI316 eh,

ive heard quite abit about you me thinks. been told your the guy to ask about 2.0ltr conversions for m10's,

is this right

[jonbuoy]

i bet it can! how does your car come up against 3.5's +3.7's in race situations??

I get left standing LOL ...........but i'd give'm a good go round a country lane

[Si316]

I know a little mate yeah, ask away

[tickle]

the bonus of having 50/50 weight distro, as apose to the 6cyl 60/40 front bias.

he he he.......

[tickle]

exactly which pistons and crank do i need withou havin rebore, i dont want to end up with low c/r

[jonbuoy]

the bonus of having 50/50 weight distro, as apose to the 6cyl 60/40 front bias.

he he he.......

But BMW say that the MTech11 is 50/50 weight distro as for the reason for the battery being mounted in the boot.
It does make me wonder about the engine change but there are time's when i want that extra torque and it's not there

[Si316]

you need the crank, pistons and rods from a 2.0L m10. These are found in all 2002's and some e21's. They will go in without having to rebore the block as long as there not oversized ones. (will probs be a good idea to give it a hone while your at it tho)

if you want high compression (like me) then look out for the pistons from a 2002tii, this is what ive got and are good for 10:1 compression.

[tickle]

sounds like bad logic from bmw there! anything for sales i suppose.

is there anyway you can gain some torque to avoid changing? whats your spec?

[tickle]

what is the difference between 2002 an 2.0ltr m10? and can you get it bigger than 2.0 with different pistons?

[Si316]

my spec is:
2.0L with tii high comp pistons
518i head
292 cam
twin dellorto dlha 40's with 40mm trumpets
new bearings, rings and gaskets
stock manifold (will get changed for jaymic 4 branch over summer)

[Si316]

you can get 2.4L using an m3 crank and i think the m3 pistons and rods

[tickle]

suppose you don't have room for much more, how about a straight cut box?

[tickle]

wicked!!!!! i think thats one for down the line though, damn insurace.

what difference do tii high comp pistons make?

[Si316]

im not sure about a straight cut box but i know theres a dogleg cant remember which model from tho. Ive head m3 boxes also fit.

[jonbuoy]

sounds like bad logic from bmw there! anything for sales i suppose.

is there anyway you can gain some torque to avoid changing? whats your spec?

Standard engine (Well looked after)
Standard gearbox with short shift
Stainless exhaust from manifold, 2.5" pipe with resinator box
Pressure boost valve
Adjusted afm for more fuel intake
K&N Panel filter, hole's drilled in air box
Standard diff for 316i (4.27 ratio)
15" BBS's with 195/50R15
Koni adjustable's all round (Shock's only)

I've mainly noticed a difference when using Shell Optimax aswell

[Si316]

wicked!!!!! i think thats one for down the line though, damn insurace.

what difference do tii high comp pistons make?

im not sure yet mines still not running, apparently it makes for a good engine tho. very torquey!

[tickle]

hope jonbouy kept track of this if he's after torque.

ill go with 2002 crank/rods and 2002tii pistons then me thinks, are these parts readily availiable or is it a case of good second hand

[jonbuoy]

I'm still here mate

[tickle]

jonbouy is yer engine m40 or m10?

[jonbuoy]

M40

[tickle]

ive just lobbed my m40 in place of an m10, they aint very tunable without big money and then its mostly in vain,

build an m10, you can follow one of the specs weve been talking about or use your own.

you wont need to swap diff, propshaft suspension

[Si316]

ill go with 2002 crank/rods and 2002tii pistons then me thinks, are these parts readily availiable or is it a case of good second hand

There gettin harder to find now. i got mine off http://www.bmw2002.co.uk/forsale.htm keep and eye out on ebay aswell. There is a small mod that needs to be done to the top of the pistons just to be sure they dont contact with the head.

[jonbuoy]

ive just lobbed my m40 in place of an m10, they aint very tunable without big money and then its mostly in vain,

build an m10, you can follow one of the specs weve been talking about or use your own.

you wont need to swap diff, propshaft suspension

I had this in mind but as Si said, alot of the old skool stuff is becoming alot harder to get hold of
I was gonna get myself a toy (Mk2 Escort) but they're even not about as much anymore and they keep getting nicked from owner's as alot are being used in Rally's Still might get one but it will be garaged lol
A mint Escort Mexico goes for around the £10,000 mark now Amazing

[Morat]

6 cyl Tourings handle better than 4 cyl ones though.

[jonbuoy]

6 cyl Tourings handle better than 4 cyl ones though.

That's probably because the weight is more 50/50. My friend had a touring 325i and that handled like it was on rail's but it did have decent suspension

[Demlotcrew]

6 cyl Tourings handle better than 4 cyl ones though.

Please explain?

Andrew

[pacerpete]

So much 4 pot wrongness !

[Morat]

6 cyl Tourings handle better than 4 cyl ones though.

Please explain?

Andrew

Well, I've owned two tourings. One a 318, one a 325. Both were well maintained and running on standard suspension - I find the 325 handles better. It feels more "planted" and I can boot it harder round corners. The tyres on both were cheapo rubbish, but with good tread. I've never driven an E30 saloon so I can't comment on them.

[Morat]

been reading through a few posts and seen how much 318's are slated, i think that this is a bit false all in all.

all that keeps coming into my head when it boils down to it is power to weight ratio.
as best my understanding goes and have recently been re-assured that the scale for power to weight ratio is as follows-

if you double the weight you need to * weight by a multiple of 4, that equates to a ratio of 2/1 power/weight,

so:

enigine specs

m10 318i = 105bhp

m20 320i = 129bhp

m20 325i = 170bhp

as a rough guide as i have no weights (will amend if supplied) i will assume that a 6yl is to have an extra 40% in total weight (ENGINE + BOX).

as standard this means that the m20 will need 42bhp extra just to meet the m10, and anything extra it has is halved,

so if the m20 needs a total of 147 bhp to match m10 the actual gain once power to weight has been considered is,


m20 320i = -36bhp

m20 325i = 11.5bhp


SHOCKING EH???

although it does need to be considered that all spesc are not using the same box and diff, so i expect that there is a margin of around 30% error on my calculations (yet again will ammend if flywheel bhp can be supplied)
m10 and m20 ebgines where only chosen as rough comparison aswell

so really the square headed germans where spot on by making the m3 a 4cyl, and also for making f1 cars with 4cyls, and considering that this car ran 1400bhp and was basically an m10

you can't meet the sound of 6cyl with 4 cyl's though

Power to weight ratios (From HERE)

318i (m10) - 97bhp/metric tonne
318i (M40) - 106
318iS (M42) - 125
325i (m20) - 141
M3 (s14) - 159-189 (Evo3)

These are not my figures, I'm sure they'll be debated but they're a good starting point.