325i flywheel into a 318is

[ScottyE30]

I heard they were lighter and fit into an 'is' is that true, if so it will obviously benefit the speed of the car. Is a sport flywheel in anyway modified from standard???

[jono]

they do fit onto the i.s. but you have to swap the ring gear around as the 325 one is slighty larger in diameter and the tooth pitch is slightly different hence the starter motor will not engage if they are not swapped.

hope this helps

[Dan318-is]

i read that they were heavier

also, cant you just change the starter so its a 325i ?

Iv also read that it wont fit pressure plate, nor gearbox input shaft

maybe its still possible tho

[Demlotcrew]

Early 318i M40 flywheel anyone?

A

[Dan318-is]

know i no thats lighter than the m42 one, will it fit

however a lighter flywheel means you need a bigger pulley to counter act it surely

[Demlotcrew]

what pulley? (yes it will fit)

A

[Simon13]

no 318is came with these flywheels if u have an early one. 1991 cars have the heavier ones

[Dan318-is]

and its lighter?

my lecturer at college who worked for bmw for 40 years told me that if i put a lighter flywheel on a bmw engine i would need a larger crank pulley?

just what i was told

Is it worth putting an m40 fly on?

[Demlotcrew]

is it worth it? yes its a cheapo mod.

All BMW parts are balanced individually so i dont know why you would need a larger pulley. i think this would be a pointless excercise as your just moving the weight around ( to the front also )

A

[Dan318-is]

hmm fair play then

have you done it to your IS??

is there any noticable performance increase?

i take it the teeth pattern for the starter is the same?

[Demlotcrew]

Dude its the same fly, its just lighter!

Im not sure what fly ive got on mines, i think its the early non twin mass unit, as i get a hum at around 3.2k RMP and its not the engine making the noise.

A

[Dan318-is]

simon, what if my IS is a 1990? light one or heavy one?

ok guys opinions: im taking the engine out for a college project is it worth putting an m40 fly on a 1990 m42 engine?

[Demlotcrew]

Its heavy.

Yes its worth it.

A

[Dan318-is]

another mod on my list then

how much do m40 flys go for then

[Demlotcrew]

Ԛ£30 if you can find one

A

[Dan318-is]

nice, do they use the same bolts?

what BHP you running on your IS? iv heard its a bit of an animal lol