m43 engine, lasting ?

[vincent]

so mine is m43, so i should be using 3.38 , i think tht is the best ....i was using 4.44 for a week and now using 3.46 i notice the low end is not tht big diffrence ,

albundy , for my car im travelling at 110, the rpm is @3700 NOW .then i travellel @140kmh the rpm is whooping 5000rpm ! tht is high for me

if i do tht an high way at 160kmh i will be redline already , engine will not be reliable , i think .....

 

[ALBundy]

Are you sure you are having a 3.46 diff now????

At 100km/hr your rpm should be around 3k. From what you have mentioned, its unlikely you have a 3.46 rear diff.

 

[vincent]

yes lar , i never tried to look at 100kmh . but @110 is around 3600-3700rpm

i saw the little tag on the rear deffrential 3.45, but he say by just looking at that some thimes cannot trust tht , so he did a manual counting ,
the result was
on the big gear, the count is =40.
on the smaller gear near inside is(located inside the big gear) =9

al . maybe can culculate from here anyone know ?

 

[fabianyee]

40 divide by 9 = 4.4444444444444444444444

 

[vincent]

huh really ar , but why now my rpm is lesser than original 4.44 lar

 

[fabianyee]

Try this...
The calculation is for the E30 but your 5th gear ratio is 1:1.0, so just look at the speed for 4th gear.

Calculation based on the following figures:

Tyre : 205/60/15 (Stock E36 size)
Rear diff / Final Drive : 3.45

View attachment 751

So theorectically can get 100kmh at 3000rpm if using the 3.45 diff...
if 3.15, can get 109kmh at 3000rpm...

However, the speedometer always reading 5-10kmh higher...

 

[elwine30]

my cousin m40 manual at 5th gear is running about 3.1K @ 110 km/h.

 

[kelvinp]

my M40 is at 3K rpm @ 100kph. hope it helps.

 

[vincent]

thank everybody for the input , i will get the rear diff 3.46 from albundy hehehe .

 

[ALBundy]

Due to high demand and scarce supply, price going up kakakaka....

 

[vincent]

Due to high demand and scarce supply, price going up kakakaka....

noo lar where got high demand le , duck rice will kau tim

 

[Zoggee]

yes lar , i never tried to look at 100kmh . but @110 is around 3600-3700rpm

i saw the little tag on the rear deffrential 3.45, but he say by just looking at that some thimes cannot trust tht , so he did a manual counting ,
the result was
on the big gear, the count is =40.
on the smaller gear near inside is(located inside the big gear) =9

al . maybe can culculate from here anyone know ?

so..

40 divide by 9 = 4.44

swap the pinion gears la.

 

[LCP]

vincent, don't worry about the engine blowing up, it's more reliable that you think it is, anyway, meanwhile, enjoy the short ratios (very good for track use, for those without long straights), you will miss it once you get it down to 3.45/3.38/3.15.

 

[vincent]

hahaha yeah , im enjoying it at the moment but i still preffer the 3.45 .....
hopefully m43 is not tht fragile ...