Expected gains from 2.0 to 2.5 conversion

[MarkF]

Hi guys this may seem like a lame question but can anyone tell me how much of a noticeable difference changing my 2.0 to a 2.5 (Keeping all 2.0 running gear) is going to make. I know obviously it will be faster for a start but i mean differences more in terms of drivability, acceleration, torque figures etc etc. Will retaining 2.0 running gear make it much different to a standard 325? Im just trying to get an idea as i have never driven a 325 and am eager to know what gains my conversion will bring!

Thanks in advance

[Gunni]

same-ish mileage
everything else better.

keep the 2.0 drivetrain, it doesn´t make a lick of difference on a stock 2.5 engine.

[Coyote_ar]

regarding the 2.0 drivetrain, is there any weakpoint there? will it hold a 250-300hp engine?

[e30bmlover]

i have had this swap on my 320... the 320 box is man enough for the job, use the 320 flywheel and clutch. the 4.1 diff on the 320 provides rapid acceleration... but lacks economy, you will be changing gear allot, i think its 3000 rph @ 60 mph in fith, so motorway driving will do your head in... dont get me wrong the diff is up to the job its just the gearing is too short. i have just bough a 3.61 lsd for mine so i will see how that goes.

[Coyote_ar]

i thought the 320i had the 3.25 diff, not the 4.10.

mine doesnt feel that short geared.

[Gunni]

I don´t think a 320i came with a 4.1 as it came with a overdrive box
0.81:1 in 5th gear.

[Ziggy]

Depending on age, a 320i could have pretty much any diff. Mine ('83) had something like a 3.45, but the later ones did indeed have a hugely different ratio - 4.1 for the saloons & 4.27 on the tourings!

Just do the swap, & change the diff afterwards if you feel the need - no need to do them at the same time.

& on the original question, a 325i feels totally different to a 320i! The 2.0 is a pleasant car to drive; smooth, sounds nice etc, but at the end of the day they're plain slow. A 325i isn't particularly 'quick' in modern terms, but certainly feels a huge amount faster than the 2.0.

[MarkF]

Thanks for the advice folks! Roll on with the conversion!!!