Showing posts with label comparison. Show all posts
Showing posts with label comparison. Show all posts

Wednesday, 15 January 2025

BMW E30 323i Spec Comparison to contemporary early-80s rivals...

How does the E30 stack up next to its five most common early 1980s stablemates, the MG Montego Turbo, Peugeot 505 GTi, Renault 25 GTX, Saab 900 Turbo and Subaru RX Turbo?

Great review from MOTOR Magazine, November 1985.

Tuesday, 3 December 2019

BMW E21 / E30 323i Engine Comparison [M20b23 2316cc]

Here's another quick engine comparison, this time the E21 and original E30 flagship models, the 323i. BMW introduced the E30 323i in 1983 using the same M20b23 2316cc injected 6-cylinder motor as the E21 had in its top model since 1977 and displacement was not increased until the better known 325i emerged in 1985. Even with sightly more weight, the E30 323i was still billed as a quicker car than its predecessor, but I have no idea what improvements were made to the engine, so lets see how the specs stack up:

M20 Engine323i [E21]323i [E30 <1987]
Bore80.0mm (3.15")80.0mm (3.15")
Stroke76.8mm (3.02")76.8mm (3.02")
Capacity2316cc (141.3 cu in)2316cc (141.3 cu in)
Comp. ratio9.5 : 19.8 : 1
Power (BHP)141 @ 5800rpm148 @ 6000rpm
Power (PS)142.8 @ 5800rpm150.0 @ 6000rpm
Power (KW)105 @ 5800rpm110 @ 6000rpm
Torque (Lbs ft)140 @ 4600rpm151 @ 4000rpm
Torque (Nm)190 @ 4600rpm205 @ 4000rpm

A little more compression, along with a few extra horse power and a slightly higher redline make for a harder pulling engine in the high rev range, but the big difference seems to be in the torque figures. Not only does the E30 323i have a bit more, but peak-torque is delivered 600rpm lower down than the older engine and that is clearly what makes the E30 feel quicker.

Monday, 2 December 2019

BMW 1990cc [2L] Engines 4 and 6 Cylinder Comparison - M10b20 and M60/M20 [E21 320, 320i, E12]

Up to 1977 BMW used 4-cylinder engines for its original 320 and 520 models, evolving from the trusty M10 used in the 2002. After 1977 they began to use freer-revving 6-cylinder engines for all the 2 litre models, the M60 and after 1981 the M20, both still using the same 1990cc, the latter of which has evolved into all the modern BMW straight sixes we know today. The 2 litre four pot is still a very sought after power-plant though, with its light weight and torquey character making for a more responsive front-end, particularly in the smaller chassis models.


I have wanted to compare the specs of these two engines side by side for a while now to see how the bore/stroke and power outputs stack up, so here goes:

CARBURETTOR:
M10 4-cyl.M60/M20 6-cyl.
Bore89.0mm (3.504")80.0mm (3.15")
Stroke80.0mm (3.15")66.0mm (2.60")
Capacity1990cc (121.4 cu in)1990cc (121.4 cu in)
Comp. ratio8.1 : 19.2 : 1
Power (BHP)109 @ 5800rpm120 @ 6000rpm
Power (PS)110.5 @ 5800rpm122.4 @ 6000rpm
Power (KW)82.5 @ 5800rpm90 @ 6000rpm
Torque (Lbs ft)115.7 @ 3700rpm118 @ 4000rpm
Torque (Nm)157 @ 3700rpm160 @ 4000rpm

The 6-cylinder looks to be the faster motor, making a good 10 bhp more, with the shorter stroke and higher compression ratio no doubt making for a peppier drive. However, with its longer stroke and bigger pistons, the 4-cylinder still makes very similar torque, so unless you are screaming it all the time, the lighter engine might still make a more balanced drive under normal use.

INJECTION:
M10 4-cyl.M60/M20 6-cyl.
Bore89.0mm (3.504")80.0mm (3.15")
Stroke80.0mm (3.15")66.0mm (2.60")
Capacity1990cc (121.4 cu in)1990cc (121.4 cu in)
Comp. ratio9.3 : 19.8 : 1
Power (BHP)125 @ 5700rpm123 @ 5800rpm
Power (PS)126.8 @ 5700rpm125.1 @ 5800rpm
Power (KW)94.6 @ 5700rpm92 @ 5800rpm
Torque (Lbs ft)126.6 @ 4350rpm122 @ 4500rpm
Torque (Nm)172 @ 4350rpm165 @ 4500rpm

The injected engines are a different story, with the compression ratio of the M10 not too far behind the 6-cylinder and both making the same power, though I would say the M20 is going to pull harder and smoother as you get up the revs and, ultimately have a higher redline. On the other hand, the 4-cylinder actually seems to be giving a bit more torque this time, obviously the higher compression and bigger bore contribute to this and it is all produced lower down the rev range. This could be why I have heard M10 enthusiasts saying it is more torquey, but either way it stands to reason that the lighter, more responsive handling and low-end grunt makes the 4-cylinder a better choice for round-town driving or even short-track racing.

I actually owned one of the rare 1990cc 4-cylinder M10 engines in 2012, having been given it with the '83 E21 316 I bought. The previous owner had intended to build it up and drop it into the E21, but never got round to the project and I decided not to pursue it given that the M10b18 1.8 litre unit was plenty quick enough for the car fitted with a twin-choke Weber carb, so I sold the 2 litre lump in bits, missing suitable con-rods, for £350!

More 1977 engine changes included the 1.6 litre engine used in the E21 316 now badged as the 315. The 316 now received a restricted-power version of the 1.8 litre M10 engine and a new model, the 318, was given a hotter version of the same engine. The 316 dropped back to 1.6 litres for economies sake with the newer M4x series of engines in the late E30 and E36.