e12 M535i & e28 M5

[MattC]

I am wondering if the e12's performance might be underestimated? Autocar magazine tested both cars and the e28 M5 was only 8 mph faster. The magazine also noted the e12's dogleg 5 speed really hindered the 0-60 mph time with the slow 1 to 2 shift.

e12 M535i at Zolder

Autocar's non a/c plain spec e12 M535i was only 2,971 lbs, whereas many M5s come loaded with powered toys. So maybe there are some aspects of performance where the light, torque biased e12 can shine?

e12 & e28

[John Turner]

I owned an E12 M535i for many years and it was a fabulous thing. I wish I had been able to afford to keep it. Unlike the E28 M535i (a 535i with cosmetic upgrades) the E12 is a genuine M sport car and you could argue that its replacement was really the E28 M5 but in truth the earlier car sporned both E28 models.

Official figures suggest

E12 M535i 0-60 - 7.1 secs, top speed 139mph
E28 M535i 0-60 - 7.4 secs, top speed 141 mph
E28 M5 0-60 - 6.2 secs top speed 153 mph

The E12 was a bit heavier than the later E28 version but had a close ratio box which allowed it to stay ahead of the later car up to 110mph. They both had a quoted 218 bhp whereas the 24 valve version in the M5 had 286 bhp, a significant increase.

[MattC]

Originally Posted by John Turner

I owned an E12 M535i for many years and it was a fabulous thing. I wish I had been able to afford to keep it. Unlike the E28 M535i (a 535i with cosmetic upgrades) the E12 is a genuine M sport car and you could argue that its replacement was really the E28 M5 but in truth the earlier car sporned both E28 models.

Official figures suggest

E12 M535i 0-60 - 7.1 secs, top speed 139mph
E28 M535i 0-60 - 7.4 secs, top speed 141 mph
E28 M5 0-60 - 6.2 secs top speed 153 mph

The E12 was a bit heavier than the later E28 version but had a close ratio box which allowed it to stay ahead of the later car up to 110mph. They both had a quoted 218 bhp whereas the 24 valve version in the M5 had 286 bhp, a significant increase.

BMW Motorsport have said the e12 M535i was their basis for the e28 M5, and ran e12 M535is as test mules with the M88 engine.

The first two sets of figures you gave above for the e12 and e28 M535i came from Autocar magazine. I think Autocar got 147 mph out of the M5. The official BMW figures for the e12 and M5 were:

e12 0-100 kph 7.5 secs 138 mph
M5 0-100 kph 6.5 secs 148 mph

Magazine tests varied. The thing people forget is that the e12 had a tall 3.07:1 final drive ratio, whereas the M5 had 3.73:1. 3.07:1 is too tall for sprinting and the CR dogleg gearbox doesn't help because 1st and 2nd are very similar in the CR and overdrive (M5) gearboxes.

I know when the e28 came out BMW said the e28 had been lightened a lot compared to the e12, but if you look at the weights the difference isn't much. Definitely the bare spec e12 M535i Autocar tried was under 3,000 lbs, but I haven't seen an e28 M5 under 3,250 lbs. Probably because of all those powered toys it had.

The M88 had a lot more top end power, but torque was effectively the same. You can see this with Chris Harris' video of his M5. He has to cane it to move. It reminds me of when the Porsche 944S came out with the 16 valve 2.5, up to 100 mph it was even with the 2 valve 944.