e30 Weight Distribution

[lukeADE335i]

Hi all

been researching the weight distribution of different model e30s as I'm preparing to get my M30 properly registered. I need to show the RTA that I have maintained stock weight distribution (shouldn't be a problem as I started with an AC equipped 320i with the battery up front, now I'm running no AC & battery in the rear). Going to axle weigh my car soon to check what the weight distribution with the M30 actually is.

I was just going through old "Auto Motor und Sport" reviews from back in the day over on e30.de & they make for an interesting read as all reviews include kerb weights for the different models & weight distributions. The most interesting one I find is that the 318iS actually has worse weight distribution than the 325i, in opposition to common belief. Thinking about it logically though, it's not so hard to believe, as the G240 is lighter than the G260 + the small case vs medium case diff would logically shift weight forward in the chassis (despite the M42 not being as long as the M20). The M42 is not as close to the firewall as the M20 is either & isn't that much lighter with its twin cams & iron block.

Anyway - I did a search, and couldn't find a thread comparing the weight distribution of different models, so here's what I found (sorry if this is a repost & the distributions are buried in on of the sub-forums somewhere).

320i - kerb weight: 1084kg, distribution: F 54.8% / R 45.2% (note battery in front)

323i - kerb weight: 1173kg, distribution: F 54% / R 46%

325i - kerb weight: 1209kg, distribution: F 52.4% / R 47.6% (Battery moved to trunk)

325i vert - kerb weight: 1301kg, distribution: F 52.3% / R 47.7%

318iS - kerb weight: 1132kg, distribution: F 53.3% / R 46.7%

320iS - kerb weight: 1218kg, distribution: F 52.1% / R 47.9%

M3 - kerb weight: 1237kg, distribution: F 52.2% / 47.8%

[word is bond]

Interesting stuff! Are we confident this is accurate? The weights seem just a bit low, but I would love if someone who has had their car on a scale could confirm any of this.
Google says:
1209 kg = 2665.39 lbs
1132 kg = 2495.63 lbs
And is that battery in the trunk for the 318is? IIRC some euro models had the battery under "the bonnet" - or maybe that was the M40?

[lukeADE335i]

Australian delivered 318iS had the battery in the trunk - we get euro spec cars down here, so I presume the test car would have had the same.

The articles don't indicate the state of the fuel in the car when they were weighed - could be with an empty fuel tank?

[Hooffenstein HD]

Where did you get the weights from?


Weights from the official BMW owner's handbook that came with my 323i.





Weights from the official BMW owner's handbook that came with my 318iS.

[lukeADE335i]

The weights / distributions are from "Auto Motor und Sport" magazine - equivalent of "Wheels" in Australia or "Car and Driver" in the US.

Presumably they are as tested weights for German spec. cars (which could be somewhat different from other markets).

I'm mostly interested in the weight distribution as opposed to overall kerb weight, where figures on the topic seem to be fairly scarce.

[cferb]

I don't think I buy that.

Both the M3 and the 320is heavier than a 325?

Distribution seems questionable too with the 318 being more nose heavy with a lighter engine than a 325, but they did a bunch of other things to save weight too so who knows.

[Hooffenstein HD]

The weights / distributions are from "Auto Motor und Sport" magazine - equivalent of "Wheels" in Australia or "Car and Driver" in the US.

The problem with most figures is they never tell you how the cars were weighed. What equipment/options were installed in them, full tank/empty tank etc. That's why I only go by the weights printed in the official BMW handbook because they tell you exactly how the car was at the time of weigh in.


Unfortunately that doesn't help much with the weight distribution, but perhaps for registration purposes, you'd be able to provide weight of both engines, and then weights of all removed parts? Or are those fascist assholes more stringent than that?

[lukeADE335i]

I doubt they'll be all that stringent. After all, we're only talking about 25kg difference between the M20 & M30.

Basically I'm going to work off the F54 / R46 weight distribution as my 320i had AC + battery in the front to begin with.

I was just after some published material that I can provide to the RTA for comparison. The big ticket item I'm trying to avoid is paying for a swerve test. I will have to do an emissions test, but they are cheap. If push comes to shove, I have access to a stock 320i that I can weigh back to back with mine, but it hopefully won't come to that.

[enigmaticdream]

My understand was the M3 was 47/53 and the 325 was 53/47... I though bmwmregistry had the e30 m3 weight distribution.