BMW E30 Convertible Specifications -

Contents:

body

dimensions and performance

engine and power transmission

chassis

rims and tires

Body:

The body of the convertible differs fundamentally from the body of the sedan. First, Cabrio has the sheet metal thickness e.g. wheelhouse, torpedo, transmission tunnel and floor under the back seat. Second, these parts are connected to in other ways. In detail these are:

-reinforced side members with higher thresholds

-reinforced B-pillars

-additional struts between B-pillars and rear struts

-Tonneau cover integrated into the bodywork behind the rear bench seat

– Stiffer side members between the B-pillar and the rear wheel arches

-Increased sheet metal thickness (2 mm instead of 0.75 mm in the limousine) in the frame including the windscreen

-reinforced beams under the front seats

-reinforced brackets between A-pillars and engine mount

-additional stiffening between A-pillar and strut support bearing

– Reinforced dashboard support (like sedan with airbag)

-Doors reinforced like US version

In practice, the integration of the convertible top compartment and the additional reinforcements lead to higher thresholds (approx. 60 mm), narrower floor space at the front and rear, narrower rear seats, smaller luggage compartment and the convertible weighs 110 kg – 160 kg more than the corresponding sedan model and still has a torsional stiffness of about 80% of the sedan model.

Body weight:

* Body frame = body without bonnet, tailgate, doors, front fenders

** without sunroof

Dimensions and performance:

Dimensions 318iC-325iC

M3C has the same internal dimensions as above but not the same external dimensions as below

external dimensions

* The larger wheelbase on the M3C is explained by larger caster angles on the front trailer.

Weight (with standard equipment)

Baggage and loading capacity:

luggage compartment (VDA-Norm)

Drag Coefficient:

Noise level in the passenger compartment (with the top closed)

Acceleration:

Deviation of the speedometer

Angezeigte Geschwindigkeit	Echte Geschwindigkeit
50 km/h	43 km/h
80 km/h	77 km/h
100 km/h	96 km/h
130 km/h	126 km/h
160 km/h	154 km/h
180 km/h	175 km/h

Daily mileage deviation – 1%

Auto Motor Sport, Test & Technik 8/1986, test measurement at 325iC with standard tire dimensions 195/65 x 14.

fuel consumption

Modell	318iC	320iC	325iC	M3C
90 km / h / manuell	0,70	0,77	0,72	0,66
90 km/h / Automatik	0,71	0,78	0,73	Nein
120 km/h manuell	0,88	0,97	0,89	0,80
120 km/h / Automatik	0,89	0,98	0,91	Nein
Stadtverkehr / manuell	1,07	1.33	1,29	1,25
Stadtverkehr / Automatik	1,10	1,36	1.32	Nein

DIN 70 030/1 ECE

At 90 km/h the car sucks about 0.1 liters/mile more with the hood open than with the hood closed due to the greater drag.

fuel tank volume

Modell	318iC	320iC	325iC	M3C
Tankvolumen leuchtet -09/87	Nein	55	55	Nein
Tankvolumen leuchtet 09 / 87-	62	62	62	55

Sources: Unless otherwise stated, all of the above data comes from the operating instructions, BMW Cabrio brochures 1/87 – 1/93 or ETK.

engine and power transmission

The convertible’s engine and transmission are the same as the equivalent sedan, but the ratio of the top gear usually differs between the convertible and the sedan.

BMW M40 engine 318iC

BMW M20 / M25 engine

Engine:

Modell	318iC	320iC	325iC	M3C
Motorbezeichnung	M40	M20B20	M20B25	S14
Zyl. Volumen	1796	1990	2494	2302
Anzahl Zyl	4	6	6	4
Leistung kw / PS	83/113	95/129	125/170	143/195
bei	5500	6000	5800	6750
Drehmoment Nm	162	164	222	230
beim	4250	4300	4300	4750
Kompressionsrate	8.8	8.8	8.8	10,5
Hub / Zyl.Durchm.	81/84	66/80	75/84	84 / 93,4

Gear ratios manual transmission:

Modell	318iC	320iC	325iC	M3C
Getriebe	Getrag 240	Getrag 240 el ZF S5 -16	Getrag 260 / Getrag 260 Sport	Verhalten 265
1: ein	3.72	3.72	3,83 / 3,35 *	3.72
2: ein	2.02	2.02	2.20 / 2.03 *	2.40
3: ein	1.32	1.32	1,40 / 1,36 *	1,77
4: ein	1.00	1.00	1,00 / 1,00 *	1,77
5: und	0,81	0,81	0,81 / 0,81 *	1.00
Zurück	3.45	3.45	3,46 / 3,02 *	4.23

* 325iC with sports transmission Getrag 260 Sport

Gear ratio automatic transmission

Modell	318iC-325iC
Getriebe	ZF 4HP22 oder ZF 4HP22 EH
1: ein	2.48
2: ein	1,48
3: ein	1.00
4: ein	0,73
Zurück	2.09

Top Gear

Note that the 318iC-320iC has a different gear ratio than the corresponding sedan model

Modell*	318iC	320iC	325iC	M3C
Handbuch	4,27	4,27	3,73 / 3,91 **	3,25
Automatik ohne EH	4.45	4.45	3.73	Nein
Automatik mit EH	Nein	4.45	3.73	Nein

Catalytic converter models only

** 325iC with Getrag 260 Sport transmission

EH = Electro-Hydraulic Steering

Sources: Operating instructions, BMW Cabrio brochures 1/87 – 1/93, TIS or ETK

chassis

The convertible is more than 100 kg heavier than the corresponding sedan and has a body that has around 80% of the torsional rigidity of the torsion model. In order not to accentuate the movements in the body, the convertible has softer springs than the corresponding sedan model, but at the same time harder shock absorbers. In ETK you can e.g. See that a 325iC with M Technic sports suspension has the same front springs as a standard 316! Being nearly 250kg heavier than the 316, the 325iC apparently gets as low as a regular 325i M Technic, but probably softer with the 316 springs too. On the other hand, the 325iC M Technic has both harder shock absorbers and stronger anti-roll bars (21mm) than a 2-door 325i M Technic (20mm).

Differences in shortness between chassis and brakes on convertible and sedan models

All convertibles have disc brakes front and rear, whether the car has ABS or not.
All convertibles have anti-roll bars front and rear (see specification below)
All convertibles have special gas shock absorbers (see specification below)
All convertibles 318iC-325iC have 51mm front struts
All 318iC-320iC, M3C have power steering as standard
All 325iC have standard power steering from 09/87

318iC – 325iC

Suspension struts with a diameter of 51 mm

Gas front shock absorber 31 32 1 133 560

Rear gas shock absorber 33 52 1 132 123

The above also applies to 318iC – 325iC with M Technic sports suspension

318iC

Stabilizer front 20mm
Rear stabilizer bar 12 mm

The above also applies to the 318iC with M Technic sports suspension

320iC – 325iC

Stabilizer front 21mm
Rear stabilizer bar 12 mm

The above also applies to 320iC – 325iC with M Technic sports suspension.

M3C

Gas front shock absorber 31 32 2 226 355
Rear gas shock absorber 33 52 2 225 426
Power steering
Stabilizer front 19 mm

Rear stabilizer bar 14.5 mm

BMW E30 front axle suspension:

front suspension

Modell	318iC	318iCA	320iC	320iCA	325iC	325iCA	M3C
Standard-Vorderwagen
Stoßdämpfer	SF	SF	SF	SF	SF	SF
Frühjahr -09/87	F1	F2	F5	F6	F6	F7
Frühjahr 09 / 87- 09/89	F1	F2	F5	F6	F6	F7
Frühjahr 09/89 –	F1	F2	F5	F5	F5	F6
Stabilisator (mm)	20	20	21	21	21	21
M Technic Vorderwagen
Stoßdämpfer	SF	SF	SF	SF	SF	SF	SFM
Frühjahr 09 / 87- 09/89	F3	F4	F8	F9	F9	F10	FM
Frühjahr 09/89 –	F3	F4	F8	F8	F8	F9	FM
Stabilisator (mm)	20	20	21	21	21	21	19

Spring front variant and BMW part number BMW E30 Cabrio:

F1 = 31 33 1 131 333

F2 = 31 33 1 139 068

F3 = 31 33 1 131 321 M Technik

F4 = 31 33 1 131 324 M Technik

F5 = 31 33 1 131 937

F6 = 31 33 1 131 940

F7 = 31 33 1 131 943

F8 = 31 33 1 131 027 M Technik

F9 = 31 33 1 131 030 M Technik

F10 = 31 33 1 131 330 M Technik

FM = 31 33 1 131 327

Front shock absorber BMW E30 Convertible:

SF = 31 32 1 133 560 M Technik

SFM = 31 32 2 226 355 M Technik

Rear suspension BMW E30 Convertible:

rear suspension:

Modell	318iC	318iCA	320iC	320iCA	325iC	325iCA	M3C
Standard-Hinterwagen
Stoßdämpfer	SB	SB	SB	SB	SB	SB
Frühjahr -09/87	–	–	B1	B1	B2	B2
Frühjahr 09 / 87-	B2	B2	B2	B2	B3	B3
Stabilisator (mm)	12	12	12	12	12	12
M Technic Bakvagn
Stoßdämpfer	SB	SB	SB	SB	SB	SB	SBM
Frühjahr 09 / 87-	B4	B4	B4	B4	B4	B4	BM
Stabilisator (mm)	12	12	12	12	12	12	14,5

Rear spring BMW E30 variants and original BMW part numbers:

B1 = 33 53 9 058 746

B2 = 33 53 9 057 337

B3 = 33 53 9 057 349

B4 = 33 53 9 058 543 M Technik

BM = 33 53 9 061 510

Rear shock absorber BMWE30 and original part number M Technik:

SB = 33 52 1 132 123 M Technik

SBM = 33 52 2 225 426 M Technik

Original rims and tires:

BMW E30 318iC – 325iC (four screws)

Bezeichnung

Abmessungen

Drücken

Stahlfelgen Styling 1 (silber oder schwarz)

Deck

5 1/2 x 14

195/65 HR14

ET 35

Cast Light Metal Styling E30 (lackiert oder poliert)

Deck

6 x 14

195/65 VR14

ET 35

Cast Light Metal Crucible Styling 5 (silber, schwarz, weiß oder gold)

Deck

6 1/2 x 14

195/65 VR14

ET 30

Cast Light Metal Cruiser Styling 5

Deck

7 x 15

205/55 VR15

ET 24

Gegossene Leichtmetallsterne Styling 10

Deck

7 x 15

205/55 VR15

ET 24

The wider the rim, the smaller the ET, ie you move the center line of the wheel outwards, the wider the rim will be so that the inside of the wheel does not touch the rear struts / shock absorbers. With 5 1/2 – 6 inch rims ET 35 works, with 6 1/2 inch rims ET 30 Works and with 7 inch rims around ET 25 and with rims 8-9 inch an ET from below 15-20 is required to not die The inside of the wheel should be touching the struts and with such a low ET the risk of the tire and rim touching the fender edges instead increases.

Dimensions 5 1/2 x 14 with indentation ET35