Weight Assessment#
Overview#
The original vehicle has a documented tare weight of 1,110 kg.
The purpose of this assessment is to estimate the weight increase resulting from the modifications, the final vehicle weight, and the effect on the front and rear axle loads.
The calculation is based on a component-by-component comparison between the original and modified configurations.
Component Weight Changes#
| Component | Weight Difference |
|---|---|
| AGG → BWA engine | +20 kg |
| Miscellaneous engine components | +5 kg |
| 020 → 02Q gearbox | +20 kg |
| Clutch / flywheel | -3 kg |
| K04 turbocharger | +5 kg |
| Intercooler | +3 kg |
| Radiator | -1 kg |
| Exhaust | -4 kg |
| Front brakes | +10 kg |
| Rear brakes | +10 kg |
| Suspension | -10 kg |
| Wheels | +14 kg |
| Tyres | +4 kg |
The largest increases come from the engine, gearbox, wheels and brake system.
K04 Turbocharger Weight#
The BWA engine weight already represents an engine fitted with a K03 turbocharger. Therefore, the complete K04 weight is not added again; only the difference between the two turbochargers is considered:
Turbo weight increase = K04 weight - K03 weight = +5 kg
Combined with the other component changes, the complete vehicle weight is estimated as follows:
| Parameter | Estimated Value |
|---|---|
| Original tare weight | 1,110 kg |
| Estimated modification increase | +73 kg |
| Estimated final tare weight | ~1,183 kg |
The final value should ultimately be confirmed by weighing the completed vehicle.
Axle Distribution#
The original static weight distribution is assumed to be approximately:
| Axle | Assumed Distribution |
|---|---|
| Front | 62% |
| Rear | 38% |
The 62/38 distribution is an engineering assumption rather than a measured value.
The weight change of each component is distributed between the front and rear axles according to its approximate position in the vehicle.
This is adequate for estimating axle loads, although it should not be interpreted as a precise calculation of the final weight distribution.
Some allocations are necessarily simplified:
| Component | Consideration |
|---|---|
| Engine | Located almost entirely over the front axle |
| Gearbox | Predominantly located towards the front of the vehicle |
| Exhaust | Extends along a significant part of the vehicle |
| Front brakes | Weight change effectively associated with the front axle |
| Rear brakes | Weight change effectively associated with the rear axle |
| Wheels and tyres | Reasonably distributed equally between front and rear |
For homologation purposes, these simplifications do not materially affect the conclusion.
Axle Load Assessment#
The permitted vehicle limits are:
| Parameter | Maximum Permitted |
|---|---|
| Front axle | 860 kg |
| Rear axle | 800 kg |
| Maximum vehicle mass | 1,610 kg |
Using this component-by-component allocation, which already includes the corrected +5 kg K04 turbocharger weight and the updated +10 kg front brake weight:
| Axle | Estimated Load | Maximum Permitted | Approx. Margin |
|---|---|---|---|
| Front | ~742 kg | 860 kg | ~118 kg |
| Rear | ~441 kg | 800 kg | ~359 kg |
Even if a conservative calculation assigns a greater proportion of the additional powertrain weight to the front axle, the vehicle remains comfortably below the permitted 860 kg front axle limit.
Therefore, the homologation conclusion does not depend on obtaining an exact front/rear distribution.
Accuracy of the Estimate#
Not all values used in the calculation have the same level of certainty.
| Data | Confidence |
|---|---|
| Original tare weight | High |
| Maximum vehicle mass | High |
| Maximum axle loads | High |
| Measured component weights | High |
| Manufacturer component weights | Medium-High |
| Estimated component weights | Medium |
| Original 62/38 distribution | Estimate |
| Calculated final axle distribution | Estimate |
| Actual final vehicle weight | Must be measured |
For this reason, figures such as 62.74% front / 37.26% rear imply more precision than the underlying assumptions support.
It is preferable to present the calculated axle distribution as an engineering estimate rather than an exact value.
Conclusion#
The component-by-component assessment indicates an estimated weight increase of approximately 73 kg.
This results in an expected final tare weight of approximately:
1,183 kg
A practical working figure for the modified vehicle is therefore:
Estimated vehicle weight: approximately 1,183 kg
The majority of the additional weight is concentrated towards the front of the vehicle. Nevertheless, even using conservative assumptions, the estimated axle loads remain comfortably below their permitted limits.
The assessment therefore indicates no significant weight or axle-load concern for homologation.
The final verification should be performed by weighing the completed vehicle, ideally recording:
- total vehicle weight,
- front axle weight,
- rear axle weight.
These measured values should supersede the calculated estimates once available.