Why

At TwinSpark Racing & Engineering you are the right address for a gearbox revision or upgrade. What distinguishes TwinSpark from other garages is that we are working with precision engineers who have learned the specifics of upgrading and converting 901 and 915 gearboxes.

Because TwinSpark works with a tolerance worklist where every part of the gearbox is measured against wear, you will never be surprised. The tolerance worklist also gives you immediate insight into when to replace certain parts, should it not be revised in the planned upgrade. TwinSpark has a lot of experience with FIA homologations and will also be able to provide advice on which parts do and which parts do not comply with FIA homologations.

How

For a fixed amount, your TwinSpark gearbox will be fully disassembled, cleaned and individually inspected and measured. Think of, for example, the swing of the price ax and shift forks as the flankspin on the gear pairs. (?)
Based on this inspection and measurements, the worklist is filled in and shared with the customer. Using this worksheet will decide on which level the gearbox project will be carried out and our experience will also take into account the intended use of the gearbox. In addition to the replacement of optional parts and the installation of custom gear ratios, TwinSpark also offers the possibility to perform exclusive WEVO modifications in-house.

Almost all 901 and 915 gearboxes we handle have bearing shells that are beyond the tolerances given by Porsche.
Often, a short-term solution is chosen by securing the locktite bearing shells. It is only a matter of time until this fit back is gaining what could eventually have major consequences for the internal parts in the gearbox. By tackling the gearboxes and putting the exclusive WEVO inserts into the gearbox, they will return to the indicated tolerances and be stronger than original without affecting the outside of the gearbox. Furthermore, all attachment surfaces will be flattened to prevent any leakage. In addition to inserting the inserts, TwinSpark is also able to place the original RS / RSR oil cooler. The front of the gearbox is also processed in-house. All required parts including the oil pump are available through TwinSpark.

Once the gearbox has been machined and the parts are fitted and cleaned, the gearbox will be assembled according to the prescribed procedure with the correct measurements and adjustments.

Modifications we perform for 901 and 915 gearboxes:

• Place Limited Slip Differential (LSD) with the desired adjustment
• Customized ratios
• Replace bearing shells
• Tolerance measurement
• Mount RS / RSR oil pump

End result

TwinSpark will return the gearbox with a comprehensive photo report and inspection report, fully assembled in a solid wooden flight case to prevent any transport damage. Included is a Swepco 201 vial which TwinSpark always uses as gearbox oil and therefore recommends.

Of course, at TwinSpark, it is also possible to only have the gearbox modifications done, if assembly with your own specialist is required.