The issue of rams intended for use at low pressure being used at high pressure was raised at the last FRA meeting. Firstly, I would not recommend this approach unless the individual concerned can confidently ensure that necessary modifications are correctly undertaken.

As well as the pre-requisite pressure test, the ram has to be fit for purpose. It is unlikely that an un-modified LP ram at HP can be considered fit for purpose and history supports this view.

The FRA will allow the use of LP rams at HP subject to the team being able to satisfy the tech checker that they have taken the necessary steps to ensure the ram is fit to run at these elevated pressures.

Personally, I would look for some evidence to show that the cylinder tube can cope with the HP, that tie bars are of adequate size and grade of material and that the end caps are of sufficient strength (or some alternative means to ensure the mechanical shock at stroke end is absorbed sufficiently to remove shock from the end cap).

I would ask that tech checkers assume that the LP ram at HP is unsuitable until convinced otherwise by the team in question. This does not mean that the tech checker has to understand all of the theory of the mods but wants to be convinced that the team understands and can demonstrate what they did to ensure the ram is fit for purpose.

The FRA does not want to encourage the use of LP rams at HP but recognise that it can be achieved safely when approached in the right manner.

Paul
FRA Technical Team