Darton Engineering is working with Group-S on sleevng a VR38DETT engine. Sleeving will greatly increase the amount of cylinder pressure and heat that the VR block will be able to handle. One of the unknowns in the VR38 is the plasma sprayed bore coatings. These coatings are fairly new, and some people have concerns about them flaking under large increases of horespower/cylinder pressure/boost.
Gruppe-S is working with Darton to create the first sleeved VR38DETT block. This block is required for for our target 1000hp and the 4.3 liter stroker kit under development. The machining is going to start next week, we just finalized the details of the sleeve. The ductile iron is going to be same stuff they use on the NHRA motors, that boost up to 100psi. I believe that Darton is going to be sleeving our block first, first in the worldSource : Group S Blog