hi mike
The Rotrex works really well on the Xu9j4 since as you know its technically a de-tuned T16 engine,so even at 8,000 rpm the pistons cant pull a vac anywhere near enough to fill the cylinders.Therfore with the rotrex sp30/74 as it produces around 0.7 bar of boost which has been enough for around 50% power increase@115,000 rpm thats around 7895 rpm engine speed
Its worth saying as i know you'll probably ask but the engine is the early D6C 10:4:1 one,and not the later 9:7:1 engine i was going to use although i have one of them in the shed for my next trick

,its defo worth while making sure you have a good quality head gasket mines a steel Cometic one from Petear at DP-enginnering and the rest of the engine is in good fettle,ive also fitted a set of ARP bottom end bolts and a baffled sump and a high pressure oil pump return spring
If you've ever driven a Corrado G60 then that will give you some idea what its like only a fair bit quicker
It mounts where the Air con pump would go although piping it up around the fron of the engine has been a bit of a mare due to the accumilator sphere being in the way.Ive had to move the radiator up and further forward to give room aswell as modify the front crossmember so there's ample clearence.I also modifyed the front panel to fit the range rover intercooler which incedently is almost a perfect fit(a trick ive used on pug's before

)The rotrex also uses its own oil feed system which incorporates a 13 row oil cooler which is mounted under the N/S head light which a vent grafted into the bmper
The bx is fucking quick with them mad cams and charger Faster than my 309 Turbo and my mates Renault 21 turbine.I can keep the front wheels spinning into 3rd gear,but she's torque steering quite badly till she gets to 70....anyway after much deliberation i couldnt decide if i was going to stick my BE3 box which has pug gti 1.6 ratio's and a Quaife ATB and that would have ment pulling it out of my 309

Or trying the 6 speed conversion......which im a little stuck with but hey im sure ill think of something