With regards to lower low end torque of the twin-screw units, is not something you can say per say. All supercharger types have their sweat spot pending on many variables (pressure, intake design, speed etc), and considering the roughly 750 nm its producing on my car and that’s already from 4000 rpm (lower rpm readings aren’t possible to measure on a chassis dyno, but I can sure you its high there as wel),

Although I believe the Gen V is better because of the coating, bearings and quieter helical front gears, you’re expecting way too much from it. Have done this about 10 years ago, but can;t remember that it gave any hp. If you compare the difference between the 4.0 cars and 4.2 cars (with the Gen V), there is about 30 hp more to get on the later models. But most of that can be attributed to the better injectors, 6% larger lower pulley, and the 0.2 ltr engine increase, which leaves little left for the coating. Of course a worn supercharger will have less good clearances, so by refreshing it all (i.e. bearings, rotor coatings) you again might see a small improvement. So far porting on our cars of the SC outlet (SC inlet would also be possible but requires more work also on the intake elbow) have at least shown you get more supercharger whine, I have yet to see any dyno slip showing an improvement, which should make you wonder after more than 10 years its available for our cars.

Have fun though, and attention to the full intake is where you can get some good gains.

 

Andre,

I have no expectations. Someone mentioned 20 hp and I said id be happy with that. I do however know that my inlet mods will help significantly. To what degree I dont know.

My experience comparing my 1.7L twin screw to an S ported M90 is all I can compare. I also have a 2.2 liter twin screw setup with laminovia IC's but thats still in project mode. No comparison there. Now my club has used the jaguar m112 on the 3.8's as well and we were never able to make good power out of them. Weve even used the rotor packs from an m112 in an m90 case with a spacer and still nothing. Weve just had better succes with ported m90's. Porting on the m90's made a significant difference. Its my understanding the Jaguar m112 gets little out of porting so Im just not doing it. A bad port just leads to more noise and less power. I just want the inlet to fit niceley. Currently weve tried everything from TVS units to 2.4 whipples ot the same 2.1 big bore you use. We are making over 500 to the rear wheels with the 2.3 whipple setup. Most all this information can be found on the sccoa.com if interested. my XKR is a buget build so to speak so none of this come sinto play unless I get extremely bored with it. REALLY want a twin screw on my 2004 xjr...hint hint

 

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