Why do Rotrex suck at torque?
#126
They are fairly popular to be installed on V8s in Aus. I know of several. The whipples are more common now though and generally there are far more gearbox options so stupid torque isn't an issue.
My cams are around the 310 duration and I think around the 12mm lift. They are regrinds and to make them work there are two shims, one on the valve stem,
edit: I mean one on the bucket stem... ie under the bucket. The valves are custom too though so I don't know if they are longer or not.
If I was to start again I'd think of using a later model head but this head obviously flows well and my intake is set up for the bp-05. Everyone I've spoken too including my tuner doesn't think I can run such large cams due to the overlap bleeding boost. Looking at comparisons with what the Honda Rotrex builds run, they see gains with up to 300 duration cams at high revs. They are reving to 9000 though and the power is all at the top. Maybe I just need to move up to a C38 unit to cover the loss of boost.
I was planning on regrinding some cams to work with my head setup as I doubt any off the shelf cams will work. Maybe 274 duration 12mm lift cams. I could just try it with the high duration cams and see what I get... Emilio, your the first to suggest it may work. Everyone else just says no way... too much overlap. I think with a roots this is certainly the case, but a centrifugal might be different.
I'm happy to experiment and try crazy ideas however I need to keep dyno and tuner time down as its probably the biggest cost for me pther than hardware. I was thinking of low mounting the supercharger and running a half width intercooler next to my radiator. All the fab I can do myself but I wont be able to start till end of next year as I'm running this season N/A.
My cams are around the 310 duration and I think around the 12mm lift. They are regrinds and to make them work there are two shims, one on the valve stem,
one on the bucket.
If I was to start again I'd think of using a later model head but this head obviously flows well and my intake is set up for the bp-05. Everyone I've spoken too including my tuner doesn't think I can run such large cams due to the overlap bleeding boost. Looking at comparisons with what the Honda Rotrex builds run, they see gains with up to 300 duration cams at high revs. They are reving to 9000 though and the power is all at the top. Maybe I just need to move up to a C38 unit to cover the loss of boost.
I was planning on regrinding some cams to work with my head setup as I doubt any off the shelf cams will work. Maybe 274 duration 12mm lift cams. I could just try it with the high duration cams and see what I get... Emilio, your the first to suggest it may work. Everyone else just says no way... too much overlap. I think with a roots this is certainly the case, but a centrifugal might be different.
I'm happy to experiment and try crazy ideas however I need to keep dyno and tuner time down as its probably the biggest cost for me pther than hardware. I was thinking of low mounting the supercharger and running a half width intercooler next to my radiator. All the fab I can do myself but I wont be able to start till end of next year as I'm running this season N/A.
Last edited by Madjak; 12-17-2015 at 11:26 PM. Reason: Some corrections - typed it on a phone
#129
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Vortech is another, which makes supercharger kits aimed at the American Iron crowd: Vortech Superchargers
I worked with a guy several years ago who had one of their systems on a Fox-body Mustang. It was an older design which used a rising-rate FPR. Performance and driveability were about what you'd expect.
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