ITB'd MK1
worthless in 5th. A gearbox is a torque multiplier, 4th is the only gear that's 1:1 (or close enough)
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Cams, Cams, Cams
- Thread starter Barron
- Start date
ITB'd MK1
without question. Power runs should always be done in 4th.
A lot of places do it in 3rd to get a higher figure
A lot of places do it in 3rd to get a higher figure
ITB'd MK1
you'll have an artificially high figure then
what the hell kind of rollers was that??? sounds like they had the retarder turned up too high
ITB'd MK1
possibly yes. Depends how they apply losses too, if it's done with rundown in 5th that throws even more variables in. Anything but 4th is just incorrect
The graph shown looks more like interference with the rpm pick-up for the dyno itself... maybe?
Dyno's should use an overall drive ratio, i.e the ratio between the roller and the crankshaft, so as to determine a "correct" flywheel torque figure, from which a power figure is calculated.
This means in theory it doesnt matter what gear you are in, as the ratio in the gearbox is "accounted for".
In practice the level of losses does differ with the gear, so depending on the system and the maths applied by that manufacturer will depend on the final figures.
I think 4th is typically used as it allows a better resolution on the sweep, the engine is more "controlable".
Dyno's should use an overall drive ratio, i.e the ratio between the roller and the crankshaft, so as to determine a "correct" flywheel torque figure, from which a power figure is calculated.
This means in theory it doesnt matter what gear you are in, as the ratio in the gearbox is "accounted for".
In practice the level of losses does differ with the gear, so depending on the system and the maths applied by that manufacturer will depend on the final figures.
I think 4th is typically used as it allows a better resolution on the sweep, the engine is more "controlable".
As for the cams/op, as danny has said they are designated for mechanical followers.
Since managment isnt an issue they will run fine, and the forged pistons will allow greater valve/piston clearance also.
You can get away with running a "solids" grind on hyrdo's, as the opening ramp tends to be less harsh (as the lash needs to be taken up slower than with 0 lash hydros), but the limiting factor then is the rpm ability of the hydro's themselves, and with 288deg duration I think you may be pushing it.
Though ive never personally used these cams, I would expect peak power to be 7800/8000rpm? with itb's, high comp pistons im talking.
Suck it and see!!
Since managment isnt an issue they will run fine, and the forged pistons will allow greater valve/piston clearance also.
You can get away with running a "solids" grind on hyrdo's, as the opening ramp tends to be less harsh (as the lash needs to be taken up slower than with 0 lash hydros), but the limiting factor then is the rpm ability of the hydro's themselves, and with 288deg duration I think you may be pushing it.
Though ive never personally used these cams, I would expect peak power to be 7800/8000rpm? with itb's, high comp pistons im talking.
Suck it and see!!
