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| Brendan351 |
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what is the largest cam, we the owners of AU2 XR8's can fit to our engines before piston to valve clearance is an issue.
I am looking at an X303 FRPP cam for my ute but am unsure what level of lift is the maximum i can have before the pistons need to be flycut. specs are: M-6250-X303* rocker ration: 1.60 Intake: 5° BTC 39° ABC 49° Exhaust: BBC 5° BTC Duration: | Lift: 286° 286° | .339 I .542 I 224° 224° | .339 E .542 E Lobe Seperation: 107° 117° Cheers guys, i couldn't find anything through the search function. |
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| XR9UTE |
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The F303 is the largest..it has 512 lift and 228 @ 050.
My mates Capri uses one and it makes excellent power 330 rwhp at the peak with good torque through the rev range. |
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| EBXR8380 |
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depends on valve size etc..
The F303 is a GOOD cam.. TFS 1 also.. Lift is NOT the be all on valve clearance btw.. Std valve springs won't work either..
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| schnoods |
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I have an AU2 5L motor with a comp cams XE270HR cam in it.
Very similar lift .512 and it goes very nicely indeed. http://www.compcams.com/Cam_Specs/CamDe ... =1054&sb=2 Im not sure if its more or less aggressive though.
_________________ Because of Beer, Thirst is a Beautiful Thing! |
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| EBXR8380 |
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I doubt much more lift .512 would net any more power with std heads..
In any case some clay on piston assemble head with old gasket assemble valve train , turn engine over and check thickness of clay.. Minimum is .080
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| Kilma |
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schnoods' engine has a set of AFR165s. Don't know if they are the competition editions or not though.
_________________ The fast fun: Suzuki GSXR1000
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| XH5LWEPN |
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Yep schnoods engine has AFR165's with the Comp XE270HR-14 cam and 1.6 rockers.
On the AU 220kw engine (bottom end) 1.7 rockers could not be used with the above due to piston/valve clearance issues so they were swapped for 1.6's (was another mates engine with same combo)
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| nicskitz |
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does it make any difference to run a bigger cam with smaller ratio lifters then to say to run a smaller cam with bigger ratio lifters to equall the same amount of valve lift?
_________________ Too many cars atm
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| XH5LWEPN |
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nicskitz wrote: does it make any difference to run a bigger cam with smaller ratio lifters then to say to run a smaller cam with bigger ratio lifters to equall the same amount of valve lift?
I've actually never heard of different ratio lifters, they are all the same size.
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| Scaffy |
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nicskitz wrote: does it make any difference to run a bigger cam with smaller ratio lifters then to say to run a smaller cam with bigger ratio lifters to equall the same amount of valve lift?
I've wondered the same thing, but we'll change lifters for rockers...
_________________ Trickflow Street Heat top end kit, 70mm BBK TB & EGR, 24lb injectors, Underdrives & 3.73s: 275rwhp - 13.15@105mph NA / 12.37@116mph N20 |
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| nicskitz |
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woops i messed my words up a little lol
i ment to change between the 1.6:1 or 1.73:1 ratio rockers to equall the same lift using different cam sizes?
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| EBXR8380 |
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A Crane 2031 with 1:72 rockers and AFR 165 heads work.. But still check..
Roller cams have VERY FAST ramp rates.. Fitting higher rocker ratio will give valve springs a hard time if not upgraded...
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| fairy v8 |
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the duration of the cam has as much affect if not more than valve lift as its normally in the valve overlap period when theyre most likely to hit
as said above roller cams ramp up rates are quick there are ways to get the best of both worlds .... check out the different cam specs compare overall duration with figures @50 thou ....theres big differences example comp xe 264 relatively small duration cam compared to crane 2031 which is 276 duration ..... the 264 @50 thou is only 2 deg smaller by having a real quick ramp up could be an option for you if your concerned about P-V clearance downside to the real quick ramp up is theyre real hard on valvetrain and can be a bit clattery |
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