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Registered:
August 2002
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Cams: Torque at the expense of power?
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Sun, 15 February 2004 22:12
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If a certain cam profile for a 2JZGE was to generate more low/mid range torque at the expense of top end power, would this create better gains and driveability, rather than focusing upon maximising top end power?
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Toymods Vice President
Location:
Sydney
Registered:
May 2002
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Location:
South Australia
Registered:
July 2002
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Re: Cams: Torque at the expense of power?
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Mon, 16 February 2004 12:17
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Also - alot of the time factory engine set-ups are designed so that each component complements the other. IE - exhaust port profiles are matched to the rev range that the cam would work most efficiently at, the ecu tuning/timing is matched to the same rev range etc etc etc. So modifying just one of these components (ie the cam) may put it out of sync with the rest of the components. While this won't necessarily kill performance, it does (from a objective point of view) alter 'driveability' (which is a subjective term, I know).
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I supported Toymods
Location:
I renounced punctuation
Registered:
May 2002
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Re: Cams: Torque at the expense of power?
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Mon, 16 February 2004 12:18
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304, 262 @ 0.050", 0.435" lift
Do it. You know you want to........
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Cams: Torque at the expense of power?
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Mon, 16 February 2004 13:01
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LOL, nahh, get a V8 grind 
0.550 lift and 230@ 50 thou  mmmmm lift and low rpm torque
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Location:
Ulladulla
Registered:
October 2002
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Re: Cams: Torque at the expense of power?
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Wed, 18 February 2004 02:30
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By a fluke i was looking thru Mar 02 street machine and found this bit of info in the dirty stuff column...
He has a 4 cyl NA race motor running between 5000-9500 RPM and i quote-
'Our cam drive is a duplex chain on indexing sprockets, so that the valve timing can be easily changed to impove bottom end torque or top end grunt. Advance the cam timing by 10 to 15 degrees and you pick up on mid-range acceleration. Retard by the same amount and peak developed horsepower increases.'
I think a 30 degree range in a street motor would be a little savage, but smaller changes would have a similar effect, you'd think.
IMHO i love a revy motor with a highish (6000) power peak. my car currently has a heap more mid-range grunt, and its just not as fun. esp when you go to overtake and the motors dead past 5000... I should prob add that i also have a fair gob of torque at low rpm, so its pretty easy to cruise round in to.
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Registered:
August 2002
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Re: Cams: Torque at the expense of power?
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Wed, 18 February 2004 06:36
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Dave......perhaps i missed the 'streetable' bit
i think 272 duration will have to do
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Location:
Ulladulla
Registered:
October 2002
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Re: Cams: Torque at the expense of power?
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Thu, 19 February 2004 02:29
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Uh... just thought id betta mention that you should pull out the spark plugs and wind the motor over by hand to make sure everything still misses whenever mucking round with cam timing.
pistons shutting valves is never a good thing...
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I supported Toymods
Location:
I renounced punctuation
Registered:
May 2002
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Re: Cams: Torque at the expense of power?
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Thu, 19 February 2004 03:01
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If he stays below 10mm lift he won't have an issue with interference.
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