Cam timing question
12-08-2004, 07:23 PM
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Cam timing question
Why would it help to retard the exhaust cam while advancing the intake cam? I've seen this done a lot, does it really make more power? IF so, how? 
12-08-2004, 08:28 PM
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Re: Cam timing question (n00bs suck)
not to be a dick, but your question is too vague, pendejo. lol.
i've seen this work on some motors, and do shitty on others.
basically, it all depends on the specs of the cams, and the motor.
put more details in your next post.
i've seen this work on some motors, and do shitty on others.
basically, it all depends on the specs of the cams, and the motor.
put more details in your next post.
12-09-2004, 10:45 PM
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Re: Cam timing question (n00bs suck)
see, everyone has different setups, and depending on the parts used, and the physical timing of the motor (from milling the head, etc), your results may vary.
i'll give you some quick examples...
my best streetable motor was a b18c5 with a toda header, toda spec a's, stock exhaust, comptech icebox, skunk2 p28 and tuning. it made 192 and 136 at the wheels. the best cam settings on that motor were +5 on the intake cam, and +2 on the exhaust cam.
on my friend chris' motor, which was basically an ITR motor, but it had ctr pistons, jdm 4-1 and stock itr cams... that made 189 and 139 if i remember correctly. anyway, those cams barely needed to be moved from stock settings. like +1 intake and 0 or -1 on the exhaust.
last example, which proves my point of the "physical timing of the motor" was my destroker b20. it was an 85mm b20z with custom length rods and a b17a crankshaft, making it only slightly bigger than an LS motor. but this thing REVVED, and made flat power in the high rpms. i was running jun stage 2 cams, and the best setting was -1 on the intake and -3 on the exhaust. this was the ONLY motor i ever saw actaully benefit from retarding both cams.
later
i'll give you some quick examples...
my best streetable motor was a b18c5 with a toda header, toda spec a's, stock exhaust, comptech icebox, skunk2 p28 and tuning. it made 192 and 136 at the wheels. the best cam settings on that motor were +5 on the intake cam, and +2 on the exhaust cam.
on my friend chris' motor, which was basically an ITR motor, but it had ctr pistons, jdm 4-1 and stock itr cams... that made 189 and 139 if i remember correctly. anyway, those cams barely needed to be moved from stock settings. like +1 intake and 0 or -1 on the exhaust.
last example, which proves my point of the "physical timing of the motor" was my destroker b20. it was an 85mm b20z with custom length rods and a b17a crankshaft, making it only slightly bigger than an LS motor. but this thing REVVED, and made flat power in the high rpms. i was running jun stage 2 cams, and the best setting was -1 on the intake and -3 on the exhaust. this was the ONLY motor i ever saw actaully benefit from retarding both cams.
later
12-13-2004, 08:59 AM
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ok, I have an lsvtec (12.2:1cr). when my car was tuned first with stock injectors, si cams, and small exhaust piping, and a dc header, it made best power at exhaust -2 and intake +4, since then, i have bigger webcams, an itr header, a 2.5" exhaust... im trying to get a good baseline number so I spend less time on the dyno. right now cams are both +4, should I retard the exhaust cam? if so how many degrees? total timing is 14 btdc.
12-14-2004, 02:53 PM
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Re: (Mike K)
Hey Mike K, I noticed that you're from the good 'ol northwest and since I need my cams degreed/timed right, I was wondering, where did you get this done? I had a friend of a friend (username: "LEED") tune my A/F with Uberdata to almost perfect, but since it was a street tune, we couldn't do anything about cam timing, and I have this feeling that its something my car really needs to truly shine. I've got Toda A's with I/IM/H/C/E on my GS-R, and I'm surprised to see that they needed that much adjustment. Also, my A/F is set around the low 13's area, will cam gear adjustments screw everything up?
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