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Old 06-04-2012, 02:24 AM   #1
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Default adjustable cam gears, set up? questions?

ive done some searching but havent been able to find how people set these up or if many people even run them, i have few questions because i dont know much about how to use them but im suspecting that i can tweak the cam timing to run more or less cam overlap and possibly a set up to increase max RPM? i know to run more rpm id have to tune the spark and whatnot on a MS( or other ecu ) and have better valve springs and such but how would you set the cams up to do this? any input would be appreciated
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Old 06-04-2012, 12:08 PM   #2
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What are you trying to do?

If you are just trying to run more RPMs then you need forged connecting rods, a set of billet oil pump gears, and an aftermarket harmonic balancer. Stock rods will stretch and the pistons will contact the head. Stock oil pump gears fracture and fail, and the stock harmonic balancer has proven inadequate at certain RPM levels above stock.

Then you will be able to rev the engine to higher RPM levels without grenading but it won't likely make any more power. The intake manifold is tuned for mid-range power and is not going to flow enough to make power above stock limits. In fact, it tapers off well before stock limits. The head port shape and size will also be a significant limitation. This isn't a Honda head. And then there is the cam lobe size and shape which is designed to work with the tune of the intake manifold to provide peak torque in a range somewhere between 3500 and 5500 RPM.

Phasing both cams retarded a few degrees will likely shift the torque band up the RPM range 100 to 200 RPM but will not likely increase it, just shift its location. Therefore you will likely find a corresponding loss of torque in the lower ranges.

Reducing overlap by advancing the exhaust cam, retarding the intake cam, or some combination of the two is useful on turbocharged engines to reduce intake charge loss into the exhaust or reversion of the pressurized exhaust into the intake tract. A certain degree of overlap is preferred on naturally aspirated engines as the scavenging effect is helpful in drawing the intake charge into the cylinder.

But if your goal is not to simply turn more RPMs, but instead to make more power, stop finger effing this thing with ideas on how to make 1 or 2 more hp and get a megasquirt and a turbo.
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Old 06-05-2012, 12:01 AM   #3
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"Reducing overlap by advancing the exhaust cam, retarding the intake cam, or some combination of the two is useful on turbocharged engines to reduce intake charge loss into the exhaust or reversion of the pressurized exhaust into the intake tract."

Anybody have any advance/retard numbers that are working for them? Looking to purchase a set of gears and it would be nice to know what has been found to work for turbo'ed cars other that the stock setting. (BP4W head)
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Old 06-05-2012, 01:46 AM   #4
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In for Miller cycle conversion.
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Old 06-05-2012, 01:46 AM   #5
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advance your intake and exhaust cam to improve spool

retard both to improve top end at the cost of spool

the end.
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Old 06-05-2012, 04:57 PM   #6
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Originally Posted by 2manyhobyz View Post
Anybody have any advance/retard numbers that are working for them? Looking to purchase a set of gears and it would be nice to know what has been found to work for turbo'ed cars other that the stock setting. (BP4W head)
I've read a bit about it but am not implementing because I have a dozen more glaring issues to concentrate on first. As long as I'm running a cast manifold there isn't much point in spending money on the dyno trying to capture a few extra horses when I already know where to find a whole herd.

A dyno is the place to find them if you are looking at fine tuning your cams. I think I've read of somebody here doing it.
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Old 06-05-2012, 05:27 PM   #7
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For sto k motor hp its not worth it. Unless
You have some hp restriction like hustler in which case u could just tune for spool and use toming to limit top end power
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Old 06-05-2012, 05:31 PM   #8
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I have adjustable gears, dyno-tuned and all. Picked up a gob of midrange torque with only a minor loss of peak hp. I forgot what we did with advance/retard though. I should have some pics of the gears somewhere after tuning. This is with the exhintake mod on an otherwise stock motor.
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Old 06-05-2012, 05:41 PM   #9
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thinking about doing this with NB exhintake.... but ugh $400 for both gears makes me cry.

for 400 bucks i could get some custom cams made, but i guess even more so with those it would be good to have the cam gears to fine tune it.

Maybe I do intake side only
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Old 06-05-2012, 05:57 PM   #10
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Quote:
Originally Posted by aaronc7 View Post
thinking about doing this with NB exhintake.... but ugh $400 for both gears makes me cry.

for 400 bucks i could get some custom cams made, but i guess even more so with those it would be good to have the cam gears to fine tune it.

Maybe I do intake side only
Details on these $400 custom cams. Last i checked it was $400/cam
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Old 06-05-2012, 06:58 PM   #11
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engine builder (bogus) got that figure from his go to guy for cam grinding. 375 + ship for a set. he said he could do 'street' 264 or 'race' 272... i requested a bit more info: duration at 1mm, lift, etc., still waiting to hear back to determine if it'd actually be worth it.

My original plan was to do Exhintake..got a 2nd exhaust cam which gives me a good bit more lift and duro over stock intake cam.

you got VVTz right?
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Old 06-05-2012, 08:31 PM   #12
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Quote:
Originally Posted by aaronc7 View Post
engine builder (bogus) got that figure from his go to guy for cam grinding. 375 + ship for a set. he said he could do 'street' 264 or 'race' 272... i requested a bit more info: duration at 1mm, lift, etc., still waiting to hear back to determine if it'd actually be worth it.

My original plan was to do Exhintake..got a 2nd exhaust cam which gives me a good bit more lift and duro over stock intake cam.

you got VVTz right?

Yup got VVTz. I want the cams. NOW. Contacting mr bogus.
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Old 06-05-2012, 08:42 PM   #13
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sweet. any info post up! I will do the same, but I got nothing at the moment.

Doing my own calculations/homework on my end.. I was 'assuming' similar specs to what Kelford cams are for the B6
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Old 06-05-2012, 09:16 PM   #14
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Quote:
Originally Posted by Oscar View Post
I have adjustable gears, dyno-tuned and all. Picked up a gob of midrange torque with only a minor loss of peak hp. I forgot what we did with advance/retard though. I should have some pics of the gears somewhere after tuning. This is with the exhintake mod on an otherwise stock motor.
I'd be interested in what yours are set to, did mine last year advancing the intake camshaft 3. Not dyno'd but it pulls nicely.
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Old 06-05-2012, 09:34 PM   #15
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Quote:
Originally Posted by Oscar View Post
I have adjustable gears, dyno-tuned and all. Picked up a gob of midrange torque with only a minor loss of peak hp. I forgot what we did with advance/retard though. I should have some pics of the gears somewhere after tuning. This is with the exhintake mod on an otherwise stock motor.
since you're nat aspirated i assume that gobs of hp to you means 10hp. no offense. i am gonna make my nat asp car a car similarish to yours...

also

your settings may not translate for a boosted motor. for a boosted motor, power is gained by optimizing spool.
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Old 06-05-2012, 09:41 PM   #16
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Quote:
Originally Posted by Freaky Roadster View Post
I'd be interested in what yours are set to, did mine last year advancing the intake camshaft 3. Not dyno'd but it pulls nicely.
Like I said, I'd need some pics to remind me what we changed in between dyno pulls.

Quote:
Originally Posted by Faeflora View Post
since you're nat aspirated i assume that gobs of hp to you means 10hp. no offense. i am gonna make my nat asp car a car similarish to yours...

also

your settings may not translate for a boosted motor. for a boosted motor, power is gained by optimizing spool.
How can I possibly be offended by you

But it's true, I do remember dialing in some more overlap. Not something you'd immediately want on a boosted motor. I also remember picking up ~10 ft/lbs between 4-6k and only losing 4hp up top.
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