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Old April 1st, 2005, 01:26   #31
flupstar
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Quote:
Originally Posted by cabe
tristan,

i'm curious about how the the holes in the cams/gears translate into degrees. do you know how to translate into degrees, or where i could find that info? thanks!


Ugh I hate it when people ask that question. lol.

Ok.. here goes... given 46 teeth... each tooth represents 7.82 CAM degrees.

Shifting one pinhole to the left or right (rotating the cam gear on the cam until the adjacent set of holes line up).. will change cam timing by 2.6 degrees (BGB is very specific and says "About two degrees")...

You can then bend the rules a bit by rotating the cam gear 20% to the left or right to give you even more options/combinations

Thats about all the info I can give you.. I degreed my HKS cams via the stock gears and it took some messing around... I didnt record how much adjustment was made with different combinations, you'll need to experiment!

-Tristan
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Old April 1st, 2005, 07:10   #32
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Quote:
Originally Posted by flupstar
Ugh I hate it when people ask that question. lol.

Ok.. here goes... given 46 teeth... each tooth represents 7.82 CAM degrees.

Shifting one pinhole to the left or right (rotating the cam gear on the cam until the adjacent set of holes line up).. will change cam timing by 2.6 degrees (BGB is very specific and says "About two degrees")...

You can then bend the rules a bit by rotating the cam gear 20% to the left or right to give you even more options/combinations

Thats about all the info I can give you.. I degreed my HKS cams via the stock gears and it took some messing around... I didnt record how much adjustment was made with different combinations, you'll need to experiment!

-Tristan
so in that case, the most i'd be able to retard my exhaust cam is 5.1 degrees? (i don't know how the pins are set up in the gen2 cam/gear, assuming the pin goes through the middle hole of both the cam and gear)

thanks for the info btw

ps. how can the cam gear be rotated to the left or right if it is fixed in place via the pins through the cam? (i'm not familiar with the gen2 cams) and doesn't 20% to the left or right translate into 72 degrees in either direction? that seems like quite a bit much of avaliable timing to work with..

anyway, i would be happy with just retarding the exhaust cam 5.1 degrees if that's all i can do with a stock gen2 gear/cam.
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Old April 3rd, 2005, 21:48   #33
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Quote:
Originally Posted by cabe
so in that case, the most i'd be able to retard my exhaust cam is 5.1 degrees? (i don't know how the pins are set up in the gen2 cam/gear, assuming the pin goes through the middle hole of both the cam and gear)

thanks for the info btw

ps. how can the cam gear be rotated to the left or right if it is fixed in place via the pins through the cam? (i'm not familiar with the gen2 cams) and doesn't 20% to the left or right translate into 72 degrees in either direction? that seems like quite a bit much of avaliable timing to work with..

anyway, i would be happy with just retarding the exhaust cam 5.1 degrees if that's all i can do with a stock gen2 gear/cam.


ok this is difficult to convey across but I'll try

if you want more than 5 degrees, all you do is skip one tooth and work from there... and you have infinite adjustability through the entire 360 degrees.

rotating the cam GEAR by 20% doesnt rotate the entire cam by 20%. only the gear moves hence there is no 20% change in actual timing. This brings a new cam gear hole into use and allows a whole other range of adjustment. There are typically three holes on the gear you can do this with (one 1/5 to the left, one 1/5 to the right).. to give triple the resolution that the BGB method offers.

-Tristan
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Old April 3rd, 2005, 22:06   #34
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ahh that makes sense! i may find the motivation soon to create a table with all the possible values of advance and retard then.
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Old April 3rd, 2005, 22:41   #35
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I'd like to see an almost completely stock car put on a dyno with the exhaust cam retarded 6 degrees and see what the gain is vs no retard, haha.

I like to keep things consistant with runs so I feel the only way to get the real legit numbers behind this deal is see an almost stock car do the test.

For instance mods like exhaust, intake and a boost controller.

Hey Aron, send me a set and I will do the test come May 15th at my car show I am having a mobile dyno there. Mustang unfortunetely, but its a dyno... .

I like the 5 bolts lockin the thing down. HKS using 3 worries me, but hey, they have tons of experience with these things. Whats the spec on the torque value of those bolts anyways??
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Old April 4th, 2005, 01:14   #36
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Quote:
Originally Posted by pwrslide2
I'd like to see an almost completely stock car put on a dyno with the exhaust cam retarded 6 degrees and see what the gain is vs no retard, haha.

I like to keep things consistant with runs so I feel the only way to get the real legit numbers behind this deal is see an almost stock car do the test.

For instance mods like exhaust, intake and a boost controller.

Hey Aron, send me a set and I will do the test come May 15th at my car show I am having a mobile dyno there. Mustang unfortunetely, but its a dyno... .

I like the 5 bolts lockin the thing down. HKS using 3 worries me, but hey, they have tons of experience with these things. Whats the spec on the torque value of those bolts anyways??


While the idea is sound from a practicality standpoint, it still has the same flaws as the test in this thread

..ie.. if efficiency increases with the change in cam timing... and no tuning is performed... then AFRs will lean out, and combustion will also speed up significantly.. giving a similar effect to advancing timing. Therefore the gains that the cam timing ALONE is giving is distorted. Perhaps only 40% of the power gain is from cam timing.. and the other 60% is from AFRs leaning and combustion speeding up... which is misleading.

Its not showing us how much cam timing adjustments ALONE can effect power on a car which is tuned to a particular limit in both setups. Its a bit like upgrading the exhaust and claiming a 40rwhp increase. True, that might have happened... but the 40rwhp increase is not from exhaust flow alone. its often also from AFRs leaning out, boost rising and burn speed increasing too... and you cannot expect the same gains on a car which is already tuned (and retuned) to its optimal point

-Tristan
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Old April 4th, 2005, 23:03   #37
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OK I have the final answer regarding degreeing via cam angle and crank angle. Someone asked.. if you degree by crank angle then why are there 1 degree marks on the cam gears?

The results are on HKS cam gears. YES, they do have a mark for every 1 cam degree.

BUT.. it has no numbers. Instead, it states very clearly on the gear that each mark = 2 crank degrees.



One more loose end out the way

Later skaters
-Tristan
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Old April 4th, 2005, 23:36   #38
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This is a picture of an HKS exhaust cam retarded 6 cam degrees and 12 crankshaft degrees.
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Old April 4th, 2005, 23:42   #39
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Quote:
Originally Posted by RickyB
This is a picture of an HKS exhaust cam retarded 6 cam degrees and 12 crankshaft degrees.



thanks for the illustration!

as an ammendment to everyone.. when someone is speaking of cam timing.. it really should be specified whether its cam or crank degrees..
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Old April 5th, 2005, 01:32   #40
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i agree -- like when ats retarded the exhaust cam 6 degrees. i am assuming this is crank degrees?
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Old April 5th, 2005, 10:14   #41
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slightly off topic
I always assumed crank degrees. On my old honda I had the intake advanced 2 notches on the cam gear(4*@crank) and the exhaust retarded 2 notches(4* on the crank). This netted me about 6 rwhp. Back then I was only interested in peak whp. I looked at an old dyno and gained more tq then whp and my power curve shifted back about 400rpms meaning I had more power sooner. This is what i want now since Ive recently purchased an aftermarket manifold. So the first thing Im going to do is start with advancing the intake a few degrees and see what happens and then proceed to the exhaust cam.

The max i would have advanced the intake cam gear would be 5*crank before It would stop making more power. Of course too much advance is not good so on my honda 4*crank was enough.
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Old April 5th, 2005, 14:11   #42
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Quote:
Originally Posted by flupstar

eg.. look at this. The lower power graph is also running richer. And the one point where the AFRs were almost the same is also the point where the two power graphs came very close to each other.

I put down a theory.. that if those AFRs were identical.. the power gains from tuning the exhaust cam would have been significantly smaller. Half that what is claimed actually, if that little bump in the red graph is any indication.

look closely.. you'll see what I mean.. the gap between the AFRs almost perfectly resembles the gap between the power graphs.

ATS- dont stab me for attacking your results.. just pointing out the obvious discrepancies. And Im not discounting your results entirely either.. I still agree that adjusting the cam makes a good difference in favour of your results.

-Tristan


No Stabbing necessary ;-)

The difference in AFR will not make that much difference in power. Notice between 5000-5200 AFR's are almost identical... No dip in power. Same thing @ 6200RPM... no dip in power. Only tuning AFR's, does not effect power like a lot of people think, unless the tune was poor to start with... now play with ignition timing and WOW... look out. ;-)
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Old April 5th, 2005, 14:49   #43
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Quote:
Originally Posted by flupstar
While the idea is sound from a practicality standpoint, it still has the same flaws as the test in this thread

..ie.. if efficiency increases with the change in cam timing... and no tuning is performed... then AFRs will lean out, and combustion will also speed up significantly.. giving a similar effect to advancing timing. Therefore the gains that the cam timing ALONE is giving is distorted. Perhaps only 40% of the power gain is from cam timing.. and the other 60% is from AFRs leaning and combustion speeding up... which is misleading.

Its not showing us how much cam timing adjustments ALONE can effect power on a car which is tuned to a particular limit in both setups. Its a bit like upgrading the exhaust and claiming a 40rwhp increase. True, that might have happened... but the 40rwhp increase is not from exhaust flow alone. its often also from AFRs leaning out, boost rising and burn speed increasing too... and you cannot expect the same gains on a car which is already tuned (and retuned) to its optimal point

-Tristan


I wouldn't call the test flawed. We intentionally did not re-tune and intentionally showed the AFR so everyone could see the difference, not just in power but in increased airflow. The leaner AFR is an INDICATION of increased Flow.

Consider this as well...If I added more fuel to the larger air flow, it might make more power....Don't always assume it would make less...But I'm not here to estimate power, just defending our testing method.

The test shows the difference in cam timing on stock cams. Period. This is how we test. We provided the raw data, you may interpret it how you wish.

Still not a stab ;-)
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Old April 5th, 2005, 18:55   #44
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how long does it take to install a set of camgears with the motor in???

What does Each mark on a Fidanza Cam Gear Represent??
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Old April 5th, 2005, 19:27   #45
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Quote:
Originally Posted by pwrslide2
how long does it take to install a set of camgears with the motor in???


Imagine doing a timing belt job without removing the bottom cover...

Quote:
Originally Posted by pwrslide2
What does Each mark on a Fidanza Cam Gear Represent??


2 deg. AFAIK, all adjustable cam gears have a mark every degree, which is 2 deg. @ the crank....
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Old April 5th, 2005, 21:53   #46
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I appreciate the absense of bodily harm to me

As long as its clear that the results are minus any extra tuning, its all good!
What difference the extra tuning would give.. who knows Thats on your plate more than mine

-Tristan
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Old April 6th, 2005, 00:40   #47
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I appreciate the absense of bodily harm to me


No problem, I'd do it for anybody. :-)
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