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Old 01-10-2008, 01:30 PM   #1
wittmer25
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Default Maximum AVCS Advance w/ Cosworth cams?

Whats the Max AVCS intake cam advance with Cosworth cams, 100mm wiesco pistons, cometic .051" thick head gasket, ej257 block and crank, heads surfaced .005", and block surfaced (not sure how much). Anyone have any experience with this?

Jonathon

Edit: With stock intake/exhaust valve size.
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Last edited by wittmer25; 01-10-2008 at 04:46 PM.
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Old 01-10-2008, 04:32 PM   #2
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yeah, its a not fun problem to solve...you also have to use the lift and profile of the cams too...so unless you have the complete cam profile you can't have a definative answer.
Also would need your valve size.

to get nit picky, you need to have actual valve lift at rpm in the cam.
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Old 01-10-2008, 04:45 PM   #3
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I am finally finished with my build and i am about to fire her up. I wanted to make sure that I won't hit my pistons with my valves at max cam advance. Has anyone used max AVCS cam advance with these cams? And if so, what where the your engine specs?
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Old 01-10-2008, 04:49 PM   #4
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what em are you using? open ecu or hydra?

if hydra, you may want to call phil (element), dom (kito autosport), tim bailey (?)...you get the idea.
besides, which cossie cams are you on?
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Old 01-10-2008, 04:50 PM   #5
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I think I bought them from you. 278/274 i think. and I use enginuity to tune with.

Jonathon
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Old 01-10-2008, 04:56 PM   #6
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haha, oh yeah...you did. Now the name clicked. 278/274 is correct
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Old 01-11-2008, 10:54 AM   #7
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bump for sti cosworth cam users. Whats your max intake advance?
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Old 01-11-2008, 01:33 PM   #8
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ahahahaha...that's funny Micah
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Old 01-11-2008, 02:02 PM   #9
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Quote:
Originally Posted by modaddict View Post
ahahahaha...that's funny Micah
I aim to please
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Old 01-11-2008, 08:22 PM   #10
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I would also love to know how much advance you can use with these cams...
I have the next step up from the ones wittmer25 is questioning... (284)

If nobody knows, I will be spending a lot of time to figure it out...

If you are really in doubt, zero out both maps before you fire it up.... Better safe than sorry...
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Old 01-11-2008, 11:45 PM   #11
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advance until you hear a tapping sound, then back it off a degree
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Old 01-12-2008, 09:56 AM   #12
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Quote:
Originally Posted by jigga View Post
advance until you hear a tapping sound, then back it off a degree
haha...I'm buying adjust cam gears for this reason exactly...easier than doing it on paper and also adjustable cams are a beautiful thing...
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Old 01-12-2008, 06:09 PM   #13
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bump bump bump for somebody out there that has built an engine, advanced his cosworth intake cams, and their engine is still in one piece.
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Old 01-12-2008, 11:31 PM   #14
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try contacting tim bailey
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Old 01-12-2008, 11:36 PM   #15
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Or mick_the_ginge.
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Old 01-14-2008, 09:26 PM   #16
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Cosworth cams have pretty mild lift, so I wouldn't worry to much about it.
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Old 01-14-2008, 10:40 PM   #17
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Pretty mild as compared to what. If you don't have anything of value to contribute please don't waste our time.

Charliew
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Old 01-14-2008, 11:32 PM   #18
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Hows this for ya then...

I have tuned a ton of subaru's running the Cosworth cams, even running an aggressive amount of cam advance without any piston to valve clearance issues. Cosworth cams are not a really big lift cams like some of the more aggressive Kelford ones. So like I said in my previous statement... I wouldn't worry about it.

Cosworth made these cams so the avg Joe could bolt them in and not have to worry about anything.
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Old 01-15-2008, 10:03 AM   #19
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I guess the 10.7 mm on my Cosworths (intake) are mild lift....
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Old 01-15-2008, 10:37 AM   #20
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it's true
the high lift 11.3 kelfords are another story.
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Old 01-15-2008, 10:47 AM   #21
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Ok fellows, high lift cams are a relative term. I specifically wanted to know if the 278/274 cosworth cams at 10.7mm (.421") lift will have any trouble with max avcs advance?

Jonathon

Edit: In other words, post up if you are personally maxing out the avcs cam advance in your car.
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Old 01-16-2008, 10:32 PM   #22
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You can run stock AVCS values with the Cosworth cams, or at least I have in the past without any problems. The ones you have to look out for are the Kelford cams that have more lift. With those, I recommend you run no more than 8deg pos or neg cam fluctuation. I typically tell my guys to just unplug the AVCS selenoids until they can either get a reflash to mod the AVCS settings or if they are running a Hydra or similar to get a base map to reflect the cam values.

Ron
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Old 01-16-2008, 10:42 PM   #23
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Ron,

Correct me if I am wrong, but I think the stock avcs map on an 04 STi runs 20 degrees advance. Isn't that the maximum advance that the stock cam pulleys can rotate? Anyone know for sure?

Jonathon

Edit: I can reflash the ecu with enginuity. My current map is set up to fully advance the cams at low rpm, high engine load. I may need to change it back to stock.
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Old 01-17-2008, 05:24 PM   #24
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Quote:
Originally Posted by boogerwrx View Post
You can run stock AVCS values with the Cosworth cams, or at least I have in the past without any problems. The ones you have to look out for are the Kelford cams that have more lift. With those, I recommend you run no more than 8deg pos or neg cam fluctuation. I typically tell my guys to just unplug the AVCS selenoids until they can either get a reflash to mod the AVCS settings or if they are running a Hydra or similar to get a base map to reflect the cam values.

Ron
Ron,

According to your spec sheet from TurboQueef:


You say to limit the AVCS to +/- 8*. Now the lift you spec is 10.7 and 10.2 respectively. Isn't that almost identical to cosworth's peak valve lift of 10.7 and 10.0?
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Old 01-17-2008, 05:50 PM   #25
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I am really confused here, how do you get the avcs to turn the wrong direction (8 +/-)...

I emailed Cosworth about it and have yet to get an answer....

I guess I will have to mock up my long block and figure it out for myself...
I have far to much invested to mess it up....
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