Setting Base timing with large cams

[perrytheplatypus157]

I was wondering how those of you with large cams like kelford 280's and up set your base timing? I run S3s and I have found it a difficult to get my car to idle low since base timing is supposed to be set around 750 rpm with the timing pin grounded. I usually get it down about 850 or so. I HAVE, however, found it easier if you have adjustable cam gears, to advance the exhaust cam a couple degrees in order to reduce overlap. Just wondering if anyone else has good techniques for achieving this?

 

[1990TSIAWDTALON]

Perry, I don't think there are any centrifugal advance, that I know of, on the CAS and if that is correct you can still set base timing at 900 or what ever those S3s will idle at. Ground the pin, set at 5* (if that is your base timing) and it should be fine.
Anyone else have any other insite? I thought that the CAS was merely an optical sensor without advance features.

Edit: or magnetic I cant recall.

 

[ThunderChild]

I believe you're right. Once the pin is grounded, timing is locked and you set it to 5*, regardless of rpm.
I'd just set your idle speed to what works well for the cams (mine with stock cams doesn't like 750, I have mine at 850 +/- 50) then set timing to 5* and send it.

 

[DSMPT]

I believe you're right. Once the pin is grounded, timing is locked and you set it to 5*, regardless of rpm.
I'd just set your idle speed to what works well for the cams (mine with stock cams doesn't like 750, I have mine at 850 +/- 50) then set timing to 5* and send it.

Agree.

I was wondering how those of you with large cams like kelford 280's and up set your base timing? I run S3s and I have found it a difficult to get my car to idle low since base timing is supposed to be set around 750 rpm with the timing pin grounded. I usually get it down about 850 or so. I HAVE, however, found it easier if you have adjustable cam gears, to advance the exhaust cam a couple degrees in order to reduce overlap. Just wondering if anyone else has good techniques for achieving this?

Everyone has their own techniques to tune and the way to get the same goals is not only one method sometimes, so this is just my opinion.
Normally it goes more difficult to get a stable low rpm idle when you use that kind of cams. you would sacrifice the stability of low rpm at idle for gaining more power at high rpm range. And who uses that kind of cams most likely already have a standalone ems, so recommend you to adjust it through the ems, not to through the cam gears. If you set the idle through cam gears, then it would affect the performance of engine in all rpm range and it would disturb you when you would like to tune the valve timing in the future.