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CRX ECODiesel Ram
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Discussion Starter #1
I have run 3 cams on my engine, an a6 cam, crane 0012 and now a rocket stage 4.

The amount of duration difference is HUGE. the rocket cam has 44 more degrees on the intake side and 28 more degrees on the exhaust.

As I am seeing the ignition timing tables I am using from a p28 map are much less than ideal, and it would seem that adding more advance will be required to improve throttle response.

Are there any rules of thumb regarding how much timing should be added with more duration? is this a consistent number across the board?
I have read that often you will need to add more advance initially, but will this translate to more total timing at wide open throttle as well?

Obviously the best thing is a dyno or det can, but until I am absolutely certain that I do not have a continuing distributor code I am not going to the dyno, so I will need to do some driving. A lot of the better articles I have read are more for carb'd v8s, but i am assuming much of the theory remains the same.
 

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Brokedick Millionaire
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40,267 Posts
IMHO the P28/P06 lacked timing esp. under cruise conditions, but also look at the WOT numbers

With the Crane 0016 cam I added 6 degrees at the dist. itself along with what Blundell added in the maps.

P28 Dump



Blundels magic chip



Note they are in Crome and not exactly sure which tune it was.
 

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CRX ECODiesel Ram
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Discussion Starter #3 (Edited)


this is my current map right now. I have not changed much from the stock s300 p28 low cam map. It seems like the a6 combustion chambers, the pg6b pistons and the amount of overlap/duration on this cam might allow for some pretty aggressive timing changes.

currently with the cam gear zeroed i have base timing set at 16 degrees though that takes my distributor to near full advanced, which i believe indicates the head has been milled at least 0.040".

I appreciate you those maps, i am going to play with a few degrees here and there and hope my intermittent code 9 goes away so it doesnt ruin a dyno session soon. im definitely going to keep readin in the meantime.
 
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