rotaryrex7

I've searched most of the threads re timing advance and I can't find anyone that sets theirs at an rpm that would have the full advance. Since high load is the place you really care about timing I have always set my timing on my boingers at an RPM that would have the engine at max advance. On a chevy small block all the advance (mechanical and vacuum) would be in around 3500-4000 rpm and the advance should be about 30* BTDC.

What is the maximum advance at high rpm that the stock ECU will put into the system? How advanced should you set the timing at the point of maximum ecu advance ie if the system will advance the timing a maximum of 25* then you would run the rpm up to that point and set the timing at 20*BTDC on the #1 leading wire (5*atdc + 25*advance = 20*BTDC.)

J-Rat

iTrader: (2)

Far as I know the only marks on the Crank for the CAS sensor are at idle timing, which is 5 ATDC. THere isnt anyway you could check for exact advance.

Jarrett

rotaryrex7

J- rat there are 2 ways either mark off 5* increments on the pulley. Or use a timing light with the dial back feature and use the existing marks on the pulley.

Jim

SonicRaT

iTrader: (6)

Basically, the ECU's always changing the 'max advance' throughout the rpm ranges, so it's rather hard to set a strict advance, usually people advance the idle sit it's pretty much the only time the ECU isn't fighting against you and doing things on it's own accord, usually the best bet is 20 degrees.

rotaryrex7

SonicRat something is missing from your post. Were you saying to set it at 20 degrees at idle? That's 25 degrees advanced from the stock 5atdc? That seems like a lot!

J-Rat

iTrader: (2)

Oops....Forgot about that.

SonicRaT

iTrader: (6)

No, I meant, 20 degree's past the stock point, so 15atdc is what people usually suggest setting to.

rotaryrex7

I just heard tonight that the dial back type timing lights don't work with rotaries, any one ever hear that.

SonicRat , you don't mean past the stock point. To advance your timing you need to move it before the stock setting not after so 15 btdc is 20 degrees advanced from stock. Turning the CAS clockwise advances the timing ie makes it fire earlier.

GTR

iTrader: (6)

my timing was 15* advanced and i put it back to stock and it really runs better I heard its unsafe to run it that advanced.

SonicRaT

iTrader: (6)

Sorry, I was up way too long and got the timings mixed up.