Baffled

[GregWeld]

14:1 compression ratio -- big ass cam -- 114 octane race gas... MORE TIMING needed! Holy smokes dude -- who built you a 14:1 motor!??!


I'm being serious here -- that motor can take 36 or 38* of total.

Pump gas - great heads - might make best power on 32 to 34* but pump premium with oxygenated etc - is going to take less (retarded) timing

[Track Junky]

That's some interesting info Greg. I didn't know higher compression likes more timing. When I originally dynode this motor in Muncie, Indiana at the builder shop we went with 38* total timing.

When I dyno tuned down here after the timing chain incident Joe thought it ran best at 32.5*.

[Flash68]

I disagree with Greg to a point on timing needed. Compression is part of it but the efficiency of the heads/combustion chamber has a big part to do with it.

Based on your theory Greg, tell me why my motor likes 30* timing (13:1 compression) and Rob's FE likes near 40* (less than mine, around 12:1 give or take).

It's mostly due to the difference in combustion chamber, valve angle, etc.

Typical 23* headed engines do not run low timing (relatively) like 32* so that is very surprising. 36-38* sounds more like it. I am thinking Joe built in a lot of safety for you? I dunno else why. That doesn't make much sense to me based on what you've shared.

[intocarss]

Originally Posted by Flash68

I disagree with Greg to a point on timing needed. Compression is part of it but the efficiency of the heads/combustion chamber has a big part to do with it.

Based on your theory Greg, tell me why my motor likes 30* timing (13:1 compression) and Rob's FE likes near 40* (less than mine, around 12:1 give or take).

It's mostly due to the difference in combustion chamber, valve angle, etc.

Typical 23* headed engines do not run low timing (relatively) like 32* so that is very surprising. 36-38* sounds more like it. I am thinking Joe built in a lot of safety for you? I dunno else why. That doesn't make much sense to me based on what you've shared.

[GregWeld]

Originally Posted by Flash68

I disagree with Greg to a point on timing needed. Compression is part of it but the efficiency of the heads/combustion chamber has a big part to do with it.

Based on your theory Greg, tell me why my motor likes 30* timing (13:1 compression) and Rob's FE likes near 40* (less than mine, around 12:1 give or take).It's mostly due to the difference in combustion chamber, valve angle, etc.

Totally agree with you --- until we toss in the 114 octane.
You can not compare two completely different motors -- all that will tell you is that they are completely different. For many obvious reasons.


A good running MOPAR 440 --- wants 40* total on PUMP gas with good heads. That's NOT a SBC.... or a FORD for that matter. Different motors want different timing.

Originally Posted by Flash68

23* headed engines do not run low timing (relatively) like 32* so that is very surprising. 36-38* sounds more like it. I am thinking Joe built in a lot of safety for you? I dunno else why. That doesn't make much sense to me based on what you've shared.

Good heads -- tight quench -- etc -- my 408 motor ran 34* and made best power. A dyno is going to tell you -- you don't tell it. You find it. The numbers don't lie. It was also running PUMP GAS not 114.