What are you 383 guys running for timing at WOT? Im at 35* and my plugs have been pointing to too much timing but I have no knock retard.

What is everyone else running?

Also isnt there some "mystery timing" added by the PCM at WOT?

 

Anyone???

 

i'm not running a 383, therefore i probably shouldn't respond. I have a stock bottom end heads/cam lt1 ...running 46 degrees of timing

 

Of total wot timing? Or is that the max you see at part throttle under certain conditions?

 

46* timing at WOT...

 

Dang 46* is crazy high! Mine is like mid 30's but I believe 4* of advance is ground into the same so I guess I am running just shy of 40. Not sure if nx28 has aftermarket cam or something that has no advance ground in, but either way, 46 is a lot. Top fuelers run 60 deg. though!

 

46 is crazy at wot.

 

I'm running a comps cam xe 224/230 .536/.544 on a 112lsa...not sure about it having advanced timing ground into it.

When tuning, the car didn't start to knock or detonate till 48 or 49 degrees of timing, therefore we kept it at 46 at wot.

I've talked to another member on this board that was running 45* of timing he also had a heads/cam lt1 that was pushing over 400hp at the wheels all motor.

 

I'm in the process of tuning my 385 and am at 30* @ WOT but that is with 5lbs boost and I am not seeing any KR so I might add a degree or two. My cam has 4* adavnce ground in and was set at 2* advance for a total of 6* advance.

 

46 degress? Yikes! Unless you are turning like 10,000rpm, that's too much.

Most LT1's produce maximum power with max advance at maybe 34-36 degrees, not including the 2-4 degrees of "mystery timing". So the total would really be 36-40 degrees. A really high rev LT1 might like up to 40-42 degrees total (up to 38 or so in the PCM tables).

Rich Krause

One other thing: you need to turn off the knock retard if you are trying to determine the best timing for max hp. Almost all of these motors will see some false knock at WOT. Of course, this begs the question of how to actually set the timing vs. experimenting to find the optimum.

RK

 

If the engine doensn't start to knock/detonate until 48degrees and runs perfectly at 46, why is 46 too much? It makes max hp at around 6,100 rpms...

 

Coupla questions:

Did you "experiment" as I described above? Were you scanning while testing? If so, what was the actual timing on your scan tool? Was it the 46 degrees you are talking about or is that the value in the PCM table? Was that while running N2O?

I am not trying to doubt you or dis your results, I just have never seen an LT1 that wanted that much timing.

Rich Krause

 

What's the KPA range you've set the 46 degrees in?

 

The car never saw any knock at 46 degrees of timing under WOT, this was 2 degrees under where it started to sense knock retard. THe 46 timing was shown on the program tuner cat when it was being tuned. This was running naturally aspirated.

 

i have up to 39 degrees of timing in my timing tables at 100 KPA from 3600-7000 RPMs. Its 38 from 3600-4300 and 39 at 4400-5000 and back to 38 from 5000-6800 and 37 degrees at 7000. I get no spark knock or retard from the PCM.