Question about Turbonator cal timing

[rgl10]

I have made several changes to my engine over the last few months and I am redoing my cal. I have a question about the timing. If I set the limit for hot map advance (limitforhotmapadvance) to say 20 degrees then my timing map shows no timing less tha 20 degrees advance at any point. What I need to know is what happens when the knock sensor detects spark knock and I'm at at point where I am already down to 20 degrees. Can the computer take out more timing past this , say up to the 15 degrees its capable of removing putting me down to 5 degrees or is 20 degrees the least my engine will ever see even if its knocking?

[ShelGame]

No, knock retard overrides the calculated spark timing. So, if your 'min' timing is 20, knock reatrd can still take it down, if needed, to reduce knock.

FWIW, the 'min' timing in the SMEC cals is wrong. I must have mis-interpreted what it's doing. It may only apply to part throttle.

[rgl10]

Ok so in the calculated tables I have a lot of the numbers at 20 down near the bottom, which is at higher boost levels. I've driven the car with the cal setup this way and I get audible knock from about 16 psi and up. My knock sensor voltage is over 3.8 volts and it seems that if the computer is pulling out 15 degrees putting me at 5 degrees total then I really should not be hearing anything on 92 octane pump gas. I thought maybe it was staying at 20 since thats whats shown on the timing map. I will have to investigate further and try a different brand of gas, lower the antifreeze concentration in the coolant etc to see if I can get rid of the knock. Maybe I will lower the limit to 10 degrees and see if that will make any difference.

[ShelGame]

Ok so in the calculated tables I have a lot of the numbers at 20 down near the bottom, which is at higher boost levels. I've driven the car with the cal setup this way and I get audible knock from about 16 psi and up. My knock sensor voltage is over 3.8 volts and it seems that if the computer is pulling out 15 degrees putting me at 5 degrees total then I really should not be hearing anything on 92 octane pump gas. I thought maybe it was staying at 20 since thats whats shown on the timing map. I will have to investigate further and try a different brand of gas, lower the antifreeze concentration in the coolant etc to see if I can get rid of the knock. Maybe I will lower the limit to 10 degrees and see if that will make any difference.

Do you have a scantool? It should show you the final timing advance, including knock.

[rgl10]

Yeah I just put it back on the car last night. I will make a few passes and see how it does. I also replaced my wideband sensor as it was acting weird. With the new sensor I am reading more than a little lean at high boost and high rpm, probably more of a cause of my spark knock problem than the timing. I am going to richen up the mixture on top end and see how that goes.

[rgl10]

I finally got the timing close. The engine only likes about 8 to 10 degrees advance at 20 psi boost from 4000 rpm up. I have no spark knock registering over 1 volt at any boost or rpm. Nice and safe for tuning on 92 pump gas. Now I am trying to get the fuel lined out. I adjusted the pumping efficiency slightly down at lower rpms and slightly up at higher rpms to help the lean high boost high rpm problem I had. That dropped the mixture to about the low 12's at wot. After driving the car a few days and data logging it I have noticed two problems that seem to be common. I have the rich when first started problem. Engine starts fine at around 11 on the wideband. Within 10 seconds it drops to 9.5 or 10 and puffs black smoke for no more than a minute and a half. Then it starts leaning out and within another 30 to 45 seconds its up to the mid 14's. That's the first problem. The second problem is its still slightly lean at wot high boost. That's from 3500 rpm to 6500. Now if I just back off the throttle a very small amount it instantly goes richer into the mid 10's. It cruises around 14 to 15 like it should with the narrow band switching very fast, rich and lean. Holding it over 3/4 throttle but not wide open and it goes down into the 10's. Push it on down to the floor and it instantly goes back up to the low 12's. I'm trying to get this cal adjusted by the middle of next week so I can take it to the track for a time slip before they close for the winter. I am using the T-Smec atx stage IV cal as a starting point. Nothing has been changed except the timing tables and the pumping efficiency table a very small amount. If you guys could steer me in the right direction it would save me a lot of time trying different things to get these two problems fixed. I have read dozens of pages on these two problems and still have not come up with a clear fix. The cold rich start problem I can live with but I really need to fix the rich part throttle but lean wot problem. If I scale the pumping efficiency table up any more I thought it might make my part throttle problem worse. I see there are tables named fuelpartthrottle and fuelfullthrottle. Are these the tables that I need to change? If so it already appears that the full throttle table has a longer pulse width than the part throttle one so I didn't know if this was my problem area or not. Any ideas would be greatly appreciated.

[rgl10]

Update- Figured I try something for the trip to work today. Lowered the fuel cold enrichment curve B a lot. It was only 43 here this morning and it started at 11 afr and slowly climbed over the first 3 minutes to the mid 14's. I really wont know if it helped till it sits all day and its warmer when I start it again. I lowered the fuel part throttle and raised the fuel full throttle to see what that changed. Seemed much better this morning but its so cold I cant be sure of anything. More updates later.

[rgl10]

I tried the car out this evening. Temperature got up to the mid 70's and the rich starting problem was still there. It seems to be to rich when the outside temp is warmer. On the bright side it seems the rich part throttle problem and lean wot problem is fixed. So if anyone has any ideas on the rich cold start problem I could use the help.