what could my problem be? i dynoed this morning and was rich at 12.4 and made my PE tabler smaller but still had the same A/F ratio on the other 2 runs? what am i doing wrong?
what could my problem be? i dynoed this morning and was rich at 12.4 and made my PE tabler smaller but still had the same A/F ratio on the other 2 runs? what am i doing wrong?
2008 Denali XL AWD LSA Blower
2010 CTS-V
2005 LLY Duramax SAS
2015 Denali
That's because your open loop table is richer than the pe table. So taking your stoich afr/1.18=12.38 commanded afr.
Russ Kemp
well that would make a lot of sense. i thought it went to PE at WOT. so it uses the richer of the 2 maybe? thanks for the help
2008 Denali XL AWD LSA Blower
2010 CTS-V
2005 LLY Duramax SAS
2015 Denali
[QUOTE=SUTTERERMAN85 so it uses the richer of the 2 maybe? [/QUOTE]
correct! just a safety measure!
Could you please clarify this for me, I am not sure I follow.Originally Posted by Russ K
04 Sierra Denali,370,S485B, Built 4L80E, 3barOLSD, E85
The values in the open loop table are divided by your stoich afr. So if your stoich is 14.68 and the value in the open loop table at say > 90 map is 1.13, the commanded afr at that map range when in pe or open loop would be 12.99 (13.0)
Even if the pe table was set leaner than 1.13, the commanded afr would still be 12.99 (13.0)
I always set the open loop table to be 1.00 at operating temp at all map ranges and set the pe to 1.13 (13.0 afr) at all rpm on a NA engine and 1.225 (12.0 afr) on a boosted engine. Some vehicles have the stoich set at 14.62 which will change the commanded afr, just change it to 14.68. Also if you have 2 open loop tables, make sure that they match after any changes are made. Set the pe delay to 0 rpm and the enrichment rate to the max (4.0)
Russ Kemp
Ok my whole open loop table is set to 1 once at operating temp, however I am not sure about the two open loop tables. I only know of one, sorry for the ignorance just trying to learn. Thanks for the reply by the way, it was helpfull.
04 Sierra Denali,370,S485B, Built 4L80E, 3barOLSD, E85
The other table is called EQ ratio (alcohol) and is below the EQ ratio button.
You probably don't need to change the alcohol table as it is only used for flex fuel vehicles. I always copy & paste the EQ table over the EQ alcohol table just to make sure.
Russ Kemp
some vehicles use both tables even though its not truely a flex fuel vehicle..example being GTO..
have tohave both OLFA tables the same or it averages the 2 tables
something else to remember is that everybody generically thinks that LS1 are 13.0 flat across all rpms...
I've gained people half a second in the 1/4 mile just by playing around on teh dyno and finding the ideal A/F for their setups...
most of them as rich as 12.5 has been teh best for peak torque and 12.8 has been the best for peak HP...
all vehicles are different..and some do like it leaner...
but dont blindly assue 13.0 is teh best for any car..as its well proven that every car is different
-Scott -
Guys, great discussion. At least for me. I have a Turboed LS2 GTO and the following questions:
1) Russ, you indicated to set the enrichment rate to it max of 4.00. Which table, my enrichment rate on the PE tables will go to whatever.
2) My Open Loop Air Flow Gain vs MAP vs RPM is set to 1.00. However, my EQ ratio, both gas and alcohol are set at 10 through all the ranges of ECT and outside temps. However, I don't see any MAP numbers here. What is the potential result of this and should it be at 1.0 once operating temp (198 degrees)? If those numbers should be at 1.0 do I gradually go from 10 to 1 or what. Or am I totally missing the boat here.
Thanks,
Mike M
The enrichment rate on the LS2 is 2.0 max. This is under the EQ Ratio vs RPM button. The EQ tables are multiplied by the Airflow Gain, the IVT Gain and the Injector Tip Gain tables. So leave the four open loop tables at 10.00 and the Airflow Gain table at 1.00. Now change the Injector Tip table to be all at 1.00. Now the table to set is the IVT Gain table. You want the values to be .1000 at operating temp and map. So take the open loop tables (10.00)x the airflow gain table (1.00)x the injector tip table (all at 1.00 now)x the ivt table (.1000 at operating temp) =1.00. This would command a 14.7 AFR.
Not sure of the relationship between coolant temp and the intake valve temp. But this is the table to set up so that your commanded AFR is 14.7 at operating temps. A number higher than .1000 will lower the commanded AFR. I would start by setting the 219*F column to .1000 and check the commanded AFR when in open loop. If your commanded AFR is still richer than 14.7, then set the next lower temp column to .1000 and so on. Don't reduce the low temp values too much or you will have a cold start hesitation/stall.
Russ Kemp
yeah...on LS2's its a combo of all multipliers...so dont look at it as 10...you have to look at all teh other crap to figure out commanded A/F
IVT is a calculated value..its really a GM guess...
-Scott -
Russ and Scott, thanks for the info. My question now is how much influence does the meth inj have on ivt. I know this gets back to the relationship between IVT and coolant temp, but it would seem IAT would have some effect. In 85 degree temps my IAT is about 105-110. I assume this is measured at the MAF. My meth inj is after the MAF and when it comes on would the IVT drop significantly, thus putting me in tables that would richen the system higher the PE enrichment?
Thanks again,
Mike M
Remember, stoich for methanol is 6.5 vs 14.7 for gasoline. So your PE needs to be richer if using methanol. It depends on the % of meth vs gas. As per FJO, 11.8 AFR using gasoline is 5.2 using meth. So your PE should be richer than the IVT table. Not sure how much or if meth will affect the IVT.
Russ Kemp
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