I'm running 93 octane and the 91 octane CAI tune. I've got a 195* thermostat and have the fans set to keep it running at that temp.
I logged a bit and noticed it was pulling out as much as 8 degrees of spark advance!!
I tried richening it up across the board at WOT and it helped, but only a little. I went as far as 15% richer at all RPMs and got the spark retard down to ONLY 3-4 degrees.
I set it for 10% rich aross the board and left it alone for now.
What was your actual spark at cyl_1? (timing advance). One of those pids gives you spark advance. Then the PCM pulls timing from there. Knock retard is one and there are a few others. Intake air temp, coolant temp, etc. If you take the spark advance minus the knock retard and it doesn't get you the actual spark at cyl_1 then you can tell how much was pulled due to other factors. I was running the 91 CAI tune using 91 octane gas and could only get about 18* with an a/f around 12.1
2006 Magnum SRT8
AFE Stage II
Mopar Cat Back
185* T-stat
RDP tune by Steve
Truuu, if you can get 18-20* of timing thats pretty decent. My car did not pick up anything on the dyno by adding timing. My CMR tune has a max of 23*on the high RPM's and an average of 18-20* on the low and mid RPM's with .5 ST KNK. It had the best HP and TQ like that. More timing isnt always better. Also my car hated anything above 12.7 A/F ratio. Its right at 12.2-12.5 right now.
I think at this point you need to look at your fuel quality. Get some 100 octane unleaded at the track and see if that helps. Try a different gas station as well.
ZMagnum wrote:I think at this point you need to look at your fuel quality. Get some 100 octane unleaded at the track and see if that helps. Try a different gas station as well.
93 octane should be plenty for a 91 octane tune. I've tried gas from 4 different gas stations, even though it's all pretty much the same since it all comes from the same pipelines. They may add octane at the site, so I tried it at different locations. No change.
It is about 95* outside when I've been testing. I'm sure this has something to do with it. I've not taken the time to do the comparison noted above to tell me exactly where the retard is coming from. That will be interesting.
Gas quality varies a lot where I'm from. I found that Mobil is the best. I've been having good luck with ARCO (BP) as well. I got 91 octane from Albertsons once and my knock retard was at 6 degrees. I would stay away from grocery store gas as well as Sam's Club/Costco.
No matter what gas is being used SRTs are gonna knock. Right now I have 100 octane plus nitromethane in the tank and its still knocking. Thing pulls like freaking crazy, but theres lots of ST and some LT KR. IMO its due to the speed density metering, due to the fact that they only knock when you snap the throttle open. If they were Mass Air then the ECU would know how much air was coming in and could adjusting the fueling to compensate. Just my thoughts.
Yes, that's to be expected. Some small amount of knock detection when you open the throttle. Same thing when shifting. As long as this is within a reasonable range it shouldn't be a concern. It's the consistent knock that should be addressed or looked at. Some feel that some of it is false knock because the knock sensors are too sensitive. Some tunes will cut the knock sensor sensitivity back a bit (they don't actually effect the knock sensors but raise the threshold at which the PCM intervenes).
Significant knock should be addressed. Knock retard due to knock detected by the sensors is reactive. That means that the knock occured and then the PCM reacted. The severity of the initial knock determines the level of intervention. Usually what you see is an initial spike in knock retard with a gradual taper off. The PCM will pull timing in reaction to knock detection. For example it gets a voltabge jump from the sensor over the threshold for intervention. Depending on the voltage it might pull 4* of timing. Then it periodically (milliseconds) samples the sensor reading. If it's below some value it reduces the knock retard a notch (adds back timing). If not it keeps it the same or even raises it. So even if there is some event that's momentary it will still take some time to taper off the knock retard). The point is that you engine is experiencing that initial knock.
If you log with the stock tune you will see a good bit of knock here and there at WOT (not constant though). Even up to 5* or 6*. It is hard to use this as a comparison though if you don't know whether the knock retard has been "desensitized" in your tune. To make this comparison you need to compare the knock sensor voltages as well as knock retard.
It's true that most of the gas comes from the same pipeline. In California it's allowed for the gas to come from the same refinery. What differs is the additive package that each company uses. For example, Mobile has gas stations in northern California but their closest refinery is in southern California. They are allowed to get there gas from some other company's refinery that is much closer. When the gas is loaded on a Mobile truck at the refinery Mobile has their additive package added. It's these additives that can make a difference. Especially for knock in high compression engines.
2006 Magnum SRT8
AFE Stage II
Mopar Cat Back
185* T-stat
RDP tune by Steve
Yes, what Quick said. In my CMR tune we found that the KNK I was getting was not real knock. (at least not all of it) No matter if we turned the timing WAYYYYYYYY down it still showed a big amount of ST and LT knock. We turned the timing up a bit and still the same results. (false knock) We desensitized the knock sensors just a tad bit and I still get some ST knock but .5-1.0 at the most during shifts. We DID NOT want to turn the knock sensors off. Thats no good, but we did turn the LT knock off and just let the ST knock do its job just in case I got a bad tank of gas here and there.
I am sorry I am new to the forum and I just did my tune. For a while I was getting around 17 miles to the gallon city and 21-22 on the hwy. lately I have been getting 14 - 15 miles city I use Sunoco 93 octane and Amoco (BP) 93 octane. I get around 260 total miles on a tank. I have an airaid ram air total intake package, and the predator. Any help to get my gas mileage back up. Should I recalibrate it again. Should I open the exhaust. I have an Srt8 superbee
superbee68/1000 wrote:I am sorry I am new to the forum and I just did my tune. For a while I was getting around 17 miles to the gallon city and 21-22 on the hwy. lately I have been getting 14 - 15 miles city I use Sunoco 93 octane and Amoco (BP) 93 octane. I get around 260 total miles on a tank. I have an airaid ram air total intake package, and the predator. Any help to get my gas mileage back up. Should I recalibrate it again. Should I open the exhaust. I have an Srt8 superbee
Use the Predator to monitor the long term fuel trims, and see where they are at.
Thanks
Mike Litsch DiabloSport Brand Manager Diablo Tech support by phone:
561-908-0040
M-F 8:00 AM to 5:00 PM EST [email protected]
Typically, 14-15 mpg city is pretty good for an SRT8. Most people are getting right at 14 or just under. 21 mpg is also typical for highway. 17 city sounds very high.
2006 Magnum SRT8
AFE Stage II
Mopar Cat Back
185* T-stat
RDP tune by Steve
superbee68/1000 wrote:I am sorry I am new to the forum and I just did my tune. For a while I was getting around 17 miles to the gallon city and 21-22 on the hwy. lately I have been getting 14 - 15 miles city I use Sunoco 93 octane and Amoco (BP) 93 octane. I get around 260 total miles on a tank. I have an airaid ram air total intake package, and the predator. Any help to get my gas mileage back up. Should I recalibrate it again. Should I open the exhaust. I have an Srt8 superbee
Use the Predator to monitor the long term fuel trims, and see where they are at.
Thanks
v.8r20
u7135
2007 srt8 6.1 litre
charger superbee
sorry again feeling stupid.. My first SRT8, How do I do that.. How do I monitor the fuel trims, where should they be at.
