REDEYE: Driving Observations. Air fuel ratios. Tranny shift -ability.

[coolblue]

I was driving the other day to put some break in miles on the RE. While I was futsi'n around with the tabs, knobs, and diff modes ( I'm still learning to use all this stuff, I literally don't know what half the sh&^ does or works). I noticed the A/F ratio was what seamed real rich to me , 13.6 -13.7. Now mind you I was babying this thing like and old lady, Steady 60-70 highway and absolute speed limit on side roads and traffic at 30 -40mph. I have a 6.1 that is totally stock except a Magnuson blower tuned by AJ (i.e. hemituner). Now when that motor is not on boost the A/F gauge reads 14.5 -14.7 which is perfect stoichiometric for mileage. When you hit it, it immediately drops to like 11 or less. What I'm asking is ,no matter if the motor is 600hp or 800hp if the motor is not under load why would it need that rich a mixture?
Next Observation: I do not like the tranny in street mode at all. It shifts real slushy. I like it in sport mode much better. (BUT you can't put it in sport mode with 500HP setting which I think makes no sense at all). I drove one other RE before buying mine and it drove the same way in street mode.
Any thoughts or opinions for this RE newbie?

 

[EricG]

I'm a little frustrated that the tranny will only allow 1-2 shifts at redline in track mode, not sport mode. So I had to create a custom mode for normal driving with the tranny in track mode which is a little much for normal driving, but if you think you may have a street race or want to show off, nothing worse than having the car short shift on you! Driving around in full track mode is a little much as the A/C turns on to run the chiller.

As far as the air/fuel ratios, I just trust the stock tuning but hear what you are staying. Stock tunes are usually very rich and safe.

 

[motorhead]

I was driving the other day to put some break in miles on the RE. While I was futsi'n around with the tabs, knobs, and diff modes ( I'm still learning to use all this stuff, I literally don't know what half the sh&^ does or works). I noticed the A/F ratio was what seamed real rich to me , 13.6 -13.7. Now mind you I was babying this thing like and old lady, Steady 60-70 highway and absolute speed limit on side roads and traffic at 30 -40mph. I have a 6.1 that is totally stock except a Magnuson blower tuned by AJ (i.e. hemituner). Now when that motor is not on boost the A/F gauge reads 14.5 -14.7 which is perfect stoichiometric for mileage. When you hit it, it immediately drops to like 11 or less. What I'm asking is ,no matter if the motor is 600hp or 800hp if the motor is not under load why would it need that rich a mixture?

It isn't rich, it is just how it is displayed. From the factory these cars are tuned for 10% ethanol which richens up the AFR a bit; using Lambda makes way more sense when looking at oddball fuel compositions.

This explains it a bit:
https://forum.hptuners.com/showthread.php?65786-On-a-Hell-Cat-is-the-stoic-really-13-85

In short your car is fine.

 

[coolblue]

It isn't rich, it is just how it is displayed. From the factory these cars are tuned for 10% ethanol which richens up the AFR a bit; using Lambda makes way more sense when looking at oddball fuel compositions.

This explains it a bit:
https://forum.hptuners.com/showthread.php?65786-On-a-Hell-Cat-is-the-stoic-really-13-85

In short your car is fine.

Thanks for the link. I've read a little about lambda (googled it) and am still trying to wrap my mind around it. AFR is still clearer to me right now but I'm getting it. Oh and nice pic. Now that's what a WB should be. LOL

 

[Hickster]

I looked at it and my head is at warp speed. Confusing.

 

[coolblue]

I looked at it and my head is at warp speed. Confusing.

Well it's Greek. Shouldn't that be like some fraternity symbol or something? Now I can really say "it's Greek to me" . I'll get it...eventually.

 

[motorhead]

Thanks for the link. I've read a little about lambda (googled it) and am still trying to wrap my mind around it. AFR is still clearer to me right now but I'm getting it. Oh and nice pic. Now that's what a WB should be. LOL

It is really a lot like the metric system or an integer. Left of centre is rich and right of centre is lean.

The Trans Am TA2 Challengers are sweet looking cars. But, I will have you know that the factory widebooty cars have special fenders and quarter panels... not just a set of JC Whitney flares bolted on.

 

[Hickster]

I wood have to visit a couple of caves in Tenn, if I remember correctly, pot smoken days for weeks. I could figure it out. Help to eat a Greek salad before entering Caves Cove and a few others my pot smoke is still lingering. Sold a lot of pot out of those caves. One way in and who knows how to get out. Those long haired Cherokees new about that and smoked the same stuff. Roll up a big fatty, eat a Greek salad, smoke another one and figure it out. Hell,,, I am still trying to figure out the cat.

 

[coolblue]

It is really a lot like the metric system or an integer. Left of centre is rich and right of centre is lean.

The Trans Am TA2 Challengers are sweet looking cars. But, I will have you know that the factory widebooty cars have special fenders and quarter panels... not just a set of JC Whitney flares bolted on.

That concept does make it easier to comprehend it, but when I was reading they were giving it an arbitrary number of 1,then adjusting off that number . But is that value different for all fuels? Like does each fuel have it's own value of one to adjust from? Don't want to take up your night. I'll get it.

 

[Hickster]

$84,000 not impressed. Only critter that I saw that got my attention was the green belt. Other than that, not impressed. Interior was sub superior than mine, leather, sawed, dash, no great huge stereo like mine. Was not impressed.

 

[Slowpoke387]

I'm a little frustrated that the tranny will only allow 1-2 shifts at redline in track mode, not sport mode. So I had to create a custom mode for normal driving with the tranny in track mode which is a little much for normal driving, but if you think you may have a street race or want to show off, nothing worse than having the car short shift on you! Driving around in full track mode is a little much as the A/C turns on to run the chiller.

As far as the air/fuel ratios, I just trust the stock tuning but hear what you are staying. Stock tunes are usually very rich and safe.

That’s what manual mode is for. Track mode in manual, using the shifter.

 

[Hickster]

M6 doesn't allow that. For the hard core drivers. Never wood purchase a high performance auto with out it. The book is 412 long. Great reading for xmas.

 

[Udaloy]

Can't get the Redeye in a manual...

 

[Hickster]

Calipers were not as big, seats were not the same, car was awful for $84,000. I spent 2 hours looking at this car and looking at mine. Not even close. Sorry for the guys that paid all that $$ and got that. Just bad. I

 

[motorhead]

That concept does make it easier to comprehend it, but when I was reading they were giving it an arbitrary number of 1,then adjusting off that number . But is that value different for all fuels? Like does each fuel have it's own value of one to adjust from? Don't want to take up your night. I'll get it.

Lambda is one scale of measure for all fuels and/or fuel compositions. It is the relationship of oxygen to everything else downstream of a combustion event. That isn't to say there is a magic number for all boosted engines (like 0.740 Lambda) you still have to tune for your combination. It is just easier to tweak moving in increments of 10th or 100ths of 1.00. As opposed to doing a bunch guess work on the gasoline scale with other shit mixed in.

 

[coolblue]

Lambda is one scale of measure for all fuels and/or fuel compositions. It is the relationship of oxygen to everything else downstream of a combustion event. That isn't to say there is a magic number for all boosted engines (like 0.740 Lambda) you still have to tune for your combination. It is just easier to tweak moving in increments of 10th or 100ths of 1.00. As opposed to doing a bunch guess work on the gasoline scale with other shit mixed in.

View attachment 8868

Again, I understand the ratio of A/F ratio of gas to the value of 1 the best. Have never even played with the other fuels but I get the ratio's. Like A/F of 12.8 (gas) is 87.4% of the "1" lambda (i.e. the most efficient 14.7 A/F combustion ratio for fuel) . I don't have HP tuners or DS but will prob start playing with that some time in future. I'm guessing they all use this as a bases not A/F? Also, 02 volts?(have no idea) 02 sensor reading? Thanks for the chart. You don't have to feel obligated to be my personal tutor, appreciate the input and info.

 

[motorhead]

Again, I understand the ratio of A/F ratio of gas to the value of 1 the best. Have never even played with the other fuels but I get the ratio's. Like A/F of 12.8 (gas) is 87.4% of the "1" lambda (i.e. the most efficient 14.7 A/F combustion ratio for fuel) . I don't have HP tuners or DS but will prob start playing with that some time in future. I'm guessing they all use this as a bases not A/F? Also, 02 volts?(have no idea) 02 sensor reading? Thanks for the chart. You don't have to feel obligated to be my personal tutor, appreciate the input and info.

I don't mind helping. Typically O2 volts are for narrow band O2 sensors, which Hellcats don't have (but most GM products suffer from (along with open loop tunes)). But, in the case of the HCs they do use Lambda as a basis for their tunes and are closed loop corrected using real-time info from the WB02s.

For anyone venturing into tuning it is important to remember these are oxygen sensors, not fuel sensors. They react to residual oxygen content and don't care what other crap is suspended in the exhaust. Some people get so wrapped around the gas-scale they forget their purpose. These sensors are some of your most powerful tools.

 

[Speedy!]

Get used to lambda and your life will be much simpler. It was tricky for me at first as well since I'd been using AFR for a long time, but it'll make sense over time. AFR changes for each fuel type as Motorhead mentioned, so for gasoline stoich is 14.7:1 but for E85 is like 9.7:1. Using lambda no longer requires any conversions as lambda is labmda for all fuels.

For example, the reason you see 13.5ish at idle and cruise is because the stoich point for the Hellcat is set to .0722 from the factory. To convert to AFR divide 1 by this number: 1/.0722 = 13.85. That's basically your base.

Factory power enrichment fueling is .0110 addition. So .0722 base plus .0110 = .0832. To convert again just divide 1 by this and you get 12.01 (that's LEAN to me!! but is what it is from the factory.

I think it's 12.0 from the factory because there's an add'l fueling table that comes in to play called Cat Over Temp (COT). This table is used when the cats hit a predetermined temperature and the car basically dumps fuel to cool them off (this is bad for performance) and I turned this off in my custom tune. When you're getting on it and the AFR displayed on the dash goes from 11.9 suddenly to 10.0 - 10.3 COT has kicked in. Stock in my car this occurred about mid way through 3rd gear.

In my custom tune I call for .83 - .84 lambda (to convert to AFR this time you multiply by your stoich AFR of 13.85)
.83 x 13.85 = 11.49 AFR
.84 x 13.85 = 11.63

It's a tad richer than 11.8 - 11.9 for max power since I turned off COT and provide a bit of safety for so so 93 octane fuel.

 

[coolblue]

I don't mind helping. Typically O2 volts are for narrow band O2 sensors, which Hellcats don't have (but most GM products suffer from (along with open loop tunes)). But, in the case of the HCs they do use Lambda as a basis for their tunes and are closed loop corrected using real-time info from the WB02s.

For anyone venturing into tuning it is important to remember these are oxygen sensors, not fuel sensors. They react to residual oxygen content and don't care what other crap is suspended in the exhaust. Some people get so wrapped around the gas-scale they forget their purpose. These sensors are some of your most powerful tools.

Thanks Mike.
Tony.

 

[coolblue]

Get used to lambda and your life will be much simpler. It was tricky for me at first as well since I'd been using AFR for a long time, but it'll make sense over time. AFR changes for each fuel type as Motorhead mentioned, so for gasoline stoich is 14.7:1 but for E85 is like 9.7:1. Using lambda no longer requires any conversions as lambda is labmda for all fuels.

For example, the reason you see 13.5ish at idle and cruise is because the stoich point for the Hellcat is set to .0722 from the factory. To convert to AFR divide 1 by this number: 1/.0722 = 13.85. That's basically your base.

Factory power enrichment fueling is .0110 addition. So .0722 base plus .0110 = .0832. To convert again just divide 1 by this and you get 12.01 (that's LEAN to me!! but is what it is from the factory.

I think it's 12.0 from the factory because there's an add'l fueling table that comes in to play called Cat Over Temp (COT). This table is used when the cats hit a predetermined temperature and the car basically dumps fuel to cool them off (this is bad for performance) and I turned this off in my custom tune. When you're getting on it and the AFR displayed on the dash goes from 11.9 suddenly to 10.0 - 10.3 COT has kicked in. Stock in my car this occurred about mid way through 3rd gear.

In my custom tune I call for .83 - .84 lambda (to convert to AFR this time you multiply by your stoich AFR of 13.85)
.83 x 13.85 = 11.49 AFR
.84 x 13.85 = 11.63

It's a tad richer than 11.8 - 11.9 for max power since I turned off COT and provide a bit of safety for so so 93 octane fuel.

I remember you talking about COT when you lost the motor. I also remember when you said you set lambda at .83. It stuck in my head and I googled lambda and started to read about it. BUT I always thought gasoline stoich was 14.7 (which 14.7 x .83 = 12.20 A/F ratio) but maybe I was doing A/F ratio studies when fuel was all petrol and now it's 10% ethanol standard so stoich changed to 13.85? Or is that Dodges value of stoich.?
Thanks for the input Jay.
Tony.