I have a road trip coming up and I have been considering taking the srt, but I wanted to be able to maximize the mileage I can squeeze out of it on the highway. So I came up with a few questions that I was hoping someone could help me with.
1. What would a good AFR be for the highway be (cruising)? 15.0, 15.3, 15.5, or possibly higher, what would be a safe but beneficial target?
2. Would I just set O2 Feedback for this target AFR? Or is there a different way?
3. If I should use O2 Feedback, how do I set that up? I have looked into the AEM help file but can't really digest it and I want to make sure I do it right. Right now I am looking at a "O2 FB Target Map". Currently every box in the table is 12.5 (which may be why I get such crappy mileage during normal cruising, but anyways). Would I just change all of the fields to a new value in the -10.92 thru -7.64 range from 750-4000rpms?
Am I close?
One more thing, what kind of highway mileage could I expect? I forgot what stock estimates were, was it 25 on the highway stock? Could I expect 28, or possible 30mpg?
1) 16.0 will work for starters but all the way to 16.5-17.9 will work. imo lean it out until it starts misfiring at the highway speed and then back off .2 A/F.
2) O2 feeback is the best way. It will only work if you are using a wideband as the input for the feedback. By default the AEM uses the stock O2 for closed loop. Obiviously you can't dictate such a lean A/F if you are using a narrow band O2.
3) Never tuned a AEM but several other stand-alones. With that said, imo O2 FB Target Map is the only you need to screw with. Set each cell to the A/F you want to run. Its pretty easy. Idle and low speed cruise around 14.5-15.0:1, any leaner and a lot of fiddeling with acell comps and temp trims are needed to keep it from bogging down during tip-in. Highway cruise as lean as I mentioned.
I think expecting to see a good 10%-15% mpg improvement is reasonable.
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Last edited by duster360 : 07-06-2008 at 10:54 AM.
I was just doing some searching and the stock mpg rating for the SRT4 is 22 city and 30 hwy, these were posted back in the day when the car was being reviewed
I also looked into some older posts on here from 2003 and people were averaging 28-30 on the highway.
Now I am sure those numbers were mainly based on the stock turbo and fuel system. However (and yes I am aware the turbo size wouldn't really matter as long as I am not in boost) while I am cruising would the upgraded fuel system have much effect (if any at all) on the mpg ratings/estimates? It should not matter because it would still all come down to the A/F ratio, right?
not under no load. i would run at 17:1 and the car continues to do so to this day without any problems
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Could someone just confirm that I was right when I thought I would just change the values in the O2 FB Target Map to the 17+/- AFR value.
Duster thought it sounded right but he mentioned that he hasn't tuned and AEM before, so I just wanted to be sure.
Also, then I just need to make sure the O2 FB box is checked, right?
BTW what would be a safe range of the 17+/- AFR, should I bring it anywhere near 0 psi? I was just thinking about when I increase throttle a little for passing and whatnot
Last edited by Greg_04-SRT4 : 07-08-2008 at 01:14 PM.
i just want to say that i just came back from florida(i live in ny) and with my tuned to 450 at 23lbs. by jay(n2mb) i averaged 23-30mpg. it runs better than it did stock. thanks jay
yes thats what im saying.i run it as lean as i can in cruise cells...why waste gas and it runs smoother.any throttle angle above those cells target o2fb richer
Could someone just confirm that I was right when I thought I would just change the values in the O2 FB Target Map to the 17+/- AFR value.
Duster thought it sounded right but he mentioned that he hasn't tuned and AEM before, so I just wanted to be sure.
Also, then I just need to make sure the O2 FB box is checked, right?
BTW what would be a safe range of the 17+/- AFR, should I bring it anywhere near 0 psi? I was just thinking about when I increase throttle a little for passing and whatnot
BTW, I am not saying I want to run a 17 AFR near 0 psi, I just meant how close (or far away) to 0 psi should I be?
BTW, I am not saying I want to run a 17 AFR near 0 psi, I just meant how close (or far away) to 0 psi should I be?
go for a ride and watch your o2fb target map.you will see what cells you are in when you are steady cruising.if you normally cruise at 2300 and -9 then set those cells leaner.as soon as you step on the gas you will see it come out of that cell.if you are cruising at 0 vac you are obviously going too fast lol..unless you live in germany i guess
I doubt I will ever do it again but I have driven the neon from NC to AZ and back twice. Riding for that kinda time at 17A/F wouldn't build up a bunch of detrimental heat? That's good news!
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Help setting up for highway trip (Mileage)
i averaged 23-30mpg. it runs better than it did stock. thanks jay
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