Cruising AFR and Magie gas mileage
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Page 1 of 2 1 2 LastLast
Results 1 to 15 of 24
2004-2007 Cadillac CTS-V Performance Mods Discussion, Cruising AFR and Magie gas mileage in Cadillac CTS-V Series Forum - 2004 - 2007; What are you guys with maggies getting on the highway for mpg? I feel like I'm using a ton more ...
  1. #1
    junoreactor's Avatar
    junoreactor is offline Cadillac Owners Fanatic
    Automobile(s): 05 Maggied CTS-V
    Join Date
    Jul 2009
    Location
    Central PA
    Posts
    201

    Cruising AFR and Magie gas mileage

    What are you guys with maggies getting on the highway for mpg? I feel like I'm using a ton more gas than I should be using. When doing about 70 in 6th gear i'm getting about 17-18mpg as shown on the DIC. My AFR is hovering about 10.9 to 11.3 when cruising at that speed. Also I'm getting a lot of 10.x's when driving around on these moderately hilly Pennsylvania roads. Even driving in town in light traffic I cannot get above 11.6 unless I let off the gas. I've been trying to just tickle the accelerator to see what I can get for mpg, but it's just not doing it for me.

    The car is an 05 LS6 and was tuned on a dyno to make 502rwhp. I've got kooks headers, catback, lightweight flywheel, and 90mm TB with a K&N intake. I'm not sure how these items work together to benefit or hurt the mpg. Is the tune perhaps too aggresive performance wise that I'm losing too much mpg to make power? If that's the case I'd gladly sacrifice some HP to get a more conservative tune and keep my wallet a little fatter LOL.

    Here's my dynosheet.

    I was told the AFR looks good, but this is my DD and I really wasn't expecting to take such a huge hit on the mpg. I think pre-maggie I could hit about 25 on the highway and about 29 on flat straight back roads.

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    rand49er's Avatar
    rand49er is offline Cadillac Owners 10000+ Posts
    Automobile(s): 2005 CTS-V, 2011 Cruze 1.4T 6MT
    Join Date
    Jan 2005
    Location
    South Lyon, MI
    Age
    65
    Posts
    13,379

    Re: Cruising AFR and Magie gas mileage

    On V-Day I, I drove the 490 miles to Summit Motorsports at a solid 65 MPH and got a solid 23.5 MPG. When I drove back two days later, I got the exact same thing.

    At 78 MPH, I'm right around 22 MPG, IIRC. Pre-maggie/headers (i.e. stock), I got 26+ MPG at a steady 70 MPH.

    At cruise, I think you want to be closer to stoichiometric A/F which is about 14.7:1. Slightly leaner would require you to open the throttle a bit more to produce the power necessary to move the car through the air which might reduce the pumping losses for a slightly better MPG. Your results may vary.
    '05 CTS-V, Maggie, Kooks, Hotchkis, Ground Control, Corsa, B&M, DSS/Hendrix, Full 3M Clear Bra, Autovation, V Headrests, CTS Console, STS-V 55w Fogs, Black Vette FRCs, Specter Werkes, Katech LS9 Clutch, SS Brake Lines, Heavymetals U-Turn Fuel Line Eliminator, Momo Combat Evo Shift Knob, Wldwhl Clear Sidemarkers, Linea Corse LC855 Wheels or OEM wheels w/'06-'07 Center Caps, plus a couple more. 472 RWHP/411 RWTQ (Mustang Dyno).

  4. #3
    junoreactor's Avatar
    junoreactor is offline Cadillac Owners Fanatic
    Automobile(s): 05 Maggied CTS-V
    Join Date
    Jul 2009
    Location
    Central PA
    Posts
    201
    Thread Starter

    Re: Cruising AFR and Magie gas mileage

    OH I forgot to mention I've got a Walbro 255 installed as well as a second pump. It sounds like I need to get back to the tuner to get it leaned out a bit to try for 14's under cruising. But it's 3hrs away one way ugh..

  5. #4
    ichpen's Avatar
    ichpen is offline Cadillac Owners Connoisseur
    Join Date
    May 2008
    Location
    Toronto, Ontario, Canada
    Posts
    1,383

    Re: Cruising AFR and Magie gas mileage

    Yeah you're running waay too rich at cruise. Cruise you should be in the 14.7 range. 14-15. I assume you have a guage. Under moderate throttle and above 3.5k rpm you should be dipping into the 12s. Get your tuner to lean it out quite a bit.

    BTW, dyno AFR is very different hence why most tuners take your car out for a drive to get the regular driving logs done.

  6. #5
    Twitch's Avatar
    Twitch is offline Cadillac Owners Connoisseur
    Automobile(s): '05 CTS-V, '00 SLS, 98 SLS, 89 Eldo, '80 Eldo
    Join Date
    Mar 2006
    Location
    NYC
    Age
    43
    Posts
    3,994

    Re: Cruising AFR and Magie gas mileage

    Before anything, are you sure your AFR gauge is correct? Our cars have ground offset issues. When I first connected my LC1 to my interceptor gauge, it was reading low 13s. It was actually low 14s and I corrected it.

    Like everyone said, cruising should be in the 14s. And a safe WOT afr is 11-11.5.

    Also, don't go by the DIC for mileage. Fill up, go for a ride and go back to the same pump. Do the math and see if it's close to what the DIC reads.

    PS If it is in fact that rich, I'd look for another tuner.

    Tony

  7. #6
    junoreactor's Avatar
    junoreactor is offline Cadillac Owners Fanatic
    Automobile(s): 05 Maggied CTS-V
    Join Date
    Jul 2009
    Location
    Central PA
    Posts
    201
    Thread Starter

    Re: Cruising AFR and Magie gas mileage

    I'm not sure how to tell if the AFR gauge is correct or not. It's an AEM UEGO gauge if that matters. I didn't install it and don't know how I'd go about correcting it. Maybe tomorrow I'll top off the tank, drive around for an hour or so then go back and fill it up to see how much I used for sure. While I don't hold the DIC reading as the actual mpg, wouldn't it still be taking the same measurements and calculating in the same way whether or not I have a maggie. Regardless, I'm seeing a loss of about 8-10mpg on the DIC and I'm assuming that it doesn't matter if the specific mpg is correct or not, but the difference between pre-maggie and post-maggie should be valid. I may be talking out my ass too, just throwing out some ideas. I drive the car everyday to work and used to fill it up every four days. Now I'm at every three.

    EDIT: Twitch, could you explain what the ground offset issue is? Or point me to a place to learn about it please? Hopefully it's something I could check and/or correct on my own if in fact there is something wrong causing false readings.
    Idle is bouncing around 14.4-15.0 after the engine warms up from a cold start.

  8. #7
    kevm14 is offline Cadillac Owners Connoisseur
    Automobile(s): 05 Stealth Gray CTS-V
    Join Date
    May 2008
    Age
    33
    Posts
    1,315

    Re: Cruising AFR and Magie gas mileage

    Could it be going into cat protect mode?

  9. #8
    vetteboy2k is offline Cadillac Owners Fanatic
    Join Date
    Aug 2005
    Posts
    157

    Re: Cruising AFR and Magie gas mileage

    Sounds like your PE enable is very low for all the enablers in the tune (ie MAP, TP, RPM), so instead of driving around in closed loop with the narrow bands correcting to 14.7 your in WOT mode instead.

    The DIC reading will not be as accurate as it was prior. You now have different injectors than stock and if the injectors were "not" calibrated in the tune properly (if they only changed the flow rate) then the DIC has no way to truly calculate the actual amount of fuel being used. The opening time, voltage dependency, non‐linear flow characteristics and pressure dependencies are large factors to cause this. http://calibratedsuccess.com/Assets/...%20Article.pdf

  10. #9
    Twitch's Avatar
    Twitch is offline Cadillac Owners Connoisseur
    Automobile(s): '05 CTS-V, '00 SLS, 98 SLS, 89 Eldo, '80 Eldo
    Join Date
    Mar 2006
    Location
    NYC
    Age
    43
    Posts
    3,994

    Re: Cruising AFR and Magie gas mileage

    Quote Originally Posted by junoreactor View Post
    I'm not sure how to tell if the AFR gauge is correct or not. It's an AEM UEGO gauge if that matters. I didn't install it and don't know how I'd go about correcting it. Maybe tomorrow I'll top off the tank, drive around for an hour or so then go back and fill it up to see how much I used for sure. While I don't hold the DIC reading as the actual mpg, wouldn't it still be taking the same measurements and calculating in the same way whether or not I have a maggie. Regardless, I'm seeing a loss of about 8-10mpg on the DIC and I'm assuming that it doesn't matter if the specific mpg is correct or not, but the difference between pre-maggie and post-maggie should be valid. I may be talking out my ass too, just throwing out some ideas. I drive the car everyday to work and used to fill it up every four days. Now I'm at every three.

    EDIT: Twitch, could you explain what the ground offset issue is? Or point me to a place to learn about it please? Hopefully it's something I could check and/or correct on my own if in fact there is something wrong causing false readings.
    Idle is bouncing around 14.4-15.0 after the engine warms up from a cold start.
    Can't really give you Darkman-like answers, so mine are dumbed down a bit

    Ground offset: My problem with the ground is that my gauge is grounded at one point. But the AFR meter is grounded at another point. With the crappy ground our cars have, it throws off the voltage and you get the wrong reading.
    If your always between 14.4 and 15 at idle then your gauge is probably correct, or close. If this is the case, then I suspect your tune is way off. Did you get it tuned? DO you have the Hyperchips tuner that came with the Maggie? You might be better of with there tune.

    MPG: When I messed with my injector setting this threw my MPG off quite a bit. If I used 13 gallons, the DIC would show 14.4 gallons used. Which would cause the average MPG to read lower than what it actually was. Your obviously using more fuel, at least you'll have a better idea of how much it really went down.

    You can always pull one of the spark plugs to confirm that your running rich.

    A FI tune is usually more expensive than a regular tune. And a good tuner might charge you over $600. I saw one quote $850 for a speed density tune,,,,,crazy.
    Look for a reputable tuner. It'll hurt your wallet now, but should pay for itself in the long run. No to mention she'll probably be more fun to drive.

  11. #10
    Twitch's Avatar
    Twitch is offline Cadillac Owners Connoisseur
    Automobile(s): '05 CTS-V, '00 SLS, 98 SLS, 89 Eldo, '80 Eldo
    Join Date
    Mar 2006
    Location
    NYC
    Age
    43
    Posts
    3,994

    Re: Cruising AFR and Magie gas mileage

    What is your AFR at WOT?

    You can either buy an OBD II scanner or got to a shop. Check your fuel trims. If they're near zero at idle and your AFR is in the 14s, your gauge should at least be close. Then drive it around. If your trims go to zero and stay there, your probably in PE (Power Enrichment) mode like Vetteboy said.

  12. #11
    junoreactor's Avatar
    junoreactor is offline Cadillac Owners Fanatic
    Automobile(s): 05 Maggied CTS-V
    Join Date
    Jul 2009
    Location
    Central PA
    Posts
    201
    Thread Starter

    Re: Cruising AFR and Magie gas mileage

    AFR at WOT is around 11.5 according to the gauge. Idling, it settles down to about 14.5 or so after the engine gets up to about 180 degrees. The car was tuned by Mike Kleman at Rapid Motorsports in Birdsboro, PA. He takes the car to Phoenix Performance to use their dyno but does most of their tuning himself he told me. Tune cost was 350 +150 for dyno time. I do not know if the car was tuned on the street or only on the dyno.

    I was looking for some OBD II scanners because mine is no longer working. It's been broken a while actually. Would this model be sufficient to check the fuel trims and what not?
    It's an Acutron handheld and I can buy it at Advance Auto Parts locally unless I look around online for a better price. Also they have a higher end model which is the second link here.
    http://shop.advanceautoparts.com/web...%7CGRP2018____
    http://shop.advanceautoparts.com/web...___#fragment-1

  13. #12
    Twitch's Avatar
    Twitch is offline Cadillac Owners Connoisseur
    Automobile(s): '05 CTS-V, '00 SLS, 98 SLS, 89 Eldo, '80 Eldo
    Join Date
    Mar 2006
    Location
    NYC
    Age
    43
    Posts
    3,994

    Re: Cruising AFR and Magie gas mileage

    Quote Originally Posted by junoreactor View Post
    AFR at WOT is around 11.5 according to the gauge. Idling, it settles down to about 14.5 or so after the engine gets up to about 180 degrees. The car was tuned by Mike Kleman at Rapid Motorsports in Birdsboro, PA. He takes the car to Phoenix Performance to use their dyno but does most of their tuning himself he told me. Tune cost was 350 +150 for dyno time. I do not know if the car was tuned on the street or only on the dyno.

    I was looking for some OBD II scanners because mine is no longer working. It's been broken a while actually. Would this model be sufficient to check the fuel trims and what not?
    It's an Acutron handheld and I can buy it at Advance Auto Parts locally unless I look around online for a better price. Also they have a higher end model which is the second link here.
    http://shop.advanceautoparts.com/web...%7CGRP2018____
    http://shop.advanceautoparts.com/web...___#fragment-1
    Checked one of those links, and nothing said that it does or does not read fuel trims. I guess you can just call and ask.

    11.5 at WOT is spot on. With the info your giving us, I'd assume he did your PE on the dyno and not much else. If it were me, I wouldn't even bother asking him to fix it. If he didn't/couldn't do it right the first time, he probably hasn't learned anything new since then.
    It takes a tuner with a lot of knowledge or someone who puts some real time into your tune to get it right. So your paying for their experience, or a full day of sorting through your mess. I would say it's time to cut your loses and find a GOOD tuner.

    And don't be too worried if it comes back with lower dyno numbers. 500 at the wheels seems a bit high for your mods.

    Good luck

  14. #13
    rand49er's Avatar
    rand49er is offline Cadillac Owners 10000+ Posts
    Automobile(s): 2005 CTS-V, 2011 Cruze 1.4T 6MT
    Join Date
    Jan 2005
    Location
    South Lyon, MI
    Age
    65
    Posts
    13,379

    Re: Cruising AFR and Magie gas mileage

    Quote Originally Posted by Twitch View Post
    ... lower dyno numbers. 500 at the wheels seems a bit high for your mods.

    Good luck
    IMHO, 500 is plausible considering the OP has a 90 mm TB and the lightweight FW on a DynoJet. Afterall, he's closer to the Midwest, too.
    '05 CTS-V, Maggie, Kooks, Hotchkis, Ground Control, Corsa, B&M, DSS/Hendrix, Full 3M Clear Bra, Autovation, V Headrests, CTS Console, STS-V 55w Fogs, Black Vette FRCs, Specter Werkes, Katech LS9 Clutch, SS Brake Lines, Heavymetals U-Turn Fuel Line Eliminator, Momo Combat Evo Shift Knob, Wldwhl Clear Sidemarkers, Linea Corse LC855 Wheels or OEM wheels w/'06-'07 Center Caps, plus a couple more. 472 RWHP/411 RWTQ (Mustang Dyno).

  15. #14
    Twitch's Avatar
    Twitch is offline Cadillac Owners Connoisseur
    Automobile(s): '05 CTS-V, '00 SLS, 98 SLS, 89 Eldo, '80 Eldo
    Join Date
    Mar 2006
    Location
    NYC
    Age
    43
    Posts
    3,994

    Re: Cruising AFR and Magie gas mileage

    Quote Originally Posted by rand49er View Post
    Afterall, he's closer to the Midwest, too.
    I stand corrected

  16. #15
    junoreactor's Avatar
    junoreactor is offline Cadillac Owners Fanatic
    Automobile(s): 05 Maggied CTS-V
    Join Date
    Jul 2009
    Location
    Central PA
    Posts
    201
    Thread Starter

    Re: Cruising AFR and Magie gas mileage

    I talked to the tuner a little bit through email. I described to him what was going on with my AFR when crusing and at WOT. He said it sounded like I was going into power enrichment too soon. That's reassuring to know that now two people are saying that. I'll be waiting until after the holidays to figure out what to do anyway.

    To correct it would I need to go through the whole dyno tune again or could it be simply a few values are set incorrectly in the computer? To go anywhere to the same/different tuner from me would be a 3hr drive one way. I'm really happy with how the car is driving, just using a ton of gas. I think it'd be safe to go back to the same tuner rather than have new guy start from scratch. It's not like the whole tune is a mess and running poorly. I'd prefer to give a second chance for sure because he does have a lot of experience and will definitely take care of the problem.

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting