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Mileage feedback LA3, ACT, VSS

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  • Mileage feedback LA3, ACT, VSS

    Just wanted to share some results I have. For a baseline I have the LA3 and this is my daily driver and I drive 80 miles per day, same route, same time, and most of the time the same speed. Mainly staying between 25-2600 rpm's except for the occational burst to 85 to pass or merge. 70 in my car is 2800 rpm's so I cruise between 65-68mph. Boost is static and actuator default and running in regular mode using super in the tank.

    When I first got the car I was getting 22-23mpg highway.

    Recently I had said after all my tweaks and stuff that I got 29mpg, that wasn't exactly accurate due to the speedo gear. After getting the right one that leveled off to 24mpg which still isn't bad, but not that great for what I wanted. Going back to the stock intake took me to 25mpg so I kept it on.

    I installed the ACT sensor in the upper intake and the very first tank netted me 27mpg and then back to back 25mpg tanks there after. After installing this sensor the car had much more pep than previous, it was very noticeable at low rpm and mid range. There may not be a power increase per say, but you can tell a difference in how it drives for sure.

    A month later I installed the VSS and just now filled up for the first time and got 27.4mpg. I drove 375 miles and added 13.8 gallons which is very good to me. Mind you when I first got this car I could drove 260 miles before I had to fill up.

    I hope to back this tank up with another one even better. I'm sure the bursts this morning passing cars didn't help since I went through all the gears WOT.

    Neither of the two sensors took that long to wire up. The VSS is 20 bucks brand new with a pigtail that is 8 I think. The ACT is like 10 bucks or something. Oh and you'll need the correct speedometer cable for the VSS which is a whopping 7 bucks. I think it's a good idea to take advantage of all the things the LA3 offers. There's no loss in power that's for sure and no loss in mileage adding these sensors.

    Figured I'd share since I read several times searching through that no one knew if power would go up or down, or if this affected that, or what.. hope this helps.

    B.

  • #2
    very good info

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    • #3
      I'm sorry, but what is the ACT, and VSS?

      And these were installed with a switch to an LA3 computer?

      The sage car got a steady 25 mpg on the way to and from the reunion this year.
      My wife says it's a sickness...what do you think?

      Comment


      • #4
        ACT is the Air Charge Sensor
        VSS is the Vehicle Speed Sensor

        both of these were stock on the T-birds with the LA series computers. Adding them helps with mileage. The LA series computers also have an electric fan lead as well.

        I installed them directly to the ECU to their corresponding pins in the harness.

        both of these from reading tons of posts people say you don't need them on SVO's and you won't lose any power not having them, true. Adding them didn't lose any power either, in fact I gained mileage and car is more peppy.

        take it for what you will.. I need mileage and I got it!

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        • #5
          ACT = Air Charge Temp
          VSS = Vehicle Speed Sensor

          The LA3 has these inputs available which many don't install. The ACT will require a sensor on the pressure side of the turbo and the vss I believe requires a speedometer cable change along with the correct sensor at the trans.

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          • #6
            Thanks for the education. The 'Trash car has the TC set-up in it including the entire wiring harness utilizing the LA3 computer. The engine is all TC, so I didn't have to change anything. I did need to buy the speed sensor for the tranny though. The stock speedo cable just plugs into the sensor and the sensor into the tranny. We're still sorting it out though, and it has 3.73 gears in it as opposed to the TC's 3.55 gear ratio, so MPG would be different. However, I've heard as much as 30 mpg in some of the TC's.
            My wife says it's a sickness...what do you think?

            Comment


            • #7
              Stock Speedo Cable?

              Roger,

              When you say stock speedo cable, do you mean the stock sppedo cable for the SVO or a stock Turbo coupe speedo cable. Just want to make sure the I have all the right pieces, seems wierd the SVO would be set up for this if it didn't have the sensor. I'm sure this is not all there is to it but I can attest for a big heavy car my TC is FAST, it feels faster than both my SVO's despite the weight.

              Tom
              "1st Auto-X"

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              • #8
                VSS has no connection to fuel or spark on the LA3. It is used for A4LD shift points, cooling fan control, and BCS function. It is awesome that you are getting the great fuel economy.

                Comment


                • #9
                  Originally posted by tbrody View Post
                  Roger,

                  When you say stock speedo cable, do you mean the stock sppedo cable for the SVO or a stock Turbo coupe speedo cable. Just want to make sure the I have all the right pieces, seems wierd the SVO would be set up for this if it didn't have the sensor. I'm sure this is not all there is to it but I can attest for a big heavy car my TC is FAST, it feels faster than both my SVO's despite the weight.

                  Tom
                  you can't use the stock cable, it won't work. you have to order the specific one which I asked about and went into detail about here.. http://www.svoca.com/forum/showthread.php?t=20705

                  Comment


                  • #10
                    well just an update.. the mileage seems to be pretty steady. I just filled up and got 27mpg again. This tank I got into it a few times pretty good including a WOT pass in all gears so seeing as how the only two changes I did are the ACT and VSS I'd say they are working. If I can keep my foot out of it I'm almost positive I can muster 30mpg out of the old girl!!

                    Comment


                    • #11
                      Originally posted by BrianO View Post
                      you can't use the stock cable, it won't work. you have to order the specific one which I asked about and went into detail about here.. http://www.svoca.com/forum/showthread.php?t=20705
                      I could be wrong, but I believe I did use an SVO cable. I just disconnected the plastic gear from the cable, added the sensor to the cable, then added the gear onto the sensor. I think the TC cables are different in configuration.
                      My wife says it's a sickness...what do you think?

                      Comment


                      • #12
                        the oem SVO cables don't fit into the VSS, you need the plain jane cable made to fit into the VSS. the TC's didn't use cables. the oem SVO cable has a large end peice that fits into the tranny which is hte exact same size as the VSS that has to fit in the same hole so they won't fit inside one another.

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                        • #13
                          I thought about it some more after I went to bed last night. I had stripped a few cars over last year, one of them being a later model GT (89) that had a cable with the VSS on it for cruise control. That might have been the cable we used, and I remember we had some issues with it fitting into the speedometer end behind the cluster.
                          My wife says it's a sickness...what do you think?

                          Comment


                          • #14
                            the cluster part should be the same, but the tranny sides are very different.. you got it to work,that's all that counts

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                            • #15
                              topped off the tank tonight for the week ahead.. drove 120 miles, added 4 gallons.. yep that is 30mpg!!!! dayum!! I knew it was possible.

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