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  • Peculiar

    Evening ladies and gents...

    Somehting very strange happened to me today. I hae only ever used V Power in my car bar a couple of tanks of T99 in the early says. Today I let the tank run dry and filled it full with T99. I then drove very very sedately as I wasnt in the mood for it today, for around 30 miles going and doing the days chores. Car felt quite limp but Im used to a funny feeling on a new fuel until the tank is replaced for a seond time with the same fuel.

    At one point I was drawn to a Golf GT (1.4 Turbo and Supercharged) in front of me, He was driving like an idiot, trying to go as fast as humanely possible. He started to floor it at one point and went form around 80mph to a good 120mph. Thing is, all throuhgout this, I couldnt catch him. And we are talking a drop down to 4th at 80mph with sustained revs (from 6th) so max power was achieved instantly. Changed to 5th around the 120 mark and we levelled at 130mph. He then moved over and I kept full power on to around 140mph. I overtook him VERY SLOWLY. And I mean, very slowly as the car would not go any faster. (well it probably would but was really struggling).

    Not normal in my opinion. I even had Sport button depressed.

    Other than the new fuel, I also did not rev all the way to 6.5 / 7k and changed a little earlier as I am trying out a theory at the mo regarding peak torque being achieved lower down and actually it being pointless to redline at high speeds (tactical driving).

    Thoughts?

  • #2
    I must admit mate when u get to them sorts of speeds u will only pass slowly because of the low rate of acceleration. In my old car I was doing silly speeds and an evo with 120bhp advantage only crept past. BTW you are a lucky man to have your own private piece of land for your antics. :wink:

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    • #3
      Not in the mood, 140! :P

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      • #4
        you got a good idea there dizzy mate mine peaks at 5500 so i always chnge up around that mark
        sigpic
        stealth no more but beware of the silver lightning GSI with vxr power
        M.U.F.C.
        http://www.courtenaysport.co.uk/

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        • #5
          Could be your ems had not had time to fully adjust to give the optimum performance.
          sigpic
          More than 34,900 viewings and counting
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          • #6
            I was actually gonna set up a new topic askin when the rpm to shift up is for maximum performance on a standard (stage 0) vxr. I always get confused because even if the torque is dropping off isn't it better to stay in the lower gear to set u up higher in the rev range in the next gear. Also the rate of acceleration is faster in a lower gear. :?

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            • #7
              I tried a 0 - 60 run a few times last week but changing up around 5 and a bit, felt very strong, level, consistent and powerful.

              Its just the psychological thought form my old 1.2 - redline it! redline it!

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              • #8
                could be a grip issue?

                i floored mine tonight,from around 40mph ish upwards and it felt like there was not as much power as usual, then again on the way back home (but different road) i did it again and the power was there again, im sure traction may come in without the light flashing....maybe? boths roads were wet/damp

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                • #9
                  Your changing to soon, you need to be hitting the peak torque point upon the change not working upto it from an early gear change ready for the next one, run it to the redline then change and you will be hitting the peak torque when you arrive in the next gear straight away, run through all the gears at peak torque that way.

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                  • #10
                    OK...

                    So, you are saying....

                    What I said?

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                    • #11
                      No, he's not saying what you are.

                      What he means is that you need to hit peak torque after you have changed into the next gear i.e. accelerate in third, change at red line to hit peak torque in fourth gear after the change...

                      NOT change up into fourth at peak torque in third and then let the torque build in fourth...

                      If a car is geared well (and the VXR is :wink, a change up into the next gear at the red line will result in achieving peak torque in the next gear, therefore ensuring maximum acceleration.

                      Andy

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                      • #12
                        does that not mean from 5500 to redlin e it's not actually doing anything ?????? i am probably wrong but it just seem's to make more sense to change at 6k then accelerate through your gears
                        sigpic
                        stealth no more but beware of the silver lightning GSI with vxr power
                        M.U.F.C.
                        http://www.courtenaysport.co.uk/

                        Comment


                        • #13
                          What you should do (when e.g. in 3rd) is keep it in 3rd well above the top torque point(by 500rpm-750rpm) so when you shift into 4rth and the revs drop (no ALS installed!),they do not drop waaaay down from that top torque
                          point (no less than 500-750rpm).In this way your revs hover around that optimum point and the car pulls away as fast as it can.An old motorsport say
                          is that you sould always keep your gear changes between top torque point
                          and top bhp point(usually higher) but that has to do with what sort of mapping your car has and how are it's gear ratios.The two lit Astra engine
                          with 86 x 86 internals is a revy engine (type R's is exactly the same !).
                          BUT the standard turbo can't produce enough pressure at this engine speed
                          (so it's pointless to use over 7000 rpm maps) and i'm not sure the rods are up to the job too.With a bigger turbo, strengthened internals and different cam(s)we could see
                          some REAL gains in power at high revs(maybe not at 8250rpms but surely
                          at 7500).The theory behind this is to mimic with a turbo engine the power
                          delivery of a high reving atmo engine .But to obtain this you must bild up the power slowly (no mid rev ramp here!) by using appropriate mapping.This way you protect your engine and gearbox from sudden bursts of torque and use your full turbo potential at high revs (where your
                          car can put all this power on the tarmac!).I once tested a SUBARU STI 2.0
                          lit made this way and was amazed.Engine limiter was at 8200,the power was coming on very gradually and the car would go crazy after 5500rpm.
                          It was a 420hp engine with over 50kgs torque.It felt like i was driving a 5lit M5.Now this is a project for our estimed tuners...

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                          • #14
                            There is also the issue of Torque Management that is programmed into the ECU, if the car decides that if it gives you all the power in one go it may have an adverse effect on drive train then it will invoke reducd power (albeit slightly) to ensure that everything is ok, once it has pulled spark to do this it takes longer for it to get back to where it was giving the impression of loss of power. Accelerate progressively dont bang foot to the floor.
                            Insignia VXR, quite nippy!

                            Comment


                            • #15
                              There is also the issue of Torque Management that is programmed into the ECU, if the car decides that if it gives you all the power in one go it may have an adverse effect on drive train then it will invoke reducd power (albeit slightly) to ensure that everything is ok, once it has pulled spark to do this it takes longer for it to get back to where it was giving the impression of loss of power. Accelerate progressively dont bang foot to the floor.
                              Insignia VXR, quite nippy!

                              Comment

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