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Toyota Yaris GR-4 AWD Turbo

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    I was wondering whether just a front diff upgrade alone on the base model would inhibit some oversteer ??

    id imaging 245s up front on a 9 inch rim would help too....

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      Originally posted by Stevil View Post
      I was wondering whether just a front diff upgrade alone on the base model would inhibit some oversteer ??

      id imaging 245s up front on a 9 inch rim would help too....
      Wouldn't both those give the opposite effect? Fairly sure the manual excerpts someone posted said the AWD system is on demand, i.e. it only sends drive rear when the front starts pushing wide or slip detected. So if you give it a heap of grip on the front it will reduce the amount of drive it needs to send rear which would limit the rear biased oversteer potential, no?

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        Luke pretty sure the early blurb for the GR4 was that it wasnt On demand, it is permanantly in 4wd, has a clutch infront of the rear diff.

        3 setting 30/70, 60/40, 50/50, Tommi Makkinen was involved in the 4wd settings and the development too.

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          Originally posted by Gussy View Post

          Amazing! Thanks

          Interestingly I've heard it's meant to be on demand 4WD? This seems to confirm it?


          Active torque split AWD



          Automatically from FF (front wheel drive) driving state to AWD (four wheel drive) driving state according to various driving conditions such as normal driving, cornering, climbing, starting, accelerating, and slippery road surface due to snow or rain. Contributes to ensuring stable maneuverability and running stability.


          Originally posted by jasonp1977 View Post
          That's controlled by the electro-magnetic "Transmission Coupling Assembly" that bolts to the nose of the rear diff
          Click image for larger version  Name:	reardiff.JPG Views:	293 Size:	221.5 KB ID:	7180964
          Originally posted by lukevl View Post
          That’s a haldex style diff. Nothing new to soft-road territory- been around for decades.

          What would have been cool would be the newer version with a version of torque vectoring. They run a dog clutch at the front of the tailshaft, a full spool diff (not a diff), and clutches on either side of the diff output. The driving dynamics are epic with this config. We tested an evoque and a mini on low mu in Sweden with it and it was so much better for high speed handling and low speed off road.

          That excerpt Gussy posted was from the Japanese manual that Kev linked to. Reading that I would interpret it as AWD on demand with the selectable split simply setting the maximum it will send to the rear.
          Last edited by Luke352; 11-10-20, 10:33 AM.

          Comment


            Thanks Luke I missed that, I'm a bit torn about this diff development as I was starting to think about ordering 1 mid next year and being AWD was a big factor.

            here's the article I got my sauce from back at the beginning of 2020 and it clearly states

            Speaking of, a Haldex clutch-type all-wheel drive system will run as front-wheel drive most of the time, sending power rearwards only when necessary. This isn’t the case with the GR Yaris’ setup, which is not an ‘on-demand’ system. Further separating it from Haldex, it’s capable of a rear-bias with a 30/70 default split given in ‘Sport’ mode. It’s 60/40 in ‘Normal’, while in Track, it’s 50/50.

            https://www.carthrottle.com/post/6-t...yota-gr-yaris/

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              Wholesale date now November 2nd
              Swedish Soot Chucker
              Orange Accident KE10

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                Originally posted by Cock Fist View Post
                Wholesale date now November 2nd
                Whats this mean exactly?

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                  Originally posted by kedderz View Post

                  Whats this mean exactly?
                  When they start turning up at dealerships, essentially.
                  Swedish Soot Chucker
                  Orange Accident KE10

                  Comment


                    Originally posted by Stevil View Post
                    here's the article I got my sauce from back at the beginning of 2020 and it clearly states
                    Speaking of, a Haldex clutch-type all-wheel drive system will run as front-wheel drive most of the time, sending power rearwards only when necessary. This isn’t the case with the GR Yaris’ setup, which is not an ‘on-demand’ system. Further separating it from Haldex, it’s capable of a rear-bias with a 30/70 default split given in ‘Sport’ mode. It’s 60/40 in ‘Normal’, while in Track, it’s 50/50.
                    https://www.carthrottle.com/post/6-t...yota-gr-yaris/
                    Yeah, that's not quite correct really.

                    See Toyota's own press release:
                    https://www.toyota.com.au/news/new-t...r-for-the-road
                    GR Yaris performance is supported by a new GR-FOUR AWD system designed to optimise drive power to each wheel, while also being simple and lightweight.
                    The distribution of torque between the front and rear axles is governed by a high-response coupling.
                    The ingenious system uses slightly different gear ratios for the front and rear axles and allows for a theoretical range of front/rear torque balance from 100:0 (full front-wheel drive) to 0:100 (full rear-wheel drive). This flexibility gives a performance advantage over AWD on-demand systems that use twin-coupling or permanent AWD systems with a centre differential. The GR FOUR system is also considerably lighter in weight.
                    AFAIK....
                    It is a Haldex style electromagnetic/hydraulic clutch on the nose of the rear diff, but has completely controllable engagement from full open to fully engaged, and can handle continual slipping.
                    The rear diff ratio is lower than the front, so that plus the controllable clutch gives F/R torque control.

                    It is "on demand", as that clutch is ECU controlled.

                    It's kinda similar to the Ford Focus "drift mode" rear diff that changed diff ratio (switched in a different gear-set) when drift mode is enabled.
                    The GR effectively does the same thing, but more far more precisely.
                    Last edited by MWP; 13-10-20, 02:56 AM.

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                      Does anyone know the definitive spec for the first batch of aussie cars? Will it have the intercooler spray setup?

                      Comment


                        "slightly different gear ratios front to rear". Land Rover did that with the Freelander 1 and they are notoriously shitful. Hopefully Toyota have done it eleventy thousand times better (I would expect so).

                        Comment


                          Originally posted by 35R View Post
                          Does anyone know the definitive spec for the first batch of aussie cars? Will it have the intercooler spray setup?
                          No definitive list, but it seems to be a mixture of RZ "High Performance" and RZ from this page, https://toyotagazooracing.com/jp/gr/yaris/grade/ plus the full safety sense pack, https://toyotagazooracing.com/jp/gr/...yandconnected/
                          My take on the main specs are below.
                          - RZ wheels and brakes (non-painted calipers, everything else the same)
                          - RZ diffs
                          - RZ suspension
                          - No i/c water spray (probably only on the Rallye if at all)
                          - RZ High Perf seats but with white/silver stitching
                          - RZ stereo, JBL, 8 speakers etc, think it has an external amp too
                          - HUD is unknown

                          Few guesses there but I reckon its going to be pretty close to the actual.
                          I survived the patio flooding catastrophe of 2012.

                          Comment


                            Originally posted by 23Kev View Post

                            No definitive list, but it seems to be a mixture of RZ "High Performance" and RZ from this page, https://toyotagazooracing.com/jp/gr/yaris/grade/ plus the full safety sense pack, https://toyotagazooracing.com/jp/gr/...yandconnected/
                            My take on the main specs are below.
                            - RZ wheels and brakes (non-painted calipers, everything else the same)
                            - RZ diffs
                            - RZ suspension
                            - No i/c water spray (probably only on the Rallye if at all)
                            - RZ High Perf seats but with white/silver stitching
                            - RZ stereo, JBL, 8 speakers etc, think it has an external amp too
                            - HUD is unknown

                            Few guesses there but I reckon its going to be pretty close to the actual.
                            Interesting, thanks.

                            Comment


                              A Yaris GR-4 has been spotted in testing with some more serious aero
                              https://www.carscoops.com/2020/10/lo...dcore-gr-yaris

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                                Checking them out on the wharf and they look wicked in black. Do want.
                                I climbed Mt Druitt

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