P_BA_XR6 Member 271 Member For: 16y 11m 7d Gender: Male Location: Castle Hill Posted 22/02/09 09:28 AM Share Posted 22/02/09 09:28 AM Has anyone carried out a diff ratio upgrade on an fg auto turbo or for that matter any turbo . im thinking of swapping out the 2,73 ratio for a 3.45 would love to hear what success if any others have had Link to comment https://www.fordxr6turbo.com/forum/topic/54885-345-diff-ratio-change-on-auto-fg/ Share on other sites More sharing options...
fordboy1981 Donating Members 2,075 Member For: 22y 3m 21d Gender: Male Location: Sydney, NSW Posted 22/02/09 09:33 AM Share Posted 22/02/09 09:33 AM I'm not sure about an FG, but someone another ford forum put 3.23s in the back of a BF XR8 to great success! Link to comment https://www.fordxr6turbo.com/forum/topic/54885-345-diff-ratio-change-on-auto-fg/#findComment-828831 Share on other sites More sharing options...
01txr Member 861 Member For: 18y 3m 24d Gender: Male Location: QLD Posted 22/02/09 01:31 PM Share Posted 22/02/09 01:31 PM Will have a 3.45 diff from my XR6T sedan for sale as soon as I get a 3.73 or 4.11 .Will take $600 or concider nearest offer.Will have to be a deposit until I can purchase my choice of diff and do change. Approx 2 week wait once deposittaken.PM me if interested. Link to comment https://www.fordxr6turbo.com/forum/topic/54885-345-diff-ratio-change-on-auto-fg/#findComment-829040 Share on other sites More sharing options...
bcl Toughest BA Turbo Lifetime Members 3,408 Member For: 22y 4m 14d Gender: Male Location: Sydney Posted 22/02/09 09:22 PM Share Posted 22/02/09 09:22 PM P_BA_XR6 said: Has anyone carried out a diff ratio upgrade on an fg auto turbo or for that matter any turbo . im thinking of swapping out the 2,73 ratio for a 3.45 would love to hear what success if any others have hadI wouldn't; it would be far too low an overall ratio.... unless you are going for a huge turbo with heaps of lag.Best to do the maths.fyi 1st overall ratio in a manual with 3.73 diff is 9.9218 stock1st overall ratio in a manual with 4.10 change is 10.9061st overall ratio in a ZF is 10.2375 stock1st overall ratio in a ZF if 3.45 change is 12.9375 .... that is a very big number..... in a modified car with stock turbo you would get major wheelspin.Brian Link to comment https://www.fordxr6turbo.com/forum/topic/54885-345-diff-ratio-change-on-auto-fg/#findComment-829076 Share on other sites More sharing options...
senna_T Forged Member Lifetime Members 15,818 Member For: 18y 3m 1d Gender: Male Location: SW Sydney Posted 22/02/09 09:55 PM Share Posted 22/02/09 09:55 PM Not to mention the increased fuel consumption on highway trips - one of the main draw cards in these cars is their ability to be quite economical on long trips. Link to comment https://www.fordxr6turbo.com/forum/topic/54885-345-diff-ratio-change-on-auto-fg/#findComment-829080 Share on other sites More sharing options...
fordboy1981 Donating Members 2,075 Member For: 22y 3m 21d Gender: Male Location: Sydney, NSW Posted 23/02/09 12:26 PM Share Posted 23/02/09 12:26 PM (edited) bcl said: I wouldn't; it would be far too low an overall ratio.... unless you are going for a huge turbo with heaps of lag.Best to do the maths.fyi 1st overall ratio in a manual with 3.73 diff is 9.9218 stock1st overall ratio in a manual with 4.10 change is 10.9061st overall ratio in a ZF is 10.2375 stock1st overall ratio in a ZF if 3.45 change is 12.9375 .... that is a very big number..... in a modified car with stock turbo you would get major wheelspin.Brianyeah, but big turbo'ed engines need load to make decent boost... hence why BIG turbo'ed supras with 1000+rwhp don't really make full boost in the lower gears... Edited 23/02/09 12:26 PM by fordboy1981 Link to comment https://www.fordxr6turbo.com/forum/topic/54885-345-diff-ratio-change-on-auto-fg/#findComment-829659 Share on other sites More sharing options...
bcl Toughest BA Turbo Lifetime Members 3,408 Member For: 22y 4m 14d Gender: Male Location: Sydney Posted 23/02/09 08:58 PM Share Posted 23/02/09 08:58 PM Dave,It's not just big turbod cars that don't make full boost in 1st gear.I remember back in the mid 80's when I tried a bigger exhaust housing on my ET with a Garrett T02; could no longer pull full boost in first.My personal experience is that if you're struggling to get going in first because of lag with bigger turbo a lower gear ratio makes a big difference to drivability. When I changed to a 4.10 diff general flexibility in driving felt far easier, downside was a lot more changing gears. Brian Link to comment https://www.fordxr6turbo.com/forum/topic/54885-345-diff-ratio-change-on-auto-fg/#findComment-829715 Share on other sites More sharing options...
fordboy1981 Donating Members 2,075 Member For: 22y 3m 21d Gender: Male Location: Sydney, NSW Posted 28/02/09 05:49 AM Share Posted 28/02/09 05:49 AM bcl said: Dave,It's not just big turbod cars that don't make full boost in 1st gear.I remember back in the mid 80's when I tried a bigger exhaust housing on my ET with a Garrett T02; could no longer pull full boost in first.My personal experience is that if you're struggling to get going in first because of lag with bigger turbo a lower gear ratio makes a big difference to drivability. When I changed to a 4.10 diff general flexibility in driving felt far easier, downside was a lot more changing gears. BrianHmmm, valid point... The turbo is only going to make full boost if it needs it. So if it doesn't need it like in the case of a low first gear then that doesn't necessarily mean the car will be any slower...makes sense Link to comment https://www.fordxr6turbo.com/forum/topic/54885-345-diff-ratio-change-on-auto-fg/#findComment-832524 Share on other sites More sharing options...
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