Xtreme F6 Team Xtreme Donating Members 1,680 Member For: 20y 4m 5d Gender: Male Location: Perth Posted 04/02/07 05:21 AM Share Posted 04/02/07 05:21 AM Problem with the .7 was no matter what we did with fuel or timing it just couldnt make the boost down low of the stock cover, as is apparant in the graphs that Ben has put up. We tried to give it more down low but just couldnt. Put the stock cover back on and its back. Link to comment https://www.fordxr6turbo.com/forum/topic/32271-50-and-70-comp-cover/page/3/#findComment-493699 Share on other sites More sharing options...
RAP1D Member Donating Members 3,739 Member For: 19y 25d Gender: Male Location: Sydney NSW Posted 04/02/07 07:49 AM Share Posted 04/02/07 07:49 AM How would the .7 cover go with 4.11 diff gears? I'd imagine you would see the low down punch the .5 had again? Link to comment https://www.fordxr6turbo.com/forum/topic/32271-50-and-70-comp-cover/page/3/#findComment-493744 Share on other sites More sharing options...
F6 UTE - Track Bound EVO III - Member 3,367 Member For: 20y 5m 29d Gender: Male Location: Strapped in and holding on Posted 06/02/07 05:34 AM Author Share Posted 06/02/07 05:34 AM RAP1D said: How would the .7 cover go with 4.11 diff gears? I'd imagine you would see the low down punch the .5 had again?←MM, not sure. The 4.11 might effect how the driveline loads up the engine and hence boost, ie delayed boost buildup?? Link to comment https://www.fordxr6turbo.com/forum/topic/32271-50-and-70-comp-cover/page/3/#findComment-494348 Share on other sites More sharing options...
RAP1D Member Donating Members 3,739 Member For: 19y 25d Gender: Male Location: Sydney NSW Posted 06/02/07 09:41 AM Share Posted 06/02/07 09:41 AM My mate has a TD07 25G on his sr20, just looking at the size of this sucker spells lag, and it was laggy with the stock 3.4 diff. We put a 4.2 in it and wow, huge improvment, alot less lag and very drivable. Its easilly on boost 500 to 750 rpm earlier now, so maybe the same happy results would work on the xr6... we also re tuned it as the maps were right out with the dif change Link to comment https://www.fordxr6turbo.com/forum/topic/32271-50-and-70-comp-cover/page/3/#findComment-494431 Share on other sites More sharing options...
DennisRB30 Member 49 Member For: 21y 11m 14d Posted 06/02/07 01:46 PM Share Posted 06/02/07 01:46 PM RAP1D said: My mate has a TD07 25G on his sr20, just looking at the size of this sucker spells lag, and it was laggy with the stock 3.4 diff. We put a 4.2 in it and wow, huge improvment, alot less lag and very drivable. Its easilly on boost 500 to 750 rpm earlier now, so maybe the same happy results would work on the xr6... we also re tuned it as the maps were right out with the dif change←Unless you made a typo, that is the EXACT opposite of what will happen when you fit shorter gears. Taller gears load the engine up more, and allow more time for the turbo to spool up. This is easily to demonstrate in any turbo car. At what RPM can you make 15psi in 1st gear from a low RPM pull? And at what RPM can you make 15psi it 4th gear from a low RPM pull? You will reach any given boost level a LOT quicker in the higher gears. No question. Same thing happens when fitting shorter gears. You will need to rev the engine slightly higher in each gear to reach the same boost level as before. However you will have greater torque multiplication so it may actually accelerate faster overall anyway. This is why choosing the correct final drive for a turbo car is so important. Its quite common for smaller capacity engines with short gearing and large turbos to not even make any boost in first gear. Link to comment https://www.fordxr6turbo.com/forum/topic/32271-50-and-70-comp-cover/page/3/#findComment-494523 Share on other sites More sharing options...
Ralph Wiggum Moar Powar Babeh Lifetime Members 19,332 Member For: 19y 8m 21d Gender: Male Location: Perth Posted 06/02/07 01:48 PM Share Posted 06/02/07 01:48 PM (edited) explained well Dennis.... hows your conversion going? Edited 06/02/07 01:48 PM by hiddeous Link to comment https://www.fordxr6turbo.com/forum/topic/32271-50-and-70-comp-cover/page/3/#findComment-494524 Share on other sites More sharing options...
DennisRB30 Member 49 Member For: 21y 11m 14d Posted 07/02/07 12:31 AM Share Posted 07/02/07 12:31 AM hiddeous said: :rl:explained well Dennis.... hows your conversion going?←Its still all pulled apart. I'm half way through porting the wastegate. Should be going a few weeks. I'm still waiting for some parts to arrive from the US like my 550cc US spec supra injectors and cams....Great thread BTW. I thought my 0.5 cover would be loosing me power so I wanted to change if for a 0.7 (everyone else uses 0.7 covers on 2JZ's). But I think I am on a winner now. Link to comment https://www.fordxr6turbo.com/forum/topic/32271-50-and-70-comp-cover/page/3/#findComment-494609 Share on other sites More sharing options...
RAP1D Member Donating Members 3,739 Member For: 19y 25d Gender: Male Location: Sydney NSW Posted 07/02/07 01:55 AM Share Posted 07/02/07 01:55 AM DennisRB30 said: RAP1D said: My mate has a TD07 25G on his sr20, just looking at the size of this sucker spells lag, and it was laggy with the stock 3.4 diff. We put a 4.2 in it and wow, huge improvment, alot less lag and very drivable. Its easilly on boost 500 to 750 rpm earlier now, so maybe the same happy results would work on the xr6... we also re tuned it as the maps were right out with the dif change←Unless you made a typo, that is the EXACT opposite of what will happen when you fit shorter gears. Taller gears load the engine up more, and allow more time for the turbo to spool up. This is easily to demonstrate in any turbo car. At what RPM can you make 15psi in 1st gear from a low RPM pull? And at what RPM can you make 15psi it 4th gear from a low RPM pull? You will reach any given boost level a LOT quicker in the higher gears. No question. Same thing happens when fitting shorter gears. You will need to rev the engine slightly higher in each gear to reach the same boost level as before. However you will have greater torque multiplication so it may actually accelerate faster overall anyway. This is why choosing the correct final drive for a turbo car is so important. Its quite common for smaller capacity engines with short gearing and large turbos to not even make any boost in first gear.←Yeah we kind of thought that too... but theories aside, it worked and solved the lag issue. Thing is, with so many different turbo size/motor size/ gear ratio combos around these days anything can result. No one can sit there and say what will and what wont work, I wont argue about this kind of thing, there's way to many of contributing factors to take into account Link to comment https://www.fordxr6turbo.com/forum/topic/32271-50-and-70-comp-cover/page/3/#findComment-494641 Share on other sites More sharing options...
DennisRB30 Member 49 Member For: 21y 11m 14d Posted 07/02/07 02:49 AM Share Posted 07/02/07 02:49 AM Quote I wont argue about this kind of thing, there's way to many of contributing factors to take into accountAbsolutely. Whatever caused the reduction in lag certainly wasn't the shorter gears. Too many other factors. Link to comment https://www.fordxr6turbo.com/forum/topic/32271-50-and-70-comp-cover/page/3/#findComment-494648 Share on other sites More sharing options...
Evil F6 Donating Members 830 Member For: 19y 5m 5d Gender: Male Location: Sydney Posted 07/02/07 03:34 AM Share Posted 07/02/07 03:34 AM What about a compromise; make a 0.6 comp cover. Link to comment https://www.fordxr6turbo.com/forum/topic/32271-50-and-70-comp-cover/page/3/#findComment-494656 Share on other sites More sharing options...
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