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dallas when you say mid-corner binding you mean it was locking up too much mid-corner i assume? interesting though, i feel a similar experience where corner entry is great but then there's some post-entry understeer, but could be a multitude of factors. i really wish there could be further developments on the acd tune but it seems people don't really want to go there. i think it should be very open except in straight-line braking and ramps up lock as the throtlte is applied. anywhere else, i don't see a value in having more than a small amount of lockup. i've got an old email from sabin (who helped develop the ER tune and a few others) that I should look back through.
in terms of the front diff - ats sent me a can of their gear oil, which i told them i would use in my t-case and rear diff to appease them before they send me the flat washers to reduce the preload. it's not going to do anything, as discussed, but it's the first step in this process. i have noticed though, after flushing my t-case many times now, that it comes out grey - interesting. even after many track days, the fluid has always come out yellow, but maybe the acd doesn't like the figure 8s. t-case and rear diff are filled with their fluid now and since i've got the valve cover on i'll go back to breaking in the diff. i also put motul gear 300 in the trans.
as an aside, their 85w90 is the thickest fluid i've ever had the misfortune of putting in my car. it broke two hand pumps before i decided to use funnel & hose. i had minimal stuff with me so this is what i did for the rear diff. i had enough time to pour that amount into the fluid, put down the bottle and close it, take off my gloves, pull out my phone and snap the picture, and it hardly moved. 66 degrees in the garage as I worked. very thick stuff. i'm debating sending a sample to blackstone for analysis, but so few are ever gonna run this fluid so i doubt anyone would care.
dallas when you say mid-corner binding you mean it was locking up too much mid-corner i assume? interesting though, i feel a similar experience where corner entry is great but then there's some post-entry understeer, but could be a multitude of factors. i really wish there could be further developments on the acd tune but it seems people don't really want to go there. i think it should be very open except in straight-line braking and ramps up lock as the throtlte is applied. anywhere else, i don't see a value in having more than a small amount of lockup. i've got an old email from sabin (who helped develop the ER tune and a few others) that I should look back through.
At speed on track and when I was essentially lower grip at AX it seemed to work great. But with what I need now, it struggles for tight stuff and is why Ive gone totally custom. What I have now is pretty amazing but I cant share it cause I didnt do the coding for this. But with the motec I will be trying to replicate the behavior. Theres some magic to be found in the timing of how quickly pressure builds and drops but steady state I want the center to be open and on throttle or heavy braking needs to be locking. Just gotta figure out the balance and timing.
Originally Posted by kyoo
in terms of the front diff - ats sent me a can of their gear oil, which i told them i would use in my t-case and rear diff to appease them before they send me the flat washers to reduce the preload. it's not going to do anything, as discussed, but it's the first step in this process. i have noticed though, after flushing my t-case many times now, that it comes out grey - interesting. even after many track days, the fluid has always come out yellow, but maybe the acd doesn't like the figure 8s. t-case and rear diff are filled with their fluid now and since i've got the valve cover on i'll go back to breaking in the diff. i also put motul gear 300 in the trans.
as an aside, their 85w90 is the thickest fluid i've ever had the misfortune of putting in my car. it broke two hand pumps before i decided to use funnel & hose. i had minimal stuff with me so this is what i did for the rear diff. i had enough time to pour that amount into the fluid, put down the bottle and close it, take off my gloves, pull out my phone and snap the picture, and it hardly moved. 66 degrees in the garage as I worked. very thick stuff. i'm debating sending a sample to blackstone for analysis, but so few are ever gonna run this fluid so i doubt anyone would care.
So again why are you changing t-case fluid expecting a difference in front diff noise?
At speed on track and when I was essentially lower grip at AX it seemed to work great. But with what I need now, it struggles for tight stuff and is why Ive gone totally custom. What I have now is pretty amazing but I cant share it cause I didnt do the coding for this. But with the motec I will be trying to replicate the behavior. Theres some magic to be found in the timing of how quickly pressure builds and drops but steady state I want the center to be open and on throttle or heavy braking needs to be locking. Just gotta figure out the balance and timing.
So again why are you changing t-case fluid expecting a difference in front diff noise?
who did the coding?
and i'm not - per my post, i'm doing this to appease them so they can check their box and send me the flat washers.
as an aside, their 85w90 is the thickest fluid i've ever had the misfortune of putting in my car. it broke two hand pumps before i decided to use funnel & hose. i had minimal stuff with me so this is what i did for the rear diff. i had enough time to pour that amount into the fluid, put down the bottle and close it, take off my gloves, pull out my phone and snap the picture, and it hardly moved. 66 degrees in the garage as I worked. very thick stuff. i'm debating sending a sample to blackstone for analysis, but so few are ever gonna run this fluid so i doubt anyone would care.
I made the mistake of trying to do fluid changes in an unheated garage in winter a few years ago. Took forever until I started putting the fluid bottles in a hot water bath before pouring them in. I haven't used anything that thick, but heating things to 100-110F is a game changer.
and i'm not - per my post, i'm doing this to appease them so they can check their box and send me the flat washers.
Its @ROB-80E here. Hes a friend of Merlins in AU and has probably done more to decode the factory ECU than anyone else at this point. Covid really messed up getting quality testing but the tune he has from my feed back is pretty close for AutoX. I need to do more testing with it back to back between two of the settings and see if we combine them or they're good as is.
Right now the 1 setting I haven't tried much in the dry high grip was a big improvement in the wet. I think it releases a little slower and ramps in a little faster, but I'd have to go back and look at my notes.
I obviously and friends with ER, so if you're doing track stuff or dirt stuff I know that tune work really well. Aldo's setup that we're working on tho, that one is closer to AutoX magic.
Its @ROB-80E here. Hes a friend of Merlins in AU and has probably done more to decode the factory ECU than anyone else at this point. Covid really messed up getting quality testing but the tune he has from my feed back is pretty close for AutoX. I need to do more testing with it back to back between two of the settings and see if we combine them or they're good as is.
Right now the 1 setting I haven't tried much in the dry high grip was a big improvement in the wet. I think it releases a little slower and ramps in a little faster, but I'd have to go back and look at my notes.
I obviously and friends with ER, so if you're doing track stuff or dirt stuff I know that tune work really well. Aldo's setup that we're working on tho, that one is closer to AutoX magic.
HMMM, interesting. BTW - not sure if this is covered elsewhere or not - does the fluid itself (viscosity) impact lockup of the clutches? I assume it can, by a litlte, depending on how thick the fluid is. I may try a lighter fluid, maybe a mix of D6 and D4 ATF from Red line.
sent an email to ATS that I used their differential oil and it obviously did not help. They are going to send me 2 flat washers that can be used to decrease preload
They said with the 2 spring washers, it is 30-40 kgm - again, their measurements seems way way off - but this is the stated measurement in all of their documentation.
Replacing the 2 spring washers with flat washers they are sending will reduce preload to 10-15kgm - which again seems crazy high, but will be about 1/3rd of the preload the diff currently has. Mixing and matching will result in numbers in between, as the flat washers are slightly different thicknesses.
I told them I would race first with it before changing preload and will keep my word on that. If it's still clunking more than I'd like, I will reset the diff with both flat washers, and compare my time at the same track, and note experience, etc., if there is a dramatic increase in wheel spin due to lack of lock-up, all that stuff. If the performance is good/the same and the diff makes less noise with the decreased preload, I would suggest asking ATS to set your front diff the same way, if there are any consumers in the future interested in this diff. Hopefully more to report in 2021 once the season is underway.
Have you at least checked the preload yourself? Remove the 4 bolts on the driveshaft at the rear diff then use a torque wrench on the axle nut to figure out what the break free torque is (set wrench above what you expect and keep dropping till it clicks before moving). And there will be a stiff direction and soft direction. You want to check the soft direction. The stiff direction is in the direction of ramping against the plates.
Have you at least checked the preload yourself? Remove the 4 bolts on the driveshaft at the rear diff then use a torque wrench on the axle nut to figure out what the break free torque is (set wrench above what you expect and keep dropping till it clicks before moving). And there will be a stiff direction and soft direction. You want to check the soft direction. The stiff direction is in the direction of ramping against the plates.
no but the rear is a 1.5-way so wouldnt I encounter ramping in either direction? though one will be softer, yes.
HMMM, interesting. BTW - not sure if this is covered elsewhere or not - does the fluid itself (viscosity) impact lockup of the clutches? I assume it can, by a litlte, depending on how thick the fluid is. I may try a lighter fluid, maybe a mix of D6 and D4 ATF from Red line.
Which fluid and which clutches?
If you are talking about ACD, I would not run anything than LS gear oil in the transfer box... and that is the fluid that lubricates the ACD clutches..
