chucktoo Posted July 31, 2005 Share Posted July 31, 2005 Has any one figured out how to reprogram the ABS computer for different tire sizes ? As best I can tell it sends a ground speed informationl to the ECU and the Dash over the CAN bus ? The Legacy and Outback have two different rolling diameters that have to be programed in some where ? Legacy ~847 rev/mile Outback ~775 rev/mile Link to comment Share on other sites More sharing options...
meier motor sports Posted July 31, 2005 Share Posted July 31, 2005 see dealer Link to comment Share on other sites More sharing options...
IwannaSportSedan Posted July 31, 2005 Share Posted July 31, 2005 I believe that there is a flag that can be set for 18" rims in the legacy. There is probably a rate setting for the speedometer that gets changed with that, but I am not sure if the rate is adjustable directly... not sure. The "vacation pics" might have some views of that... Link to comment Share on other sites More sharing options...
Kaos22B Posted July 31, 2005 Share Posted July 31, 2005 EDIT: read further on our legacys are different Link to comment Share on other sites More sharing options...
chucktoo Posted July 31, 2005 Author Share Posted July 31, 2005 Are you sure about a VSS on the 5 mt ? All I can find in the shop manual are backup and neutral switches on the transmission . The AT has a front and rear VSSs The "Combination Meter" aka the dash dispaly does not have a VSS signal going into it I can find - am I missing something ? i can not find it any where in the wiring harnesses also - where have I missed it ? I want to change an Outback to the smaller rolling diameter of a Legacy and have a speedo that is more or less correct. The tires I want to use [ 285/30/18s] are ~835 rev/mile which is close enough to LGT diameter for me. There are a lot of very high performance tires in this size. There would cause about an 8% speedo error - if have to live with it fine but that would not be my choice. Link to comment Share on other sites More sharing options...
PGT Posted July 31, 2005 Share Posted July 31, 2005 Charlie - 'Opie' mentioned this in a previous thread. He claimed the dealer could do it with their ECU tool. I pressed for more info and didn't get anything more. I went with a 245/35/18 to get it as close to the stock diameter as possible for this reason. -Dan Link to comment Share on other sites More sharing options...
chucktoo Posted August 1, 2005 Author Share Posted August 1, 2005 Hi Dan That is why I am using 245/45/18 now because they are the same rolling diameter as the 225/50/17s that come on Outbacks . After looking around at really large tires it appears they are mainly in the 830-840 rev/mile range. The 285/30/18 appear to be a very common size for large high performance tires. These will require 10" wide rims but I think I have that under control. I have Topspeed also checking with the Subaru shop in Ga that is installing the ATS LSD in my 6 mt to see if they know to change tire size. My local subaru dealer is clueless. Charlie Link to comment Share on other sites More sharing options...
Kaos22B Posted August 1, 2005 Share Posted August 1, 2005 edit, I seem to be incorrect, read further on.... Link to comment Share on other sites More sharing options...
Opie Posted August 1, 2005 Share Posted August 1, 2005 Charlie - 'Opie' mentioned this in a previous thread. He claimed the dealer could do it with their ECU tool. I pressed for more info and didn't get anything more. I went with a 245/35/18 to get it as close to the stock diameter as possible for this reason. -Dan This is true the ECM (on the Legacy 2.5GT) has a choise of 17" or 18" wheels that can be changed with the Subaru Select Monitor tool at the dealer. It only allows for a selection of 17" or 18" not for exact tire sizes (like setting it specifically for 245/35R18 or 225/40R18, etc.) so in order for it to be accurate, you would need to select a size that most closely matches the stock sizes. Those are 215/45R17 in the 17" size and 215/45R18 in the 18" size. Link to comment Share on other sites More sharing options...
chucktoo Posted August 1, 2005 Author Share Posted August 1, 2005 Great Opie - will get programed for smaller size - real easy. There are the first two pages of Turbo wiring including instument pannel hard to read when shrunk to allowable size. We will have to try it. 215/45/R17 is about 840 rev/mile 215/45/R18 is about 810 rev/mile I would guess they use the 18 to put the value in for the 225/55R17 of 775 rev/mile ? Link to comment Share on other sites More sharing options...
Kaos22B Posted August 1, 2005 Share Posted August 1, 2005 This is true the ECM (on the Legacy 2.5GT) has a choise of 17" or 18" wheels that can be changed with the Subaru Select Monitor tool at the dealer. It only allows for a selection of 17" or 18" not for exact tire sizes (like setting it specifically for 245/35R18 or 225/40R18, etc.) so in order for it to be accurate, you would need to select a size that most closely matches the stock sizes. Those are 215/45R17 in the 17" size and 215/45R18 in the 18" size. I dont understand how this is possible since there is a wire that goes uninterrupted from the vss to the combination meter? Link to comment Share on other sites More sharing options...
chucktoo Posted August 1, 2005 Author Share Posted August 1, 2005 I put all the wiring up on my site to you can look - pages 43 on are the most interesting. http://users.rcn.com/crbarker/Engine%20Electrical%20System%205.pdf I will leave it up for a couple of days/ Link to comment Share on other sites More sharing options...
Kaos22B Posted August 1, 2005 Share Posted August 1, 2005 wow, you're absolutely right, nowhere in those can I find the typical VSS setup that are in the rest of the models, I have all the downloads for our legacys and I looked again at the ABS wiring, it looks like the only feed is from that to the ecu itself. I'll look into it further tomorrow and see if there really is a VSS on the tranny, I know the hole will be there, but If the sensor is in it or its plugged will help determine whats going on... Link to comment Share on other sites More sharing options...
chucktoo Posted August 1, 2005 Author Share Posted August 1, 2005 Here is the transmission if you do not have it. I can not find the VSS - the hole maybe there but there is no sensor to drive our speedo I can find. http://users.rcn.com/crbarker/5%20mt/ Link to comment Share on other sites More sharing options...
chucktoo Posted August 2, 2005 Author Share Posted August 2, 2005 The mechanic doing my drive train confirmed there is a place on the 5mt for a VSS sensor - there is no sensor and the hole is plugged. My 6mt has a VSS sensor that I will use to drive a DEFI link display to have atleast one accurate speedo. Link to comment Share on other sites More sharing options...
Kaos22B Posted August 2, 2005 Share Posted August 2, 2005 The mechanic doing my drive train confirmed there is a place on the 5mt for a VSS sensor - there is no sensor and the hole is plugged. My 6mt has a VSS sensor that I will use to drive a DEFI link display to have atleast one accurate speedo. I have that display on my RS Its great since my stock cluster doesn't go that high Link to comment Share on other sites More sharing options...
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