voltron_boi Posted March 27, 2012 Share Posted March 27, 2012 I went ahead and purchase me a 5' electrical speedo from summit. I was just wondering what modification will I need to do to make the speedo work on my rb25 transmisson along with my rear end that I have. I have a 3.7 ratio, clutch type LSD from a 87 z31 turbo. I will like to no which VSS will suit my setup. Quote Link to comment Share on other sites More sharing options...
rejracer Posted March 30, 2012 Share Posted March 30, 2012 One thing you will need is to get the RB25 VSS that is matched to the rear gears in your car. I don't know how to interface it to the RB25, for example I don't know if the 25 ECU's have a speed out circuit or of you have to grab the speed signal directly from the VSS. Quote Link to comment Share on other sites More sharing options...
voltron_boi Posted March 30, 2012 Author Share Posted March 30, 2012 According to this thread http://forums.hybridz.org/index.php/topic/55189-getting-an-autometer-speedo-to-work/page__p__499908__hl__%2Bautometer+%2Bspeedo+%2B__fromsearch__1#entry499908 they mention About autometer speedo color of gear is based on your final drive ratio - based on your tire size and and rearend ratio you can pick the appropriate color to get the best estimate of your speed on the speedo. Per Datsun Garage YELLOW is the 16 tooth for the 3.36 BLACK is the 17 tooth for the 3.54 BLUE is the 18 tooth for the 3.70 WHITE is the 19 tooth for the 3.90 RED is the 20 tooth for the 4.11 PURPLE is the 21 tooth for the 4.38 So since mine is a 3.70, do I just get the 18 tooth 3.70 for my rb25 transmisson? Quote Link to comment Share on other sites More sharing options...
rejracer Posted April 3, 2012 Share Posted April 3, 2012 Vang, I believe the cog info above is applicable to L series transmissions. I don't know if it applies to RB's. Regardless, you need the right cog if you want the odometer to work correctly. If you don't have an odometer, then perhaps the speedo can be adjusted for whatever cog you have in your transmissions. Take a look at the autometer to determine how adjustable it is. In the thread you mention, it says you can use a 300zx VSS. If that's the case then get a 300zx VSS that comes from a 300zx equipped with the FS5r30a transmission as it's the same as your RB25 transmission (not identical but very close). An early 300zx that has the FS5w71C transmission has a different transmission cog. As I recall from WRCBONK's VSS, it's a different body diameter. Because there are 2 different style of VSS's I don't know if the color of the cogs is the same. But since you have a RB25 transmission, I believe the VSS's will interchange between the two. The 300zx's that came with the Fs5r30A transmission are the 87-89 turbos and all from 90-96 NA and turbo. Since almost all 300zx's came with 3.70s, it's the easiest cog to find. I would hit the yards near sacramento to find the VSS your looking for. Quote Link to comment Share on other sites More sharing options...
docaam Posted November 12, 2012 Share Posted November 12, 2012 Can anyone explain/picture for electrical autometer where to conect the speedo cable in gear box (or differetial?) I am running RB26DEt with Sti differential most pobably 3.5. Quote Link to comment Share on other sites More sharing options...
ihiryu Posted November 14, 2012 Share Posted November 14, 2012 Personally I would sell the autometer and go with a Speedhut because they offer a GPS speedometer. So no matter what wheels, tire size, rear end, trans, engine etc changes speedometer will always be right. Hit me up, I can get a decent discount on 'em. Quote Link to comment Share on other sites More sharing options...
docaam Posted November 18, 2012 Share Posted November 18, 2012 Can anyone explain/picture for electrical autometer where to conect the speedo cable in gear box (or differetial?) I am running RB26DEt with Sti differential most pobably 3.5. Anyone please, will appreciate a reply Quote Link to comment Share on other sites More sharing options...
stony Posted November 19, 2012 Share Posted November 19, 2012 you can also purchase a GPS sender for you autometer speedo. http://www.summitracing.com/parts/atm-5289?gclid=CJu_qcLj2rMCFQuCQgodfxgAtA Quote Link to comment Share on other sites More sharing options...
docaam Posted January 9, 2013 Share Posted January 9, 2013 I connected the wire coming out from the auometer and plug it to the gearbox wire its not working, sorry to ask again and again but have seen people running it most probably like a simple job but not working for me. I showed it to the electrican who did the wiring he said some kind of sensor is required but what confuses me sensor is required when you want to hook a mechanical speedo to an electrical sensor or vice versa Quote Link to comment Share on other sites More sharing options...
Dat240 Posted January 15, 2013 Share Posted January 15, 2013 Just buy the Autometre GPS unit. They are reliable, acurate and much cooler than a gearbox driven speedo. 80 bucks, really a no brainer Quote Link to comment Share on other sites More sharing options...
docaam Posted January 15, 2013 Share Posted January 15, 2013 Just buy the Autometre GPS unit. They are reliable, acurate and much cooler than a gearbox driven speedo. 80 bucks, really a no brainer I have been quoted 190$ and shipping 55$ so a bit steep on price. Quote Link to comment Share on other sites More sharing options...
S30rb25 Posted February 1, 2013 Share Posted February 1, 2013 Not sure if this has been covered already, but aren't most of the autometer electronic speedos programable? And if you have a programable one their website says that you can change tire size or gearing whenever and just re calibrate it, so based on this would we even need to find a different cog to match whatever rearend we have? Quote Link to comment Share on other sites More sharing options...
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