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Subaru power rack options


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The Subura rack swap is well documented utilizing 90's and early 2000 Subaru cars here and around web.  As donor cars become newer their rack utilize large diameter tie rods thereby needing different compatible tie rods.  The swap using most current rack I found was by winstonusmc and has sorted out the parts for larger tie rods

 

I would like to source a 15:1 ratio rack with 2.5 turns lock to lock.  The stock S30 rack has 2.6 or 2.7 turn to turn correct?

2004 WRX rack has 16:1 with 3 turns lock to lock I believe.  The 2004 STI rack is 15:1 but finding one used is not easy, rare beast.  From what I gather all the 2005-2007 WRX and STI cars came with 15:1 rack but they differ slightly in mounts.  The 2005-2007 have round mounts while the 2004 older have a round mount on passenger and a square mount on driver's side.  This nasioc link states the 2005-2007 racks can be fitted to the 2004 Subaru cars so assuming these racks will work as outlined in winstonusmc swap.

https://forums.nasioc.com/forums/showthread.php?t=2867695

 

A saddle can be easily made for the square driver's mount on the S30 to accommodate the round mount on 2005-2007 rack.  Seems many Subaru owners are running the newer racks in 2004 and older cars without modifying the square mount.  Questionable practice which I'll do my best to avoid.  Need to confirmed the threads M16 x 1.5 and overall width of 2005-2007 are identical to 2004 rack.  

Am I missing anything?

 

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  • 2 weeks later...

I really don't find the ratio to be any issue with my rack. Granted I don't autocross or race it, just spirited mountain driving. The car is easily driven one handed with the way it is now. With the amount of fabrication required to get the hydraulic lines to clear, the square or round mount is really moot. I would probably prefer the square mount because it has no way to rotate in the subframe. I am sure it could be mitigated on the round mount. One thing I have to do the next time the engine comes out is to recenter the rack and widen the upper mount so it doesn't let the rack shift from side to side. 

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Since the mount style is a non issue will be on the lookout for 2005-2008 15:1 rack I can pickup locally to play with.  I do plan to track the car so want to try the 15:1 rack.   I have tig welder so adding mount tabs on rack to fit S30 stock rack mounts is not a problem if need be.  Only issue will be possibly melting seals in rack.  The input shaft seals are cheap and easy to replace, which I would do anyway, just don't know procedure to replace the seals on the tie rod sides.  I think they are more entailed and may require special tools.

 

Did you run the stock hard lines on rack?  Would the swap be easier if custom hard lines or stainless steel braided lines are used?

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It's easier to weld on the subframe. If you look at my pictures, I had to pocket out the subframe to clear all the lines. I wouldn't suggest modifying the rack to fit the subframe, but fit the subframe around the rack. I used compression fittings on the lines to put them in front of the subframe because the Subaru lines would not clear the subframe. If you are not wanting to modify your subframe, you can find an extra and modify that one. The rack can be completely disassembled. I replaced all the seals in mine when I put it back together. Now that my rack is custom, this is what I will do Everytime it gets leaky.

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The pics on your swap thread are out of focus or low resolution making it hard to see detail.  I see lower res photos on other sites also and don't know the cause.  The "pocketing" of the sub-frame is not a big deal, actually enjoy this type of metal work.  Another member here used a newer style JDM RHD rack to convert to a RHD car.  That rack has the 2005+ mounting tabs design instead of the older style round and square type mounts.  He had to cut off the mount ears to make it work, basically ending up with two round mounts.  Not sure why he needed to cut the ears off, maybe it would not clock correctly to have input shaft line up with steering shaft.  As you suggested it would be better to fab mount on sub-frame to accommodate the mount ears of newer rack.  Good to hear the rack seals are easily replaced. 

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On their build thread, you will have to click through the pictures to see the unblurred version. Just something Photobucket does to ensure they lose more customers and reach bankruptcy faster.

 

I think the pictures they were referring to were these, on a hybridz album. 

 

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