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Underdog Motorsports - 2015 STI Steering Rack Swap


Underdog

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Rack went in smoothly on my 06 OBXT limited; steering heavier at low speeds (wife displeased) and very tight/true at high speed. No dead zone on center, very quick responses to inputs. No VDC on ‘06 so not an issue though others report problems. Mechanic (The Shop in Norwalk, CT) said went in easy, ~3/4” thread left available on tie rods (more than expected, possibly due to 1.5” drop on coilovers?)

All in all very pleased since old rack was weeping like crazy and this was same price as oroginal OEM.

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Rack went in smoothly on my 06 OBXT limited; steering heavier at low speeds (wife displeased) and very tight/true at high speed. No dead zone on center, very quick responses to inputs. No VDC on ‘06 so not an issue though others report problems. Mechanic (The Shop in Norwalk, CT) said went in easy, ~3/4” thread left available on tie rods (more than expected, possibly due to 1.5” drop on coilovers?)

All in all very pleased since old rack was weeping like crazy and this was same price as oroginal OEM.

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  • 4 weeks later...

What's going on with this guy? He's talking about using modifications to the CAN signals to adjust for steering rack differences to keep VDC after an STI steering rack swap.

 

"STEERING SENSOR CAN-ID 0X2 ...

 

This info has been successfully used for steering rack swap, i.e. mating STI part with standard model. By translating this CAN frame data, a different steering ratio can be used with properly functioning VDC."

 

https://subdiesel.wordpress.com/ecu-analysis/can-messages/

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^ used an arduino with 2 can shields to intercept the can signal for steering wheel angle, apply a correction factor as the can output to vdc.

 

One of these posts:

https://www.google.com.au/search?client=safari&hl=en-gb&ei=AbpFXO3TC8H6rQHP6ouQCA&q=site%3A+legacygt.com%2Fforums+arduino+&oq=site%3A+legacygt.com%2Fforums+arduino+&gs_l=mobile-gws-wiz-serp.3...2086.5797..7482...0.0..0.472.2583.2-8j0j1......0....1.........0i71j35i39j0i22i30j33i160j33i21.N2TB6sLItJM

 

Specifically:

https://legacygt.com/forums/showpost.php?p=5373883&postcount=193

 

Absolute genius but last time I searched little extra detail was available :)

 

Picking up the trail of breadcrumbs :) :

https://forums.nasioc.com/forums/showpost.php?p=45331980&postcount=79

 

Ozfoz:

http://ozfoz.com/forum/viewtopic.php?f=29&t=56658&start=0&st=0&sk=t&sd=a

 

GitHub:

https://github.com/Phrewfuf/sas-scaler

Edited by bigBADbenny
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  • 1 year later...
  • 2 months later...

Does the LGT/Whiteline steering rack bushing kit fit the STI rack?

 

Underdog, do you still supply these racks?

"Striving to better, oft we mar what's well." - Bill Shakespeare - car modder
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Does the LGT/Whiteline steering rack bushing kit fit the STI rack?

 

Underdog, do you still supply these racks?

 

Yup the Whiteline steering rack bushing kit does fit. More details in the “what other parts are needed?” section of the OP.

 

Unfortunately no. I’ve been out of the parts business for a few years now.

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  • 2 months later...

Doing this mod next weekend on my 08 spec b. I have the whiteline rod ends already and tried to find those jam nuts locally but wasn't convenient from the metric supply places so looks like I'm buying the 5 pack from McMaster so I don't have to cut the ends. Doing U-Joint also, one of like 3 left in the US apparently. Gotta think they make small runs of these rarer parts when they run out. Also the Cusco brace.

 

Did you also replace your hanger bracket and paint it?

 

Sent from my Pixel 3 using Tapatalk

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  • 4 weeks later...
Has anyone else read that you can use outer tie rods from an '88 GL for this swap as they are shorter? Downside is that they are the curved type. Here is a link for where it was done.

 

https://www.blingstrom.com/diy-project/2020/5/4/15-sti-steering-rack-install-on-a-2005-sti-how-to-fit-the-quicker-rack-in-your-older-subaru

 

I don't know why you would do that. The modifications in this thread (i.e. cut them) are super easy and free.

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I don't know why you would do that. The modifications in this thread (i.e. cut them) are super easy and free.
Not saying I would or will. I was just curious if anyone here has because some didn't want to cut their tie rods. This would give them the same adjustability without cutting the tie rods.

 

Personally, I would cut the tie rods so I could use oem tie rod ends rather than aftermarket.

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i did not have to cut the tie rod ends. I was able to get the car aligned perfectly. i used my 2005 LGT end Links on the 2015 inner tie rods and no cutting was necessary.

 

When I put the new rack with my whiteline ends the other day i just matched the distance 7-7/8" from the end of the rubber boot to the start of the end (minus nut). This matched to what distance I had on the old rack and I ended up using the smaller jam nuts just because otherwise I would've only had about 3 rows of threads left to the inside and I already had purchased them so this gave some more adjustability if needed in the future. Now I just have two sti tie rod ends to sell along with a leaky steering rack haha.

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  • 1 month later...
When I put the new rack with my whiteline ends the other day i just matched the distance 7-7/8" from the end of the rubber boot to the start of the end (minus nut). This matched to what distance I had on the old rack and I ended up using the smaller jam nuts just because otherwise I would've only had about 3 rows of threads left to the inside and I already had purchased them so this gave some more adjustability if needed in the future. Now I just have two sti tie rod ends to sell along with a leaky steering rack haha.
This ended up me not having center on the rack somehow but it's aligned now aside from being pretty much bottomed out on one tie rod end of the threads. I can probably get it close to center next time if I just turn the wheel to the other side some, undo the u joint, then turn it back and reconnect while adjusting the tie rod ends an even amount. Next time I need an alignment for other reasons I'll do this. Also just rebuilt my pump with new seals/orings successfully, but that's another thread. Other than that the upgrade went great and the car as been driving equally as good. With the upgraded u joint I definitely feel more in control with the finite response to the steering!

 

Sent from my Pixel 3 using Tapatalk

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  • 5 months later...

I just finished this install but on a swapped GC, which was a bit more work.

New crossmember, new column, custom adaptor for column to rack, modified thread adaptors to use factory ITRs, factory 15+ lines and pump.

Waiting on a driveshaft and finishing up some other driveline parts to drive it and compare it to my swapped RS that has a GD STi 15:1 rack, to see if all that work was worth it. I'm thinking on a super light and small GC, it may be too quick for a street car. It will be nice to compare and give an idea of what the Spec B would be like with it however, and the install on that should be easier.

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  • 4 weeks later...

I've got a brand new sti rack and associated bushings. Should I:

1. Leave bushings stock

2. Replace with whiteline ksr207

3. Replace with energy suspension 12344.58697.123 or whatever their pn is

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