CapnJack Posted September 11, 2014 Share Posted September 11, 2014 For those interested in what changing out to a Spec B aluminum suspension setup saves in weight, see below. I don't expect it to be much and don't expect much improvement, but I got the parts cheap and needed new bushings anyway. Front A-arms - Approx 3 lbs savings per arm Rear trailing arm - Approx 6.5 lbs per arm Rear lateral links - Approx 1.5 lbs savings per link Total savings of approximately 22 lbs. Still think it's worth it? Link to comment Share on other sites More sharing options...
Underdog Posted September 11, 2014 Share Posted September 11, 2014 I measured less difference in the LCA, but the others look similar. Okay, here it goes: 20202AG160 - Front RH Control Arm - Bought from Legacy_Otaku, used with AVO bushings ($237.50) 20202AG170 - Front LH Control Arm - Bought from Legacy_Otaku, used with AVO bushings ($237.50) 20252AG021 - Rear RH Trailing Arm - Bought from K.O.P. ($296.17) 20252AG031 - Rear LH Trailing Arm - Bought from K.O.P. ($287.55) For reference: 20250AG030 - Rear RH Upper Lateral Link - Bought from K.O.P. ($57.75) 20250AG040 - Rear LH Upper Lateral Link - Bought from K.O.P. ($57.75) 4BoxParts Adjustable "Forward" Lateral Links - ($175) Differences: Front Control Arms: Steel 7.5lbs - Stamped and Welded Construction Aluminum 6.5lbs - Cast/Forged Construction Rear Trailing Arms: Steel 17.8lbs - Cast Construction Aluminum 11.2lbs - Cast/Forged Construction Upper Lateral Links: Steel 4.9lbs - Cast Construction Aluminum 3.3lbs - Cast Construction Rear "Forward" Links: Not yet measured. The Crimson Dynamo Link to comment Share on other sites More sharing options...
fahr_side Posted September 11, 2014 Share Posted September 11, 2014 I've done this and you can certainly tell it's different. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
RallyMachine Posted September 11, 2014 Share Posted September 11, 2014 Don't control arms count as unsprung weight which would make a significant difference in handling? Same effect as lighter wheels, less weight moving up and down so responsiveness increases, only thing is right quality might suffer a bit. Link to comment Share on other sites More sharing options...
scoobyscoodle Posted September 11, 2014 Share Posted September 11, 2014 The aluminum control arms are the Spec.B's magic mojo. They are what allow it to be a luxurious, high performance rally machine that can hit 1.8g's on the skidpad and click off a 3.2 sec 0-60 in the rain. Don't doubt the mojo. Link to comment Share on other sites More sharing options...
Underdog Posted September 11, 2014 Share Posted September 11, 2014 Don't control arms count as unsprung weight which would make a significant difference in handling? Same effect as lighter wheels, less weight moving up and down so responsiveness increases, only thing is right quality might suffer a bit. Their mass is not entirely sprung or unsprung since they are attached to the chassis. Use 1/2 for approximation sake. I agree with fahr - they make a noticeable improvement (more nimble and more comfortable), although I would argue if they are worth it at retail price. If you can get a clean used set for a good price then it becomes easier to justify. The Crimson Dynamo Link to comment Share on other sites More sharing options...
CapnJack Posted September 12, 2014 Author Share Posted September 12, 2014 I'm curious now how it will feel. I'm wondering if the bushings I'm replacing will make the biggest difference. It's going to be a while though. This car has been in salt for half its life and I am having to replace knuckles from rusted bolts and I might as well replace the bearings, tie rod ends, and balljoints while I'm in there. Link to comment Share on other sites More sharing options...
fahr_side Posted September 12, 2014 Share Posted September 12, 2014 I had installed Powerflex bushings into my old steel arms before coming across the alloy ones used. I didn't like the Powerflex bushings so I installed GrpN bushings into the alloy which are a little more compliant. For sure the ride quality got better but I can't say if that is the weight difference or the bushings. What I can tell you is that I had to back the damping on my Konis off a little to compensate for the decreased weight. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
boxkita Posted September 17, 2014 Share Posted September 17, 2014 I only did the rear lateral link in aluminum. Everything else was done with bushings/camber/coilovers. I was doing 1.5g turns on the track (on slicks), so I didn't see the benefit of another $1000 for a couple pounds of weight savings. Build my car Boxkita Track days Link to comment Share on other sites More sharing options...
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