Gollum Posted September 10, 2010 Share Posted September 10, 2010 So I've been under quite a few STI's lately. One of my friends has gotten really into them in the last few years, and now he's tuning at a very well respected shop with cars that come in from around the country. So as he was giving me a tour of the shop the other day, showing the 4 wheel dyno etc, something dawned on me that I'd somehow overlooked for quite some time.... So looking under the rear side, it's an R180... And R180 that's proven to hold TONS of power, and torque. Even the guys that convert to RWD only for drifting and still put out absurd amounts of power don't seem to blow these things. And the rear hub design has almost the identical mount design as the S30. The main different is that instead of a lower control arm it uses two lateral links that basically work like a lower control arm, allowing toe adjustment. The strut mounting is close in design, just on the wrong side. But I can't see any reason you couldn't just flip sides, using the right as left and vice versa, and make it work. Then I started looking at the front.... The front uses a lower control arm that acts as our lower control arm AND TC rod in one. It only has one mount point on the front hub, so one could design a custom control arm with the mount point for a TC rod. The front hubs are also front steer like our Z cars. The main obstacle I see on the front is that the strut angle is facing a bit towards the back of the car. Not a huge issue though as new top hats will be needed all around anyways. Some welding and camber plates should fix that problem. I'd say overall the biggest issue is just making lower control arms, but it's not like that hasn't been done before. You obviously want it done by a competent welder, and probably TIG welded as well. But here's what I see you GAINING: HUGE brakes Suspension allowing a bit more offset 5x114.3 Lug pattern for common wheels Easy access to adjustable spring perches TONS of strut options TONS of spring options Might as well swap to their R180 while you're at it so you can USE THEIR AXLES. Get rid of those stub axles, yay! Some of the obvious downsides: Lots of work (but so is any hub swap) HEAVY brakes (worth it?) Expensive brake pads Having to trust your welding/welder with your life Backwards compatibility I'd like to get some feedback and see what you all are thinking? Worth the effort? Totally stupid? Etc. With my friend being so engulfed in the STI world, I'm just dumb enough to ask him to keep a lookout for a car being parted out that I could snag the suspension from. I think all in all it's an interesting idea worth looking into. I'll try to get some pics and measurements next time I'm under one of these beasts. Oh, and I should note I'm talking about the 2005 STI. I think the 2004 is almost identical, but STI's do change A LOT from year to year. The newer "wagon" STI's are completely different animals when it comes to the suspension. Quote Link to comment Share on other sites More sharing options...
Forcer Posted September 11, 2010 Share Posted September 11, 2010 The only real difference on the '04 STI is the bolt pattern, they are 5x100. I can't really comment on whether or not STI's would be a good donor car, but I do wish to comment on the expensive brake pads. I have the StopTech Posiquiets on my STI that cost $90 total for front & rear. So far they are actually good for street, and spirited driving. Quote Link to comment Share on other sites More sharing options...
johnc Posted September 11, 2010 Share Posted September 11, 2010 So I've been under quite a few STI's lately. One of my friends has gotten really into them in the last few years, and now he's tuning at a very well respected shop with cars that come in from around the country. So as he was giving me a tour of the shop the other day, showing the 4 wheel dyno etc, something dawned on me that I'd somehow overlooked for quite some time.... So looking under the rear side, it's an R180... And R180 that's proven to hold TONS of power, and torque. Even the guys that convert to RWD only for drifting and still put out absurd amounts of power don't seem to blow these things. And the rear hub design has almost the identical mount design as the S30. The main different is that instead of a lower control arm it uses two lateral links that basically work like a lower control arm, allowing toe adjustment. The strut mounting is close in design, just on the wrong side. But I can't see any reason you couldn't just flip sides, using the right as left and vice versa, and make it work. Then I started looking at the front.... The front uses a lower control arm that acts as our lower control arm AND TC rod in one. It only has one mount point on the front hub, so one could design a custom control arm with the mount point for a TC rod. The front hubs are also front steer like our Z cars. The main obstacle I see on the front is that the strut angle is facing a bit towards the back of the car. Not a huge issue though as new top hats will be needed all around anyways. Some welding and camber plates should fix that problem. I'd say overall the biggest issue is just making lower control arms, but it's not like that hasn't been done before. You obviously want it done by a competent welder, and probably TIG welded as well. But here's what I see you GAINING: HUGE brakes Suspension allowing a bit more offset 5x114.3 Lug pattern for common wheels Easy access to adjustable spring perches TONS of strut options TONS of spring options Might as well swap to their R180 while you're at it so you can USE THEIR AXLES. Get rid of those stub axles, yay! Some of the obvious downsides: Lots of work (but so is any hub swap) HEAVY brakes (worth it?) Expensive brake pads Having to trust your welding/welder with your life Backwards compatibility I'd like to get some feedback and see what you all are thinking? Worth the effort? Totally stupid? Etc. With my friend being so engulfed in the STI world, I'm just dumb enough to ask him to keep a lookout for a car being parted out that I could snag the suspension from. I think all in all it's an interesting idea worth looking into. I'll try to get some pics and measurements next time I'm under one of these beasts. Oh, and I should note I'm talking about the 2005 STI. I think the 2004 is almost identical, but STI's do change A LOT from year to year. The newer "wagon" STI's are completely different animals when it comes to the suspension. So there's a minimum of $5,000 worth of design and fabrication work to get to the point where you can start buying and installing all those Sube' aftermarket parts. And you won't be any quicker around a race track with your Sube30 in comparison to properly setup S30 with its OEM style suspension. If its a project your want to do for fun and to learn something, go for it. Just don't figure your Sube30 will handle any better the a regular S30. Quote Link to comment Share on other sites More sharing options...
Gollum Posted September 13, 2010 Author Share Posted September 13, 2010 (edited) As always I enjoy your constructive criticism john. I personally don't see where you get a 5k figure, unless you're calculating one's own personal time for engineering it. This definitely isn't something someone will do in their spare time in the driveway, but from what I see it's just time, some cheap metal, and tools. I'm short on the first thing there, but the other two I'm not. Oh, and I never thought this would be a good "go fast cheap" or even "go fast" option. I merely like the idea of the ease of swapping in the bulletproof rear diff and axles, and combined with much easier to find rims. The brake size is an added bonus, especially since many people spend well over 1k getting comparable wilwoods on their Z. Edited September 13, 2010 by Gollum Quote Link to comment Share on other sites More sharing options...
johnc Posted September 13, 2010 Share Posted September 13, 2010 When I quote a price its generally a guess as to what a fabricator would charge a customer to do the work. Also, don't use cheap metal when you build the front lower control arms. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted September 13, 2010 Share Posted September 13, 2010 I was looking at struts some time ago and ran into something that said that the WRX inserts were close to or the same size as the S30. I never followed up on it, but you may be able to adapt Subaru struts on the Z as it is. Quote Link to comment Share on other sites More sharing options...
Gollum Posted September 14, 2010 Author Share Posted September 14, 2010 When I quote a price its generally a guess as to what a fabricator would charge a customer to do the work. Also, don't use cheap metal when you build the front lower control arms. Touche, I shold be more careful with my words. I'd most certainly use something like chromoly tubing. Not sure what grade for sure. I was looking at struts some time ago and ran into something that said that the WRX inserts were close to or the same size as the S30. I never followed up on it, but you may be able to adapt Subaru struts on the Z as it is. That'd most certainly interesting. I hadn't heard that before. I'll get some measurements soon to see if I can confirm that. Quote Link to comment Share on other sites More sharing options...
Bare Speed Posted September 14, 2010 Share Posted September 14, 2010 (edited) I like the idea. I have tons of coil overs sitting around. I thought about doing this at some point but dont have a the knuckles or donor car. Something to look in too. I do think it would take a few days to fab it up. Ill take a look around to see if I can find some parts. Edited September 14, 2010 by Bare Speed Quote Link to comment Share on other sites More sharing options...
FlatBlack Posted September 14, 2010 Share Posted September 14, 2010 This seems like alot of work. Just to let you know, I have two Subaru parts cars at my boss' ranch. One is a first gen Legacy, the other is a first gen Impreza [GC]. Parts interchange is basically the same from these cars to the GDs [02-07 Imprezas] I've put a Legacy LCA on my Impreza, vice versa, I have a GD WRX sway bar on my GC, etc etc - they are all the same parts. The only difference should be the STi hub, which as you know, are 5x114.3 Let me know if I can help you out with parts measurements, etc Quote Link to comment Share on other sites More sharing options...
Gollum Posted September 14, 2010 Author Share Posted September 14, 2010 Yea, it's been kinda creepy in my researching to see how easily people have put sti suspension parts on other subie's, RS's included! I don't think I've seen any other company with that kind of part compatability. Quote Link to comment Share on other sites More sharing options...
FlatBlack Posted September 15, 2010 Share Posted September 15, 2010 Yea, it's been kinda creepy in my researching to see how easily people have put sti suspension parts on other subie's, RS's included! I don't think I've seen any other company with that kind of part compatability. It's fantastic Quote Link to comment Share on other sites More sharing options...
Forcer Posted October 3, 2010 Share Posted October 3, 2010 Agreed. I love my STI as much as my Z. Apparently the VF series of turbos are like legos as well. Quote Link to comment Share on other sites More sharing options...
Pzary3233 Posted October 5, 2010 Share Posted October 5, 2010 (edited) Ah yes, Subaru suspension stuff swaps so easily between the Subaru Chassis! If going with subaru stuff do yourself a favor GET THE 05+ STI hubs and kunckles. They have much stronger wheel bearings. With tracking and autoxing my '02 WRX (GD chassis) I burnt up three sets of bearings in thr front hubs with stickies. Subaru also has the bolt on ability to use the Z32 TT calipers and they even borrowed them and made them their own from Fuji Heavy Industries. I've got a Subaru suspension graveyard that's for sure! But if you are going to engineer stuff to make the subaru knuckles fit, why not just go ahead and design a SLA double A arm suspension? Edited October 5, 2010 by Pzary3233 Quote Link to comment Share on other sites More sharing options...
Gollum Posted October 5, 2010 Author Share Posted October 5, 2010 Because chassis mounting then becomes much more complicated. You now need reinforced mount points higher up, etc. If I was tube framing the chassis then sure, but I'm talking about using the OEM LCA mounts and keep the geometry relatively stock by maintaining similar LCA length. Thank you for the information on the wheel bearings though, I hadn't heard that. It's also good news about the Z32 brakes, since the 05 brakes (and even pads) are SO OUTRAGEOUSLY PRICED. Plus I'm not sure a 2200 pound S30 needs that big of pads, even with a 275+ tread. Quote Link to comment Share on other sites More sharing options...
Pzary3233 Posted October 5, 2010 Share Posted October 5, 2010 Oh I understand the task of engineering a double A Arm suspension... No easy task by any means. NOT something I want to engineer. Yes, the wheel bearings love to cook! There is apparently a wheel bearing from some Nissan product that works well as a replacement that is considered to be up to the task, but I never tried that. The 5x100 cars are the only ones with this issue. Subaru swapped to much larger bearings on the 5x114.3 STi hubs and that is no longer a problem. Yes, they really are priced stupidly... I actually wanted to run the Nissan stuff but came across the Subaru bits cheaply. When those brakes first came out in I think '06 on the WRX I was ready to buy pads so I though I would just get pads with the calipers... Not so fast... Had to order the Nissan spec pads as apparently no one in the marketing world had figured it out yet... ALSO, the Subaru dealer NEVER has the hardware in stock, but the local Nissan dealer does! Quote Link to comment Share on other sites More sharing options...
Forcer Posted October 7, 2010 Share Posted October 7, 2010 Because chassis mounting then becomes much more complicated. You now need reinforced mount points higher up, etc. If I was tube framing the chassis then sure, but I'm talking about using the OEM LCA mounts and keep the geometry relatively stock by maintaining similar LCA length. Thank you for the information on the wheel bearings though, I hadn't heard that. It's also good news about the Z32 brakes, since the 05 brakes (and even pads) are SO OUTRAGEOUSLY PRICED. Plus I'm not sure a 2200 pound S30 needs that big of pads, even with a 275+ tread. I paid $90 for a full set of pads. StopTech Posi-quiets, pretty good pads so far. Quote Link to comment Share on other sites More sharing options...
Pzary3233 Posted October 7, 2010 Share Posted October 7, 2010 ^ $90 for STI Brembos or Z32 Calipers? Quote Link to comment Share on other sites More sharing options...
Forcer Posted October 8, 2010 Share Posted October 8, 2010 The STI Brembo's. Quote Link to comment Share on other sites More sharing options...
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