• Forum membership has its advantages....

Class 7/7200 Subaru Forester

Jeremiah Stewart

Active Member
Take the title with a grain of salt. Please insert any tips throughout.

The goal is just to race the Mexican 1000 and just have a prerunner Subaru. I wanted to race in their "Rally Raid AWD" class using my Hotbits coilovers as they were at the max travel for that class (10" front, 12" rear), but most years there is nobody in that class. Might as well try to be competitive if i'm entering a race right? So the class I'm shooting for is Score Class 7 or BITD 7200. In the Mexican 1k it'll either be "Heavy Metal Class" or "Pre-run Truck".

For now I will only be focusing on suspension so I can stay on track to be able to take the foz on a roadtrip planned for May 2017. The cage will need to be built after the roadtrip unless I have the time to do it this winter. Shooting to make the race in the spring of 2018, but if the foz is ready sooner than then, then I will enter a domestic race to get my feet wet.

IMG_4192 by jeremiah stewart, on Flickr


Plan:

  • Dual A-arm front suspension cycling 18-22" of travel
  • Dual A-arm rear suspension with toe link (will make sense later - similar to the PPI 015 Toyota) cycling 20-24" of travel
  • 32" tires on factory offset wheels to allow for longer arms and more travel while keeping it under the BITD max width of 85"
  • Either King or Fox internal bypass coilovers all around
  • High compression EG33 (11:1CR 3.4l H6 I built for a different Subaru) unless the length is more than I want to build around, then it'll be an EZ30
  • Extended length axles (+8") probably from DSS


Sponsored in Part By:

Anderson Design and Fabrication

Follow on Instagram: www.instagram.com/thewanderingfoz/
 

Jeremiah Stewart

Active Member
Got all of my heim joints in, as well as all of the pieces that I drew on CAD and got from Anderson Design and Fab


DSC00408 by jeremiah stewart, on Flickr


DSC00411 by jeremiah stewart, on Flickr


DSC00423 by jeremiah stewart, on Flickr



Started on the front subframe, using the old subframe as a jig:



DSC00421 by jeremiah stewart, on Flickr


Heims are 3/4x3/4

DSC00419 by jeremiah stewart, on Flickr


Need to start boxing it in and reinforcing it, then get it under the car to tie it into my other mounts.


Below is my crazy ball joint replacement idea, let's hope it works out. The big hole is to hold a uniball joint, which I am still waiting on. I may need to just fab a whole knuckle for more strength though, we'll see.
But basically, i'll fusion weld all of the disks together, then weld the rest to the disks, then of course the uniball cup inside of it.


DSC00414 by jeremiah stewart, on Flickr


DSC00415 by jeremiah stewart, on Flickr



The upper and lower joints will be 1" uniball joints, probably overkill.

From the looks of it, depending on CV angles, I can get up to 20" of travel in the front with 3.5" of scrub, or more likely, 18" of travel with about 3" of scrub. From ride height to full bump, there is just 2.5" of scrub. Camber never goes positive.

Side note: This will be a rally car type build, so the unibody will stay mostly intact, with subframes that bolt to it, and a rollcage very similar to those in stock full suvs and stock mini suvs.
 
Last edited:

Jeremiah Stewart

Active Member
I hope it's at least a little bit interesting; different if nothing else :D

I made some good progress yesterday, but got cut short by having to go pickup an engine block for mockup.
So I started off by bolting the subframe in to mockup the knuckle and make sure everything was gonna work before I started boxing it in:

DSC00499 by jeremiah stewart, on Flickr

DSC00500 by jeremiah stewart, on Flickr

Measured the track width from the center of the subframe, 42.5" then moved the tire inward 2 inches to 40.5" to give me room in the future for 32x11.5 tires with an inch for wheel offset differences. This will be the stance with stock fenders:

DSC00533 by jeremiah stewart, on Flickr

Bolted the knuckle into a wheel as well:

DSC00544 by jeremiah stewart, on Flickr

DSC00545 by jeremiah stewart, on Flickr

There's about 1/2" clearance all around in a 15" wheel, pretty good. Most likely going to be running 16's anyway.

Mocked up the steering rack location:

DSC00534 by jeremiah stewart, on Flickr

Looks like the inner heims are going to stick out just past the LCA pivot after the clevis is bolted on, so I may see some bump steer, but it looks like if I play my cards right, I can mount the LCA down one hole (UP in the pic) and then the inner tie rod heim would be in-line with the LCA and UCA pivots. So either way, we should have very minimal bump steer:

DSC00535 by jeremiah stewart, on Flickr

So I cut the original mounts out of the old subframe to save time, and welded them in the new subframe, and plated them a bit:

DSC00537 by jeremiah stewart, on Flickr

DSC00538 by jeremiah stewart, on Flickr

Mounted:

DSC00539 by jeremiah stewart, on Flickr

Fits like factory (the true test will be to see if the steering shaft fits right up like it did...)

DSC00541 by jeremiah stewart, on Flickr

View from wheel well:

DSC00543 by jeremiah stewart, on Flickr

And lastly, I just need to add these gussets:

Changes by jeremiah stewart, on Flickr

I made the shape the way it is to give clearance for the exhaust and the cylinder heads, but made way more than is necessary which would cause this thing to fold up the first time i landed a jump off-kilter. So anyways, that's the progress so far! My uniball's finally shipped out, so next weekend I may have some control arms mocked up! That's the exciting bit :D
 

Dezertpilot

Well-Known Member
Wow, nice start! not what I expected coming from Alaska, no offense lol. Keep it up I'm definitely interested in your project.
 

Jeremiah Stewart

Active Member
Wow, nice start! not what I expected coming from Alaska, no offense lol. Keep it up I'm definitely interested in your project.
Lol, definitely understandable! Thanks man.

You have all winter to get it fab'd and running
Yep, hopefully have the suspension and drivetrain done by May for the roadtrip. College kills a lot of fab time though.

This would be a good read for you. Good luck on the build!
Thoughts on and questions about V2R from the Subaru guy
Thanks, I read through that and have seen his build thread before, he actually emailed me today. Good person to get some info from. He's actually running a custom setup similar to what I was running before.

In other news:

Found some clearance issues with the transmission and oil pan:

DSC00548 by jeremiah stewart, on Flickr

You can see that the oil pan is going to contact the subframe before the engine is fully seated, and the transmission is hitting the backside just barely, but enough to hold everything up:

DSC00549 by jeremiah stewart, on Flickr

But those issues are easy to fix, and it looks like I have a lot of room for reinforcing in the area adjacent to the engine mount. Now i'm worried about how i'm going to route the exhaust though. Normally it would go under the subframe, to the back, but that would be very low with where the rack is. I'm going to look at mounting the engine and transmission a little higher to allow the headers to go above the subframe. But the limiting factor is the front CV angle which will kill droop travel. So I'm going to cut and sleeve an old CV axle to use as a mockup, and when I get the uniball joints in, I can figure that all out. If nothing else, I can route the exhaust some crazy ass way. Now I think it's time I bring in the big ole engine i'm actually gonna use, then I can see head and valve cover clearances also. I was just using the 4cyl above to check the engine mount location and transmission height because it's a light, empty block. Anyway, stay tuned.
 

pontoontodd

Well-Known Member
Remember the engine and trans will move around quite a bit on the mounts. Up to 1" from my experience, and that's with the group N engine mounts. You could possibly route the exhaust over the crossmember like you said, have you seen how the Subaru turbo cars route the exhaust?
 

Jeremiah Stewart

Active Member
Remember the engine and trans will move around quite a bit on the mounts. Up to 1" from my experience, and that's with the group N engine mounts. You could possibly route the exhaust over the crossmember like you said, have you seen how the Subaru turbo cars route the exhaust?
Yeah, that's where the idea came from to go over the subframe, but i'll just wait until I have the h6 in there to see.

Small Update: Uniball joints came in, so I tacked two of the cups into the knuckle brackets to just to look at it:

DSC00569 by jeremiah stewart, on Flickr

But the bad thing is that the none of the local steel places have the DOM I need, and Amazon doesn't offer it via Prime anymore -lol- so it's going to be about 2.5 weeks until I have the tubing, which is when I'll be in Wyoming for Christmas. Probably should've checked that out a long time ago lol. Time to work on the wire harnesses I guess.
 

Jeremiah Stewart

Active Member
Small Update:

I got the engine over to my garage this weekend and test fit the subframe on it to start beefing it up. But first, for those that don't know anything about the engine, it's an EG33 out of a 1992 Subaru SVX. I had it bored out to 98mm (raised displacement by about .6 liters) to fit the forged 11:1CR pistons from JE Pistons. The crank and rod bearings are by King. Also, I deleted the EGR system.





Subframe bolted under it:

DSC00620 by jeremiah stewart, on Flickr

Clearances look great, I have a lot of room for strengthening, keeping in mind engine movement of course:

DSC00621 by jeremiah stewart, on Flickr

DSC00622 by jeremiah stewart, on Flickr

Upside down:

DSC00623 by jeremiah stewart, on Flickr

This shows why I shaped the subframe the way I did, for the exhaust:

DSC00624 by jeremiah stewart, on Flickr

But I don't like how low the exhaust will be since I was shooting for about 4-5" of ground clearance to the subframe at full bump. The exhaust would have like an inch like this, so i'll be building some weird headers later on. Oh, and I've got 20ft of 1.25" DOM on the way which should be way more than enough to do all of the control arms, so once I get back from vacation I'll need to get my **** in gear.
 

baja_racer

Well-Known Member
Why not????? I would think your round trip from Fairbanks would be the biggest challenge.
 

Larry4

New Member
Hell yes! Always wanted to make a long traveled subaru...definitely going to have to pay attention to this.
 

Jeremiah Stewart

Active Member
So i started on control arms this last weekend, but just in the nick of time before I really made anything, I came across vsusp.com and decided I might as well plug in my numbers and see what I'm working with. It appeared to be limited to about 14inches of travel due to the camber going -20 degrees at full bump, and the upper arm being too short to get enough droop travel. So apparently my initial mock up was crap lol. But I've determined that if I move the upper heims inward 1.5" (can't go further due to valve cover position) and the lower mount down 2" and outward 1.5", I get what looks to be pretty good geometry:
Camber at full droop: -2*
Camber at ride height: -2*
Camber at full bump: -10*
KPI looks good at about 14*, giving a scrub radius of .58" with 32" tires. So I didn't do too bad on the knuckles, and if I can ever get the gearing for it, going to 33" or 35" tires, the scrub radius only improves.
Actual lateral tire scrub I'm unsure about, but from ride height to bump looks very minimal.
Only other things to account for are CV's and tie rod ends, the latter of which I have a lot of freedom with on the knuckle end, and the rack end can be adjusted to put the heims inline with the upper and lower mounts. As for the axles: I'm unsure right now about how much plunge the front axles will have, but I'm planning on running factory style inner joints which have about 2" of throw, and I'm sure it'll be much less than that. Plus the lateral location of the inner cv joint can be adjusted to put it inline with the upper and lower joints as well which might help. On the knuckle, I tried to get the joint inline with the uniballs so that there is no steering plunge.

So anyway, that seems like the best I can do to get 18" of travel without making custom knuckles which I'd love to do, but would be a lot more money. I'm glad I checked that out though; now to hack up the subframe and try again.
Here is the link to the updated suspension setup on VSusp: Click here then let me know if you think it's bad. For reference: I'm looking at +9" to -9" on the bump travel displays.
 

Jeremiah Stewart

Active Member
So after running through a bunch of different ways in my mind to relocate the lower mounts, I came to the conclusion that there was no good way to do it and not have it look like crap. Generally my philosophy is "don't get it right, get it running" but I'm really shooting for the opposite this time around. So after wasting time trying to change the subframe, I started on a better way.

I used some of my tube tabs to hold this piece of DOM in place, with a heim mounted to the tube with two other tabs:

DSC00872 by jeremiah stewart, on Flickr

This allowed me to get the lower joint moved down 2" and over 1.25" like i need (the subframe will not be permanently connected to the tubing like this):

DSC00869 by jeremiah stewart, on Flickr

Then I bent the tip up to mate to a bar I installed that welds to my mounts that bolt to the factory tow hook spot, which is one of the strongest areas in front of the subframe. This will later be where I build my bumper and skid plate off of:

DSC00874 by jeremiah stewart, on Flickr

DSC00876 by jeremiah stewart, on Flickr

DSC00875 by jeremiah stewart, on Flickr

You can see the piece of tubing sticking out of the tow hook mount here, which will be where I can send tubing to the front for the bumper:

DSC00873 by jeremiah stewart, on Flickr

So now I've got a much more solid frame for the control arms to mount to, and will be perfect for bolting skid plates to. I'll be adding some smaller tubing in X's for strength as well. The whole thing will extend to the tailshaft of the transmission and will be mounted to the body in 8 places: front tow hooks, subframe mount, rear factory control arm bushing mount (see below), and the transmission mount spots. So basically the whole front half of the car will be tied together. I haven't decided yet how i'll do the upper arm mounts. I may re drill the holes to move the heim inward 1.5" then just run 1"DOM from the bottom of those mounts to the lower piece of DOM. But I don't think it'll look great. Might ditch the subframe i made and replace with 1" DOM.

This is my mount that takes the place of factory rear control arm mount:

DSC00570 by jeremiah stewart, on Flickr


Also, I have calculated that my CV plunge might be 1.1". I don't think that's too bad?
 

pontoontodd

Well-Known Member
I vote for building the subframe out of 1.25" or 1.5" tubing and getting rid of those plates. If you mount it to all the things you listed it should be great, just have to connect to a-arm and engine mounts and protect the oil pan, right? I don't even think I'd bother going back to the trans mounts. Unless you were just planning on using those drop spacers in the background of the last picture for the trans, those look scary.
 

Jeremiah Stewart

Active Member
I vote for building the subframe out of 1.25" or 1.5" tubing and getting rid of those plates. If you mount it to all the things you listed it should be great, just have to connect to a-arm and engine mounts and protect the oil pan, right? I don't even think I'd bother going back to the trans mounts. Unless you were just planning on using those drop spacers in the background of the last picture for the trans, those look scary.
Those drop spacers used to be all throughout the car lol. They aren't as sketchy as you'd think, but I am getting rid of those pictured.

Alright I did a little bit this weekend after making the most of the warm weather. First I cut up the subframe tremendously and bent a tube:

DSC01001 by jeremiah stewart, on Flickr

There will be smaller tubing connecting the upper and lower together at some point.

Tacked on some tabs which i feel are pretty similar in setup to the upper A-arm mounts that guys put on the top of their frame rails. I think the biggest worry would be the tube twisting:

DSC01003 by jeremiah stewart, on Flickr

A little mockup to ensure full droop would be obtainable without the upper heims hitting the tube they are on:

DSC01002 by jeremiah stewart, on Flickr

I then began to bend the piece of tubing that will go around the back of the transmission so that i could get the mounts figured out, but apparently when they say "up to .095 DOM" can be bent with this bender, they weren't lying. I need to get a new bottle jack now:

DSC01010 by jeremiah stewart, on Flickr

The shaft is so bent that I can't retract it at all, so the tubing is stuck under tension. I left it for tomorrow.
The plan now is to either get rid of the remaining laser cut subframe pieces and replace with DOM, or box it in and reinforce it with a small amount of DOM since it's only holding the engine and rack. It'd just be a bitch to make it all out of DOM.

Random question: why does everyone make their control arms with the heim pointing straight out, and either having tubing notched into another like the dotted lines in the pic below, or a bent piece like i'd do, instead of mounting the heim like it is on the right side, where a straight piece would be stronger and of course the heim is designed to be just as strong in this position. I just want to hear your thoughts on it because it seems like it's for either just for looks or tab clearances:

DSC01012 by jeremiah stewart, on Flickr
 

pontoontodd

Well-Known Member
To answer one of your earlier questions, 1.1" of CV plunge in 18" of travel sounds good.

We have built a-arms like you're suggesting with the heim joints in line with the tubing. It is definitely easier and stronger. We built our tabs in line with the tubing as well (bolts not parallel to each other) and didn't even use those high clearance spacers. The biggest problem is that if the tubing is too stiff and/or the arms are too short, it can be a pain to flex them enough to bolt in if you adjust them too much.

Make sure to brace those arm mounts so the longitudinal tubes don't bend under lateral loads. Maybe the engine crossmember will be enough for that.
 

RedRide

Well-Known Member
Those drop spacers used to be all throughout the car lol. They aren't as sketchy as you'd think, but I am getting rid of those pictured.

Alright I did a little bit this weekend after making the most of the warm weather. First I cut up the subframe tremendously and bent a tube:

DSC01001 by jeremiah stewart, on Flickr

There will be smaller tubing connecting the upper and lower together at some point.

Tacked on some tabs which i feel are pretty similar in setup to the upper A-arm mounts that guys put on the top of their frame rails. I think the biggest worry would be the tube twisting:

DSC01003 by jeremiah stewart, on Flickr

A little mockup to ensure full droop would be obtainable without the upper heims hitting the tube they are on:

DSC01002 by jeremiah stewart, on Flickr

I then began to bend the piece of tubing that will go around the back of the transmission so that i could get the mounts figured out, but apparently when they say "up to .095 DOM" can be bent with this bender, they weren't lying. I need to get a new bottle jack now:

DSC01010 by jeremiah stewart, on Flickr

The shaft is so bent that I can't retract it at all, so the tubing is stuck under tension. I left it for tomorrow.
The plan now is to either get rid of the remaining laser cut subframe pieces and replace with DOM, or box it in and reinforce it with a small amount of DOM since it's only holding the engine and rack. It'd just be a bitch to make it all out of DOM.

Random question: why does everyone make their control arms with the heim pointing straight out, and either having tubing notched into another like the dotted lines in the pic below, or a bent piece like i'd do, instead of mounting the heim like it is on the right side, where a straight piece would be stronger and of course the heim is designed to be just as strong in this position. I just want to hear your thoughts on it because it seems like it's for either just for looks or tab clearances:

DSC01012 by jeremiah stewart, on Flickr
Since the heim on the right side is already angled within its housing it will have less range of motion compared to the one on the left. It may not be an issue, just depends on the cycle of your suspension.


Sent from the RDC Mobile App. Get it for your IOS device today
 
Top