'86 Subaru GL Coupe Autocross/Track Build

[ckgeorge]

Hey Everyone,

I haven't posted on here for years and thought I would share my build progress and findings. The end goal of this build is to have a fun autocross machine and weekend canyon carver.

To start off this car was given to me as a grad present from my grandmother 10 years ago and I daily drove it for many years before tinkering with it. The car is an '86 fwd coupe with a 5 speed.

This is essentially what the car looked like when I received it at only 80,000 kms. Currently the car sits at 275,000 kms.

For the past 4ish years I have been autocrossing the car on and off while making changes to improve the handling and grip. I feel this chassis does have potential and certainly has light weight(2100lbs currently) and a low center of gravity going for it. I have been asked why not jump to a newer platform such as a BRZ/FRS for autocross but the challenge of making this a competitive car seems to keep me hooked and will be far more satisfying in the end. Up until now I have made several undocumented changes to the car such as a Weber carb swap with a wideband o2 for tuning, 6 lug conversion, 15x8 -19 wheels with 225/45r15 BFG Rival S tires, Ground Control coilover sleeves with stock struts up front and KYB AGX NB Miata rears, 2002 WRX seats, slotted rotors with semi metallic pads, Momo Prototipo steering wheel, RX body kit and Datsun 240z fender flares. 

The car has been like this for the past couple of years but it is time to make some changes. 

Addco 7/8" rear sway bar added to reduce understeer and increase lift-off oversteer for rotation.

Fabing up seat rails with original brackets to fit bucket seat.

Omp First R bucket seat fitted to keep me in place. 

I have always struggled to find a decent suspension setup while maintaining stock hubs and I have finally come up with the answer. The BMW e30 chassis has the same diameter front strut tube at 45mm. This allows you to fit a BC Racing coilover weld-in kit designed for an e30 on the front along with GV Impreza coilovers for the rear. The folks over at BC Racing allowed me to place an order with the BMW fronts and the Subaru rears. If anyone else decides to go this route the part numbers are I-04-BR for the front and F-08-BR for the rear *You will have to use Impreza camber plates up front as the BMW bolt pattern is different up top and the stock shock mounts out back*. Since this car is no longer a daily driver I decided on 10k springs up front and 12k springs out back. 

All you have to do is chop off the factory strut, slide it into the coilover base and weld it in. I decided to chop an additional inch off the coilover side to get the desired ride height.

Here is the finished product with GC Impreza camber plates up top and helper springs added to get the desired ride height.

As you can see this setup allows you to gain much needed camber/castor adjustment as well as dampening/rebound adjustment.

This is how the car currently sits with the new BC Racing suspension in.

Next on the list is 10" wide slicks on a 13x10 6 lug wheel. I am currently having Diamond Racing wheels built to spec and will post an update when they arrive.

Now that the suspension is in order and a racing slick setup is on the way chassis flex is going to have to be addressed. I picked up this roll bar kit locally off craigslist for an s10 pickup and it seems to be a pretty close fit. I have begun the planning process and will post more updates as the progress continues.

Thanks for reading and feel free to ask any questions regarding the build. Cheers!

Edited January 22, 2020 by ckgeorge

[carfreak85]

I love that there is another member still trying to go fast in a vintage Subaru!  We parked beside one another at the Old School Reunion several years ago, I have the maroon EJ-swapped 3-door, had gold outback wheels at that show.  I would be interested to see how those BCs hold up on track, I pulled the ones that came on my 3-door and replaced them with Ohlins off an 05-09 Legacy.

[charles_thomas]

Thanks for the research on the front suspension. Good option for when I EZ my 86,(Gotta finish the 77 first, haha). Keep updating about the cage, it is always nice to see other people finding and using other options.

[ckgeorge]

2 hours ago, carfreak85 said:

I love that there is another member still trying to go fast in a vintage Subaru!  We parked beside one another at the Old School Reunion several years ago, I have the maroon EJ-swapped 3-door, had gold outback wheels at that show.  I would be interested to see how those BCs hold up on track, I pulled the ones that came on my 3-door and replaced them with Ohlins off an 05-09 Legacy.

Hey man, I love what you've done with your coupe... I actually just found a photo of our cars that I took at that meet and set it as my cover photo. After a quick drive on the street the car feels much more responsive with the BC's and surprisingly not too harsh. The first autocross is in March so we'll see how they hold up there. How do you like the Ohlins in your coupe?

45 minutes ago, charles_thomas said:

Thanks for the research on the front suspension. Good option for when I EZ my 86,(Gotta finish the 77 first, haha). Keep updating about the cage, it is always nice to see other people finding and using other options.

My pleasure! The car wouldn't be where it is today without the research people have done on this forum so it is nice to be able to return the favor for once. I hear yah, I'm always bouncing back and forth between this and my '85 c10... it's hard to "finish" a project vehicle when you have more than one. I look forward to seeing what you do once your '77 is complete. 

[carfreak85]

2 hours ago, ckgeorge said:

Hey man, I love what you've done with your coupe... I actually just found a photo of our cars that I took at that meet and set it as my cover photo. After a quick drive on the street the car feels much more responsive with the BC's and surprisingly not too harsh. The first autocross is in March so we'll see how they hold up there. How do you like the Ohlins in your coupe?

Thanks!  Like any old car it's an ongoing project and I've got some pretty major updates to make in the next few months (once I'm done updating my shop).  Your 3-door is so much cleaner than mine it's almost not fair!

I think I blew the center diff last summer so the car has basically been sitting since June 2019.  While I was diagnosing the drivetrain I pulled the BCs and installed the Ohlins, but had to have a few parts custom machined to get the fitment I wanted with the 05-09 Legacy coilovers.  The Ohlins don't have adjustable lower mounts like the BCs did, so I won't be able to go as low, but my plan for the car has always been about outright speed so pavement-scraping ride height was never on the table.

You can keep up to date on my progress and take a look at the custom coilover parts on my IG @templeoffuji

Edited January 22, 2020 by carfreak85

[ckgeorge]

On 1/22/2020 at 1:35 PM, carfreak85 said:

Thanks!  Like any old car it's an ongoing project and I've got some pretty major updates to make in the next few months (once I'm done updating my shop).  Your 3-door is so much cleaner than mine it's almost not fair!

I think I blew the center diff last summer so the car has basically been sitting since June 2019.  While I was diagnosing the drivetrain I pulled the BCs and installed the Ohlins, but had to have a few parts custom machined to get the fitment I wanted with the 05-09 Legacy coilovers.  The Ohlins don't have adjustable lower mounts like the BCs did, so I won't be able to go as low, but my plan for the car has always been about outright speed so pavement-scraping ride height was never on the table.

You can keep up to date on my progress and take a look at the custom coilover parts on my IG @templeoffuji

Hey man, sorry for the super late reply. Looking forward to seeing where you take your build... I bet those Ohlins are gonna ride great! I'm considering making my way down for the Old School Reunion again this year and would like to meet up if you're attending and check out the coupe if you get er fixed up. Cheers!

[ckgeorge]

After tinkering away for a few more weeks I figured Id post an update.  

I decided to swap the chassis bushings with poly Superpro bushes as it wouldn't make much sense running slicks with 34 year old bushings. The only bushings I was unable to find in the aftermarket were the transmission cross-member and the rear sub-frame bushings.

Here are the part numbers from the ebay seller. 

I don't own a press but this tool was a life saver.

 

It might be from launching on sticky tires at autocross but I seem to go through a CV axle a year and find the Cardone axles to be junk. I found this "heavy duty" set on Rock Auto from TrakMotive so we'll see how they fare this year. 

A rotor freshen up and new CV's, bushings, and semi metallic pads in... along with a power rack with lines looped as a manual conversion. 

While I was at it I decided to replace the engine and transmission mounts. 

In the past I've had problems with the exhaust heating up the steering rack boots causing them to crack so I decided to pick up some DEI header wrap to mitigate the problem. As you can see I had some leaky rocker cover gaskets that left their mark... rust prevention anyone? 

I've had great success using Remflex header gaskets on my small block chevy and wanted to give them a try on the GL manifold... this part number fits perfectly. 

The custom Diamond racing steelies showed up so I had the slicks mounted. The specs are 13x10 5.5" backspacing and they seem to just clear everything inboard with no rubbing.

I think the setup looks pretty tough and can't wait to take them for a spin on course... til next time!

[Crazyeights]

Very Nice! Thank you for the great thread. Can't wait to see what you do next

[KiwiGL]

This looks awesome. I'm very tempted to set up my wagon like this but with some RE003s as a daily.

[ckgeorge]

On 2/12/2020 at 11:33 PM, Crazyeights said:

Very Nice! Thank you for the great thread. Can't wait to see what you do next

My pleasure... I will be sure to post an update when I make some progress on the roll bar. Cheers!

5 hours ago, KiwiGL said:

This looks awesome. I'm very tempted to set up my wagon like this but with some RE003s as a daily.

Thank you! It sure is a blast through the twisties and handles like a go kart... I would definitely recommend.

[Crawlerdan]

I’m really digging this lil car. Are you planning an awd swap?

[ckgeorge]

18 hours ago, Crawlerdan said:

I’m really digging this lil car. Are you planning an awd swap?

Thanks man, I'm actually planning to go rear wheel drive. Still deciding what engine I'd like to go with but strongly considering a carbed 13b rotary and trans setup. With some porting I'd like to be in the 150-200 whp range... nothing crazy but plenty for what I do with the car. Cheers!

[idosubaru]

You use the wide band O2 just for measuring and then later adjusting the carb mixture?

If carfreaks center diff failed and is locked, causing torque bind, it could be used for a RWD conversion, LOL.

[ckgeorge]

7 minutes ago, idosubaru said:

You use the wide band O2 just for measuring and then later adjusting the carb mixture?

If carfreaks center diff failed and is locked, causing torque bind, it could be used for a RWD conversion, LOL.

Sure do! It feels like cheating but makes tuning super easy. It's amazing to see just how much the mixtures change driving at sea level versus up in the mountains. Haha, true that regarding the center diff... I do want to go to a platform that came RWD from the factory so I can swap the engine and trans then just get a driveshaft made to connect to 4wd rear running gear. That whole project wont begin til next winter though as I'd just like to get the chassis sorted and have some fun this season.

[Crawlerdan]

I’m headed back to your neck of the woods soon ( I’m from nw Montana)

hit me up if you need an extra set of hands! I love projects like this

[ckgeorge]

On 2/22/2020 at 3:21 PM, Crawlerdan said:

I’m headed back to your neck of the woods soon ( I’m from nw Montana)

hit me up if you need an extra set of hands! I love projects like this

Thanks man, I will keep that in mind. Cheers!

[carfreak85]

On ‎2‎/‎22‎/‎2020 at 1:19 PM, ckgeorge said:

Thanks man, I'm actually planning to go rear wheel drive. Still deciding what engine I'd like to go with but strongly considering a carbed 13b rotary and trans setup. With some porting I'd like to be in the 150-200 whp range... nothing crazy but plenty for what I do with the car. Cheers!

Might want to consider a rear suspension conversion as well, in that case.  Our rear wheel bearings really don't like RWD.  I killed the rear bearings in my RWD EA81T wagon with just 100 hp...

On ‎2‎/‎22‎/‎2020 at 2:11 PM, idosubaru said:

You use the wide band O2 just for measuring and then later adjusting the carb mixture?

If carfreaks center diff failed and is locked, causing torque bind, it could be used for a RWD conversion, LOL.

I've got an STI-catalog 20kg center diff to replace the blown one in the RX-RA's V3 JDM WRX transmission, she will live again!

[ckgeorge]

58 minutes ago, carfreak85 said:

Might want to consider a rear suspension conversion as well, in that case.  Our rear wheel bearings really don't like RWD.  I killed the rear bearings in my RWD EA81T wagon with just 100 hp...

I've got an STI-catalog 20kg center diff to replace the blown one in the RX-RA's V3 JDM WRX transmission, she will live again!

Thanks for the heads up! I usually go through a set of wheel bearings in the front every year or two... I'm sure they weren't designed for the track width and lateral forces they are experiencing. I suppose as with most things on this car I will have to get creative with the rear setup. 

Awesome to hear you will have the coupe back on the road again soon!

[carfreak85]

Yeah, caged ball bearings don't especially enjoy side loads, much less the forces you're putting on them with 10 -in. wide slicks!  The EJs moved to a pair of tapered roller bearing that tend to do MUCH better with side loads.  If you move up to the 5-lug conversion no only do you get the nicer bearings, but the brake options and steering knuckle geometry both improve over the EA parts.

I was hoping to have my coupe rolled into the garage to start replacing that center diff (Track season is just around the corner!) but the RX in the garage decided to throw a couple new codes after I replaced the knock sensor, so the RX-RA repairs are delayed again...

[ckgeorge]

5 hours ago, carfreak85 said:

Yeah, caged ball bearings don't especially enjoy side loads, much less the forces you're putting on them with 10 -in. wide slicks!  The EJs moved to a pair of tapered roller bearing that tend to do MUCH better with side loads.  If you move up to the 5-lug conversion no only do you get the nicer bearings, but the brake options and steering knuckle geometry both improve over the EA parts.

I was hoping to have my coupe rolled into the garage to start replacing that center diff (Track season is just around the corner!) but the RX in the garage decided to throw a couple new codes after I replaced the knock sensor, so the RX-RA repairs are delayed again...

Okay, I will have to look into that for sure. I'm sticking to fwd this year and will probably look into something like that next winter. And I hear yah, owning multiple older vehicles myself there is always something going wrong with at least one of them!

[573417h]

Any updates to this build?