912 + Subaru STi motor +WRX trans project, conversion Options

[RonW]

Hey guys, I know its not a 914 but hoping to share info and request help on my project since the 912 board is fairly devoid of these conversions.

car is a '68 912 and last year I installed a 2005 STi Spec-C JDM motor and running the stock ecu and stripped down harness. I used an adapter plate and adapter flywheel and stage 2 Sach pp/clutch.

for exhaust i used a pair of 2 into 1 header stubs that outback makes and brought each bank up to a turbo flange, then exhausted it to Coast Fabrication muffler. used twin turbosmart EWG with a locked out IWG.

on the inlet side, ran it thru the stock MAF thru the turbo to a water/air intercooler and a turbosmart BOV

up front im running a ron davis radiator and a fuel safe fuel cell with the mostly bent tubing run under the car just inboard of the pinch seam, similar to how the factory ran the oil cooler lines and short sections of 1.25" hose connecting.

with the stock ecu ive have the stock tach sent in to North Hollywood Speedo to modify to take the ecu tach signal and redo the face to 8k redline

the rest of the car is set up with 82SC front end and fresh Bilsteins and elephant polybronze bushes all around and lowered ride height.


So that was phase one and been running her for the last 4 months or so. drove from SF area to Santa cruz and if i kept the revs at 3k then got 30 mpg but was only doing like 60 mph. if i increased to 75mph then 3400rpm and 24mpg. so i decided to go down this subaru path yet further and scored and 2010 WRX 5 speed that only had 20k miles on it. I am swapping in a reveres ring and pinion and will utilize 930 adapter flanges.

Problem: one of many come with this swap for a 901 bodied car.
1) 930 axle wont bolt to the short wheel base trailing arms - solution, take later model LWB and have them modified to SWB dimensions by a shop that has a jig for this very mod. this will then allow for clearance and use with those larger stub axle flanges. plus the bonus of bigger brake options - this should be straight forward

2) transaxle mount - modify stock or subaru mount to bolt to the stock location - again wont know til im there

3) shift rod - hoping to mate the stock shift rod and retain the wevo shifter set up but wont know until i get there. i wish i could cable shift like many here have with an MR2 but no room.

THIS IS WHERE I NEED YOUR COLLECTIVE HELP
4) hydraulic slave for clutch - stock is obviously a cable actuated system and i really do not want to try to graft in a Tilton pedal cluster. any recommendations of making this work? ie cable actuation to some type of master to a slave???


any advise would be much appreciated and i hope i'm ok posting my 912 project here.

[RonW]

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[d914]

Problem: one of many come with this swap for a 901 bodied car.
1) 930 axle wont bolt to the short wheel base trailing arms - solution, take later model LWB and have them modified to SWB dimensions by a shop that has a jig for this very mod. this will then allow for clearance and use with those larger stub axle flanges. plus the bonus of bigger brake options - this should be straight forward

Or use the inboard suby cv and have the porsche axle cut to length and re-spline??2) transaxle mount - modify stock or subaru mount to bolt to the stock location - again wont know til im there

3) shift rod - hoping to mate the stock shift rod and retain the wevo shifter set up but wont know until i get there. i wish i could cable shift like many here have with an MR2 but no room.

If you see pics of the tranny when used on vw or buggy, you can cut down the case, and make it look like 915ish.. maybe a 911 shifter????

THIS IS WHERE I NEED YOUR COLLECTIVE HELP
4) hydraulic slave for clutch - stock is obviously a cable actuated system and i really do not want to try to graft in a Tilton pedal cluster. any recommendations of making this work? ie cable actuation to some type of master to a slave???

The master slave is not that big a deal on the 914,, weld a tab to the crossmember, bolt to tab... Im sure we can find some pics...pretty much same frontend as ours.

[a914622]

I like your idea of a cable actuated master for the clutch. I just picked up a suby trany for the svx thats going in the 914. I am going to use all suby hydraulics, master/slave. I found on the vanagons and jeeps when you start changing one end it effects the other.

So you are useing the pull clutch? right?

Im going to make a mounting bracket that holds the master and the end of the cable. attach the cable to an arm that pushes the master and in turn pushes the cluch in. All back at the tranny, no cutting or welding to the body.

oh ya
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jcl

[DBCooper]

I have the Tilton pedals in mine, using short M/C's for both clutch and brake, but damned if I can remember which right now. It'll come to me. There's more information in my build thread, link in my sig. Clutch works great, but the larger brake size leaves me with way more pedal pressure than stock.

Edit: I remember now, Howe M/C's, the shortest out there, so they'd fit in the footwell without cutting any metal and still provide sufficient (max) leg room. I did use a nicely bent banjo fitting on the slave cylinder for clearance. It's been a while though, and don't remember right now where it came from, but again, it's mentioned in my build thread.

[jpnovak]

Ron, I used a Honda application for my MC. drilled a secondary hole next to the brake booster, built a 90 deg tab and welded it to the floor in the steering tunnel. Let me check the notes and see what the part number is. I had to make a connection rod that went from the stock cable trunion to the MC operating "pin".

The biggest problem I see with this conversion is the location of the slave cylinder. It is top center on the transmission. I do not think it will clear the center tunnel or more importantly the rear suspension cross member/shock tower. It sticks up quite high. Since I cut the rear truck out of the 914 there are no clearance issues.

Is the 901 showing problems yet

[a914622]

The biggest problem I see with this conversion is the location of the slave cylinder. It is top center on the transmission. I do not think it will clear the center tunnel or more importantly the rear suspension cross member/shock tower. It sticks up quite high. Since I cut the rear truck out of the 914 there are no clearance issues.

Is the 901 showing problems yet

Actually the wrx slave cylinder sits lower and behind the clutch rod. It is the same pull to release as the 915 porsche boxes. The rest of the sbarus use a push style clutch and the slave mounts in front of the arm.

jcl

[RonW]

d914: yep, ive seen the video of how the Todd at subaru gears cuts down the case to make it essentially like a 915 so it turns out like this

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ill look into the sub cv to 930 mating but may end up being close to same price to cut down the 930 axle/respline and get a cv for the tranny. good option though thanks

i'll look for some photos that you are referencing w regard to installing a hydraulic clutch.


DBCooper:
LOVE your build! it was a frequent reference during planning and build. Good to know about the tilton and the howe masters. does the pedal positioning feel the same as the stock pedals ie L to R offset?


Jamie:
hey man, miss talking to you. when you gonna be in SJ again, we should try to hook up again. you planning on the treffin this year? ive got an empty seat if you want.
-Interesting your Honda MC set up, do you have pics? i'll try to search for your build thread so i can visualize it.
-The stock slave is bolted to the top and is a push style but i was thinking of dumping that slave for a Wilwood and mount it as a pull from the other direction like DBCooper
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-I've been somewhat gentle to the 901 in first. It's never leaked since I've resealed it at the time in put in the 914 3/4/5th gears but no there is a very slight leak at the intermediate plate so it must be feeling it on WOT pulls in 2nd when she is pulling like a freight train.


a914622:
the 2010 wrx is a ty758 and the clutch slave is mounted to the top so its facing the transmission bell housing to "Push"
here is a shot of the tranny but i dont think you can see where it mounts. i'll try to get a better pic later
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thanks again to everyone for the assistance.

btw, i did forgot to give a big thanks to Britain Smith for all his advise on the install and getting the electrical up and running with the stock ecu/harness. (IMG:style_emoticons/default/piratenanner.gif) (IMG:style_emoticons/default/pray.gif)

[Britain Smith]

Looking great Ron!

[jpnovak]

I did not realize that the transmissions were so different. I am using a late 90s Impreza/GC8 (forrester) transmission. the slave cylinder is on the top next to the starter.

My slave is a push style. I have some pictures of the bracket I made. I will get them up later tonight.

Ron, I was in SJ two weeks ago. I would have called but I was there less than 24 hours and there was no time for any fun. (IMG:style_emoticons/default/sad.gif)

[RonW]

no worries jamie, im sure we'll hook up again soon

here is a video identifying some of the differences between the pull vs push type release. in 2008-2010, subaru switch the wrx 5 speed in a few ways.

http://www.youtube.com/watch?feature=playe...p;v=gJ_96JZhJmI

1) from a pull type to a push like the 2nd tranny in the video
2) the output axle in the wrx in the video ty754 has the axle attached to the diff in side but in the 2008 to the 2010 the small stub axle is part of the CV assembly so it just slides in. to use the subarugears adapter flanges, the small stub axle from the earlier needs to be installed into the diff.
3) the speed sensor was moved off of the transmission and is on the hub at the wheel with a trigger wheel/sensor located there. so i'll just run the same set up i am running now with a trigger wheel bolted to the inboard CV along with the vr sensor

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[RonW]

here is the pedal cluster that DBCooper is using that I'm considering. looks like i wouldnt have to do any cutting in my 912, just do the same pedal board and move it far to right so brake and gas are in the same relative position

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here is britains
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[Britain Smith]

Is that the same speed sensor I am using Ron? They work great.

The pedal assembly works good as well. I use tilton master cylinders for the brakes and a Howe Racing one for the clutch.

-Britain

[dfelz]

Ron, car looks fantastic!

About your 5-gauge pod, what did you use to hold the A/F ratio gauge in there? I have a 911 dash for my 914 and want to do exactly what you did instead of having the clock there.

Thanks

[RonW]

Is that the same speed sensor I am using Ron? They work great.

The pedal assembly works good as well. I use tilton master cylinders for the brakes and a Howe Racing one for the clutch.

-Britain

Yep same sensor!
I need to get in pedal box area and make take some measurements and see how it will fit. I know it will be different and take some getting use to im sure.

Ron, car looks fantastic!

About your 5-gauge pod, what did you use to hold the A/F ratio gauge in there? I have a 911 dash for my 914 and want to do exactly what you did instead of having the clock there.

Thanks

thanks for the kind words. i gutted the non functioning clock. I gently pried from the back of the black bezel ring and it came off. removed the glass, removed the guts then used a scrap piece of black textured ABS plastic to fit within the bezel and mounted the ARF gauge to it. ran the wires thru the back of the clock body. reinstalled the bezel to the clock body and recrimped the bezel in place. then the clock body just mounted as it did before. cost = $0.00 (IMG:style_emoticons/default/welder.gif)

[Kraftwerk]

Sorry, I can't help but I will say your car looks like lot of fun to drive and very well put together.

[RonW]

first off, thanks for all the positive comments, must appreciated but only way this car ever came to being was due to helps from guys like you sharing info!

first day ax here in pca-ggr for the season and had a blast. fast course but got to stay in second all the way around (8k rev limiter)! i mounted the WAIC radiator in back and was hoping it would keep the IAT's down. I used the Tactrix connector to the OBDII port and was able to datalog on the micro SD card. Even after getting a re run at the end of the day so basically hot lapped it, the temps were mostly in the mid 70's on only breached 80 for a short duration and ironically, never under high rpms (ie 6-8k) but more around 3-4k and quickly dropped back to the 70's.

trannys weaping at the intermediate case so i'll have to get moving on the suby tranny sooner than later.

anyway, here was my last run of the day.

http://www.youtube.com/watch?feature=playe...p;v=OsZ4F1cwgeA



got a chance to hang with Britain and is partner in crime Alan the night before and check out his rig, fucking sweet! and the aero is just as impressive. Brit offered me a right but it would have been Gangnum style sitting on the rear deck lid holding the B pillar of he cage, ya, no thanks <insert gangnam emotocon here> watching them drive that car was equally impressive! way to put down some times guys. great seeing you again and hope to see you at a future event soon.

[RonW]

Time to start on the TY758 WRX tranny. Here are a few shots taken during the tear down, pretty simple, lots of case through bolts, only 4 internal bolts, a few love taps and she opened right up :wink: . Btw, the new LSD pictured is a factory JDM unit and will receive the Subarugears reverse ring and pinion and outside will get a 930 to Subaru flange.

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Finished up trimming the new nose cone and plugging it up. Ready for assembly. I wanted to compare my spare 4 speed 901 before I gave up on the 901. It nearly identical!!! Overall, Bell hosing face to tip of shift rod housing 73.5 vs 74.0 cm (Porsche to Subaru respectively), bell housing face to flange center 16.5 vs 20 cm (Porsche to Subaru respectively). My only fear is the actual position on the shift rod at 10 o’clock vs 6 but I think I'll have it enter above the shift tunnel and have the shift rod above the tunnel as well and make raised platform for the 915/wevo shift tower sit on.

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got a chance to start pulling the bearing off the open diff and install them on the LSD keep the matched bearing/race together.
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then pull the gears and bearings off the original pinion and install it on the new subarugears pinion
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bolted the pinion assembly to the case and used the pinion depth tool and with the original 2 shims, nearly perfect. i'll have to get some gear marking compound to check the pattern this week and install the seals/gaskets
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[DBCooper]

Wow, great work, beautiful car, super fun project. One of my all-time favorite 911 colors, too. Light weight and big horsepower are fun, aren't they? Best possible combination, and any way you can get it it's good.

[RonW]

thank your for the kind words. it is very fun but always cautions with first gear fearing the worst. hopefully i'll be able to launch and leave a block long strip of rubber (IMG:style_emoticons/default/biggrin.gif) neighbors are gonna love that lol.