John's EZ36R H6 818R Build

[Hobby Racer]

Ahh yes, the answer to most mechanical problems...buy more tools

[Hobby Racer]

Here is my tale of transmission upgrade failure. It began simple enough. I wanted a shorter 5th gear as the step from 4th to 5th was too large and the car has trouble building speed down the long straights. No problem, Subaru's are like Lego's, all the pieces from different cars seem to fit together. So I did my research and found that a 2009 Outback when equipped with an EJ253 and a manual has a 5th gear ratio that will suit my needs. Great, I order the gear set and begin tearing my transmission apart. Initially it looked like I could just slide both the drive and driven gear off their shafts and replace them without removing the transmission from the car or splitting the case apart. A fellow builder has even done it this way. There is one catch, one of the gears is pressed on and needs to be cut and cracked in half to get it off. This seemed difficult but doable so I proceeded.

While I was waiting for the parts and tools I needed to arrive I thought I would try a different approach. I cut two slots in the gear teeth perpendicular to the shaft to allow me to get a gear puller attached to the gear.

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Then I made a tools that fits over the tail shaft to give the puller something to push against (you can't push against the pinion shaft, you will ruin it).

IMG_20180830_165151.jpg IMG_20180830_173741.jpg

Everything seemed to be working well. But after many attempts that darn gear would not budge. So now it looks like I will have to pull the suspension, remove the transmission, split the case do this the hard/right way

[taco20]

Here is my tale of transmission upgrade failure. It began simple enough. I wanted a shorter 5th gear as the step from 4th to 5th was too large and the car has trouble building speed down the long straights. No problem, Subaru's are like Lego's, all the pieces from different cars seem to fit together. So I did my research and found that a 2009 Outback when equipped with an EJ253 and a manual has a 5th gear ratio that will suit my needs. Great, I order the gear set and begin tearing my transmission apart. Initially it looked like I could just slide both the drive and driven gear off their shafts and replace them without removing the transmission from the car or splitting the case apart. A fellow builder has even done it this way. There is one catch, one of the gears is pressed on and needs to be cut and cracked in half to get it off. This seemed difficult but doable so I proceeded.

While I was waiting for the parts and tools I needed to arrive I thought I would try a different approach. I cut two slots in the gear teeth perpendicular to the shaft to allow me to get a gear puller attached to the gear.

IMG_20180830_173203.jpg IMG_20180830_172205.jpg

Then I made a tools that fits over the tail shaft to give the puller something to push against (you can't push against the pinion shaft, you will ruin it).

IMG_20180830_165151.jpg IMG_20180830_173741.jpg

Everything seemed to be working well. But after many attempts that darn gear would not budge. So now it looks like I will have to pull the suspension, remove the transmission, split the case do this the hard/right way

You have already used the cutting wheel on the gear so it is trash. Just turn the wheel to an angle and cut the gear. Once you get it cut and cracked your puller should take the gear off easy. So much wasted time and energy to remove the trans when 5 minutes of cutting and your done. More chances of something going wrong taking the trans apart then the effort to finish cutting it off.

[Hobby Racer]

You have already used the cutting wheel on the gear so it is trash. Just turn the wheel to an angle and cut the gear. Once you get it cut and cracked your puller should take the gear off easy. So much wasted time and energy to remove the trans when 5 minutes of cutting and your done. More chances of something going wrong taking the trans apart then the effort to finish cutting it off.

Did you use a cut off wheel like the one I used or did you use a small Dremel tool? It seems that the larger wheel I was using would be difficult to get close enough to the back of the gear without cutting into the bearing race. How deep did you go? I assume you left a bit of material on the gear when you got close the the shaft.

Also, how did you crack the gear? Did you use a small pry bar and twist. I don't think it would be good to hit it with anything, might damage the bearing.

[taco20]

Did you use a cut off wheel like the one I used or did you use a small Dremel tool? It seems that the larger wheel I was using would be difficult to get close enough to the back of the gear without cutting into the bearing race. How deep did you go? I assume you left a bit of material on the gear when you got close the the shaft.

Also, how did you crack the gear? Did you use a small pry bar and twist. I don't think it would be good to hit it with anything, might damage the bearing.

I used a cutter just like that one. I just cut at an angle, I did nick a few spots but nothing to worry about.
Use whatever you have that will cut it. A smaller wheel might help.

I used a chisel and hammer to hit the cut area to crack it. Might need to make several cuts to weaken the gear.
Could use an air hammer if you have one. I didn’t worry about the bearing and have had no issues since.

[Hobby Racer]

So the gear is finally off. I ended up cutting it vertically so I could get a good angle on it with my die grinder. This way I was able to cut nearly all the way through without gouging any other parts.

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@taco20 How did you clean out all the grinding grit from the bearing behind the pressed on gear? The bearing is also pressed on so I can't simply remove it for cleaning.

[taco20]

So the gear is finally off. I ended up cutting it vertically so I could get a good angle on it with my die grinder. This way I was able to cut nearly all the way through without gouging any other parts.

IMG_20180902_175033.jpg IMG_20180902_182633.jpg

@taco20 How did you clean out all the grinding grit from the bearing behind the pressed on gear? The bearing is also pressed on so I can't simply remove it for cleaning.

Great job I knew you could do it. Wasn’t that bad and saved all the time of pulling the trans apart.

I just used an air gun to blow all the stuff off. You could use cleaner and then blow through the bearing also. Then maybe add some fluid in the case and then drain it out if you are worried about the metal.

Once you get the gear started good on the shaft the nut should pull it the rest of the way up.
Then put it back together and hit the track. I am excited to hear about your results.

[Hobby Racer]

Cleaned up the bearing and got the pressed on gear installed! Tomorrow I'll put everything back together.

new_5th.jpg

@taco20 - did you try torquing the 50mm nut to 194 ft-lb or did you just seat the gear with the impact gun and nut and call it good?

[taco20]

Cleaned up the bearing and got the pressed on gear installed! Tomorrow I'll put everything back together.

new_5th.jpg

@taco20 - did you try torquing the 50mm nut to 194 ft-lb or did you just seat the gear with the impact gun and nut and call it good?

I just set the nut with the impact gun. I think I went until the same spots to be staked lined up.

[Hobby Racer]

Hah, I did the same thing. Its all back together now and ready for my next event at Watkins Glen at the end of the month. I'm really looking forward to see how the shorter gearing does on the long straights.

[Hobby Racer]

Thought I would post an update to let you know how the new close ratio 5th is working out. In a word, fantastic! The car now pulls hard all the way down the long straights at Watkins Glen. No bog when shifting from 4th to 5th. The RPM's drop ~1200 which is perfect to stay in the power band when pushing through the air at 120+ mph.

Definitely worth the effort

[bbjones121]

Nice to hear that it paid off. Any idea what the Subaru part numbers were for the mod? Thanks, Paul

[Hobby Racer]

Nice to hear that it paid off. Any idea what the Subaru part numbers were for the mod? Thanks, Paul

Yup, Subaru part #32315AA390. I posted details back on this post. Shorter 5th gear needed in the 5MT!

The part is no longer being made and is in short supply so get it before inventory runs out!

[Mitch Wright]

John what final drive are you using (4:44) and rear tire size? With the 3:90 ratio I am close to 135 in 4th at 6800. (04 WRX trans)
So far I have rarely had to use 5th but if I make a trip to someplace like Atlanta it would be useful.

[Hobby Racer]

I have the tallest final drive ratio (3.70) it came in the 06 WRX for one year only. I am running a 255x35x18 tire in the rear (~24.5" tall). I need to shift into 5th at around 120 MPH. I shift at ~6k right now as I am still fine tuning the ECU and not sure how far I can push it on stock internals. At 6K rpm in 5th I could hit 143 MPH theoretically, if I could push that much wind

[Mitch Wright]

I went back and looked at my data, at 7000 I see 134mph. The difference is the extra 1000rpm with the .972 4th gear.

[Sgt.Gator]

At Spokane Raceway in my Legacy GT Wagon I was hitting 150 mph at the end of the main straight. I expect The Ridge, PIR with no chicane, and Pacific to be close to that too in the 818R, so a taller 5th gear is needed around here.

[turbomacncheese]

At Spokane Raceway in my Legacy GT Wagon I was hitting 150 mph at the end of the main straight. I expect The Ridge, PIR with no chicane, and Pacific to be close to that too in the 818R, so a taller 5th gear is needed around here.

You're going 150 in a wagon? Where did I go wrong with my life choices?

[Sgt.Gator]

You're going 150 in a wagon? Where did I go wrong with my life choices?

It was built by the Subaru Road Race Team in 2006 for the Grand Am Cup. After I got it I modded it to make it faster...:





There's a few "Race Wagons" now in the NW doing HPDE days. A couple are faster than this one because they have bigger turbos and no cage weight to slow them down.

[turbomacncheese]

just....nasty. And cool. Very cool.

[Hobby Racer]

Now that the car is in the garage for the winter I am starting on the modifications for next season. If you have been following my build you might remember I had some issues with wind buffeting my helmet at speeds over 120mph. I decided to lower my seats as much as possible with the hope of eliminate the buffeting. Side benefits include lowering the center of gravity a bit and being safer for me!

I was able to lower both seats 2 inches by removing my adjustable sliders and cutting out the X brace under the seats. I then welded in new H pattern supports that allow the seats to slide between them and rest on the floor pan.





Here is a picture from the driver's bottom side. You can't get any lower than that without hanging below the bottom of the car. With the seats so low there is no way to use the bolt in sub harness bracket that came with the car. Instead I used a 3/4" square tube welded between the the 1" H supports so I can wrap the sub belt around. It should be a better/more secure way to mount the sub belt. Some custom side brackets secure the seats to the new H supports and voila, lower seats. Only down side is that the seats are so low that I can not use the sliders anymore, there is no room to move either seat forward or backwards, but they are in excellent seating positions (at least for me ).

[C.Plavan]

Now that the car is in the garage for the winter I am starting on the modifications for next season. If you have been following my build you might remember I had some issues with wind buffeting my helmet at speeds over 120mph. I decided to lower my seats as much as possible with the hope of eliminate the buffeting. Side benefits include lowering the center of gravity a bit and being safer for me!

I was able to lower both seats 2 inches by removing my adjustable sliders and cutting out the X brace under the seats. I then welded in new H pattern supports that allow the seats to slide between them and rest on the floor pan.





Here is a picture from the driver's bottom side. You can't get any lower than that without hanging below the bottom of the car. With the seats so low there is no way to use the bolt in sub harness bracket that came with the car. Instead I used a 3/4" square tube welded between the the 1" H supports so I can wrap the sub belt around. It should be a better/more secure way to mount the sub belt. Some custom side brackets secure the seats to the new H supports and voila, lower seats. Only down side is that the seats are so low that I can not use the sliders anymore, there is no room to move either seat forward or backwards, but they are in excellent seating positions (at least for me ).

You will still need the aero for your helmet. I was just as low, even with the original seat pad removed and still had buffeting. Once I installed the aero devices on my helmet, all was good.

[Hobby Racer]

You will still need the aero for your helmet. I was just as low, even with the original seat pad removed and still had buffeting. Once I installed the aero devices on my helmet, all was good.

Did you use the Bell stick on pieces?

[C.Plavan]

Did you use the Bell stick on pieces?

This was on my Arai helmet. But yes, they were the stick on clear Lexan pieces.

[Hobby Racer]

So I've been pondering how to cut the airfoil I have to fit around the upper roll bar. I ended up soliciting advice from fellow builders and came up with a great way to get it done. You read about it over in this thread.

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Now I need to start working on securing it to the roll bar. Once secured, I will wrap the foil in the same carbon fiber vinyl wrap I used on the interior, both for looks and to seal up the cut along the trailing edge.

The one thing I have not decided yet is whether or not to close off the ends. I was thinking of putting on small end plates like I have on my rear wing, what are your thoughts?

[Hobby Racer]

Trying to wrap the air foil around the curved end parts of the roll bar by pie cutting end caps and then joining them to the straight center section. Once everything is covered by vinyl wrap it might look good. I'm not sure how much value that extra 6" on each end is worth compared to the extra effort though.

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[Hobby Racer]

Mounted the air foil on the top roll bar today. I decided to go with wing end plates. I used 1/8" polycarbonate with a slit on the bottom so I can twist it to fit over the roll bar tubing.



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I have to think of a way to attach the end plates to the wing / bar.

[Jetfuel]

Racer, will "L" shape brackets inside the airfoil, upper and lowers and then attached to the end cover with countersunk rivets work for you??

[Hobby Racer]

Racer, will "L" shape brackets inside the airfoil, upper and lowers and then attached to the end cover with countersunk rivets work for you??

They would, I just need to come up with a sturdy method of joining the metal brackets to the ABS plastic. Its too thin near the trailing edge to use rivets (can't counter sink them).

Maybe some type of epoxy.

[Jetfuel]

Sure it will work, by the pics I can tell there's enough meat to countersink the foil
If you need some tiny rivets in length or diameter let me know and I will mail you an envelope full.
How thick is the foil skin?
The rivet hole will be drilled with a#40 bit and 100* countersink.....tiny...

Jetfuel

[Hobby Racer]

I got the air foil end plates mounted today. I ended up making small tabs and welded them to the roll bar. I installed #10-32 rivet nuts in the tabs to allow easy install and removal of the end plates should I need to remove / replace the air foil.

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Now I just have to paint the tabs, end plates, and vinyl wrap the air foil.

[Hobby Racer]

I finally got the carbon fiber vinyl wrap today and applied it to the air foil surface. It came out very nice. A few small wrinkles on the underside near where the ends come together. Man its hard to work with vinyl wrap upside down, on a curved surface, by yourself



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[Mitch Wright]

Looks really nice, great job.

[AZPete]

I agree, it's beautiful!

[Hobby Racer]

If anyone is interested in adding a fairing, I have an additional piece I will not be using. Since I have the jig already, I can make the lengthwise cut for you if you want.

PM me if your interested.

[biknman]

PM sent

[Frank818]

Very nice CF wrap!!! Looks like a real CF wing.

[Hobby Racer]

I am finally getting some time to work on a new header design that exits out the back like normal cars.

This time I will be using 304 stainless steel instead of mild steel. Figured I need to learn how to use that TIG welder I bought. After cutting up a few bends I found it difficult to mock up the header tubes in the confined space. Add to that the fact that you can't use magnets to temporarily affix the tubes to anything and it was clear I needed another, easier way to design this set of headers.

Free Onshape 3D CAD to the rescue again! I took the critical dimensions from the frame, header flange, motor mounts, suspension pickup points and the general head configuration and modeled it up in CAD. This let me play with different tube routing options easily and ensure nothing was interfering.

So here is a screen shot of the initial design looking from the rear frame section. Once I'm happy with it I will add in the collectors and pipes out the back.

It's really cool spinning it around in 3D to see it from all angles. Maybe I'll post a video like I did last time.

Thanks to DSR-3 for posting his header pics; I took my design inspiration from him.

[Zach34]

Now that's a cool project! A difficult one, too. How are you going to make the flanges?

I've never done headers, but I did do sidepipes for my roadster years ago (out of much larger stainless tubing). Leave yourself as much room for error as you can in your design. The tube bends you will use will inevitably not be 100% dimensionally perfect and the welds will distort things A LOT. I mean, really really a lot. Stainless grows and contracts with weld heat much more than steel or aluminum.

What kind of back-purging setup are you planning on?

I'd love to see more angles and pictures.

[Hobby Racer]

Now that's a cool project! A difficult one, too. How are you going to make the flanges?

I've never done headers, but I did do sidepipes for my roadster years ago (out of much larger stainless tubing). Leave yourself as much room for error as you can in your design. The tube bends you will use will inevitably not be 100% dimensionally perfect and the welds will distort things A LOT. I mean, really really a lot. Stainless grows and contracts with weld heat much more than steel or aluminum.

I ordered the flanges online. racemufflers.com laser cuts them from 3/8" thick 304 stainless. I also ordered mandrel bent 16 gauge 180 degree tube pieces and collectors from cone engineering. The bends are really accurate as they are done on a CNC bending machine. The inaccuracies come when I start cutting them . I know that stainless distorts a lot with heat, but I have to learn some time. The CAD mock up allows me to find the configuration with the most room around the tubes without doing the trial and error thing, which is real expensive when using stainless tubing. The mild steel version I did previously was a good practice run working with thin wall tubing. I plan on welding many test tubes prior to lighting up on the final pieces. Hopefully I can get the hang of the stainless expansion and get good results.

What kind of back-purging setup are you planning on?

As you know, normally you need to back purge with argon, but that requires either a dual outlet regulator setup on your argon tank or a separate argon tank and regulator, neither of which I have. I looked around for other / less expensive solutions and found a product called SolarFlux Type B. You apply it to the back side of the weld joint and it forms a hard glass like protective layer when heat is applied, shielding the back side from oxygen contamination. It works a lot like the flux that you see covering stick welding rods, it just works on the back side of the weld instead of the front side. It is very cost effective and easier to use than setting up argon back purging on all those joints.

I'd love to see more angles and pictures.

I'll post up a video of me rotating the CAD assembly when I get a chance so you can see it from all angles. If there are any specific angles / section you would like to see, I can zoom in and post pics of those specifically.