instigator wrote:
here my take on this. first off it is a rev. cut ring and pinion. thats cool. you have to do cut a releaf in the case to clear. no big deal. heres my point. you do not have to have the rev. cut to run them backwards. it the same. so why not try it with one you have lying around before you spend all that money. i know you would be running on the coast side of the gear. i have done that with vw trans when i was running corvairs and they lasted for a long time. so somebody try it. ill water jet the mounts with your help.
Hey Guys, this is Todd here, the owner of
http://www.subarugears.com Steve sent me an email enquiring about the boxes so I thought I'd get on here and see what sort of rigs you guys have and what sort of trails you do.
First off, I need to correct the post quoted above. You cannot just 'flip' the ring gear and pinion. If it was that easy everyone would have done it years ago. The design of the Subie trans is an 'offset hypoid' differential which is more compact and stronger than your regular bevel ring and pinion. However, this means that when you flip it, the gears no longer mesh because their angles are all wrong. This is why I had to go and get my own forgings done and cut the gears on a different angle, so that they mesh again once they are flipped. I went through all the other options, like running the box upside down and running the engine backwards but they were more expensive and worse solutions than doing the transmission properly. Also, most Honda engines rotate clockwise (same as all other engines) - it's only a few of the older smaller engines that rotate the other way. If you're after a modern, strong, efficient Honda it will rotate clockwise.
Stock Subaru turbo boxes will handle 265hp in a 4WD 3200 lb car so it's likely that in a 2WD lightweight buggy, say 1600lbs they will handle in excess of 530hp (theoretically). Wheelspin will most likely be your fuse, not the strength of the box. Aftermarket billet gearsets are available that hold 650hp in a 4WD 3200lb car so using that theory again, these should hold well over 1000hp in a lightweight 2WD buggy. I say all this "theoretically" because we have just got our test buggy on the road and are starting our test program with different trans options, ratios and power plants to see what works.
For you guys that are keen on the auto boxes, I have worked out how to reverse them, it will take me 6 to 12 months of R & D to complete and test it before releasing it. However a paddle shift 4 or 5 speed auto that can hold 1,000 hp easily in either 2WD or 4WD is a pretty awesome thought. It's a big box though, same length as the 4WD manual and quite heavy.
Anyway..... here's some info on our test buggy :
The test reversed 5 speed Subaru was fitted to a Sharpbuilt V2 buggy here in Sydney, powered by an EJ25 quad cam naturally aspirated. This motor puts out around 160hp standard. This motor runs a standard ECU and the transmission has been converted to 2WD and shortened so that it fits into the pan without cutting the torsion bar.
The box I built as a test transmission houses the original Impreza gears, the weakest gearset I can fit, just to see how it holds up in this application. The buggy is a LWB buggy which is licensed for the street and should come in just under 1000kgs (2100lbs) or so.
I used a Subaru cable operated transmission as opposed to hydraulic transmission just to retain the original clutch cable and bowden tube in the test buggy. I could have used a Subaru hydraulically operated transmission converted for cable use with my adaptor, but no need at this time.
We fitted a 3.9 final ratio reversed ring and pinion to this setup as it was the first one I produced, this is the standard WRX 2000 ratio. The owner of the buggy had wanted a different ratio more like 4.4 because of his tall tyres and sand dune driving.....but we needed to get this done and driving. More ratios will be trialled in this setup soon.
Here's the engine and box in place
The simple shifter connection, 2 tubes welded to 2 plates and bolted together
Here's how well it sits underneath, Subaru motor is fitted with a shortened sump
CV joint clearance to frame horns
The buggy was fired up and taken for a long drive around the block tonight. The owner commented to me that he was surprised that the 3.9 ratio seemed quite good actually, with 4th gear 60kph at 1600 revs.
He also commented that the cable clutch with bowden tube worked well and softly, no problems at all. He made some bowden tube holders to fit on top of the Subaru transmission as you can see from the photo.
The gearbox selected all 5 gears and reverse but he did comment that the sideways gate selection was shorter than his old 6 rib kombi box. Forward and backward was fine. We will try some different width plates and see if this makes the sideways movement to select gates a bit larger.
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If your clutch ain't slippin,, you probably got it adjusted right!!!!!
