North/south mid-engine transaxles...

**jzk25** · 11-09-2006, 10:16 AM

A little info about the Subaru 5 speeds.

The front split housing is the same on 2 and 4wd boxes with the exception of the dual range box (which has provision for the extra gears and a lever) and the turbo box has a different clutch actualtion method so has an extra casting in the bellhousing.
The gearsets are interchangeable right up to the present boxes with some very slight mods to the reverse idler. There is however a difference in the shafts between 2 and 4wd where the transfer bolts on. This is easily accounted for if you were to get a PPG gearset though.
The case strength between 4 and 8 bolt cases becomes less imortant when an aftermarket gearset is used. The 8 bolt case started in 98.

Both cable and hydraulic actuation is used in the NA gearboxes and hydraulic only in the turbo box. I don't believe there would be any advantage to using a turbo case and pull clutch as you can get puch clutches that are just as good as the turbo clutches.

the bellhousing is integral but uses a simple 4bolt symetrical layout(similiar to VW/Porsche) and has a gearbox mounted starter which helps simplify making an adaptor plate becasue the starter is already sorted.
The 550 spyder replica I mentioned has a std $100 1990 NA Liberty FWD box and has been pushing at least 300hp thru it for a few years in motorsport situations.

If you used an 8 bolt split case with LSD(about $1500 from Subaru or aftermarket) and PPG straight cut dog engagement you would have an indestructible box with very fast shift speeds. It would owe you $6k ish by then but would be brand new and race ready so is pretty good value.

**kingmick** · 12-09-2006, 08:33 AM

hey mullet! i havnt looked at the spread sheet but it sounds pretty good as it compares transaxles

download here and there is more info on this site

http://www.statikdesign.com/scratchb...nsmission.html

http://www.statikdesign.com/scratchb...rivetrain.html
mates use audi box he will ring me with numbers latter in the week!

its in pdf as well and i just had a look! not a bad find at all

**kingmick** · 12-09-2006, 08:45 AM

http://www.924.org/techsection/7transaxle.htm

http://www.924.org/techsection/transapps.htm

http://www.kitcarmag.com/featuredveh...cas_shop_tour/

**510rob** · 16-09-2006, 04:09 AM

Porsche used a 901 transaxle in early 911s, then a stronger 915 mag case, then a stronger aluminum case 915, then went to the Getrag-produced G50 series units...

For a mid engine application, you can either run a 915 with a flipped diff carrier+ring gear to get correct rotation from the output stubs, or you can run an inverted case G50

Kennedy Engineering in the US sell a conversion set to use the 915 with a Lexus V8 (i.e. 1UZ/3UZ engine)

http://www.kennedyeng.com/

Nothing that says Porsche on it or in it is ever cheap, but apparently the 915 box can take some torque if it isn't being abused by a ham-fisted jerkoff driver. As well, the basic layout of the 915 was shared with the 916 racing transmissions, and all ratios are changeable and there is an amazing array of gearsets available for the 915, as well as the newer G50 boxes.

**wagonist** · 27-09-2006, 05:44 PM

If you could grab an early Lib FWD box, I reckon it could handle it with a few mods.
The biggest reason that Sub boxes get munched is that they are trying to transfer power to all the wheels, where there is basically no slip & the weak point is usually the clutch. Upgrade the clutch & the weak point becomes 1st gear....
Sub boxes converted to RWD last a lot longer because the tyres lose grip with the road & the shock loading isn't there.

A FWD box with a PPG gearset & an LSD (either STI or aftermarket) mean for the front Sub diff should be able to handle that power in such a light chassis.
Current WRXs are gettign to be lardy bastards....

remember that most Porsche boxes (excluding Boxster & some of the newer ones) are meant for a rear engine, not mid engine, therefore they'll spin the wrong direction for your use.

**wagonist** · 27-09-2006, 05:50 PM

oh yeah, jzk25 is right about the clutches.
Pretty much the only reason the turbo subes have a hydraulic clutch is because the cable setup won't fit past the intercooler & plumbing (they run in the same space), whereas the hydraulic setup runs along the firewall & then out.

**mullett** · 27-09-2006, 11:22 PM

mmm, and AFAIK the scoobs from the factory run a weak clutch intentionally as a weak point to save the box from the 7000rpm dumps of the ham-fisted driver. So the first thing the average dodgeball does is dump a heavy-ass ceramic clutch in there. Kills the box. Me, I'd rather replace the clutch every 30000km than the box...

RM.

**wagonist** · 28-09-2006, 09:20 AM

Originally Posted by mullett

mmm, and AFAIK the scoobs from the factory run a weak clutch intentionally as a weak point to save the box from the 7000rpm dumps of the ham-fisted driver. So the first thing the average dodgeball does is dump a heavy-ass ceramic clutch in there. Kills the box. Me, I'd rather replace the clutch every 30000km than the box...

RM.

Ditto.
It's not that hard a job & even easier once you realise it's quicker to take the engine out on the AWD versions.

**vanman** · 14-10-2006, 12:40 AM

Just found a feature article in Street Machine April/May '98 of a car called a 1997 JWS (John Wright Special) Le Mans Coupe, owned by a John Collins. It was an Individually Constructed Vehicle with a Leyland/Rover alloy 5.0L V8, mid mounted and running through a modified Kombi box.

Article lists the gearbox as modified with 'Albin' gears to take the power of the engine - 300+bhp at flywheel, 248bhp measured at the wheel. The car weighed in approx 800kg, and was even road registered!

Considering the similarities in weight, it might be worth investigating how far the VW boxes can go reliably - the featured car had already done 2761km on both road and track with no signs of problems...

Cheers
Vanman