In light of the fact that it is possible to use either transmission in a 914, it poses a couple questions.

Which transmission is stronger, 915 or boxster 5 speed?

Which has the best support for repair?

Which has the best selection of aftermarket gears?

After going through the expense of doing the Wevo conversion on the 915, would it shift as well as the boxster with cable shifter.

Am I correct that the total cost of converting a 915 using the Wevo kit would come to close to $2500 minimum. ($2000 for sideshift kit and another $500 for shifter) This assumes you do the work your self.

It seems like the 915 would cost twice the amount (for all hard parts and used transmission) that a boxster would cost.

Wes

The 915 is going to be cheaper to do. As I understand, the Boxter transmission requires a fair amount of work to get it to fit into the 914. One member here (abc123 I believe it is) did a Boxter transmission. There is a writeup here as well as on the Pelican Parts board. He hired it out and I believe the total cost was close to $20k. The 915 has been done many many times and there is a lot of help out there for getting it in.

The Boxter tranny is easier to shift. It is also stronger.

Depending on what you're doing, the 901 may be your best choice. Replace the shifter bushings and put in a Rennshifter and you should notice marked improvement. I plan to run my 901 with a Rennshifter behind my 3.2. I'm sure others with more knowledge than me will chime in on some of your other questions.

i believe andys stuffed an audi or boxster tranny in his 914. cool little sub frame.

there is a pic of it in the 'paddock section' in a thread called 'springs and perches'

I'm not sure how one would go about adapting the Boxster/Audi 012 transaxle to a type IV motor. The starter mounting provision is not in the traditional 914 location. You'd also need an adapter plate, as the bellhousing is not the standard Porsche circular type design. The 6 speed Boxster transaxle, though circular bellhousing design, has the starter in the 12 o'clock position.

Andys

You can not use a Boxster transmission in a 914 with either and aircooled 6 or a four cylinder. There is no provision for starter.

Its been done Brett . . . how I don't quite know. This scar has a Boxster 6spd and 3.2L /6. I wish there were more pictures to figure out how.

Here's a slightly better photo of the install. Transaxle is an 01E 6 speed. This is however a V8 conversion.

Doesn't the 6 speed Boxster locate the starter on the engine block at 12 o'clock and points forward? No starter mounting provision on the trans, right?

Andys

Not sure about the 6 speed but my five speed would not work behind any four or 6 without an adapter plate and some sort of starter setup.

Here is another pic.

Notice the cutout for the nose of the starter.

The 915 gives some nice options...I bought a used one for $500.00 and rebuilt it.

Gears are readily available in almost any configuration
WEVO kit makes a nice installation and works great
No cable shifter required
Bolt in deal, no fab required

No need to buy a $500.00 shifter. WEVO, good shift linkage (Patrick) and 911 sport mounts will give the desired results.

A stock 915 shifter can be had for about $50.00 if you look

I have a re-geared 915 in my car with the above. It shifts like butter and I'm quite happy with it. First gear is good for 52 mph.

doesn't 915 require RP to be flipped? at what cost and who does it?

my understanding is that the 930 box is the best of the bunch?

but a 901 box can handle 300hp and long as you don't have fat grippy rubber.

patrick motorsports for linkage - http://www.patrickmotorsports.com/category/10/

fun 901 box video - http://www.renegadehybrids.com/914/Subie/Videos/Video01.avi

jim

Yes the 915 Requires the ring or the tranny to be flipped.

as do any rear engine trannies that are going into a mid engine config

g50 - upside down
930 - flip or run upside down
915 flip or run upside down

Brett,

I've never actually seen a Boxster 5 speed engine and trans assembled together. Does the starter fit the pocket of the trans, or is it located elsewhere? In that pocket location, would the strater not run into the right cylinder bank? I don't quite see how it would fit. Got a photo of the assembly?

BTW, that model of transaxle is the same as the Audi 012 5 speed found in nearly every Audi/Passat front drive car from somewhere around '97 and up. You don't need to pay Porshe prices. I've seen low mileage 012's for $300. The only thing you get with the Boxster version (if it's included in the sale), is the shift linkage for the two push-pull cables.

Andys

I have a Boxster 6-speed, and the starter pocket is at the 12-o-clock position. I really cant comment on what would be required to make that fit with a aircooled 4 or 6.

The issue with the Boxster 6 speed mated to non-aircooled motors looks to be how tall it is and modifications are required to the trunk to make it fit. The rear trunk support (dog-bone shaped support) needs to be notched. I think the pelican thread on the subject had some good pics, IIRC.

Jim

Actually my gearbox is from a 99 Passat. According to the Getrag website it is the same as the Boxster tranny. But I know for a fact the output shaft flanges are different, but they are interchangeable. I thought the starter came out at the twelve o'clock position but didn't see it in the pic of a Boxster engine.


The tranny featured in the Pelican article is a different tranny. It is a G50 variant.

What are you going to put it on? V8, /6, /4?

Me?

Anyone have any good souces for info/tips/specifics etc. on what should or should not be done when running a 915 upside down?

Thanks,

The 915 is fairly simple to flip the ring and pinion internally, so it's uncommon to see them run inverted.

The 930 requires quite a bit of work to flip the ring and pinion, so you'll see several cars running them inverted instead. The G50 diff is not able to be flipped, so they all run inverted in a mid-engine configuration, but do so without complaint.

what about oiling mods when they are run upside down?

Dr Evil (and others);

I want to put in a V6 due to feeling that this best fits the character of the car. It could be a Nissan or Audi.

I like what neo914-6 is doing in regards to drivetrain! The Audi V6 (I'd get the car running NA before worrying about twin turbo's) bolts to the boxster transmission and using the boxster's shifter should be fairly straight forward. The comment by a prior poster that the Audi 012 transmission is the same opens up another option.

I could run a 915 transmission and use adapters to mate to which ever engine I wanted, but when you think about the money involved, it's a bit of a "turn off". The cost of the Wevo conversion is $2000 just to start off and I keep hearing that the "quality of shifting" isn't all that great (some will say that it's fine). Then there is the added cost of adapters for the engine.

I wouldn't want to run the 6 speed boxster due to it's physical size plus I'd guess that it comes at a pretty high cost. That's why the original title is specific in regards to the 5 speed unit.

Now all this may just sound like I'm cheap (and it may be true), but I've got a problem with putting in transmission that costs (when all costs are factored in) 4 times the cost of the initial car.

Wes

Brett,

The output flanges on the transaxle in your photo are the same as the ones on my 01E 6 speed. The round Boxster style output flanges are far more common on the 012 than the spider type, and the advantage is that they fit the 911/Boxster CV's. Give me the code on your trans, and I'll look up the ratios and R&P if you don't have them already.

Wes,

If you want to run the Audi V6, then I'd suggest you simply buy the engine and transxle assembly, and not fool with trying to source two different components. The shfiter linkage on the trans is not all that difficult to fab up, and can be modeled after the Boxster.

Andys

Wes,

I fogot to stress again the cost of the Boxster 5 speed, vs. the Audi/Passat alternative. At minimum, you'll pay double for the (same)Boxster (5 speed) transaxle. About two years ago, an '02 Passat 5 speed on Ebay didn't sell at $300. I shoulda grabbed it, as it had 22K miles on it AND it was local!

If you just gotta have the 6 speed, then you'll need to look in Europe for and Audi/Passat engine/trans assembly. Cars with front drive only 6 speed transaxles were never imported to North America. Since they don't commonly separate good engines from good transaxles over there, plenty should be available. Down side right now is the exchange rate is not so hot. The EURO is not too bad, but the GBP is double. You would of course have to pay to ship it. I can put you in touch with freight forwarders, if you wish. It's a lot of hassle though; I'd suggest you stay with the 5 speed stuff.

Andys

five speed it is!

Wes

Andy, I'll check the code for you. I picked this tranny up for 350 shipped I believe. Have to check, but you are right I see them all the time. The output shaft flanges interchange so I can change themif I need to. But since I am going to be running a twin turbo V8, I will need stronger axles. So I will probably make some kind of adapter for the 930 or Vette axles.

How about the differences between the Audi 01E and 012??

Wes

Brett,

A twin turbo V8 sounds like some serious HP! Do you plan to put the 012 behind it? I would sure like to learn from your experience exactly how durable it turns out to be, as few have ever used an 012 behind high HP application, AFAIK. European 4.2L Audi A8's use the 012 5 speed, and that's a pretty heavy car.

BTW, Quaife makes an LSD for an 012 that's reasonably priced (as LSD's go). Also, the differential has four spider gears which in theory ought to provide strength to an otherwise weak area. Earlier Audi transaxles had two spiders.

I suppose at the low prices and abundant supply, it's no big if you wear it out or break it. Cheap to replace.

Andys

Since I am a cheap Bastard I bought it to test. It will probably hold up decent for a while. I will probably only be putting 500-600 through it on the front end. Doubt it will make that much torque. Supposedly it is only rated at 280ft/lbs. Guess we'll find out.

Wes,

Here's an example of a NA V6 Audi transplant with auto gearbox: http://cgi.ebay.com/ebaymotors/ws/eBayISAP...A:IT&ih=016

Post your progress once you've begun...

My god! Please don't hold your breath. I'm still doing research and have to get rid of my old project car first (and don't really want to).

I'm leaning toward the drivetrain that Neo has (but Audi 012 transmission, not boxster). I agree that it would have the same "character" as the original cars concept.

I've gotten a lot of input also from "Andys" and given a chance, want to go and check out his car. Some of the work he has done, that doesn't appear to be posted here, is totally amazing. Quite the engineering and fabricating!!!

Wes

Wes & others:

Seems we all have our own comments and opinions on what will work, what is best
or the way to go. We should also take into consideration that IF you have the time,
money, abilities or contact everything is possible it you persist and work out the details.

In my case "I have" a Boxster 5 spd. behind my late model Chevy V8. and it didn't
cost $ 10,000 to do the conversion/custom installation of the Tranny. However it did
require some engineering and design by myself and others, along with fabrication.
There were challenges as well as some bumps along the way. But today I am
happy to say that it works fine on the street and on the race track.

Challenges along the way with my conversion:

A/ Custom make own adaptor plate
B/ Custom make own balanced flywheel
C/ Custom starter mount & special Porsche ring gear
D/ Custom hi-torque starter
E/ Custom make Clutch disc/pressure plate (Porsche)


Comments regarding my application after completion and use:

1/ Great shifting tranny with Boxster cable shifter setup and generally the tranny
is very good to work with.
2/ Actually the tranny has the Audi marking on the case since Audi
make the unit. (similar to Audi 5000Turbo components, and gears)
3/ Much stronger than the 915 and no need to flip the R&P
4/ Electric Speedo from a 911 works just fine.
5/ Uses a dual mass flywheel, thus a custom flywheel is needed if attaching
to another engine that Boxster.
6/ No one make an adaptor plate (custom item)
7/ Starter issue can be solved in most cases with a (custom mount and
slight modification to the actual Boxster bellhousing case. (non structural)
8/ Disadvantages currently, no aftermarkets gears or R&P available and thus
your top speed is limited to the engine RPM / tire sizes. In my case at 6,000
in fifth I only hit 130 MPH with the V8 engine. First gear is quite low and much
like the 901 not really needed or used much with the V8

Durability should be fine, even though I have had on the road for over a year,
but only a few thousand actual miles. According to the Porsche experts here in
Toronto, they state this tranny is very good and well suited for use with the V8.

Just my thoughts and comments after seeing this post and though I should pass
along whatever info and or experience I had available for others considering
something different. But like some others who posted I would also suggest if
possible doing a conversion to stick with the tranny that matched the engine as
it would usually appear to be the best arrangement. If anyone wants further info
on my project please drop me a line. Happy Motoring !

Allan
Toronto, Canada.

Allen,

Perhaps for everyone's benefit, you ought to post some photos of your efforts.

AFAIK, you're the only one that has mated a non-Audi V8 to the Boxster/Audi 012 transaxle (The Audi 5000T used a model 016, and nearly everything on it is different). Please keep us abreast of its durability.

As for ratio's, nearly every Audi trans is limited to rather low ratios (not unlike the 901). There is rare exception however with certain 012 transaxles where taller gearsets are available, but they're not easy to find.

Andys

In the FWIW dept, an outfit in Oregon - GTA - was re-working the Audi 016 transaxles with a 3.22 R&P - to make them much more "ratio friendly" for a V8 conversion. Early reports were that the ratos were working out great on a 400+HP SBF/GT40 conversion. Not sure if this would work with the Boxter trans?
http://www.gtainc.biz/index.php

I believe the last update reported the reworked gearbox, including rebuild of a donor trans, + new Quaife LSD + new R&P was running around the $5K mark. I guess that places it somewhere in between a beefed up 901/914 and re-worked 915 cost-wise.

Too bad the Renault UN1 transaxles aren't more widely available in the states - these seem like the ideal transaxle to use with a mildly built V8 (when appropiately rebuilt with the HP components).

GTA is a great bunch!
FWIW, A couple of years ago I spoke to them extensively about retrofitting the 016 with a 951 (944T) 3.44:1 ring and pinion resulting from the demands mostly from the GT40 replica builders. After some R&D (On their nickel), it was decided that an entirely new R&P was the best option. I hooked them up with some interested parties, and the rest is history. That 3.22:1 R&P transforms the 016 transaxle into a very well matched package for a high power, light weight car.

Andys

Wow, I didn't realize the 5000T used an 016 trans. I do know that the 5000T trans can hold a ton of HP. My buddy runs over 500hp (and about an equal amount of torque) through the transaxle on his 5000, and its basically a sleeper drag car. That is the only piece of the car he hasn't broken while doing 5K clutch drops with slicks.

I too would like to see pictures of the boxster/v8 mate.

Reply to Andys and other of interest !

Please find below some info I provided to another member regarding some info on this project along with some photos taken during the build phase about two years ago. The key components to the project are what you don't see, flywheel, clutch,
starter, etc. The adaptor plate was actually not too difficult. Here's some of the info:

A BIG QUESTION for many is more than just Tranny Prices vs Conversion costs !!
you can quite easily pick-up a used Boxster tranny (5 spd.) for about $ 1,500 - $ 2,000. BUT you need to know the following items are necessary for the conversion in addition to the actual tranny costs:

- two minor modifications to the tranny casing, non structure mods.
- hydraulic Clutch pedal assembly conversion.
- conversion of axles/hubs/brakes to the Porsche 5 bolt.
- Porsche 5 bolt axle assemblies and special length axles.
- Custom made adapter plate
- Custom built flywheel (for your particular engine)
- Custom Pilot Bushing/Bearing Spacer
- Special Porsche Starter Ring Gear
- Custom Clutch Assembly, Kelvar Disc.
- Custom Starter & Mounting Bracket.

No of the above items are commercially available, but would need to be designed, engineered and then custom built for you. This project was a project car for me and not
a business for me, however I did make templates of all the components mentioned above (except the hydraulic clutch conversion & 5 Bolt axles) and retained all my engineering drawings in order to re-duplicate the process or to sell to others if and when the need might arise. In my personal opinion to do this conversion it would cost over $ 5,000 for all the pieces including the tranny to complete the project. This would also depend upon your abilities as to what you can do yourself and what you would have to pay others to do. So you can see it is still a costly undertaking, BUT one sweet tranny, shifter and well working unit !

NOW I will provide some of photos which only give part of the project:

Couple more photos

ajaracer/Allen,

It's been several years since my last visit to Kennedy Eng'g (they are local to me). I had their 016 tooling plate in my own hands to see if by chance it would fit my 01E 6 speed. For a SBC application like your's, I seem to recall that the starter pocket would allow the use of their starter (they use a Toyota truck starter). From that, it seems you wouldn't have to machine the trans bellhousing. Everything else (clutch, flywheel, and PP) should fit with a little modification, and needs a new extended pilot bearing adapter. I think they also have the correct 15/16"-23 disc spline to fit the input shaft, IIRC......it's all from memory.

I haven't accurately measured the 012, but I believe the output flanges are not symmetrical about the centerline of the trans. If you offset the engine/trans assembly by 3/4" (which is what I did), won't the stock length 911 axles (assuming you've made the requsite 5 bolt upgrade) bolt right in?

I like your set up. It looks like the stock shifter cables and cabin shifter drop right into place.

Andys

I sure wish GM produces a car someday that utilizes a transaxle suitable for high HP applications. The list of possible transaxles that can be easily packaged into a 914 or other mid engine projects is narrow...reconfirming the fact that the mid engine configuration is a true rarity. If only GM made hundred's of thousands of midengined cars, the rest of us would salivate at the cheap American made junkyard prices, unlimited supply, and hopefully a wide array of gearing. Until something like this happens, we will be squeezed into using more expensive and less abundant gearboxes from mostly European cars. The handy thing about a GM box would be that it would fit a bunch of GM motors (no adapter plate). Sadly, My dream will more than likely remain a dream.

Bill

I currently use a flipped cable shifted 930 box mated to a 525HP LS6

Wow, now the idea of using a "flipped" 930 (in a 914) brings up a bunch of other questions!!

Now I'm a Noob at a lot of the Porsche stuff (but fairly smart otherwise), so please bear with me.

By calling it as "flipped", I'm assuming that you are talking about mounting it upside down, to correct for the rotation of the axles when mounted mid-engine.

This would result in the axle centerline moving above the engine crankshaft center line. It also places the main body of the transmission above the engine crankshaft centerline.

Now if you don't want to lower the engine, then the CV joint angles may be excessive, limiting the torque they can handle.

It would also mean that you would have to cut out the rear trunk floor pan in order to clear the transmission body.

None of this would be a problem in a GT40 replica, but in a 914 it just seems like you are adding up a lot of issues.

I'd not be resistant to cutting out the trunk floor pan (and replacing it with something for lost strength), but that CV joint angle shouldn't be taken lightly.

I once had a conversation with the guy that owns Raxle (they make up cutsom axles) and he said that a CV joint looses strength based on every additional angle off centerline.

So; let's say that you put in a transmission (930) that can handle 600 hp, but due to placement of the axle flange, the CV joint looses 50% of it's strength. You then start blowing CV's at 300 hp. You end up with an assembly that's only good for 300hp!!!!!


Just food for thought, and as I said at the top, I'm a noob.

Wes Vann

i believe he is running a flipped ring gear. trans stays in its original orientation, with the ring gear on the other side, giving you a mid engine config.

I'll add my 2 cents. While I agree that building a Porsche tranny is expensive and alternatives would be nice, Porsche trannys can be re-geared with ease (but not cheap)

If you are going to build a dream car with a big motor, re-gearing is almost essential. Why build a tranny and then not use first? Or it's too low to be useful

For these reasons I stuck with a 915. It has a very tall 1st and 5th. 1-4 is close together and very fun and 5th is a cruise gear. Basically I geared it exactly as I wanted. Can you do that with another brand?

Does it shift like a late model car? Not quite but it shifts pretty darn nice and I'm very happy with it.

Anyway, alternatives are nice but make sure that after all that money is spent, you have what you want and not some gearing that was developed for a station wagon.....It's all a compromise. I would rather have a car that is geared properly and shifts a little more firm than a car that shifts like butter and the gearing is way off....OK you got 10 cents worth.

This is a very good point PRS914-6, and often overlooked. However, most transaxles are in fact geared pretty darned low in first so as to facilitate parking lots and other forms of daily driving needs. As you say, re-gearing is usually pretty expensive though do-able on Porsche transaxles; something most alternatives usually lack.

My friend's V8 914 w/930 has gearing that seems very well matched to the car. The gear spread takes good advantage of the torque from a 383 cu in 500HP SBC.

Andys

Just a wee bit more......

On my 3.6 and I'm sure on about any V-8 conversion, first gear is a waste of time and most just start in second. If you install a tall 5th for freeway, that leaves you with a 3 speed box for the street.. Unacceptable in my opinion.

I wanted to use ALL my gears. Car manufacturers have to gear a tranny for the worst case application. Starting on a steep street in San Francisco or up a tall pass in the Alps combined with high altitude comes to mind. You HAVE to be able to get moving without burning up the clutch. Most vehicles I have driven have a top first gear in the 20-30 mph range. I would blow through that gear as fast as I step on the throttle.

I don't live near hills that are a problem so a real low gear is not necessary. My first is good for 53mph. If you live in a stop and go traffic area or around hills this would not be the gearing for you but for me it works great. Bottom line....just think it through and build what's right for your application.

Here is my gear chart to make the point. Note gears 1,2,and 5
Click to view attachment

Aaron is correct, I have a flipped ring & pinion in my 930 and the box is in its normal upright position. I have heard of a number of guys who have successfully run their 930 boxes inverted (negating the need to flip the ring & pinion) without any mention of excessive CV joint angles.

Every CV has a safe operating range measured in degrees:

Type 1 = 12 degrees (Bug)
Type 2 = 17 degrees (Bus)
Type 4 = 22 degrees (944/181)
930 = 25 degrees


930 CV's are used extensively in off-road racing at extreme angles with very few problems and the angles encountered in a 914 would pale in comparison.

On the issue of gearing vs. shift quality, I'm with Paul. I'm running a 915 with a rare 10:31 ring and pinion and that makes the ratios perfect for a V8 or hot 3.6L application. A G50 would be a pretty easy swap, the costs would be comparable and the shift quality would be great, but the gear ratios would be horrible.

My first gear is 53mph at 7k, so it's a hair shorter and more usable than the 930 first. Fifth is a comfy 76mph at 2500 rpms where as the 930 would be at 70mph. A built 915 is good to around 400 ft/lbs, beyond that you should start looking at the 930, a custom geared G50, or a G50/50.

It's worth noting that driving and shifting style is the most significant factor in how long a transaxle will last with a given amount of horsepower. There are race cars running a 3.6L and 12" slicks through a 914/901 trans and lasting several seasons without failure. Likewise there are people who can run a 915 at 600hp for years without an issue and there are others who can kill them with a stock 3.2L.

By the time you get a G50 up and running with the proper ratios it's close to $10k. There are several companies with high performance mid-engine transaxles at the end of testing that will be released to the open market soon. They will be good for around 600 ft/lbs and they will cost $12 to $14k by the time you factor in the adapters, clutch, flywheel, pressure plate, and shifter.

A G50/50 is even more cake...

What is hard to see is that this gearbox has a plate welded to it, and the starter is in the "stock" 914 location, they cut a hole in the bellhousing for it...

Felix has pictures of the starter side I believe...I had them, but cannot find 'em