I'm thinking about using a 915 behind my 3.6 teener. AutoAtlanta makes a 916 kit for ah.. Well a few bucks!

Just wondering if anyone else has bought their kit and can give me feedback on the setup?

Also, any feedback on reversing the 915 would also be helpful. I understand the process is "fairly" simple. Especially when compared to a G50 installation. I believe you just flip the rear-end and machine the casing for it to fit reversed.

I searched the garage forum for anything on 915 transmissions but got zero results.

THANKS!
-JR-

don't do it!

Is this Automobile Atlanta's opinion on their own product? Or is it in reference to use of a 915 on a 3.6?

-JR-

On AA's website it looks like the Velios kit which is no longer manufactured. I have the Velios kit on a 930. Can't say how well it works as my car comes last around here!!!

I might disagree with the good Doctor, there are a few alternatives.

The first was the George Vellios conversion. He basically copied the factory 916 tranny linkage, and designed the shifter console patterned after a side shifter tranny. It took a bit of fiddling to get it right, but it did work if properly installed and adjusted. I've had mine for a few years now, and have been very satisfied with the transmission. It is not being used for tracking or autocrossing, so that is a caveat to my response. Definitely not a job for a novice, and I'm not sure if the Vellios kits are even available anymore. I believe this iswas the kit that AA had available a while back. I have heard that Vellios did have some available (according to Glenn Stazak), but don't know of anyone that's installed one in the last few years.

The second alternative is the WEVO conversion for a 915 box. They're known for making quality stuff. Their system probably works better, but I don't believe they will fit with a stock muffler system on a 914-6.

Some folks have also designed cable shifters for the 915 box, using the stock linkage at the back of the transmission. I haven't heard much about how well they work. I do believe that Patrick Motorsports has/had such a system available.

You have to do a bit of design work on the linkage, but that's quite straightforward. I imagine that a flipped G50 would probably work better as the syncro design is better, but none of these alternatives are by any means cheap.

As an owner of a 916 with the 915 box installed and a 1972 3.0 914-6 with a 915 installed I get to comment here. The 915 gearbox in a 914 makes the car a heavy feeling slug and much more tail happy, and just like the original 915 shifts bulkily and slovenly just like the original 915 when installed in a 911 but in this case has a lot further to go to shift. One has to fabricate linkage to work with the 916 conversion as well as fabricate clutch release mechanism. As the Vellios kit is hard to find these days, the Wevo kit disallows use of ANY standard aftermarket muffler (unless you want to cut and beat and chop), and after turning around the ring gear and pinion one has to rig an electronic speedo pickup.
I would much rather install the beefy intermediate plate in the original 901 and install that in my 3.6 conversion

Thanks George.

I've heard the 916 kits aren't as simple as bolt on solutions. They need extra cleanup / machining / tweaking to get them to work well.

However the Wevo kits I've seen are usually more than $5K and being a tail shifter I wonder how great the shifter feedback is.

The cable kits also caught my eye. Haven't seen any "product" available for sale yet in this department though. Patrick MS offers one for the G50.

I wouldn't mind going for a G50, but I've found very little info online about this conversion. How well it fits a stock 914 body, how the oiling is done, what bell housing changes are needed and on...

I have also been considering a beefed up 901. But it seems like a half way measure. I still hear that a 901, no matter how beefed up, can't take the torque in first gear. Then again... I could build two or three 901's for the cost of 1 915 or G50 setup.

-JR-

Glad you chimed in. Do you feel any difference in the shifting of the factory 916 transmission to the aftermarket Vellios one. I think that he basically copied the internals. There was a lot a talk about quality issues with Vellios, but I always gave the man credit for coming up with some neat ideas. Do you know if any of his stuff is still available? I seem to remember that he got out of the conversion parts business and got a real job, though he did have some fellow running he website for a while.

Having an original -6 with the 901 and a conversion car with the 915, I do agree that it feels heavier with the 915. However, I wonder why the factory developed the 915 transmission if they felt the 901 was strong enough? They were pretty thrifty in the early 70s (since a lot of the budget was going to the race team). If a billet plated 901 can handle the torque loads of a big engine, that certainly would be the easiest and cheapest way to go by a long shot.

A year ago I did a bunch of digging around and it seems that none of the Vellios kits are available anymore. Unless you managed to find a used one somewhere.

The 901 is still the way to go unless you're above 350 HP. You could have one primary and a few Dr Evil back-ups for the cost of a 915 & WEVO

The 915 you have to flip the Ring & Pinion as they are not set up to be run upside down from an oiling standpoint. The WEVO set up is about $2,400 Good Product. I wouldn't take a Velios kit if you gave it to me.

G-50's are expensive

If I was looking for a different piece, I would look at the 930 tranny. You can't flip the R&P, but running it upside down is not a problem. However it is just a 4 speed.

T.C.

The 930 is only available as a 911 sytle tail shifter, is it not?

Once again, your good friend Vellios had a conversion available for the 930 transmission, but I've only seen one picture of one installed, and have never spoken to anyone that actually had used one.

If anyone would know, I think the good Doctor would have the best information if any of these were available. I'm sure that he would be willing to sell you one if it was sitting on the shelves for all these years. We are probably going back 20 years or so! Time sure flies by quickly when you're trying to get a project off or jackstands!

Couldn't disagree more. Will a 901 work in a 3.6 powered 914? Sure....But lets look at the truth.

First gear in a 901 (stock) is nearly useless behind a 3.6 so you end up with a four speed. It's too low geared and if you abuse first you'll likely break it.

Fifth gear is too low so you end up screaming your big torque engine and end up with a noisy car from all the revs.

The 901 is not nearly as strong as a 915, compare the parts side by side

A WEVO equipped 915 is a GREAT shifting tranny if the tranny has been built correctly. Balky 915's are typically from poor builds or worn out parts. They don't shift quite as fast as a 901 (gears are larger) but it's not a huge difference.

WEVO + Rennshift= Very fast and accurate shifting like a modern day car.

A M&K muffler fits perfectly behind a 915 and sounds great (search here)

The clutch hookup is almost as easy as a 901

The extra weight is rather insignificant in the big picture when switching to a big six, hell a small battery makes up the difference.

A beefy intermediate plate would only partially help but why throw money at it when in the end it's still not very strong?

The Bad.....

Lots of $$$ to do right (WEVO is $2k alone)
Yes an electronic speedo is required but it's not hard to do (search here)
You'll have to machine the ring bolts to clear the case when you flip it
You will have to make a shift linkage but if you can swap a six, the linkage is easy.

My opinion for what it's worth......To get a 901 to survive any abuse and to get the gearing right takes significant money. If I have to invest a bunch I'd rather start with something that's stronger in the beginning that will last. Lets say you re-gear, buy a limited slip (you'll need it), add a billet plate etc. You still have a weak tranny and you spent a LOT of money that could have gone to a 915. On the other hand you can build a lot of 901's for the price of a properly built 915 so if money is tight, it's an easy decision.

Others that have been in my car can chime in on the gearing and shifting portion since it's a subjective area. Good luck with your decision.
Comparison of WEVO equipped 915 and 901
Click to view attachment

Thanks for ringing in on this Paul. I've been keeping close tabs on the Excellence articales as they come out. I have a 928 as well and I've been told a 915 shifts very similar to the older 928 5 spds like mine. My 928 certainly doesn't shift like an import car, but if you give it some respect it does just fine.

I've been waiting for the article that talks about your transmission selection process but haven't seen anything yet. (maybe I missed it) If I have missed the article already, can you remind me what month / issue it was in?

On your site (http://www.sayegh.org/Paul/914.htm) you have a spreadsheet at the bottom for "901 gearing as installed". Did you end up putting a 915 or a 901 in your car?

Do you know if the Wevo kit connects to a stock tail shift 914 linkage?

The clutch, spedo, machining and muffler clearance doesn't worry my too much. I'm a pretty good fabricator. Hoping to get my CNC machine built during my 914-6 project as well, which should help for custom parts.

Thanks Paul!


-JR-

The 915 part of the Excellence articles is Part 8, Aug 08. The 901 went in for a ride around the block. After one block I thought the gearing sucked and built the 915, not wanting to invest big money in a 901

One thing that really helps the 1-2 shift on a 915 is light weight gears. Second gear is rather large and a lot of weight to slow down plus add some worn parts and they get "balky" I changed 1st, 2nd and 5th and used the light gears on 1st and 2nd where it really matters (Note the holes in the picture). Add a clutch disk with a reduced marcell spring and you get a 915 that shifts perfectly. The Excellence articles explains that and I have commented about it on this forum so you'll have to search a little bit. Also, if you look at the chart you will notice that 1st is good for about 53 mph and that tall gear and closeness to 2nd significantly reduces the balkiness that people complain about. I also use....prepare to gasp....synthetic oil with extremely good results. Works great in fresh trannies but I wouldn't on worn out units. Add up fresh parts, WEVO, light weight gears and reduced clutch marcell and my 915 shifts better than my new Subaru. You will have to custom modify the shift shaft from the firewall to the tranny since it needs a bow in it to clear the 3.6....easy task
Click to view attachment
Here is the final gearing for the 915
Click to view attachment

Found a Lambo kit car site that the guy used a 915 in.
Here is his account of what was done to make the 915 run mid-engine.

2) Machine the case to accept the flipped diff.
- In the case, where the original pickup was machine down about 0.05
- Below the input shaft there needs to have clearancing about 0.1 where the ring gear sits. You can see where the part is clearanced by the factory for the non flipped dif runs
- Clearance the retaining bolts on the diff. These are very large bolts with very thick heads, they are clearanced 0.05 - basically remove the lettering on the heads and a hair more.
- Install the diff
- shim the pinion shaft so that you have 0.015 gear spacing - best to let a tranny shop do this because you need the porsche shims, it takes only about half an hour.

I run a stock 901 behind my 3.6L. So far, so good.

As Paul mentioned, i don't use 1st gear anymore, i take off in second.
5th gear is OK for cruising on the freeway.
I'm happy with it.


Eventually, i was planning to go with a WEVO 915, but right now i'll stick with the 901 ...
Andy

I've run a 914 trans both with a 2.7(3 years) , and now a 3.6 (11 years) with no issues. Just rebuilt it to fix a shifting issue unrelated to synchros or dog-teeth/slider wear.

I've run since the beginning with synthetic. First Mobil-1 (I know) and now LE. No synchro problems and shifting effort is low.

I have two 915's and haven't found a good reason to spring for the conversion. Mechanically I'm interested and will eventually if I've run out of other things to do!

But would Amoy agree with that?

Great information. Really make a 915 with wevo sound like the best option when built right. But most important the wevo transmission looks really cool. Who makes the lightweight gears I have been let down by google once again.

I'm very happy with my Wevo 915 behind my 3.6. I thought about going with a beefed up 901, but felt I'd always be paranoid to really hit it hard and I couldn't see building a 3.6 914 that I had to baby.....just my $.02.

Some really good info here. Thanks for sharing

Deckman runs a 915 in his....

Lightening the 1st and 2nd gears is done on the 901 gears as evidenced by the large groove on the undersides. I hadn't thought about that until you mentioned the 915 gears with the material removed.

I run a bone stock 901 behind my 3.6L and some of the local CA guys can tell you that i don't "baby" my car ...


Like i said earlier, as long as you don't use 1st gear, the 901 will last a long while for a fraction of the cost of a WEVO 915 ...
Andy

Yep, Andy is correct. There is no doubt that 1st is the weak part of the 901. It is cantilevered off the back with no support and pops off like a bottle top when abused. If you are willing to live with a 4 speed without the ideal gearing, it's certainly a smart decision when it comes to $$$$

As I stated earlier, losing a gear and living with a low 5th is not a a situation I wanted and the 915 build is VERY expensive. However, once you decide to regear, add posi etc you have to decide if you want to invest large sums of money to get a marginal tranny that can not use 1st for any abusive driving. Remember that when Porsche went to a 3.6 they went to a G50 tranny which is far better than a 915 and has a nice "overdrive" for the freeway. A G50 compared to a 901 is ....well it's not worth comparing.

Bottom line: The 915 is a very expensive compromise but you can get the gearing and strength to tolerate the torque of a 3.6 (barely). The light weight of the 914 saves most of the trannies anyway.

The 901 does not have the design to tolerate big torque in first and you will live with a 4 speed. However used 901's can be found for pennies. Regearing can be done but cost a lot and you still have the inherent weakness of first

So it ultimately boils down to $$$. The 915 is stronger, gears are easily available and all 5 speeds are usable for BIG $$ The 901 is dirt cheap, easy to find and easy to replace. Is it worth pouring money into? Only you can decide....... You could build at least 3 or 4 901s (or more) for the price of a WEVO 915

The 915 is not a cure all. Weak point is the intermediate plate....the bearing shell gets loose and then the shaft flexes breaking second gear.

The fix involves pressing in a sleeve, new bearing and a WEVO or Guard GT bearing retainer that ties the two shafts together. BTDT.

The retainer is stock in the 930 and G-50 boxes.

That's a point that I didn't even bring up.....The later 915's made out of aluminum eliminated the steel cast into the middle for the bearing bores. The bearing races are pressed into the bare aluminum. I haven't seen a high mileage aluminum 915 come apart that didn't have worn out bores. The solution is to buy the earlier magnesium trannies that have steel cast in at the bearing bores. They were used in the early 2.7 engines that were low powered and typically didn't see much abuse. I never understood the drive by everyone to get the aluminum 915's. Yes, aluminum is stronger but how often do you see a broken Mag unit? Add a one piece bearing retainer (more $$) and that problem is solved.

Indeed, every tranny alternative has a drawback or two and the 915 is certainly not exempt but probably a better starting point.

There is one more cool thing about early 915's. They use the same carrier bearings, shims and spacers, and LSD as the 914 box. Why is that cool you ask?

I just put a new LSD into my 914 transaxle after 15 years of hard running. I also, over the years, acquired 2 early 915 boxes. One, with a not-so wonderful case, has a broken tooth on the pinion, but is otherwise in good shape. The other is very nice but neither has an LSD. A later reinforced side-cover and single-piece bearing retainer and I'm in business... ok I still have to install a shifter but I'm good. BTW they are both still 7:31 and yes... I know.

If I want to build one up for my 914 I'll transfer the LSD to it. Life is good sometimes. The moral of the story... always be lookin' for stuff.

Curious will the 7:31 915 ring and pin rev high in 5th like a 914 901 trans? I am running a 3.2 with a stock 901 trans and yes 5th gear is rather irritating on the freeway.

the 7:31 box uses a taller 5th than the 8:31 but only because the R/P ration is lower. What I did was to take the taller 5th from a 7:31 box and used it in my 8:31 tranny. Gives a nice tall gear for 3.6 torque in a light car. Gets almost 30 mpg. Note the 8:31 is much stronger if you are running big torque.

Here is a chart for your review
Click to view attachment

Paul are your 1st and 2nd gears custom machined by you or did you get these from a shop? Do you know if they required re-balancing after they were lightend?

I'm not sure if anyone here is with Patrick Motorsports, but I noticed that all of their big 6 street 914-6 cars are outfitted with 915's exclusively. I didn't even see one G50 despite all of the G50 goodies they make as well.

I've been thinking of the G50 as well, but I hear the G50 when inverted doesn't fit with the rear trunk also installed. I'm not into cutting up my project car's trunk.

I'm with Paul and East Coaster... When building a car like this and putting enough cash into it to make it nice... But then putting in a 901 only to not be able to use all that power at will. So if I have enough in my budget I will install a 915, but if I'm running short I'll run my 901 to get it going and upgrade to the 915 later.

Running a 901 for awhile is actually a good move. You learn what you like and don't like about 901 gearing and can build a 915 accordingly. It's so expensive to build a nice 915 that when most people start adding up the cost they can't stomach it. I know I had that reaction at first but eventually just sucked it up. It can certainly exceed the value of the car or pay for a paint job. Here is what you are in for....

Core Tranny $500- $1000
First gear change (welded\changeable) $800\$1500
second gear $500
Misc bearings, syncros and dog teeth $1000
Used late style reinforced side cover $75-$100 or WEVO $300
WEVO kit $2000
5th gear (used early style) $200
Machine bolts and clearance case for R/P swap (estimate) $100
Rennshift $500 or used OEM 915 tower $100
Electric speedometer $75.00
R/P and carrier setup for proper load and clearance $250.00
One piece bearing retainer $200.00
Limited slip $1000
You assemble free/shop $500
Shift linkage?

And the list goes on. As you can see you are in for a $5k bill at the minimum. Swallow that one

The gears are made in Germany by custom gear manufacturers but can be bought from numerous vendors. A G50 is another matter especially since you will be required to use a cable shifter

[/quote]

There is one more cool thing about early 915's. They use the same carrier bearings, shims and spacers, and LSD as the 914 box. Why is that cool you ask?

I just put a new LSD into my 914 transaxle after 15 years of hard running. I also, over the years, acquired 2 early 915 boxes. One, with a not-so wonderful case, has a broken tooth on the pinion, but is otherwise in good shape. The other is very nice but neither has an LSD. A later reinforced side-cover and single-piece bearing retainer and I'm in business... ok I still have to install a shifter but I'm good. BTW they are both still 7:31 and yes... I know.

If I want to build one up for my 914 I'll transfer the LSD to it. Life is good sometimes. The moral of the story... always be lookin' for stuff.
[/quote]

I also have a 914 transaxle with an LSD. I am guessing that the 914 LSD would only work in a 7:31 915 Trans. The down side to that is the 5th gear is roughly the same in both boxes and would still rev high. Which is around 3500 RPMs at 80MPH. It would be nice to get 80MPH down to around 3000 RPM's in 5th.

This is from memory....The early 915's I believe 915/02 and /06 is the same carrier size as the 914. These same trannies have the non bolt on front sleeve where the throw out bearing slides. They upgraded those trannies to a larger carrier bearings and being honest if you go to a 915 for big power, that's what you want. The 901 carrier bearings are really small for big HP. Unfortunately the 901 LSD won't fit the later 915's with the more appropriate and larger bearings. Again, that's from memory and I'm old.....

Thanks Paul!! BTW love the 3.6 project in excellence. Hopefully they will sell the series as a separate book, so we don't have to rip up a stack of magazines.

I made a little price for a 915 build myself awhile ago with lots of wevo parts. It does really add up...

2000-transmission
2000-estimate for builder
895-gate shift
249
368
1975-side shift
oil system-700???
938-case mod 1
541-case mod 2
298-case mod 3

$$$9964

total estimate minus other parts like possible light weight gears that have been drilled.

quaife lsd $1648
shift tube and joint figure another $1000


roughly $12612

Paul you missed my question in my last post...

"Paul are your 1st and 2nd gears custom machined by you or did you get these from a shop? Do you know if they required re-balancing after they were lightend?"

Thanks!

In my post above it says "The gears are made in Germany by custom gear manufacturers but can be bought from numerous vendors."

No balancing required and gear making is well beyond the average machinist. The holes are done in the machining process by the gear manufacturer. Basically you buy them and install them as is.

Thanks Paul, I wasn't entirely sure what the context was for the statement in that post.

For those interested in more background on the 915 trans...

I found this WIKI article on a 914 site.

-->...HERE...<--

Sorry for the hijack, but this is turning into a good trans thread. When I bought my car the previous owner already sunk $8k into the 901 trans. So I am kind of stuck for now. Isn't there a gear flip option to make 5th gear higher so it doesn't rev so high? When I get a chance I will research the other threads. I know the 901 turned into a four speed, eliminating first is still popular with the v8 crowd.

Installing a flipped H gear is the most economical way to make a taller 5th and is a popular option. The only other ways, besides the H gear, to get a 901 to have taller gearing than stock is to either have custom gears made, or find the correct year auto tranz and grab the smaller r/p out of it.

Doing a quick check on the net, different 5th gears are available for the 901 as well. So you should be able to physically replace it. The only tricky one for the 901 is 2nd gear because it's attached to the main shaft.

Dumb question Mr. Evil, but where might I find an H gear? What make and model did it come in? How hard is it to change? Enquiring minds want to know. Do I need to pull the trans or would all the guts slide out the rear? Hate it when that happens

Steve, if you are unfamiliar with how the guts go into the box, you need to read up You would need to remove the whole stack and do some serious work to swap the gears. H gears are for sale from me, or other gear vendors like carquip (see link in my sig).

For stock 5th gears the stock ZD in the 914 901 box is the highest. That is why you are left with flipping a 2nd gear (H).

[/quote]

For stock 5th gears the stock ZD in the 914 901 box is the highest. That is why you are left with flipping a 2nd gear (H).
[/quote]

What does an H gear cost? I didn't see any pricing in the links.

You must call for pricing. Prices vary from $300-500.