916 kit on 915 trans, Who dunnit? Options

[-JR-]

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-

[dr914@autoatlanta.com]

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!

[-JR-]

don't do it!

--------------------
George Hussey
Automobile Atlanta Inc.
dr914@autoatlanta.com
770 427 2844 ext. 16
505 South Marietta Pky
Marietta, Georgia 30060

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-

[Wilhelm]

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!!! (IMG:style_emoticons/default/sad.gif)

[GeorgeRud]

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.

[dr914@autoatlanta.com]

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

[-JR-]

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-

[GeorgeRud]

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.

[-JR-]

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.

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.

[carr914]

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.

[-JR-]

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.

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

[GeorgeRud]

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!

[PRS914-6]

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

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

[-JR-]

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-

[PRS914-6]

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

Here is the final gearing for the 915

[-JR-]

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.

[SirAndy]

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 ...
(IMG:style_emoticons/default/shades.gif) Andy

[pcar916]

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!

[PRS914-6]

5th gear is OK for cruising on the freeway.
(IMG:style_emoticons/default/shades.gif) Andy

But would Amoy agree with that? (IMG:style_emoticons/default/slap.gif)

[turboman808]

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

Here is the final gearing for the 915

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. (IMG:style_emoticons/default/smile.gif)