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Our new reinforced 915 differential cases are nearly ready for sale. We are currently doing the final milling procedures on a 5-axis machine to the casted gearbox cases. The cases are made from casted alumnium and are heat treated. Very solid material, which has been used on many other very stabile products yet. They were engineered much stronger than the original cases ever were. Differential bearings of 930 gearbox can be mounted. Differences on shape only on 2nd sight.
First finnished parts in the next few weeks.
First internal project is building a 915 gearbox with this case for a G-model with 964 engine.
Sorry
for being that quick with info.
First want to introduce myself.
Have been in revision and optmization of Porsche gearboxes for at least 20 years. Company results of my hobby. Originally I was working as a MBA in different bigger companies. We are producing a lot of parts on our CNC mill, mainly for and around Porsche gearboxes, but also parts for VW Beetle, vintage motorbikes,.... Have a lot of molds at a foundry working for us and producing casted aluminium parts.
We have learnt over the last years, that there are not so many 915 gearbox cases left, that are in good quality. Many 915s have been used for different conversions. not many are left in the market. Most early ones are in bad condition. Later ones are worn ouit in the bearing areas. We also know the problems of these gearboxes and tried to eliniminate them in our new case. The case is much stiffer than the OEM part. Fins are longer and by this give more stability. Material is very good. We made experiences wjth it over the last years. First parts were x-rayed to check if they are free of bubbles in the cast.
I originally came (like many others) from the VW Beetle Tuning Scene, but have been with Porsche over the last 15 years. It´s always been my aim to improve existing parts or to create newer better parts to use instead..
If you Need more info, I will like to give them to you. Sorrry that I started th eother way!
Martin
Have a 914/6 Project car (916 gearbox and 2.3 litre engine), but also a G-model waiting and a daily Driver VW Beetle 1303 with lot of Porsche technique, but also a Subaru boxer engine.
Hi,
thanks for your positive comment. You´re very welcome to follow. Today or tomorrow the final milling should have been or will be started. It is made at an external company with a 5-axis CNC mill. We only have a 3-axis with round table (4th axis) We did the first two milling procedures, but now have to give it out of house, cause mill is a little too small. The case was completely new designed after measuring some OEM cases. It is designed in the final Shape of a ´85 915 gearbox. Means it already has the area at the bellhousing where the sensor sits at the late 915 gearboxes.
The whole project took us about one and a half year until now and we hope that it will be ready to test with these first two samples. We have another 2 raw cast parts stored and the next batch (some more) is already reseved at faundry. We have a first project for a customer with a 964 engine in his G-model. He´s waiting for his gearbox to come and I hope I can help him out in the next weeks. 2nd case is reserved also, but will only have to stand a 2.7 S engine. No big deal I think.
As soon as final milling is completed I will post further Pictures.
Hi,
the first case is completely finnished and I assembled this one case to a complete gearbox to check all dimensions. All bearings were mounted, also the shafts with gearwheels, differential, cases, side plate, etc. Everything fits and works fine. Checked measurement for the pinion also. Only 2 minor adjustements for milling the second one next week. See some further Pictures.
first gearbox case is completely milled and we did test Assembling of one gearbox with this part. Everything fits and works, only two minor adjustments to the milling procedure for the next gearbox case and for future. Attached some Pictures.
Embarrassed to ask - but can you ELI5 what benefits a reinforced diff case provides for us non-handy folk If someone were to rebuilt a 915 transmission would something like this make a vast difference? Not talking bad about your work or the product - just genuinely curious!
@ksluna: no reason to be embarassed. We made the case, cause there have been none in stock at Porsche for a longer period, also because many of the early ones are in very bad condition, also because many of them are used for different conversions (916, Beetle, busses, kitcars,...), because we know that OEM parts are too weak for some kind of engine, ....
Altogether many reasons.
Our first Project is a gearbox with such a case for a G-model with a 964 3.6 litre engine. Have the OEM gearbox here, that has been used for a while. Bearing bores are that big that you can "throw in the bearings". Too much pressure for the OEM case.
Think today the second case should be finnished at the CNC-Company where we have some of the milling procedure done (5-axis).
When I have it here I will post firther Pictures.
For the future the surface of the cast will be much smoother. Faundry blasted them with rough material. Surface of the cast is very good. They made it worse by blasting with that material.
This looks like a great product for those of us that are looking to use a 915 in a higher hp application. Do you have any estimate with regard to how much hp can be applied to your new case? When do you anticipate them becoming available and who will distribute them in the US?
@Tonger:
what you write is absolutely corrct. This was my main aim.
I wait for the second case coming. Then will assemble this gearbox for the customer waiting. He will drive it at short notice and we will know quite soon how it works. Have two more casted cases in my workshop that can be milled at short notice. Others to come from faundry in about 4-6 weeks.
Yet have no dustributor in the US for this product, but have had some for other products in the past. We will see. Besides, it´s no problem to order directly from me. I regularly send goods to the US (mainly 916 kits and Beetle conversion parts).
martin congratulations . this is brilliant. i have recently switched from a G50 race car to a vintage 915 based . 911 74 RSR .. making about 300 hp at wheels . turning 17 inch slicks... i am on a very steep learning curve for use of the 915 , even a sturdied up race box, and learning its traditional faults the hard way. look forward to when these are track tested with hi hp motors. frank
Martin; you show a single piece gear stack support in one picture, but when you assembled the trans you did that with the o.e. two piece supports. Why?
BTW: BRILLIANT undertaking of a major project! Congrats!
took some weeks to come forward with the Project. CNC supplier destroyed gearbox case no. 2 on his 5-axis. Then vacation time and I had to prepare no. 3 and 4 on my mill. Last week I could pick the latest two ones from there. In the meantime I completed the first one for a customer gearbox. It was the pre-serial case that was shown earlier. Next week I will assemble the one for the 3.6 engine car. Some Pictures attached to give you some impressions.
@Peter Zimmermann: I did mount the two pieces Support cause I only wanted to make a test assembling and measurements. Therefore the two pcs-support is much easier to handle. Gearbox next week will be assembled with the single support.
Last days I assembled the 2nd gearbox with the new case. This time with the 90 mm diameter differential bearings of the Turbo. This time also with the single piece gear stack Support, CNC millled differential side plate, oilcooling prepared, limited slip differential. Mounting was easy and everything fitted well. This gearbox is for my customer with the G-model with a 964 engine installed.
06-11-2019, 05:19 AM
NEW reinforced 915 gearbox differential cases
If someone were to rebuilt a 915 transmission would something like this make a vast difference? Not talking bad about your work or the product - just genuinely curious!
