Formal Introductions...Turbo 912 Project

Britain Smith · 06-22-2004, 03:47 PM

First off, let me introduce myself. I have been around here for quite some time adding my two cents in here and there, but never really involved in the conversations. I hang out over at 914club.com most of the time due to my close ties with some of the founding members there. I have actually owned my '69 912 since I was 15 and through high school I did an extensive restoration on the car to keep me out of trouble. I then left the car in my parents garage while I got an engineering degree at UT Austin...well, I finally earned my graduate degree, moved to Silicon Valley, and I am back into the Porsche scene full time.

Anyway, enough with the introductions...

I have never been really happy with the lack of power that a stock 912 makes. Therefore, I decided to sell the prestine motor on ebay and begin the long journey into more horsepower. However, since I have an early LWB car that handled marginally well I decided to stick with the 4-cylinder powerplant. I am currently about 75% done with the build-up of a turbo charged, electromotive TEC-3 controlled, Type-4 Engine. Before you start turning aways, let me explain that this motor has all the goodies conceived by the type-4 gods and will hopefully perform to expectations. For those who are interested, the engine specs can be found here (the cam selection has since changed however)...

http://www.britainsmith.com/Porsche/TurboMotor/index.htm

As a summary: it has 98mm Mahle Aluminum Cylinders, 78mm Forged Counter-weighted crank, Carrillo Rods, Ceramic Lifters, Pauter Roller Rockers, Thermal Barrier Coating, and a 911 style upright fan shroud, just to name a few.

While I was working on the motor build, I decide that I wasn't happy with some of the work that I did while restoring the car in high school, so I got to work. This work has included stripping the engine bay, front trunk, interior, and underside to bare metal to be painted to color match the rest of the car. I built a rotesserie for this and it is still in progress. You can see the details on the rotessire here:

Rotessire Thread 2.3L Turbo Type-4 Motor Specs

Britain Smith · 06:38 PM

Before the car could be mounted, I had to repair a little bit of rust that I uncovered in the front suspension pan area. I also decided to remove the battery box on the passenger side for a Carrera Fender Mounted Cooler that I acquired.

So far, I have made great progress on stripping everything done:

Interior:

Engine Bay:

Underside:

Britain Smith · 06-22-2004, 03:48 PM

The drivetrain will consist of the type-4 motor as mentioned above, and a 923 transmission. This is the 915 transmission from the 912E which incorporated a type-4 mainshaft. I had to modified the center tunner just a bit to clear the upper ear on the 915 nosecone, only about a 1/4" dipple in the tunnel...

Here is a quick mock-up I did for the custom engine mount bar I had made to incorporate the 912 stock engine mounts (wouldn't want to cut the car up you know). This is also a quick view of what you all are used to seeing...a 911 fan poking up.

To top off all the extra power that I am going to adding, an upgraded suspension was in order. I picked a complete '87 carrera suspension to replace the steel trailing arms, non-vented rotors, and tiny calipers. I think these will have no problem stopping my relatively lightweight car.

Anyway, I will continue to post pictures here as I get farther along. I am sure that I will have several questions when I start putting everything back together. Thanks for such a valuable resource here.

-Britain

TRE Cup · TRE Cup's Garage

looks like you are well on your way. nice work. the type 4 is a natural for the turbo (especially over the old wheezer 912!) consider that the 912e trans may not hold up well to all the torque you should be producing with the turbo. the ring and pinion may not last too long if you are doing hard and fast starts
best of luck with the project- looks like it will be a lot of fun

}{arlequin · }{arlequin's Garage

Welcome (again, I guess) and from the looks of it, some of us might have some questions for you too.

Looks like a great project.

Edit: That fan shroud is a work of art!!

Britain Smith · 06-22-2004, 04:08 PM

Quote:

Originally posted by TRE Cup
consider that the 912e trans may not hold up well to all the torque you should be producing with the turbo. the ring and pinion may not last too long if you are doing hard and fast starts

How does the ring and pinion in the 923 tranny differ from that in a earlier 915 tranny? I know the case is mag but I won't be making huge amounts of power...I know that my stock 901 won't hold up.

-Britain

Yellowbird RS · 06-22-2004, 04:15 PM

great project!
good luck!

TRE Cup · TRE Cup's Garage

input shaft is smaller too. the ring and pinion is the same as other 7:31's. consider using the heavier 8:31 SC or Carrera trans (aluminum housings, bigger input shaft) and changing the gear ratios

Britain Smith · 06-22-2004, 08:51 PM

Quote:

Originally posted by TRE Cup
input shaft is smaller too. the ring and pinion is the same as other 7:31's. consider using the heavier 8:31 SC or Carrera trans (aluminum housings, bigger input shaft) and changing the gear ratios

I know that the aluminum housing is stronger and that the 8:31 r&p are stronger, but I didn't know that the input shaft was actually smaller. Does it use interchangable gears with the normal 915's or are the gears different also? The reason that I was going with the 923 is that it uses the type-4 mainshaft and will allow me to use the lightened, dowel-pinned flywheel that I already have instead of gettting a conversion flywheel machined to go with my set-up.

-Britain

atlporsche · 06-23-2004, 03:06 AM

britian...

join us at 912bbs.org those guys would love to see the project...plus it'll help us get a "renegade" forum.

I've got a '95 subaru engine in mine...first firing should be tonight.

sjd

jpnovak · 06-23-2004, 05:18 AM

Great project. Those engine specs sure sound like fun.

Let us know if you ever come back to Austin. We will have a fun run.

Shuie · 06-23-2004, 05:33 AM

nice job!

Britain Smith · 06-23-2004, 08:04 AM

Quote:

Originally posted by atlporsche
britian...

join us at 912bbs.org those guys would love to see the project...plus it'll help us get a "renegade" forum.

I've got a '95 subaru engine in mine...first firing should be tonight.

jd

I hang out around there periodically, but they are not very open to members who are not completely originally. I also hate the format of their forum...I wouldn't mind being a part of the renegade portion.

-Britain

Britain Smith · 06-23-2004, 08:06 AM

Quote:

Originally posted by LynnsABCs
Looking good so far. How are you going to keep the Type 4 heads from dropping their valve seats? Just curious.

The heads have been throughly gone through and coated with a thermal barrier film to help remove the heat generated by the increased combustion pressure. The cam selection and valce train has also been optimized to reduce these issues.

-Britain

atlporsche · 06-23-2004, 08:18 AM

Quote:

Originally posted by Britain Smith
I hang out around there periodically, but they are not very open to members who are not completely originally. I also hate the format of their forum...I wouldn't mind being a part of the renegade portion.

-Britain

it's changed a bunch...and the new forums are even better...unless you've seen the new forum....I hated the old format too...

I'm trying to get a renegade section up..."lunatic fringe" we'll call it...

check out the new format...and as for originality...I'm the SE coordinator and board member...I'm about as far from original as you can get, and they accept me.

sjd

vash · vash's Garage

yowza

hook em horns! that is an amazing project.

Britain Smith · 06-23-2004, 09:09 AM

Quote:

Originally posted by atlporsche
it's changed a bunch...and the new forums are even better...unless you've seen the new forum....I hated the old format too...

I'm trying to get a renegade section up..."lunatic fringe" we'll call it...

check out the new format...and as for originality...I'm the SE coordinator and board member...I'm about as far from original as you can get, and they accept me.

sjd

Thanks, I will check it out...

-Britain

Britain Smith · 06-23-2004, 09:10 AM

Quote:

Originally posted by vash
yowza

hook em horns! that is an amazing project.

Yea, if and when I build a race car...it will be burn't orange and have longhorns painted on the hood.

-Britain

sammyg2 · 06-23-2004, 11:06 AM

You can't turbo a type 4!
LOL I had to say it, kind of an inside joke on the 914 board.

The 901 will handle the torque just fine as long as you don't rev it all the way up and side step the clutch in 1st.

That thing should be a blast, SWB, light weight, balanced, plenty of power.
Any guess on what boost level you will run?
On my 914 I found that around 7 psi was the sweet spot, anything over that needed an intercooler.

Britain Smith · 06-23-2004, 12:15 PM

Quote:

Originally posted by sammyg2
You can't turbo a type 4!
LOL I had to say it, kind of an inside joke on the 914 board.

The 901 will handle the torque just fine as long as you don't rev it all the way up and side step the clutch in 1st.

That thing should be a blast, SWB, light weight, balanced, plenty of power.
Any guess on what boost level you will run?
On my 914 I found that around 7 psi was the sweet spot, anything over that needed an intercooler.

Actually, the car is a '69 so it is a LWB. I will start out around 10psi of boost or so. It will have an intercooler which will be tucked under the stock engine lid (no tail).

-Britain