tacker

Has anyone considered putting a 997.2 electro magnetic clutch in to replace the viscous clutch?I'm looking at doing this conversion pulling together info.
The EMC has been holding well for the 997s and has a controllable lockup. I have a standalone and can connect to the traction control. Maybe it can work with the 993 factory ABS?
any thoughts?
any interest?
off the cuff, i think making a custom transmission nose to put the EMC and then a custom torque tube

Basal Skull

Sounds interesting, I assume you're having traction issues with your power levels and want to be able to control the power delivery to the front better?

OverBoosted28

^^^^^^ safe assumption. That car probably grabs as much as possible, clawing to scream down the track. Would love to see some good footage of it. I'm sorta bad about "reliving" things. I like to record surfing, or track videos, so I can live it again. Could get some neat footage, of his runs. :-)

tacker

Because of the issues I had at the Mile I changed coils and I'm now running 6 CHT k type thermocouples. I need to start testing the car to create some heat. It's been a challenge to find a good spot to go WOT. So I decided to take it to the drag strip next week end and we'll see how the temps look.
The traction issues have been masked thru boost by gear and traction control. But all this makes the car slow the R888 either went bad after 2 years or they are just lame. The car only traps around 134 in the 1/4.
So I got a set of Hoosier drag radials and they transform the car I will do some testing soon.
The drag radials suck around turns and don't like swapping tires around if I don't need to.
This leads me to the 997.2 AWD unit. The 997 guys are getting 1.6 60ft times on R888 without all the drama of 2 wheel.
I believe the 997 EMC can be fitted into our cars without to much hassle. The 997 unit is to big to fit in the tunnel but the actual clutch is only slightly longer then our VC so I'm thinking
Make a custom nose for the tranny and make a shorter torque tube

I have videos of the mile I will try this week get on u tube

TB993tt

Fascinating please keep it coming

carguy19

I love this.

My car traps ONLY around 134

tacker

Launch tested tonight with the drag radials. It's hard to be consistent, I have a clutch office to control the engagement rate and this helps but I either spin tire or bogg the engine. I think I need to raise the launch rpm from 4600 to 5500 or so this way I'm above the torque curve when I take off. If I can consistently spin then I can drop tire pressure.

Kinda learning

Basal Skull

^sounds like you might find launch control - type that causes random misfires to keep at pre set rpm on launch and a flat shifting device - which also causes misfires when clutch is depressed so that you can keep your throttle wide open the whole time. I understand that the misfires keep boost up while staging and when shifting. Got to be hard on the drivetrain though, better get spare upgraded drive shafts!

tacker

I'm using the launch control now. I floor the pedal and the Rpms hold at whatever I set it to. I can change boost settings as well. As the car starts to move the Rpms ramp up as speed increases. The launches don't feel that hard mostly due to the clutch orffice I guess. I built the driveline to handle some abuse and maybe I can get the AWD working and let the front diff take some load. I ordered the EM clutch should have it next week.

carguy19

If you can get a 2 step/WOT box wired into your car or if its part of the ecu you are using it will help your launches and also spool the turbos to max boost on the line.

I've been drag racing my whole life. (not Porsches, mostly mustangs) but the concepts are the same.

My last turbo mustang I built picked up .7 in the 1/4 mile, when I wired in the 2 step and found the sweet spot on the launch between hooking up, bogging and murdering the tires with spin.

tacker

Carguy19. The EMS I'm running has 2 step and although I'm stilling working on dialing in the launch I find it to be consistent. I'll get it figured out soon. I'm running a tall 1st gear so the launch RPM will be pretty high.
Got the EM clutch and it look as thou it won't fit in the tunnel in its stock 997 front diff housing. Kinda what I thought. Also the spines don't match the transmission or torque tube driveshaft. So it looks like a bit of custom work. And after looking at the front diff in our cars I'm starting to think the diff belongs on a go cart. Not a sturdy looking piece at all.
I need to collect more info about the different front differentials that can be adapted. I'm leaning towards the 997 unit and modify the torque tube so the EM clutch is mounted on the transmission.
Maybe a 964 front diff, looks more rugged. I need to call around.

tacker

So I figured out how to build a custom transmission nose to will allow the 997 EMC to fit in the tunnel. It's tight but not too bad. The housing has a separate oil compartment for the EMC . I made a foam model to test fit up and some day soon I will machine the 3 piece housing. The remaining bits will be cutting the torque tube and replacing the driveshaft with a shorter one.
All the other projects are near completion as well.



997 emc mock up

997 emc mock up

foam mock up

modified spline pressed and pinned waiting welding



gutted viscous clutch






section view of housing assembly

Basal Skull

^ wow, is all I can say...

tacker

can't wait to wrap it up and dial in. Maybe I'll see a 1.6 sec 60 foot on street tires. We'll see

tacker

mock up fitment. i need to add some clearance between the housing and the cross brace. Fits as expected.

billet housing, need to add oil fill holes


interface plate seals tranny oil from clutch and mounts housing

I have to make a custom shifter extension and weld the torque tube flange. I finished the drive shaft and it's in place. I will add a front brace to front differential kinda like the 997. I can build off the bolt holes for the sway bar.
almost done!.. The intercooler/intake project is almost complete as well. Car should be running in a month.