The IF2 thread

[Peter Bull]

Originally posted by beepbeep
Anyone knows good G50 clutch that holds for 1200 Nm? Tilton? Dual disc?

Sachs Race Engineering have some really mean rigid sintered discs, as do Spec, but I do not know if they can cope with 1200 Nm.

/Peter

[livi]

Sorry to hear about that, Göran.

No Bilsport then ?

[Kroggers]

Hay Göran, are you all at Barkarby this weekend for the car thing??

[beepbeep]

Originally posted by Kroggers
Hay Göran, are you all at Barkarby this weekend for the car thing??

Tokan will take the car to some sort of Street Car fest (dunno if it's at Barkaby) but most of us won't be there. I'm not fond of styling and bling-bling stuff and F1 Hockenheim goes on telly tommorow...

[beepbeep]

Engine is dropped...err....I mean separated. They have strict noise rules at Nurburgring so some last minute touch-ups of muffler are made. It's going to be detachable. When you need full flow, you just pull it off (peel off the gaffa-tape ).



Tranny is also out for some R&R. G50 side plate was flexing so much when drag-racing that one of bolts holding the differential (Torsen) hit the plate and broke one of reinforcement ears (on inner side). 1000 Nm is a lot, but only side-plate took a beating. Tranny feels OK (we are going to dissassemble it tonight to check shifting forks for cracks) New billet side-cover (sourtesy of Powerhaus II) is on order. Differential doesn't have a scratch on it.

Also, sintered clutch pads were worn down to rivets, probably due to all drag-racing. They will be replaced so clutch will hopefully hold for couple of laps of ol' ring on lowest boost setting. Pressure plate and flywheel were OK. Just usual wear, no need to turn the flywheel.

[herman maire]

Goran,

Do you have any tricks to check "back lash" in the ring&pinion or gears in general
That does no require fancy tools? How do you check yours for wear?

Also how easy is it to reshim the diff after you pull it out?

Cant wait to see the ring video...You better post something or I'm gonna show up at the shop in sweden one of these days.

[beepbeep]

Originally posted by herman maire
Goran,

Do you have any tricks to check "back lash" in the ring&pinion or gears in general
That does no require fancy tools? How do you check yours for wear?

Also how easy is it to reshim the diff after you pull it out?

Cant wait to see the ring video...You better post something or I'm gonna show up at the shop in sweden one of these days.

In theory, you don't need to re-adjust backlash if you just pull the side-cover to swap diff. Diff lives inside crown-wheel and doesn't really change anything.

We changed side-cover, both bearings (supporting diff/crown gear) and side-plate. Theoretically, backlash should still be the same as long as pinion/crown-wheel are in same position. In reality, position of crown-gear probably changed. There is adjustment bolt in PHII side plate who's function isn't clear yet.

As soon as we get info from PHII, we plan to do check backlash. Factory of doing this usually means dial indicators. Then there is also a way where you check footprint on crown/pinion with white grease. You open the side plate, smear some white grease on crown wheel, bolt the plate back and turn the gearbox until crown-wheel goes full circle. Then you open the plate and check the pinion footprint on crown-wheel. If footprint indicates that pinion touches crown gear in wrong pattern (on tooth edges, for example), it needs to be shimmed back to specs.

Example:



If backlash is out of spec, we'll probably have to find somebody who's pro on final drive adjustment as it's beyond our skills. Ring is in two weeks so it's kinda tight.

[beepbeep]

Engine is now installed with new billet side-plate in place.



We also made "interesting" observation. When we removed one of front wheels it was obvious that lock-pin securing the pads worked itself out and one of pads was about to jump out. According to wear-marks on disc, car probably went trough Superstage like this

No harm done but I bet result would be even better if brake force was 100% even on front wheels.

[GJF]

Tilton 7.25 3 disc carbon/carbon will hold 1260 ft/lbs of torque. That's about the most clamping force I know of in a race clutch configuration.

[beepbeep]

Here is old OEM side-plate. We found marks on one of bolts and pieces of metal broken off the plate inside the case. According to Powerhaus II, side plate can flex as much as half of inch(!!) when abused with side-stepped clutch start on sticky surface .





New plate, made by PHII:

[beepbeep]

The very direct update (120 seconds old):

[PorscheGuy79]

RING IT! Thanks Goran.

[beepbeep]

I haven't updated the thread for a while, here is a rundown:

1. A month ago car was run in Superstage (normalized track run) for swedish car magazine. After that, car was quite worn.
We found out that one of brake pads worked itself out of the caliper and that one of turbochargers that was rebuilt on previous occasion actually had wrong wheel fitted. Impeller was too small! So car run the whole track run with unbalanced turbochargers. Also, there was a severe understeer felt in every turn. We believe that it was Torsen-style differential that was too aggressive together with lot's of power and light front end.

2. Latest week car got:
- Porsche Motorsports clutch-type differential
- New rear brakes
- New turbocharger identical to the left one
- Torrough service.

3. Car was trailed to Nurburgring yesterday and is going to be driven in Scuderia Hanseat. Before that, it is going to be driven on turist laps. During turist laps, you cannot exceed certain noise limits, so Frankenmuffler was built and installed.

Frankenmuffler (TM):


Muffler is built so it can be taken off when it's time to kick Carrera GT track time

Right now, car is driven on a turist laps on ring using 0.8 bar chip which is the very lowest boost setting. Later during course, 1.2 bar is going to be used.

Car just did 283km/h GPS-speed trough Schwedenkreutz on 0.8 bar with Jocke behind the wheel. That is seriously fast considering that Radical SR3 Turbo posts 257km/h trough the very same part of the track.

[PorscheGuy79]

Originally posted by beepbeep
Car just did 283km/h GPS-speed trough Schwedenkreutz on 0.8 bar with Jocke behind the wheel. That is seriously fast considering that Radical SR3 Turbo posts 257km/h trough the very same part of the track.

That is wicked fast...

Goran, what are those metal plates bolted do the back on either side of the wing? Are those the more secure rear end hold downs?

[herman maire]

Awsome Goran
Did you get that understeer under control or did you have to change the diff?

Understeer is the worst...

I forget.... are you using factory connecting rods in the motor?

[livi]

In some aspects, I am still proud to be Swede.

[beepbeep]

Originally posted by PorscheGuy79
Goran, what are those metal plates bolted do the back on either side of the wing? Are those the more secure rear end hold downs?

Those are fast-release hatches that secure removable rear end.

[beepbeep]

Originally posted by herman maire
Awsome Goran
Did you get that understeer under control or did you have to change the diff?

Understeer is the worst...

I forget.... are you using factory connecting rods in the motor?

Joakim Qvarnström (the owner of the car) complaned a lot about understeer when taking off from the bend. Steer-in was just perfect, but accelleration from the apex (usually the part where 911's excell the most) was disaster. Car just ploughed straight untill you let of the gas, despite 285's and lot's of camber up front.

After lot's of head scratching, we concluded that it must be the differential. It's a 80% locing Torsen/Quaife unit that is just perfect for drag-racing (doesn't need rebuilding, never wears out and never slips) but it just locked too hard in tighter bends. This, connected to a fact that car has gazzillion horsepower and is lightened up front just made it hard to drive. I could be that car was doing a wheelies as well.

New clutch-type diff is installed and never tested prior to ring. We didn't have time to adjust backlash either...Tokan just slapped the diff into the tranny and off it went.

About connecting rods:

No, they are H-beam steel rods delivered by local company called Verdi. They are very similar to Pauter rods. I even heard that Verdi actually sells Pauter rods but I'm not quite sure. They are very sturdy. Pistons are OEM.

[herman maire]

Soooooo...... Goran, How did the car hold up/run. Any understeer with the new diff also what lock% is the new diff?


This is in no way a comparison but my old 73 911S understeers the same way..... Turn in is awsome.... Hit apex perfectly....Then when I get on the power the front starts to run wide until I let off the power and thats only 200HP. I have never had that feeling of understeer with any BMW I have ever owned . FWIW my 73 S does not even have a LSD and it still understeers.

I hear that 993's understeer pretty bad also unless your running a major race
set-up.

[Facey]

not to hijack the thread or anything....

but on my carrera sway barred, 20/29mm tb set up with blisten sports, riding on 18's 235/265. at high entry speeds i get some intial understeer....which if handled poorly can be scary.....after that though the car settles down bigtime....and right as i start to unwind the wheel i can usually start feeding in some throttle again.....of course all judgements made my the wicked communication the early 911's have...

however i guess your 911 is in a whole other league....

i want more pics!!!!

i show your car to my buddies all the time that say things like "theres no old 911's that could take down a new turbo....or even worse the Z06 guys...."

keep it up...