Long story short

gtx2863 running 1.3-1.4bar, clutch holds fine in open loop setup - plex tuning ebc

with closed loop and boost hitting earlier, clutch in slipping and sometimes when very hot (after 5+ laps on the track) doesnt upshift perfectly and gives some shocks to the gbox

if still going to change it, I am looking for a setup to keep the torque even for race gas setup, that would be 800wtq or 1100Nm or so (might move to gtx2967/gtx3067 or even gtx3071 later if building the engine to 3.8L)

As I still run the stock FW, I am looking for all components needed to have a very nice clutch setup and be over with it.

I have used ERP triple, but thats not the solution for me. Also tilton isnt what I am looking for as ooking for OEM parts as much as possible, I know something like 764 discs or so.

Also I guess a double disk setup would be better than a single disc as guys are using for motorsport applications on the track. I guess also a light FW is needed or at least recommended. Any thoughts?

I know my tuner has also a clutch (dual disc) but would like to be able to buy it from Europe if possible, any ideas ?

 

I've heard (and seen photo's) of protos dual disk setup and from my perspective it looks perfect.

It does require a single mass flywheel, and then uses 2 organic plates and a 764pp. Pressure plate needs to be modified and then a floated plate installed. Holds twice the torque while running all stock parts.

Will be my next order.

 

Turn the boost down. Will help both the car and the driver and save you some money. 800 wheel torque is hurting you on the track. Not helping. I bet you could be faster (and it would be much easier to drive) on track with 600 whp especially with the handling mods you have. You are well past the point of diminishing returns.

Not only that but longevity, pushing thatuch power through your drivetrain lap after lap is going to cause havoc.

 

Wow is the OP on stock rods and head studs?

 

Yes this is a big boy clutch, maybe not going so far. Also that is like a 4000$ clutch, I would be looking maybe for something a bit cheaper if possible. But yes, leaving money beside I guess that is one of the best clutches on the market.

I am running only 1.3, maybe 1.4bar t the track, so maybe 600-650hp and wtq, I was considering 800+ just as my engine is built and for some times can get out for some fun on the straights too

Problem is even at 1.4bar with perfect boost control (make boost hit sooner) my clutch is slipping, surely can do boost ramping and be happy. That can translate into a flat torque "curve", decrease the boost target till 4000rpms and add some boost after 5500rpms for example

Nope, pauter rods and raceware studs. Engine has seen 2.2bar last year

 

Why not the Tilton Triple from SRM? Like $2700 all in.
That's probably the route I'm going

 

Tilton for 2700$ sounds good but last time I checked was 6000$

 

Carbon/Carbon is...Metallic isn't. Contact Sean at SRM. He makes his own flywheels for the kit too.

 

I would advise a separate map for the track. You will still be unable to use a lot of hp for the vast majority of your laps with your current mod list. And you will most likely be a worse driver to boot. But at least you are taking it to the track so I applaud that.

But to answer the original question I run a tilton cup clutch, good to 700 wheel torque. Ran 2 years before needing to replace the clutch pack. Track only. I would go with tilton of some sort though the one I have may not hold under the power of your new build.

 

I have a almost new ERP clutch for sale in the for sale section, pretty light pedal pressure and it will hold more power than you'll ever have...

 

Turn the boost down Fadi. You are going to start breaking stuff fast. I've broken 2 set of rear hubs in the last year since my 3.8 engine rebuild and I'm only at 600hp/670tq at the wheels. Breaking a hub causes a lot of destruction $$$. I'm in the process of having some hubs made from 300M but they're going to be over $2000 each versus $200 for the factory part. I'd turn it down...

 

You broke the stock 996 TT pieces? Do you run hoosiers? I have never heard of a 996 TT hub failure.

 

Did you ever try cyro treatment? Fairly cheap way to add strength to parts. We used to use it on lots of parts for dirt track cars and the strength and wear differences are actually quite impressive. Probabaly cost about 50 bucks a hub to do it.

 

After I originally broke the original factory 996TT rear hub we replaced it with a 997GT3 hub which is a little beefier in certain areas but one in the area of the failure point which is where you have the apart radius of the neck and the flange itself. This area can be make thicker resulting in a larger radius to match that of the bearing race. The larger the radius, the lower the stress. Naturally a straight 90º point will have the highest stress concentration.

6 months after putting in a new 7GT3 hub (which I believe are the superseded hubs for the Turbo/GT2 now) I broke that one too in the exact same placer. In both cases it was the left rear hub which is the most heavily loaded as the tracks I run are mostly right turns. After having a stress analysis done on the broken hubs, the conclusion was that there was metal fatigue as a result of repeated lateral and twisting loads on the hub. Yes, the large center axle nut is frequently checked for correct torque and has never come loose.

I run mainly NT01s and Kumho V710s with Motec showing constant lateral loads of 1.2-1.3Gs with spikes in the 1.5G range. Engine torque to the wheels is 673 ft.lb at 4000rpm.

Here is the abbreviated correspondence from the company that will be making the 300M hubs:


"I have got a couple tests done on the metal on the stock hubs. There are a couple different ways we can approach doing a high strength replacement.

Option 1, we would to do them out of a high grade billet carbon steel, 4340. Should see a 20%+ increase in strength.

Option 2 we would utilize an extraordinary high strength vacuum arc re-melt steel, 300M, the same thing used to make landing gear components for aircraft. It will never get any better without physically making the hub bigger and thicker in the stress zone. Approx. 30% strength increase. The other advantage is that with the VAR process there is much less likelihood of having inclusions in the base metal.

I can make the root radius as large as possible and there is also a possibility I could regrind the radius on the bearing race to allow for a larger root radius on the hub.

Strength increase is based on rudimentary calculations from the material that the sample hub you gave me. There are a lot of things that go into calculating the actual loads that these can support that I don’t have readily available. I can’t guarantee the results from the material change but it should be a vast improvement.

Prices discussed include all reverse engineering, programing, heat treatment with cryo, and wireEDM of the splines on a prototype basis. If you were to decide to go ahead with larger quantities and the design doesn’t change the price and come down a good bit.

Thank you,"



Failed 996TT hub:

[url=https://flic.kr/p/oBB2Px]




Failed 997GT hub:
[url=https://flic.kr/p/Fiw6Jm]

 

How many track days on the 997 hubs? That would concern me as 6 months is a VERY, VERY short time on the hubs. Porsche usually overbuilds these items I dont imagine the v710's can hold 670 during anywhere near maximum cornering g's. 1.3 is high but shouldnt fatigue them in that short of an order. Could it be some other combination of suspension mods putting extra stress on the hubs?

Is your gearbox built? Ratios's? 3rd gear has been the weak link for several of us. I would think that would have gone before the hubs. Whats your ride height?