Alex (UK)

Yeh, I am probably going to go with a Sachs stage 2 kit and a 890Nm pressure plate. Whether I go to a LWFW is what's holding me back right now. I'd love more freeness though the revs but a rattle is probably not particular in character with a luxury GT car....

Alex (UK)

I took the Turbo out this morning and tried to replicate the slipping clutch. Temperatures were between 5-7 degC. In 5th gear and below I couldn't get any slip no matter what I tried. In 6th, with full acceleration from 60mph with overboost (1.2 bar) on a flat motorway - nothing.

So it seems that only at 50mph in 6th gear do I get clutch slip. I can still smell the clutch from last week when I did it though!

So I'm not so sure I need a new clutch right now after all. I think if it starts slipping more often then a Sachs stage 2 clutch with the OEM dual-mass-flywheel will be required. If I was going to move to a single-mass-flywheel then I would upgrade right now as it would be a performance enhancement. But for just a functional upgrade, I think I can avoid 50mph 6th gear runs in cold temps for daily drives and stick with OEM

GTRNICK

I used to get this in my 996tt and the clutch never did go, it happend about 6 times over the time frame of about 3 years and always happend on the motorway in 6th gear! (i did ask my porsche mechanic about this too and he said it could be due to the fact the plate is not warmed up properly yet and the surface might be smooth at the point that it slipped?)

If your clutch was really gone it would not bite at all and just fly up the rev range without your car going anywhere.

Just keep an eye on it as you never know!

Have a sachs plate sitting there ready and waiting or you could with a lightwieght fly wheel kit as this would help with performance but im not sure about it for a daily drive although some others could advise you on this.

P.S. My old 996tt had exhaust and remap and i got it with 24k miles and sold it with 50k miles and clutch was still fine as I never launched it.

98C4S

Why is the 560BHP Kit cheaper?

http://www.cargraphic.de/index.php?/...,3103/&start=3

Alex (UK)

Looks like the difference is in the exhaust.



I dont think you have any cats in the 560PS version. Hence no TUV approval.

Alex (UK)

PS: my OEM clutch is still holding up fine BTW...

avader906

Hi All,

Im getting the 600hp cargraphic upgrades finished up here in UK on my 997tt. I had the ECU tune + headers + full exhaust done last march. Upgrade changed the car. I also report some clutch slipping in cold temperature (below 10deg C) and under load (uphill full throttle low revs in 4th) on stock pressure plate. During the summer I got 7k or so miles on and also report substential power decrease in 30 deg C ambient tem and the car noticably running rich etc.

This time around I went with further cargraphic/rs tuning modded VTG's + ECU re-tune + 997.2/gt2 rs coolers. It looks like v2 997tt/gt2 rs coolers are significantly more efficient as reported elsewhere - and considerably cost effective when compared with other options (thx Toby). My car is mainly for street and hence that was the deciding factor.

I decided against plenum and tb upgrade - mainly not convinced it will add power under the curve on a turbo engine and have concluded that it might give back some low end torque against better high end - again something i dont want in a mainly street setup. The kit contains cargraphic carbon turbo inlet pipes and i thrown in some silicon hoses as well. Uprated pressure plate concludes main upgrades.

I've driven 7k miles or so this summer in high heat and hard driving (london to south france/spain and back a few times) - and was pleasantly surprised that clutch disc is ok and been also told that turbos looked fine as well (knock knock knock). Further to tuner recommendations I've added uprated DVs, front mesh grill, steel break hoses + better fluid. Car went through main service with all liquids change (including transmission) as well as plugs change (went with oem on tuner recommendation).

In terms of suspension - its next area I would be working on. I went against rushing through with lower springs (even if progressive). I already have fast road geo setup and this time requested stock mounts to be changed for yellow WEVO mounts. I dont like how whippy backend feels in tight S turns even when tires loaded - and hence this is my first suspension mod. I am also considering to get wider front fenders and go with that cargraphic setup (9.5x19 front with 265/30r19 and 12.0x19 with 315/30r19 ) but currently unable to light enough rims - apart BBS FI - still looking around.

Will finish the write-up after I pick up the car

Alex (UK)

Sweet! Parr?

avader906

yep

98C4S

Looks like the cheaper kit does without the rear cats, does a UK car need all 4 cats? Will it pass the MOT on just two cats?

emmo.84

Hi avader, I did not understand if you went on with the RS tuning turbo modification... that is modifying turbos in exchange + new carbon ducts + new ECU remap.
I have the exhaust + ECU + filter on my GT2 and it goes great for racing on the track with slicks.
I was afraid that I could lose some drivabilty with the new turbos... RS said the new GT2 RS intercooler are only a very small modification...
I know also SPORTEC in Switzerland modifies the turbos, and I Guess it's all the same Borg-Warner stuff... also the pictures in FVD web site look the same.
They all change the air side part in the turbo, and that has a larger diameter, so the ducts are different too.
Bit worried reading your conrod discussion... I have 7 races to do and a broken rod would stop me...
Last question: do you think turbos need mainteinance after one race season and 30.000 Kms. showing on the dash?
Thanks for your precious help.

avader906

Sorry for delay replying - i am travelling and have already done 2.5k miles since the conversion. In terms of what was done on my early 08 997 turbo (UK). This is part of cargraphic kit retailed by Parr in UK (developed by rs tuning - they did ECU and modded turbos)

- modded VTGs. done by rs tuning through cargraphic/parr in uk. pretty standard stuff here - obviously will never get exact specs short of taking turbos apart - machined housing both sides (larger diameter more flow capacity) as well as exducer/inducer wheels mods. my stock turbos had 15k miles on them with last 10k inside 8 months running ECU+headers+exhaust and had been inspected prior to sending to rs tuning with no damage reported.
- compressor inlet pipes in carbon
- pressure plate
- uprated DVs
- 997.2 (same as gt2 rs) coolers
- wevo engine mounts
- bits and pieces such as steel hoses; front radiator grills etc

overall upgrade ment to bring 560 hp or so (tune/headers/race cats/exhaust) to 600 hp.

i took delivery of the car during uk snow nightmare start of december. so at first it was impossible to gauge upgrade impact on the car (picture 70mph wheelspin in 4th on any decent WOT attempt on bold rubber). ironically first thing i noticed were wevo mounts. call me biased but i hated that stock turbo "boat" feeling from backend of the car. new mounts got rid of 80pcnt of horizontal and vertical travel and i could finally feel suspension working clearly.

anyways. i drove to spain and got to test the car properly. would i do turbos modd again ? my car is for long distance mainly highway drives and generally i dont track it more than few times a year. modding turbos is shifting the balance from stock compromize between restrictive turbine but faster spool times vs cooler temps / more flow / more power but more lag. Turbos now spool higher in rpm (around 3150) so there is definetly some low end loss. there is zero drivability loss if u adapt; it does feel much stronger through rpm range and is truly linear. higher end is much much stronger and u can use (keep in mind this is turbo and not gt2) 6300+.

i think that its a nice mod. 600hp is defo beyond what stock turbo chassis can handle without upgrading suspension. if i had to do it again i would of made sure to get a test ride with larger non VTGs turbos on 996/997 to get sense of exactly how much (lag) benefit VTGs would bring to a similar setup. i think the benefit of VTGs is now marginal (as measured by change in exhaust pitch and intake pitch dynamics). marginal in terms of not performance but performance vs price.

i think turbos are items that if you looking into 100k hard driving miles ownership would be replaced once or twice. if you race you defo have hours limit on all components and will be looking at rebuilding a lot of things besides turbos. non VTGs upgrades are inexpensive in comparaison if need to be replaced. if i was racing 997 gt2/tt i would look for non vtg solution for sure. I do love the upgrade though.

Stock 997.1 coolers are pretty bad. 997.2 is decent upgrade for 600hp area applications. think this been shown in detail in other forums. its not ideal but best performance / cost. also in long run (think backfire that destroys coolers - replacement cost on 997.2 oems is very decent). on a series of hard pulls in 15deg C temp ive felt timing pulled even on current setup. though it could be other factors (gas; ecu re-learning etc).

Think sportec conversion you would be looking at similar to parr costs. keep in mind that you would need manifolds as well.

Rods. Again. think a lot of had been said on these forums. 820 nm torque limit on stock rods is pretty much what you would expect it to be. im defo not expert but it does seem reasonable. As far as i am concerned, 600-630hp / 820 torque does require retuning the chassis - ie for it to be usable on track and fully exploitable i would look for upgrading suspension/breaks even on GT2.

In terms of my turbo. Next steps are getting rid of weight (CF front fenders, lighter rims; replace heavy turbo back wing assembly with CF GT2 look like. plexy/plastic back window etc); getting wider (and likely going 18") rubber; gt3 sways and front control arms etc.

ps: nothing prevents you from asking your tuner to take a look at turbos and/or send them for maintenance if you have concerns. everything has hours rating on mechanical wear, particularly if you race.

venkatreddytx

You could try the untouched hot-side moded VTG's, mine are such and start building boost 2000-2200 rpm and @10 psi by 3000 rpm.

Clipping of turbine wheel/extrude honing the hot-side delays boost response but gains on top end due to less restrictive exhaust flow.

Mine are Champion Gen1 turbos that have 63.5 billet compressor wheel in machined compressor housing.

Car dynoed 560WHP/572WTQ (baseline 387WHP/398WTQ) on a AWD dyno, car has the following modes
Protomotive E85 Tune, GMG Headers
Champion Gen1 Turbos, Werks1 Inter-coolers
Cargraphic Race Exhaust, 80lbs Deka Injectors
GT3RS LWFW\Clutch\764 PP,Brembo GT 380mm BBK

Specs-

Stock Turbos
Exducer Size - 60mm
Inducer Size - 43.8mm
Bore - 45

Champion Motorsport Generation 1 VTG Turbos
Exducer Size - 63.5
Inducer Size - 45.8
Bore - 46.7

avader906

would recommend taking a quick look at this

http://www.6speedonline.com/forums/9...explained.html

overall you have turbine and compressor sides and housing. every modification is a trade-off. for street you would want early boost build up and would prefer to have low end torque vs. power up the rev range. for GT2 which sees a lot of track time - you would rarely be below 3k revs anyways and other factors would start to be more important - such as powerband/EGTs/efficiency/temps. this further trade-off raises the issue of maintenance costs, durability. for racing applications few people choose VTGs - and you are also restricted by class rules.

its difficult to discuss technical details without clear comparing compressor perf maps - its not as simple as putting on a larger compressor wheel - think stall vs surge etc.

my personal tradeoff is shift of powerband/max torque from 3.2k to 4k and overall cooler temps. my car sees a lot of sustained highway speeds. there is a lot of cheap reading material around on tuning / turbocharger applications - few come to mind such as "turbocharging performance handbook" and "turbo real world high-performance turbocharging systems".

There are non-VTG borg turbos compressor maps around on the internet but I am yet to see a compilation of different VTGs maps.

emmo.84

Hi Avader906 you are great!!!! Thanks for the detailed answer and sorry for the late thanks... got stuffed into work for some serious problems and did not even open rennlist.
If you are looking for fantastic Gt2 wheels you can get the Rays Engineering Volk 37, I had them before 18 bbs and are the best. I also spotted some new 19 BBS for gt3rs but did not see or remember if thei are 5 bolts or not.

should you need infos about 18in BBs and offset I got all here.

To complete the info: if I get the GT2RS intercoolers for my 997Gt2, should I also get all the rubber tubes and the big alumninum "y" that you see from top near the airbox cover?
What else is needed to fit the RS intercoolers to the normal 2009 GT2?
I think I'll stay with STD turbos because there's little testing time and with a car at 600 HP i get more gains from chassis set up.
I use Moton motoirsport if you are interested. Great stuff with slick, no comparison, but maybe too much for street tires.