Crown

I decided to do a build thread on here and RT since I have been dribbling out bits of info on forums here and there but would really like to detail everything.

Car is a 2009 GT2 GT Silver
Brand spanker


I had a build slot deposit paid on a GT2RS but after reading the full spec when the details came out decided that I would modify my existing GT2. The GT2RS engine has very little differences to the GT2 and I wanted to build something special around the VTG platform. I need rear seat belts as I have kids and the GT2RS does not have the reinforcing metal so seat belts cannot be retrofitted, ditto no roof racks on the GT2RS so no surfboard (altho not tried that yet).  Centre lock wheels, never liked them and looking at posts from C/L owners  I am glad I don't have them. Finally my GT2 is specced lightweight and I guessed (correctly) that customer spec GT2RSs would come in within 25kg of my modified GT2, mine weighs about 1450kg full of fuel (64l tank)

So car disappeared to RS Tuning in July 2010 to have a new development, a 3.9l piston and cylinder kit and special 997 turbo based intake manifold.


The engine was built using proprietry Carrillos and pistons which RS Tuning had developed during racing which had slightly longer rods and shorter pistons which gives lower drag and more power.
Carrillos, special ones on left

Piston


The engine was completely dismantled and built up using all the RS Tuning tricks, head work, cams etc then it was put on the dyno wearing bigger VTGs  for testing.

The engine dyno showed that the GT2 expansion manifold could not flow more than 690hp and simply not big enough but to get the GT2 factory electronics to work with the 997 turbo manifold proved very difficult also the exhaust, 100 cell cats with standard rear OEM Akrapovik was too much of a restriction.

First long delay was waiting for Cargraphic to build me a bypass exhaust system which exited 35% of flow directly out of the cat to atmosphere when the valve was open, this took weeks, the final system can be seen here on the CG website.

[url]http://www.cargraphic.de/index.php?/s,6,7,18,3647,3804/[/url]

Work continued with the new exhaust fitted and a problem was occurring on the engine dyno, it would read the torque and then suddenly an erroneous reading, it totally baffled them until BANG the engine dyno broke......


Basically they were exceeding the torque limits at 3000rpm of the engine dyno and had hot wired it to bypass the safety features. They had to order up a new engine dyno from Borghi & Saveri with a third retarder (two previously) to be able to be able to brake 900+NM at 3000rpm.

[url]http://www.borghisaveri.it/English/Referenze1/Referenze1.html[/url]

More time ticked on, they could get full power out of the engine but weren't happy with the part throttle running and in particular the VTG vane control. They hired an engineer who worked for OEM supplier to show them how to do the programming, they spent three weeks solid on the engine dyno learning how to program this sophisticated engine, it was tortuous by all accounts, the project was nearly abandoned at a few stages.

The engine had to be fully rebuilt following its engine dyno work after using 5000 litres of fuel and the equivalent of 70000 miles hard work.... it broke 3 Porsche drive shafts from the torque at 3000rpm, each shaft needing 4 hours labour to replace....

The engine was almost done and the full power dyno sheets were sent to me all that needed now was road testing.....




Or so we thought......

On the road it didn't run as they wanted with the part throttle not being as smooth as they wanted and on top of that the full throttle was producing too much heat and intake temperatures were rising too high meaning the full power seen on the engine dyno using water cooled intercooler were not replicable on the road.

The engine came back out and went on the dyno, they dragged out a set of prototype VTG turbos with even bigger compressor wheels and housings, the theory being they could run less boost and have the required power at lower intake temperatures.

The OEM engineer came back in, for him it was a mission to get it right and eventually he signed the program off.....

Whilst the engine was being finished they fitted and set up some suspension parts which I had collected, dog bones, rear lower control arms and rear lower track rods and front tarrett bushing for the front adjustable lower control  arm together with Bilstein B16 Damptronics.
Lower rear cup arms

All in situ


The engine went in, the racing season had begun, I flew out to see how they were progressing and it was alive although it was quite raw, the way the boost came on at lower revs was fairly abrupt and lumpy and the traction control didn't really know what was going on so progress in first and second gear was pretty messy......

During the road tuning there was a problem with blowing exhaust sensors, mine ate three of them, it turned out this was a parts problem and the latest Porsche part (a changed number) seemed to work......

[url]http://www.youtube.com/watch?v=OnoptMSIzzk[/url]

I pushed and pushed and finally got a date for collection.

[url]http://www.youtube.com/watch?v=nJLZv4sDTb0[/url]

I drove off and there seemed to be a problem, it stalled and would not start then started perfectly WTF !!!
The engineers were all over it, it read “flywheel sensor error” so they checked inder the car and the sensor looked good, installed a new battery, took out the ECU and adjusted it to fire up after reading less flywheel notches, car fired up and ran back to the UK flawlessly.

Back in the UK I had accumulated various parts. After seeing the pic below suddenly my GT2 looked old and after waiting so long for the engine to be done I wanted a rebirth.



The car went straight to Tech 9 my preffered workshop in the UK and its transformation was completed in a day, GT2RS “look” but subtely different wearing the beautiful BBS Fi wheels with 5mm rear and 6mm front spacers to give the right look.








The car was perfect, I was very happy, then a few days later it wouldn't start, then it started and ran very rough.... back to Tech 9 who found the same fault code “flywheel sensor fault” engine dropped flywheel measured, new sensor, wiring tested, ECU back to Germany to be checked..... Started first time....

 Couple of days later we ran a test day at the airfield and it ripped, felt superb...... Then when we went to leave it all of a sudden wouldn't start......Ended up on the back of a truck back to Germany. Bottom line it was the ECU, they couldn't find the fault it was nothing they could see but a brand new ECU with the exact same program (bought from Porsche Zentrum Munchen coded to my chassis) cured it, totally although the ECU fault will remain a mystery but theories were it could have been an electrical surge through welding or something similar ?

All these trips to Germany were very tedious and taking their toll





So car is back and is on full song, did a vmax event the other day and did a terrifying 209mph


[url]http://www.youtube.com/watch?v=4h-673XWbBc[/url]
Exhaust pipes following some high speed runs.

Porsche Motorsports front radiator was fitted to try and combat the extreme heat these VTG engines generate


But as I posted elsewhere this is at the limit of the currently available VTGs due to the size of the hot side, the intake temperatures reached limit the hp to around 700 but this is plenty for the 997GT2

Some data from running fast

3.9  GT2 2011 make over

 Wow, great car and great post. 209 MPH?!!

A bit of advice, if you've been reading another thread that's hot right now, DON'T PARK THIS CAR IN BERLIN!!!

But isn't she a beauty! Congrats.

"I don't mean to brag, but I am really good at self-deprecation."

Are these NM and hp figures in the charts above misprints  Great job on a great car 

Awesome build and utterly awesome car. I can't imagine how violent this car must accelerate, those figures boggle the mind, especially in a 1.450kg car...

Respect and congratulations on your machine!

Isn't it time you got yourself a !waytag?   www.waytag.com

great work

Impressive  

997.1 C2S GT Silver/Cocoa, -20mm/LSD, PSE, short shifter, SportDesign rims, Zuffenhausen pickup, BMW Z4 2.5i Roadster Sterling Grey/Red

Fantastic car.

The secret of life is to admire without desiring.

Fantastic car

Two questions: what kind of clutch did you fit ? I'm asking because the stock clutch is a weak point of the GT2 even with stock hp (at least when you track the car). A friend of mine also has a nicely modded GT2 and he fitted a special Sachs clutch which can take as much as 1,000 nm

As for the top speed: friend's car clocked GPS 349 km/h (217 mph), but he said he won't try a second topspeed run as the tires (MPSC) may not stand it...

public roads: Porsche 987 S Seal/Cocoa, toll road  : Porsche 997 GT3 Arctic/Black

Carrageous thanks for the advice !

Marcus

Porker, I hope to upload some vids in the future to "share" the fun

Budster, the 70000 miles is probably an exaggeration but when the contracted Bosch engineer was "teaching" the programming the engine was held under full load at 900+NM for a long time hence it had to be fully rebuilt, piston, cylinders etc etc...

Intouch, Easy, Rossi

Jeck, A good question about the clutch, this was one area which really worried me as I have pals who run more torque or at least more violent torque onset who have to use triple plate clutches and they are pretty horrible. I drive this car in traffic so it was a requirement that the trusted Sachs 890NM could be used.... When they first tested it they used a single mass flywheel but the 890NM would slip with that so back went on the stock dual mass and the clutch will hold - the clutch is very nice and the car is no problem at all in traffic .....

The tyre issue is one I pondrered, apart from the maximum speed issue I have also had a few scary moments on rain soaked roads so I have had fitted a set of the Continental Vmax tyres (I saw them fitted to a 997GT2 at the Munch Porsche Centre - gave me inspiration)

http://www.conti-online.com/generator/www/uk/en/continental/automobile/themes/car-tyres/standard-car-tyres/contisportcontact/con...

They seem pretty good and are certainly certified for the higher speeds.....

More stuff

I mentioned above that the engine was finally signed off the dyno again with the bigger VTGs and I was given a set of the customary RS engine dyno sheets





You notice that they hadn't sorted the scaling out since 900NM was way above what their old dyno could measure and I guess their graphing software needed some adjustment.
I extrapolated the torque from the power curve using
 NM (Torque in ftlb * 1.36) = (hpSAE (PS*0.9863) * 5232) / rpm

and stuck it in excel to give the real engine dyno curve



Because this was the first 3.9 VTG engine they had done using the 997 turbo intake system it needed quite a lot of fine tuning on the road in terms of setting up how the boost came in at low revs and how the aforementioned traction control worked.

When I first tested and data logged the engine at the airfield I noticed that consistently it was producing its maximum MAF reading at right around 6600rpm. Now it was my guess that maximum MAF reading = peak power so the peak power was different on the road to what was recorded on the engine dyno and certainly the pick up at low revs does not seem to mirror the engine dyno numbers in terms of what rpm the boost comes in, it comes in sooner on the road. The latter will be parttly due to the fine on road tuning and the former is just the way it turns out....  



Sharp eyed amongst you may notice on the numbers above that I am doing 291kph (thats 181mph) at 6666rpm, that is gearing of 27.1mph/1000rpm in sixth gear so at factory limit of 6750rpm my car is only going to manage 183mph – something is different ?

Changing gear

I met a pal the other day in a sports club car park, he had just arrived in his new Mclaren (in orange – yuk, looked just like a Lotus on first sight) and we started chatting cars. He has done a lot of Porsche GT3 Cup type racing and owned all sorts of exotica. He absolutely loves the double clutch type gearboxes (says he prefers sequential) but even on his road cars he says he would not go back to manual......

Well I am different, I spent hours as a young kid sitting in my parents friends cars on our drive way, (keys out) pretending I was driving said cars and changing the gears using the clutch, imagining the revs soaring and timing my changes as the red line was hit...... nothing has changed all through my driving life, I love the physical pleasure of operating clutch, gearbox and engine and I know I am not alone in these forums....

So the 997GT2 ?

At 7000rpm it does about
2nd gear 84mph
3rd gear 114mph
4th gear 145mph

Now the question begs, just how much revving out gear change action is one going to get with this gearing ? Second gear is ticket time and third gear is ban time, fourth is tabloid newspaper and probably jail time !!

I had a plan, I got RS to get hold of a new ring and pinion which I think I first read about on here, it is a 9:35 set, with a view to more gear change action.

I was a bit worried about it being a bit too lively in first and second but pressed the button anyway.


On the road the gearing ended up with a 7000 gear change (7100 limit) at the following
2nd 74mph
3rd 100mph
4th 128mph
5th 157mph
6th 192mph

 

Pleasingly the GT2 is able to give some semblance of traction in first and second gears and the objective was achieved apart from that pesky 6th gear which now only managed a paltry 192mph !

I decided I wanted a sixth gear which would do this engine justice, my UK shop said I should change fifth as well otherwise I would lose acceleration as the
drop from fifth to sixth would be too great.

I played endlessly with the gear calculator and what is worth noting is that for my car the rolling circumference (ie tyre diameter) is not what the book said or even what a theoretical calculation should be and in the end it was RS Tuning who gave me the correct size by measuring a 997GT2 rear which they had in the shop. When I say “correct” I mean this number (663.6mm) gave the exact correct GPS speeds which I was observing with the current set up and they were quite different to the speeds one gets if one feeds in Tirerack's 26.7” or 678mm the numbers from the gear calculator below are not what I am observing for GPS speeds however with RS Tuning's 663.6mm the speeds are spot on (I still don't quite understand this but am happy with the result)

So I decided on a set of gears which GT in the US had in stock 30:20 to give the ratio 0.67 to hopefully achieve the result below.



You may be thinking “how come he has put in a 7300rpm change when he just said before it had a 7000rpm limit” ?

Well one of the benefits of its last trip to Germany was that I presented RS with the data about my on road peak power being at 6600rpm not the 6250rpm (which the dyno showed) and also showed them the data below which to my simpleton thinking (see my comments in red) shows that I still have 96% of peak power MAF at 7048rpm so maybe the whole power curve has shifted up somewhat and the motor is still making good power into the 7000rpms.



Now rpm limits on turbo motors and in particular on road tuned turbo motors are a bit of a “red line” (no pun intended) area for RS, he makes the power lower down so the engines last a long time and he refuses to let them rev.....but a few times I barracked him about various US Tuners allowing 7500+ on stock motors and mine was supposed to be his fuilly built masterpiece..... I also showed him a video of my pal's (who posts on here as GT) Sportec engine with the rev counter swinging round to 7800rpm and I told him they had guaranteed it !

Anyway whatever elements of the above worked because on the new ECU they fitted they announced to me that the rev limit had been raised to 7400rpm – this is quite a thing for them since customers are certainly not supposed to know best !!

So equipped with new taller sixth gear and 7400rpm limit I ran the engine again at the vmax event last Saturday (I was actually changing at arount 7000/7100rpm).


You can see the top gear doing its thing. I am running different tyres (Conti vmaxes) so I think maybe the diameter has changed and also some tyre growth at 205mph since the mph/1000rpm thing wasn't matching up perfectly.

Now here is the awesome bit of info I gleaned when analyzing the data......

A longer sixth gear, one which will allow 220mph at 7300rpm instead of 201mph at 7300rpm will accelerate slower in the gear particularly (as my UK shop pointed out) as on the fifth to sixth change the rpm drop to near 5000rpm (I only revved to about 7000rpm in the fifth to sixth gear change in the chart above) ?

Well the data says otherwise and exactly as my good friend Jean cacluated in theory the acceleration in my new sixth is just as strong if not slightly stronger as it was with the older shorter ratio – I measured the acceleration from 252kph to 310kph on same track with both gears, comparing about 4 runs each and they are nearly identical with the longer gear being slightly faster on average..... that is VTG torque magic

3.9  GT2 2011 make over

deeply impressive.......I also admire ur patience to run such a project with all it's set backs....dunno if I would have the nerve.

Congrats ! I hope the engine lasts  - what is the next level ? - bringing weights further down ?

TB993tt:

Budster, the 70000 miles is probably an exaggeration but when the contracted Bosch engineer was "teaching" the programming the engine was held under full load at 900+NM for a long time hence it had to be fully rebuilt, piston, cylinders etc

Most people have a small apoplexy when their odo clicks over another 10,000 kms, and here you are putting it on rollers at max revs for 70,000kms and not moving an inch! 

Can you do that Matthew Broderick/Ferris Bueller thing and run it another 70,000 in reverse or is the odo disconnected..?

But seriously, you get it just right, and then ...you have to rebuild it !  You are a brave man!  I presume you're not expecting to ever recover any of the rebuild cost? (Not that I think that luxury cars are an investment - they are "lifestyle assets" as best, which is a euphemism for "expense"...

Very very impressed, actually left in awe! The car looks stunning and surely drives like hell

What a lovely car it turned out, you have perfect taste for the mods

indeed shifting is ancient technology - so is a fuel burning engine..  I happen to like both :) 

Thanks guys....

Budster, the engine is out of the car on an engine dyno so it is "the equivalent" of 70000 due to the loading not actually running the whole drivetrain for 70000 on rollers 

3.9  GT2 2011 make over

Yup "reconditioned" is certainly one way you could put it

These guys strip it thoroughly and measure everything and replace anything slightly worn, sounds implausible but that is what Mr RS does, he is very meticulous - I would call it re-blueprinted

3.9  GT2 2011 make over

Toby,

what a stunning report. Thank you very much for that! Took a relaxed moment to read through all of this. The car as you specified it would be exactly my choice as well, the improvments are the icing on the cake. Huge icing, may I say...

Did you make any changes to the drivetrain (gearbox, drive shafts) other than the longer 6th gear? The increased track on the front axle is, apart from the spacers, due to the offset of the BBS rims?

Guys, thanks.....

J.Seven, I do still have the 993tt, it has been at an overpriced SOR for the last few years but I am bringing it home to stick in my garage for while in the next few weeks...... problem is I spent so much time and money on that car that I don't want to sell it unless it gets a decent price and in today's market that doesn't seem achievable...

Ferdie, appreciate your comments, I'm glad to be able to share with like minded forum pals.......

No changes to the gearbox or drivetrain other than the aforementioned 890NM Sachs...... take a look at what the engine did to Schmirler's engine dyno shaft, 3 times when they were trying to control the VTG torque at 3000rpm...

Apparently these are 1200 euro a pop and take 4hrs to change out.......he didn't enjoy parts of this project !

My souvenir

Wheels

Some may remember that I had the Dymag Carbon wheels which I had just had fully refurbished but I found out that a set of the latest Magnalium centred Dymags had failed (Dymag said the problem was with the older magnesium centred wheels and they had cured it with magnalium) so I panicked and sold them to my good pal GT on here who still uses them.

They looked awesome refurbed but I know he had a lot of trouble with them leaking which he was very reasonable about (ie he didn't blame me )

So as wisely recommended as "best available wheels for Porsche" by Cann on here I ordered a set of the BBS Fi and they ended up sitting in my garage for many months whilst the engine was being done.

When I ordered them I asked for diamond finish and grey inserts

Time ticked on, the GT2RS came out and I began to really dig the look of the matt black wheels so I had the BBS Fis re finished

The Fis are a georgeous wheel I can confirm they weighed in at 7.4kg for 8.75 X19 fronts and 8,9kg for 12 X 19 rears. The offsets were both 50.

What this offset means is that when running the 5mm spacer at the rear they stick out 1mm more than stock and running my 6mm spacers at the front they stick out 12mm exactly like the GT2RS (although the RS obviously has another 6mm of wheel on the inside due to its 9" fronts)

What is evident, I lined mine up next to a GT2RS and my offsets look much tighter to the outer body than the RS , the RS ones looked kind of whimpy

Worthy of note is that whilst the BBS Fi fronts are similar weight to the Dymag they feel heavier  whilst driving presumably because the carbon  rim of the Dymag gives less gyroscopic effect (cann ) this is definitely very noticeable and I do miss the Dymags in this respect.....

--

3.9  GT2 2011 make over

I was just contemplating my last comment about calling the GT2RS wheel offset "whimpy" and that it may upset some people so I checked its offset specs.

Fronts are exact same as mine with my spacers

Rears , GT2 has 12 X 19 with offset of 51 with a 5mm spacer (in UK/Europe) so effectively an offset of 46

GT2RS has 12 X 19 with offset of 48 and by the looks of the car I compared with zero spacer hence the standard 997GT2 rear wheel sticks out 2mm more and mine 3mm more....

I am not imagining it

3.9  GT2 2011 make over

3.9  GT2 2011 make over

Beautiful... are both your daily drivers? Curious what a speed freak as you considers driving to town.

  what an amazing work !! and the car is worth so much more to you sonce you went through the whole building process. The 993 looks stunning too, more pics of them together would be very appreciated !

Oh my god you have a 993 GT2!!!!

The 997 is nice, but the 993! What  a car!

Please please please more pics!

How does it drive? There's only 57 worldwide right? Performances?

It's soooo beautiful!!!

Futch:

Oh my god you have a 993 GT2!!!!

The 997 is nice, but the 993! What  a car!

Please please please more pics!

How does it drive? There's only 57 worldwide right? Performances?

It's soooo beautiful!!!

IIRC, between 200 and 300 993 GT2 road cars were built.

Were there 57 993 GT2 racing cars, maybe? 

fritz

fritz:

Futch:

Oh my god you have a 993 GT2!!!!

The 997 is nice, but the 993! What  a car!

Please please please more pics!

How does it drive? There's only 57 worldwide right? Performances?

It's soooo beautiful!!!

IIRC, between 200 and 300 993 GT2 road cars were built.

Were there 57 993 GT2 racing cars, maybe? 

Are you sure Fritz? That many???

Futch:

fritz:

Futch:

Oh my god you have a 993 GT2!!!!

The 997 is nice, but the 993! What  a car!

Please please please more pics!

How does it drive? There's only 57 worldwide right? Performances?

It's soooo beautiful!!!

IIRC, between 200 and 300 993 GT2 road cars were built.

Were there 57 993 GT2 racing cars, maybe? 

Are you sure Fritz? That many???

 

Best data I've found after a quick search ("Porsche Data" book published by Haynes) is 172 cars in model years '95 to '97 (430hp) and 21 in MY '98 (450hp), making a total of 193 road cars.

I don't know if the number of racing cars has been published anywhere.

fritz

Ferdie:

Beautiful... are both your daily drivers? Curious what a speed freak as you considers driving to town.

The 997  is the daily driver, I DD the 993 for 13 years (in between modification breaks !). "driving to town" means proper city traffic nose to tail for half an hour but plenty of on ramps and motorway where 900NM can make some serious progress

The 993 is not a GT2 it is a turbo which has been very heavily modified by me since 1996. It weighs 1430kg full of fuel, has 577PS/796NM twin plug 3.8 litre Secan intercooler RS Tuning engine, does 0-300 in about 27.5s. It has shaved rain gutters and internal roll cage strengthening and is in pretty much perfect condition with most parts new. I had it up for sale with a dealer for 2 years but it seems noone wants to pay what I think its worth so I still own it

3.9  GT2 2011 make over

I've always wondered what a properly tuned VTG would be like compared to one of US style 800hp motors with K24/20G hybrids, big intake piping etc.

Every tuner claims "instant spool", maximum boost at 3500rpm yada yada yada but checkout the vid below, despite how it looks we did actually hit throttle at the same time (tried it a few times and in different gears/rpm)  - the 3.9VTG jumps out a 20m lead, the 800(US)hp 996 gets on boost and the gap is no more than 30m by 190mph/306kph....

http://www.youtube.com/watch?v=9cQWMDhQ7W8

3.9  GT2 2011 make over