Slippydiff
Well-known member
- Joined
- 22 Nov 2007
- Messages
- 862
Following on from this thread ... :
http://911uk.com/viewtopic.php?t=122766
It's a hackneyed American phrase that I dislike immensely, but as **** ups go, this is a biggie. So big, it required the conversion of some rather bitter tasting lemons into what would be the sweetest of lemonade.
If Edmund Blackadder were to be commentating on this fiasco, he'd probably describe it thus :
'Baldrick this is a **** up. A large **** up. In fact, if you've got a moment, it's a twelve-storey **** up with a magnificent entrance hall, carpeting throughout, 24-hour portage, and an enormous sign on the roof, saying 'THIS IS A LARGE **** UP"
And as we all know, a large **** up requires a large plan.
Baldrick, get me my cheque book..."
Those of you that followed my previous reports on the car, will be be all too aware of my eulogising over its engine. To say I was smitten with the enormity of the performance when I first experienced the custom built 500hp, 4.1 litre engine, would be an understatement.
I went on to purchase the car in March 2018, and drove it from Manchester, to Shrewsbury, then home to Bromsgrove. There it sat sullenly for three days whilst it rained heavily, before being driven up to Wrexham and back to Shrewsbury. Five days after purchasing the car I drove it from Shrewsbury down to Silverstone to have it inspected. For those counting, that makes a total of roughly 350 miles driven in my ownership.
As I mentioned in my earlier reports, the car was not easy to drive, and to save you looking, the reasons for this centered around the on/off nature of the sintered paddle clutch, the 996 RSR inlet and exhaust cams and the trick spindleless throttle bodies. Additionally the throttle lacked any real progression from tickover to 1500rpm, add this to the hopelessly fierce clutch, and the car was never going to be happy being pottered around town.
The previous owner made the decision to replace the paddle clutch with a 4.0 litre 997 GT3RS item, and undertook this job along with the removal of the engine (ostensibly to check the valve clearances of the now non-hydraulic tappet valvetrain) over the Winter of 2017-18.
The replacement of the paddle clutch with a normal, organic faced item made getting the car off the line easier, but still a rather hit and miss affair due to the lack of any real throttle progression.
I witnessed this lack of progression first hand on the cold, wet drive down to Silverstone from Shrewsbury that Saturday morning in March last year. Approaching a set of traffic lights two minutes after setting off, in 3rd gear on cold, 10 year old Cups, in the heavy rain (and standing water/puddles aplenty) I elected to drive through the lights and make a left turn whilst still in third gear, this in a vain attempt to avoid the often recalcitrant downshift from 2nd to 3rd with a cold gearbox and Cup cables ...
All was going swimmingly (excuse the pun) until I touched the throttle accelerating through the traffic lights. With spring and damper rates better suited to Silverstone Circuit than Shrewsbury High Street, cold, old near slick tyres, a heavily cambered junction, some injudicious use of my right foot and the aforementioned lack of throttle progression and a tight LSD, the end result was rather predicable : One very sideways Mk 1 GT3 with it's beautiful O/S/R BBS E88 wheel about to get VERY intimate with the extremely solid concrete kerbstone that formed the central reservation.
Fortunately having cat-like reflexes and the car control skills of a certain Mr W Rohrl, I saved the situation whilst balancing a regular vanilla latte from Costa in one hand and a doughnut in the other AND chatting to my other half on the phone. The above is a complete fallacy, I did what anyone faced with the same situation would've done, I instinctively came off the throttle and dialled in what I thought/ hoped would be the requisite 'dab of oppo" and hoped to f*** that dab of oppo was sufficient to ensure a happy ending for the wheel, the car and my wallet...
I watched mesmerised as the concrete kerbstone hove into view, and time slowed as I visualised the delicate lightweight outer rim section of the BBS E88 wheel impacting the immovable block of concrete that was set to halt the car's progress both very brutally and very imminently.
Fate intervened and smiled that morning, and the lack of throttle and a hastily applied dab of oppo ensured the impact betwixt concrete and alloy was avoided. Another foot and the outcome would've been oh so very different. Suffice to say the drive down to Silverstone was a rather sedate affair ...
Having arrived at Silverstone and poked around inside the engine bay, doubts rapidly started to grow over the integrity of the engine conversion ...The list of what we found was long :
A crankcase breather tank with a rapidly increasing quantity of oil within it ...
A heavily frayed, poorly routed throttle cable (a standard item that had been cut off to enable connection to the throttle bodies)
Further investigation revealed the throttle linkage was attached to the underside of the carbon fibre airbox/stainless air filter backplates. Well I say attached, it was actually more akin to flapping around in the breeze ... Having digested the above, we thought breakfast was needed, so Matt elected to drive the car the five miles to the American diner. Upon our arrival there he professed the car's drivability ''king hopeless".
With a huge breakfast consumed, we returned to Silverstone and put the car on the ramp. The list continued to grow :
Chaffing oil and fuel lines ...
Some cracking to the £11,000 (yes you read that right !!) hand crafted BTB Titanium and Inconel exhaust system.
The aluminium fastenings on the very trick carbon fibre airbox/plenum worn through and missing, and others about to fail.
An incredibly crude (and utterly pointless) idle stabilisation system.
How do we know it was pointless ? Because we disconnected its vacuum supply and tried revving the engine and then allowed it to idle. It actually idled better without the system connected ...
Several key standard GT3 ancillaries had been modified to allow fitment of the throttle bodies, the biggest one being the oil tank, the power steering pump/reservoir had also been deleted (a Cup electric pump had been fitted in frunk)
Various air conditioning, coolant and fuel pipes 'bent to fit" their required new locations.
The cam covers showed no signs of having been recently removed, and as we were to subsequently find out, the driveshaft flange bolts had been left loose too ...
Another half hour of poking around and Matt and I looked at each other and said in unison 'The engine's coming out then"
Let me say here and now I'd already set funds aside to address the lack of throttle progression, the overly stiff suspension, the broken windscreen and a host of other small irritations. But that was before Matt carried out a cylinder leakdown test.
The test left a huge question mark over the integrity of the engine, and the further we dug into the innards of it, the worse it got.
Both cat substrates failed. The previous owned had told me one of the lambda sensors had failed, and he'd replaced both of them as a result. Unfortunately an inspection of the cats prior to re-starting the engine after the lambdas were replaced wasn't undertaken.
The ensuing detonation had damaged one piston catastrophically and the rest to a lesser degree, the main bearing shells had been fitted incorrectly and had been chattering in their saddles in the crankcase, the image is the resultant wear to the back of the shells ... but the crowning turd in the water pipe (© General Melchett) was finding all four cams devoid of their lobes when the cam covers were lifted.
Cam chain tensioner in "kit" form upon removal ... (we suspect it had failed due to the ridiculous 9000rpm rev limit.
At this point it became all too clear the engine was to all intents and purposes, a large pile of scrap. To quote Edmund Blackadder again, what I thought at this point , rhymed with "Clucking Bell" ...
And due to the massively modified nature of said pile of scrap, it wasn't worth trying to build anything workable out of it, Least of all a standard engine. So a complete new engine was the order of the day.
Enter stage left The Porsche Motorsport Department ... and after some deliberation, a couple of weeks later this arrived on a pallet directly from The Motorsport Dept :
It's a 6 hour since rebuild (by the Motorsport Department) 2009 997 Cup engine. Quoted power figure 420 of Stuttgart's finest gee gees at 8400 rpm (more of which later)
Fitting this into the 996 chassis wasn't straightforward, although it was made considerably more tricky by the individual who built and installed the 'Frankenstein" engine, deciding the car's original Bosch ECU wasn't up to the job of running his bespoke engine (despite it being on throttle bodies, having no Variocam and no inlet manifold resonance flaps to control (tw*t springs to mind) so he'd used a very expensive stand alone Motec M800 ECU
alongside the car's original Bosch ECU, this to ensure the dash, central locking and alarm/immobiliser still worked as intended. To do this he hacked (no let's be brutally honest about this) he butchered the car's chassis and engine looms about.
After a false start which entailed employing the services of a comedian/mapper/loom builder who clearly thought he was dealing with an F1 team (when it came to the size of his invoices) rather than an individual trying to get a 20 year old Porsche back on the road in the most cost effective manner possible. Tw*t comes to mind again ...
***Note to self, there's a lot of tw*ts in car tuning business *** (that doesn't include DynoMike on here, obviously)
With that hiccup out of the way, I suggested to Matt that we use the car's original ECU as it should be more than capable of running the 'relatively" simple Cup engine ?
Whilst the Cup engine came dressed with it's own bespoke loom and exhaust, it was decided to use a new, original Mk1 996 GT3 engine loom and repair the car's butchered chassis loom ...
Let me say here and now, the repair to the car's chassis loom is so neat and tidy as to be all but unnoticeable, in essence it looks like the factory always intended it to look that way.
As we had the superb BTB fabricated Inconel and titanium exhaust system and manifolds, it made sense to utilise them. As I've said before, they're a work of art, and having had to remove and refit them to the car myself, I can vouch for the fact they weigh nought point nought percent of chuff all.
The primaries on the BTB manifolds are larger diameter and far longer than the stock 997 Cup items, and the oil tank mounting brackets on the 997 oil tank are slightly different too, so some clearancing of the oil tank lower bracket was required to enable the fitment of the BTB Inconel manifolds.
The Cup engine uses a 997 4.0 RS inlet manifold (without the self loosening throttle butterfly screws ...) and a good old fashioned throttle cable rather than the 997 road car's electronic fly by wire throttle body.
The Cup throttle body throttle linkage cam/idle stop/adjuster is a work of art
A new throttle cable was fitted and the modified/adjusted to ensure the throttle stop actually does its job and prevents a heavy right foot stretching and eventually breaking the cable. Other modifications included using the 996 GT3's oil pressure sender unit (remotely mounted to ensure it worked with the 996 electrical architecture and kept the engine's wiring loom as straightforward as possible)
The fuel supply and return pipes between the chassis and engine's fuel rails/fuel filter are Porsche OE and are especially trick quick detachable items.
And as the fuel injector connectors on the 996 MK1 GT3 loom are different to those on the 997 Cup loom, some additional clearance was required there too
The car had previously been fitted with a 997 Cup electrical PAS pump in the frunk, which further simplified the engine install.
Cup car install :
I'd hoped we'd be able to run the factory A/C system, but that big 4.0 RS inlet manifold and more specifically it's resonance flap actuators, meant the standard A/C compressor wouldn't fit in the available space. However the install utilises 997 GT3 hard lines and flexible heater pipes and thus I'm glad to say the heater is fully functional.
I'd planned/wanted to use the 996 Cup air filter (also used on the Mk 1 996 GT3 Manthey K400 conversion) along with the Manthey carbon fibre cold air ducting, this as the inside of the engine cover had already been cut out/modified for a previous K400 conversion and latterly the Frankenstein engine's carbon airbox. The 996 Cup air filter makes a superb noise both at full chat and at tickover.
Alas the request for this arrangement was vetoed (for which read ignored ...) and in its place went a 997 2009 Cup/997 3.8 RS road car airfilter/housing purchased direct from the Motorsport Dept (complete with ill -fitting Porsche Motorsport sticker for the princely sum of €25.
Whilst this arrangement looks completely factory, it doesn't sound quite as sweet as the 996 Cup item...
The engine went in at the end of December last year, and was completed late in January.
It started on the key and the dash did NOT light up like a Christmas tree...
With the engine now successfully installed and running, it now needed mapping. Clearly there was only one individual equal to the task of both mapping the ECU, but also making the two (as opposed to one in the original Mk 1 996 GT3) inlet manifold resonance flaps work (let's not forget we're utilising the OE Mk 1 Bosch ECU, which only has one driver for the single resonance flap), that would be Wayne Schofield of Chip Wizards fame.
Let me stress now that I'd harboured serious concerns from day one as to just how we were going to operate the two resonance flaps, but not just that, how we'd formulate the opening and closing strategies for them.
Several conversations with Matt hadn't left me convinced it was either straightforward or indeed actually 'doable". He was firmly of the opinion we could leave the smaller of the two flaps closed, and use the existing driver in the ECU for the large flap. My logic was that if the factory/ Motorsport Dept had left it in the 2009 Cup/4.0 RS inlet manifold, it clearly served a purpose ...
I needn't have worried, Wayne was very much on the same page as me, and made it clear in a long (and oh so VERY illuminating) telephone conversation, just how important the resonance flaps (and just as importantly, their sequencing) are.
A few hours later a dyno plot appeared, it showed several power curves, the results of various resonance flap opening and closing strategies AND an overly rich mixture as the 996 Mk 1 GT3 ECU thought it was still operating the Mk1's stock fuel injectors, and not the larger items used in the 2009 997 Cup engine.
The headline figure was a very reasonable 430hp, though Wayne said there was probably a bit more to come with the fuelling and resonance flap strategies further optimised.
When I questioned Wayne as to whether we'd gain another 10-15 hp with the fuel maps tweaked, he said 'probably".
Upon studying the dyno curves more closely, it became clear that there was a massive difference in both peak horsepower and under the curve figures from between 3000rpm to 8400 rpm. The 'worst" and 'best" resonance flap strategies seemingly showing what looked like 35-40hp difference. I rang Wayne back and another lengthy conversation ensued that revealed the difference was probably closer to 60hp ... !! As I said previously, if the Motorsport Department saw fit to use the two flaps, they're there for a reason ... !!
A couple of days (and several tanks of fuel) later, another dyno curve appeared on my phone. The headline figure ? 465hp, and let's not forget this is all from 3.6 litres ...
I have to say I was somewhat taken aback by this number, and rang Wayne to discuss it. My first question was 'Is your dyno optimistic ?". Wayne said it may well be, 'but only to the tune of 8-10hp at the VERY most"
Further discussions with Wayne would tend to indicate the factory quoted power figures for the 997 Cup engines (both the early cars and the 2009 cars) are pessimistic to the tune of 5%. That would see the first cars actually producing 420hp rather than the quoted figure of 400, and the 2009 cars actually producing 440hp rather than the quoted 420hp.
The BTB exhaust has some beautifully fabricated manifolds and huge bore pipework, whereas the Cup cars run what are effective road car manifolds with cats integrated into them (opinions differ as to whether the Cups use different cats to the road cars, I maintain they're the same)
Cup manifold/cat :
Original R/RS/RSR manifold
BTB manifold :
Merge collector :
Lightweight silencer and huge diameter piping :
Many hours on Wayne's dyno optimising both the fuel/ignition maps AND the inlet resonance flap sequencing strategies (let's not forget the Cup cars use a sealed/control Bosch Motorsport ECU) and the headline figure of 455-465hp seems entirely plausible.
Having had the car in the garage up on axle stands for the last 3 months whilst I fettled numerous other components, I finally drove the car in anger for the first time yesterday.
I can confirm it is every bit as quick (as in ferociously fast) as both my 996 GT2's ... but with a far, far superior soundtrack.
:grin:
A further update detailing my fettling over the last three months AND a more indepth report on the driving experience will follow over the coming weeks
Enjoy
http://911uk.com/viewtopic.php?t=122766
It's a hackneyed American phrase that I dislike immensely, but as **** ups go, this is a biggie. So big, it required the conversion of some rather bitter tasting lemons into what would be the sweetest of lemonade.
If Edmund Blackadder were to be commentating on this fiasco, he'd probably describe it thus :
'Baldrick this is a **** up. A large **** up. In fact, if you've got a moment, it's a twelve-storey **** up with a magnificent entrance hall, carpeting throughout, 24-hour portage, and an enormous sign on the roof, saying 'THIS IS A LARGE **** UP"
And as we all know, a large **** up requires a large plan.
Baldrick, get me my cheque book..."
Those of you that followed my previous reports on the car, will be be all too aware of my eulogising over its engine. To say I was smitten with the enormity of the performance when I first experienced the custom built 500hp, 4.1 litre engine, would be an understatement.
I went on to purchase the car in March 2018, and drove it from Manchester, to Shrewsbury, then home to Bromsgrove. There it sat sullenly for three days whilst it rained heavily, before being driven up to Wrexham and back to Shrewsbury. Five days after purchasing the car I drove it from Shrewsbury down to Silverstone to have it inspected. For those counting, that makes a total of roughly 350 miles driven in my ownership.
As I mentioned in my earlier reports, the car was not easy to drive, and to save you looking, the reasons for this centered around the on/off nature of the sintered paddle clutch, the 996 RSR inlet and exhaust cams and the trick spindleless throttle bodies. Additionally the throttle lacked any real progression from tickover to 1500rpm, add this to the hopelessly fierce clutch, and the car was never going to be happy being pottered around town.
The previous owner made the decision to replace the paddle clutch with a 4.0 litre 997 GT3RS item, and undertook this job along with the removal of the engine (ostensibly to check the valve clearances of the now non-hydraulic tappet valvetrain) over the Winter of 2017-18.
The replacement of the paddle clutch with a normal, organic faced item made getting the car off the line easier, but still a rather hit and miss affair due to the lack of any real throttle progression.
I witnessed this lack of progression first hand on the cold, wet drive down to Silverstone from Shrewsbury that Saturday morning in March last year. Approaching a set of traffic lights two minutes after setting off, in 3rd gear on cold, 10 year old Cups, in the heavy rain (and standing water/puddles aplenty) I elected to drive through the lights and make a left turn whilst still in third gear, this in a vain attempt to avoid the often recalcitrant downshift from 2nd to 3rd with a cold gearbox and Cup cables ...
All was going swimmingly (excuse the pun) until I touched the throttle accelerating through the traffic lights. With spring and damper rates better suited to Silverstone Circuit than Shrewsbury High Street, cold, old near slick tyres, a heavily cambered junction, some injudicious use of my right foot and the aforementioned lack of throttle progression and a tight LSD, the end result was rather predicable : One very sideways Mk 1 GT3 with it's beautiful O/S/R BBS E88 wheel about to get VERY intimate with the extremely solid concrete kerbstone that formed the central reservation.
Fortunately having cat-like reflexes and the car control skills of a certain Mr W Rohrl, I saved the situation whilst balancing a regular vanilla latte from Costa in one hand and a doughnut in the other AND chatting to my other half on the phone. The above is a complete fallacy, I did what anyone faced with the same situation would've done, I instinctively came off the throttle and dialled in what I thought/ hoped would be the requisite 'dab of oppo" and hoped to f*** that dab of oppo was sufficient to ensure a happy ending for the wheel, the car and my wallet...
I watched mesmerised as the concrete kerbstone hove into view, and time slowed as I visualised the delicate lightweight outer rim section of the BBS E88 wheel impacting the immovable block of concrete that was set to halt the car's progress both very brutally and very imminently.
Fate intervened and smiled that morning, and the lack of throttle and a hastily applied dab of oppo ensured the impact betwixt concrete and alloy was avoided. Another foot and the outcome would've been oh so very different. Suffice to say the drive down to Silverstone was a rather sedate affair ...
Having arrived at Silverstone and poked around inside the engine bay, doubts rapidly started to grow over the integrity of the engine conversion ...The list of what we found was long :
A crankcase breather tank with a rapidly increasing quantity of oil within it ...
A heavily frayed, poorly routed throttle cable (a standard item that had been cut off to enable connection to the throttle bodies)
Further investigation revealed the throttle linkage was attached to the underside of the carbon fibre airbox/stainless air filter backplates. Well I say attached, it was actually more akin to flapping around in the breeze ... Having digested the above, we thought breakfast was needed, so Matt elected to drive the car the five miles to the American diner. Upon our arrival there he professed the car's drivability ''king hopeless".
With a huge breakfast consumed, we returned to Silverstone and put the car on the ramp. The list continued to grow :
Chaffing oil and fuel lines ...
Some cracking to the £11,000 (yes you read that right !!) hand crafted BTB Titanium and Inconel exhaust system.
The aluminium fastenings on the very trick carbon fibre airbox/plenum worn through and missing, and others about to fail.
An incredibly crude (and utterly pointless) idle stabilisation system.
How do we know it was pointless ? Because we disconnected its vacuum supply and tried revving the engine and then allowed it to idle. It actually idled better without the system connected ...
Several key standard GT3 ancillaries had been modified to allow fitment of the throttle bodies, the biggest one being the oil tank, the power steering pump/reservoir had also been deleted (a Cup electric pump had been fitted in frunk)
Various air conditioning, coolant and fuel pipes 'bent to fit" their required new locations.
The cam covers showed no signs of having been recently removed, and as we were to subsequently find out, the driveshaft flange bolts had been left loose too ...
Another half hour of poking around and Matt and I looked at each other and said in unison 'The engine's coming out then"
Let me say here and now I'd already set funds aside to address the lack of throttle progression, the overly stiff suspension, the broken windscreen and a host of other small irritations. But that was before Matt carried out a cylinder leakdown test.
The test left a huge question mark over the integrity of the engine, and the further we dug into the innards of it, the worse it got.
Both cat substrates failed. The previous owned had told me one of the lambda sensors had failed, and he'd replaced both of them as a result. Unfortunately an inspection of the cats prior to re-starting the engine after the lambdas were replaced wasn't undertaken.
The ensuing detonation had damaged one piston catastrophically and the rest to a lesser degree, the main bearing shells had been fitted incorrectly and had been chattering in their saddles in the crankcase, the image is the resultant wear to the back of the shells ... but the crowning turd in the water pipe (© General Melchett) was finding all four cams devoid of their lobes when the cam covers were lifted.
Cam chain tensioner in "kit" form upon removal ... (we suspect it had failed due to the ridiculous 9000rpm rev limit.
At this point it became all too clear the engine was to all intents and purposes, a large pile of scrap. To quote Edmund Blackadder again, what I thought at this point , rhymed with "Clucking Bell" ...
And due to the massively modified nature of said pile of scrap, it wasn't worth trying to build anything workable out of it, Least of all a standard engine. So a complete new engine was the order of the day.
Enter stage left The Porsche Motorsport Department ... and after some deliberation, a couple of weeks later this arrived on a pallet directly from The Motorsport Dept :
It's a 6 hour since rebuild (by the Motorsport Department) 2009 997 Cup engine. Quoted power figure 420 of Stuttgart's finest gee gees at 8400 rpm (more of which later)
Fitting this into the 996 chassis wasn't straightforward, although it was made considerably more tricky by the individual who built and installed the 'Frankenstein" engine, deciding the car's original Bosch ECU wasn't up to the job of running his bespoke engine (despite it being on throttle bodies, having no Variocam and no inlet manifold resonance flaps to control (tw*t springs to mind) so he'd used a very expensive stand alone Motec M800 ECU
alongside the car's original Bosch ECU, this to ensure the dash, central locking and alarm/immobiliser still worked as intended. To do this he hacked (no let's be brutally honest about this) he butchered the car's chassis and engine looms about.
After a false start which entailed employing the services of a comedian/mapper/loom builder who clearly thought he was dealing with an F1 team (when it came to the size of his invoices) rather than an individual trying to get a 20 year old Porsche back on the road in the most cost effective manner possible. Tw*t comes to mind again ...
***Note to self, there's a lot of tw*ts in car tuning business *** (that doesn't include DynoMike on here, obviously)
With that hiccup out of the way, I suggested to Matt that we use the car's original ECU as it should be more than capable of running the 'relatively" simple Cup engine ?
Whilst the Cup engine came dressed with it's own bespoke loom and exhaust, it was decided to use a new, original Mk1 996 GT3 engine loom and repair the car's butchered chassis loom ...
Let me say here and now, the repair to the car's chassis loom is so neat and tidy as to be all but unnoticeable, in essence it looks like the factory always intended it to look that way.
As we had the superb BTB fabricated Inconel and titanium exhaust system and manifolds, it made sense to utilise them. As I've said before, they're a work of art, and having had to remove and refit them to the car myself, I can vouch for the fact they weigh nought point nought percent of chuff all.
The primaries on the BTB manifolds are larger diameter and far longer than the stock 997 Cup items, and the oil tank mounting brackets on the 997 oil tank are slightly different too, so some clearancing of the oil tank lower bracket was required to enable the fitment of the BTB Inconel manifolds.
The Cup engine uses a 997 4.0 RS inlet manifold (without the self loosening throttle butterfly screws ...) and a good old fashioned throttle cable rather than the 997 road car's electronic fly by wire throttle body.
The Cup throttle body throttle linkage cam/idle stop/adjuster is a work of art
A new throttle cable was fitted and the modified/adjusted to ensure the throttle stop actually does its job and prevents a heavy right foot stretching and eventually breaking the cable. Other modifications included using the 996 GT3's oil pressure sender unit (remotely mounted to ensure it worked with the 996 electrical architecture and kept the engine's wiring loom as straightforward as possible)
The fuel supply and return pipes between the chassis and engine's fuel rails/fuel filter are Porsche OE and are especially trick quick detachable items.
And as the fuel injector connectors on the 996 MK1 GT3 loom are different to those on the 997 Cup loom, some additional clearance was required there too
The car had previously been fitted with a 997 Cup electrical PAS pump in the frunk, which further simplified the engine install.
Cup car install :
I'd hoped we'd be able to run the factory A/C system, but that big 4.0 RS inlet manifold and more specifically it's resonance flap actuators, meant the standard A/C compressor wouldn't fit in the available space. However the install utilises 997 GT3 hard lines and flexible heater pipes and thus I'm glad to say the heater is fully functional.
I'd planned/wanted to use the 996 Cup air filter (also used on the Mk 1 996 GT3 Manthey K400 conversion) along with the Manthey carbon fibre cold air ducting, this as the inside of the engine cover had already been cut out/modified for a previous K400 conversion and latterly the Frankenstein engine's carbon airbox. The 996 Cup air filter makes a superb noise both at full chat and at tickover.
Alas the request for this arrangement was vetoed (for which read ignored ...) and in its place went a 997 2009 Cup/997 3.8 RS road car airfilter/housing purchased direct from the Motorsport Dept (complete with ill -fitting Porsche Motorsport sticker for the princely sum of €25.
Whilst this arrangement looks completely factory, it doesn't sound quite as sweet as the 996 Cup item...
The engine went in at the end of December last year, and was completed late in January.
It started on the key and the dash did NOT light up like a Christmas tree...
With the engine now successfully installed and running, it now needed mapping. Clearly there was only one individual equal to the task of both mapping the ECU, but also making the two (as opposed to one in the original Mk 1 996 GT3) inlet manifold resonance flaps work (let's not forget we're utilising the OE Mk 1 Bosch ECU, which only has one driver for the single resonance flap), that would be Wayne Schofield of Chip Wizards fame.
Let me stress now that I'd harboured serious concerns from day one as to just how we were going to operate the two resonance flaps, but not just that, how we'd formulate the opening and closing strategies for them.
Several conversations with Matt hadn't left me convinced it was either straightforward or indeed actually 'doable". He was firmly of the opinion we could leave the smaller of the two flaps closed, and use the existing driver in the ECU for the large flap. My logic was that if the factory/ Motorsport Dept had left it in the 2009 Cup/4.0 RS inlet manifold, it clearly served a purpose ...
I needn't have worried, Wayne was very much on the same page as me, and made it clear in a long (and oh so VERY illuminating) telephone conversation, just how important the resonance flaps (and just as importantly, their sequencing) are.
A few hours later a dyno plot appeared, it showed several power curves, the results of various resonance flap opening and closing strategies AND an overly rich mixture as the 996 Mk 1 GT3 ECU thought it was still operating the Mk1's stock fuel injectors, and not the larger items used in the 2009 997 Cup engine.
The headline figure was a very reasonable 430hp, though Wayne said there was probably a bit more to come with the fuelling and resonance flap strategies further optimised.
When I questioned Wayne as to whether we'd gain another 10-15 hp with the fuel maps tweaked, he said 'probably".
Upon studying the dyno curves more closely, it became clear that there was a massive difference in both peak horsepower and under the curve figures from between 3000rpm to 8400 rpm. The 'worst" and 'best" resonance flap strategies seemingly showing what looked like 35-40hp difference. I rang Wayne back and another lengthy conversation ensued that revealed the difference was probably closer to 60hp ... !! As I said previously, if the Motorsport Department saw fit to use the two flaps, they're there for a reason ... !!
A couple of days (and several tanks of fuel) later, another dyno curve appeared on my phone. The headline figure ? 465hp, and let's not forget this is all from 3.6 litres ...
I have to say I was somewhat taken aback by this number, and rang Wayne to discuss it. My first question was 'Is your dyno optimistic ?". Wayne said it may well be, 'but only to the tune of 8-10hp at the VERY most"
Further discussions with Wayne would tend to indicate the factory quoted power figures for the 997 Cup engines (both the early cars and the 2009 cars) are pessimistic to the tune of 5%. That would see the first cars actually producing 420hp rather than the quoted figure of 400, and the 2009 cars actually producing 440hp rather than the quoted 420hp.
The BTB exhaust has some beautifully fabricated manifolds and huge bore pipework, whereas the Cup cars run what are effective road car manifolds with cats integrated into them (opinions differ as to whether the Cups use different cats to the road cars, I maintain they're the same)
Cup manifold/cat :
Original R/RS/RSR manifold
BTB manifold :
Merge collector :
Lightweight silencer and huge diameter piping :
Many hours on Wayne's dyno optimising both the fuel/ignition maps AND the inlet resonance flap sequencing strategies (let's not forget the Cup cars use a sealed/control Bosch Motorsport ECU) and the headline figure of 455-465hp seems entirely plausible.
Having had the car in the garage up on axle stands for the last 3 months whilst I fettled numerous other components, I finally drove the car in anger for the first time yesterday.
I can confirm it is every bit as quick (as in ferociously fast) as both my 996 GT2's ... but with a far, far superior soundtrack.
:grin:
A further update detailing my fettling over the last three months AND a more indepth report on the driving experience will follow over the coming weeks
Enjoy