As you drive away from the OPC with lightened wallet and just 6 miles showing on the odometer it is tempting to think engineering excellence and meticulous quality control means your new motor is as good as it could be. Everything is just spot on. Mmm I wonder?
After the excellent work Chris did on my 996GT3 I always had in mind taking the turbo for a health check at Center Gravity once the car had a few miles under its belt and the suspension had had a chance to settle in. So by the time I was home after LWOTY+ that time had come and last Thursday saw me arriving in Atherstone for a quick afternoon appointment.
This was the first 991 turbo Chris had had through the workshop so he was pleased to use my car as a reference point and calibration. In fact the car is so relatively new that it is not yet on the software for his new Hunter alignment equipment . Of course Chris had already checked out the turbo settings and so there was no problem save to the extent that some readings showed red when they were actually green, and vice versa, if you see what I mean.
But first the test drive. I thought the car had seemed absolutely fine and certainly hadn't given too much trouble on LWOTY. Not so apparently. Before we had gone 200 metres towards the roundabout test Chris had detected imbalances which he later confirmed on the dual carriageway and under load.
Back in the workshop the wobble board test was fine. However on lifting the cover in the front compartment it was evident someone had been there before. The LHS strut had white paint marks on the nuts but there were none on the RHS. Interesting!
The new Hunter equipment has some nifty gadgets which meant there was no need to wrestle with the centre locks to attach the hub devices of the old equipment.
Space age laser guided 3D beams of light and complex geometrical calculations feed the answer straight onto the screen.
And here is the before picture. Be aware that just because it is red doesn't necessarily mean it is wrong as the computer baseline is 991 C4 but the relative numbers tell a story and what they show is not pretty.
We agreed we would weight the car to DIN with compensation for fuel. There is no ride height adjustment on turbo but a check showed the readings were spot on. So from that point it was a question of adjusting camber, caster and toe, front and rear to bring the figures back into line. Simples [
]
One of the consequences of PDCC and Rear Wheel Steer is that the suspension area is quite congested. The adjuster bolts are conventionally located but very hard to get at because the free space is no longer free but instead taken up with stepper motors and hydraulic rams. After an hour or so of trying various tools Chris decided that he couldn't make the adjustments he wanted due to limited range of movement of spanners etc. To me that would have been the end of it. Not for Chris though
The rear brakes as well as being large have some complex cooling ducting which wasn't' helping access. This had to go. And so it did. Now access was much more straightforward and the iterative process of the way one adjustment affects all the others entered its Newton's Backwards Differences phase until at around 7.00pm all was green and good to go.
Not quite. The "After" test drive was still needed. So off we went and low and behold the car now tracked as it should followed cambers and cross falls correctly. Satisfied Chris asked me to take over and we set off on the extended test route.
If I am honest I would say the car felt just the same as it did before. And here's the point, it is only when someone who knows exactly what they are doing conducts specific tests against known variables that problems which are latent come to light and can be rectified.
My recommendation to any owner of a new 991 would be to invest in half a day at Center Gravity. Not only is it money well spent it is also highly instructive and a most enjoyable way to spend an afternoon.
For those who are familiar with the set up here are some highly dubious and deeply subjective results for the 991 turbo S.
Wet Roundabout. 27mph. Chris who was driving says 22mph max for 997.
Sinuous S bends at decent speed. Chris " This car corners so flat with just no roll"
B road bend normal max 60mph. There was gravel on the surface but you will have to PM me for result []
Tight B road 20mph max. 30mph comfortably.
After the excellent work Chris did on my 996GT3 I always had in mind taking the turbo for a health check at Center Gravity once the car had a few miles under its belt and the suspension had had a chance to settle in. So by the time I was home after LWOTY+ that time had come and last Thursday saw me arriving in Atherstone for a quick afternoon appointment.
This was the first 991 turbo Chris had had through the workshop so he was pleased to use my car as a reference point and calibration. In fact the car is so relatively new that it is not yet on the software for his new Hunter alignment equipment . Of course Chris had already checked out the turbo settings and so there was no problem save to the extent that some readings showed red when they were actually green, and vice versa, if you see what I mean.
But first the test drive. I thought the car had seemed absolutely fine and certainly hadn't given too much trouble on LWOTY. Not so apparently. Before we had gone 200 metres towards the roundabout test Chris had detected imbalances which he later confirmed on the dual carriageway and under load.
Back in the workshop the wobble board test was fine. However on lifting the cover in the front compartment it was evident someone had been there before. The LHS strut had white paint marks on the nuts but there were none on the RHS. Interesting!
The new Hunter equipment has some nifty gadgets which meant there was no need to wrestle with the centre locks to attach the hub devices of the old equipment.
Space age laser guided 3D beams of light and complex geometrical calculations feed the answer straight onto the screen.
And here is the before picture. Be aware that just because it is red doesn't necessarily mean it is wrong as the computer baseline is 991 C4 but the relative numbers tell a story and what they show is not pretty.
We agreed we would weight the car to DIN with compensation for fuel. There is no ride height adjustment on turbo but a check showed the readings were spot on. So from that point it was a question of adjusting camber, caster and toe, front and rear to bring the figures back into line. Simples [
]One of the consequences of PDCC and Rear Wheel Steer is that the suspension area is quite congested. The adjuster bolts are conventionally located but very hard to get at because the free space is no longer free but instead taken up with stepper motors and hydraulic rams. After an hour or so of trying various tools Chris decided that he couldn't make the adjustments he wanted due to limited range of movement of spanners etc. To me that would have been the end of it. Not for Chris though
The rear brakes as well as being large have some complex cooling ducting which wasn't' helping access. This had to go. And so it did. Now access was much more straightforward and the iterative process of the way one adjustment affects all the others entered its Newton's Backwards Differences phase until at around 7.00pm all was green and good to go.
Not quite. The "After" test drive was still needed. So off we went and low and behold the car now tracked as it should followed cambers and cross falls correctly. Satisfied Chris asked me to take over and we set off on the extended test route.
If I am honest I would say the car felt just the same as it did before. And here's the point, it is only when someone who knows exactly what they are doing conducts specific tests against known variables that problems which are latent come to light and can be rectified.
My recommendation to any owner of a new 991 would be to invest in half a day at Center Gravity. Not only is it money well spent it is also highly instructive and a most enjoyable way to spend an afternoon.
For those who are familiar with the set up here are some highly dubious and deeply subjective results for the 991 turbo S.
Wet Roundabout. 27mph. Chris who was driving says 22mph max for 997.
Sinuous S bends at decent speed. Chris " This car corners so flat with just no roll"
B road bend normal max 60mph. There was gravel on the surface but you will have to PM me for result [
]Tight B road 20mph max. 30mph comfortably.
