Some of you may be aware that my 911SC has a 993 Varioram engine fitted "" this was done about 4 years ago at JM Autos. Anyway, being ever hungry for more power I decided I'd like to supercharge it.
A used TPC supercharger came up for a sale on Pistonheads a few weeks ago and I spoke to Colin and Robin at 9M about fitting it to my engine bearing in mind the older bodyshell and more notably the 915 gearbox. They were very positive about it as they had just fitted one to a Supersport (also with 993 engine conversion obviously) with 915 gearbox. Hence I bought the supercharger and booked it in to have it fitted.
The car was taken to Warrington and left in the capable hands of Robin. They dynoed the car to check the state of the engine prior to having the supercharger fitted. It was only producing 250BHP and similar torque (should be 285BHP) and they traced this to the Varioram system not operating correctly. They sorted this out and it now produced 300BHP and 300lbs of torque "" so, good to go then!
I stressed that I wanted to keep the engine lid without spoiler (they were concerned that the pulley would foul the engine lid and may require a spoiler) to maintain the smooth lines and wolf in sheep's clothing appearance. They said that they would try and lower the engine in order to be able to do this. In the end they lowered it by 30mm "" and due to this the back box was pushing against the rear valence and creating a minor bulge - but this is barely noticeable.
Anyway, after a couple of weeks the supercharger was well and truly bolted in and it was time to test it.
Robin road tested the car and noticed a dip in power from 2700 rpm to 3500rpm. They put it on the dyno and found that the fueling was too low and the engine was pinking.
However, the power output was incredible.
At the top end it was pushing out 407.7BHP and 364lbs of torque (5000rpm) - at first they didn't believe this so they did a few more runs to confirm it wasn't a fluke. The figures were accurate and they tried to explain it by the 8.5PSI of boost that the "˜charger was generating. However as it was still 'detonating its t1ts off' they decided to lower the boost and aim for about 360BHP.
In order to do this they fitted a larger pulley to slow the revolutions. Boost was now 5.5PSI. Another run on the dyno showed 405.5BHP and 360.4lbs of torque - they explained the same power due to the fact that the temps would be lower on the lower boost. The engine was still detonating though (at 2300rpm it had 316lbs of torque and at 3500 it had 300lbs of torque) and hence it required a full remap of the digibox.
They remapped the digibox (6 hours on the dyno in all) and achieved 300lbs of torque at 2000 rpm "" this stayed constant until 4000rpm when it began to increase. There was a hefty rise to 366lbs at 5370rpm. BHP is lower than the numbers quoted above but still impressive.
The reasons they gave for the higher than usual power and torque numbers (compared to a 993 car) were:
No catalytic convertors
Free flowing exhaust (Hayward and Scott stainless back box)
Lightweight flywheel
Low drag 915 gearbox
As you can imagine I'm over the moon with it - Robin did a splendid job and even attended to the small items such as the incomplete tinware that was letting the hot exhaust air heat the engine too much - it now runs a lot cooler and the cone filter is actually cold to touch!
Oh yeah "" and flames out of the exhaust now!
Well recommended!! [
]
Whoops - just realised that maybe I should have posted this on the SC forum!
A used TPC supercharger came up for a sale on Pistonheads a few weeks ago and I spoke to Colin and Robin at 9M about fitting it to my engine bearing in mind the older bodyshell and more notably the 915 gearbox. They were very positive about it as they had just fitted one to a Supersport (also with 993 engine conversion obviously) with 915 gearbox. Hence I bought the supercharger and booked it in to have it fitted.
The car was taken to Warrington and left in the capable hands of Robin. They dynoed the car to check the state of the engine prior to having the supercharger fitted. It was only producing 250BHP and similar torque (should be 285BHP) and they traced this to the Varioram system not operating correctly. They sorted this out and it now produced 300BHP and 300lbs of torque "" so, good to go then!
I stressed that I wanted to keep the engine lid without spoiler (they were concerned that the pulley would foul the engine lid and may require a spoiler) to maintain the smooth lines and wolf in sheep's clothing appearance. They said that they would try and lower the engine in order to be able to do this. In the end they lowered it by 30mm "" and due to this the back box was pushing against the rear valence and creating a minor bulge - but this is barely noticeable.
Anyway, after a couple of weeks the supercharger was well and truly bolted in and it was time to test it.
Robin road tested the car and noticed a dip in power from 2700 rpm to 3500rpm. They put it on the dyno and found that the fueling was too low and the engine was pinking.
However, the power output was incredible.
At the top end it was pushing out 407.7BHP and 364lbs of torque (5000rpm) - at first they didn't believe this so they did a few more runs to confirm it wasn't a fluke. The figures were accurate and they tried to explain it by the 8.5PSI of boost that the "˜charger was generating. However as it was still 'detonating its t1ts off' they decided to lower the boost and aim for about 360BHP.
In order to do this they fitted a larger pulley to slow the revolutions. Boost was now 5.5PSI. Another run on the dyno showed 405.5BHP and 360.4lbs of torque - they explained the same power due to the fact that the temps would be lower on the lower boost. The engine was still detonating though (at 2300rpm it had 316lbs of torque and at 3500 it had 300lbs of torque) and hence it required a full remap of the digibox.
They remapped the digibox (6 hours on the dyno in all) and achieved 300lbs of torque at 2000 rpm "" this stayed constant until 4000rpm when it began to increase. There was a hefty rise to 366lbs at 5370rpm. BHP is lower than the numbers quoted above but still impressive.
The reasons they gave for the higher than usual power and torque numbers (compared to a 993 car) were:
No catalytic convertors
Free flowing exhaust (Hayward and Scott stainless back box)
Lightweight flywheel
Low drag 915 gearbox
As you can imagine I'm over the moon with it - Robin did a splendid job and even attended to the small items such as the incomplete tinware that was letting the hot exhaust air heat the engine too much - it now runs a lot cooler and the cone filter is actually cold to touch!
Oh yeah "" and flames out of the exhaust now!
Well recommended!! [
]Whoops - just realised that maybe I should have posted this on the SC forum!
