D-Day. Dyno Day. The day we find out exactly what power and torque this old stager puts out.
Why? Well the regulations for the 750 Motor Club Sport Specials championship demands that I have the power and mass independently certified, so today with a good weather forecast on our side, I took the Fury to Novatech in Slough to be put on their corner weight scales, and to make a few dyno-pulls.
The day didn't start well, as after half an hour of trying to get it to start it barely spluttered into life, running on 1 or 2 cylinders at best, and so had to be pushed onto the trailer. And that was after I managed to gash my head on the garage rafters!!! So with blood pouring from my head we made our way over to Novatech and hoped for the best...but as any bad mechanic knows that you have to cut yourself before you finish a job!
After we unloaded the car from the trailer and wheeled the car into Novatechs shiny new premises at Ipswich Road in Slough, Bernie and Andy quickly pulled the spark plugs to check for condition and a spark, cleaned & dried them off, then took their time to understand the wiring loom and how it routes to the MBE ignition from the coil pack. Having confirmed that all seemed to be in order, Andy hooked up a good battery and Bernie fired her up. Now running on at least 3 cylinders, Andy checked the exhaust temperatures with a laser guided gauge and found number three cylinder was still quite cool and so not firing; a quick tweak with a screwdriver to the carburettor idle mixture screw and suddenly the engine started to run on all 4 cylinders.
After carefully positioning the car on the lift, Bernie lowered the car down on to the corner weight scales, and it turns out that my Sylva is a bit of a fat boy - 655 kilos with a full (endurance sized) tank of fuel. I reckon there must be over 50 litres in there so my estimate of 620 seems about right, but shows how heavy that old Vauxhall/Cosworth XE is compared to a more modern 4 pot. Fury's with a K Series weigh in at about 525kilos and those with a Motorbike lump are well under 500. Only a Pinto is more of a boat anchor, but I must remember that the XE was the class of it's day, but that day is now nearly 20 years ago!
Next up - the dyno test. As you might have read in my previous blog posts, I had done some calculations based on actual drag race time slips and figured out that it must only make (a rather weedy) 165bhp at the rear wheels, equivalent to about 200bhp at the flywheel.
The engine is a lightly modified Vauxhall Cosworth XE "red top" - 2 litres in capacity, normal aspiration via 2 Weber 45 DCOE carburettors; SBD dry sump lubrication, and SBD airbox; QED cams of unknown profile; a hand built exhaust manifold with Caterham R500 silencer; and stock bottom end. In the road cars such as the Astra GTE or Calibra 16v with fuel injection these engines made 156bhp at the flywheel.
Bernie fired the Sylva up and made the first of several dyno pulls. It sounded really crisp as he ran it through the gears, and with a strong flapping from the carbs it sounded torquey as he accelerated from around 3000rpm up to the rev limiter. We had trouble reading rpm from the electronic rev counter so obviously still a few gremlins in the system but plugged in a laptop to the MBE ignition and used a timing light to determine actual rpm.
Spitting flames from the exhaust with a snap, crackle, and pop as Bernie backed off the gas, the dyno pull proved that the car was making 179lb ft torque @5,000 rpm and 197.9 flywheel bhp @7,000rpm (164.7bhp at the rear wheels). So my calculations were pretty much spot on...and even having sat in storage for several years this is still a 100bhp / litre carburettored engine. So power to mass ratio with fuel but without driver stands at 306bhp/ton or 267bhp / ton with driver. In metric that is 302bhp/tonne static or 263 bhp/tonne with driver; to put this perspective this sort of power to weight ratio is on a par with a Porsche 997 GT3. An oil change along with new oil filter and air filter will do the world of good and might release the last couple of horses to reach the 200 mark.
With so much weight to drag around the car is hardly going to be a front runner in the 750MC SS championship, but it will certainly be a lot of fun to drive. Here's looking forward to Brands Hatch at the end of April!
Massive thanks to Paul for his tow car skills, time, and for the ride in his awesome 30th Anniversary 4th Gen Camaro SS this morning!
Why? Well the regulations for the 750 Motor Club Sport Specials championship demands that I have the power and mass independently certified, so today with a good weather forecast on our side, I took the Fury to Novatech in Slough to be put on their corner weight scales, and to make a few dyno-pulls.
The day didn't start well, as after half an hour of trying to get it to start it barely spluttered into life, running on 1 or 2 cylinders at best, and so had to be pushed onto the trailer. And that was after I managed to gash my head on the garage rafters!!! So with blood pouring from my head we made our way over to Novatech and hoped for the best...but as any bad mechanic knows that you have to cut yourself before you finish a job!
After we unloaded the car from the trailer and wheeled the car into Novatechs shiny new premises at Ipswich Road in Slough, Bernie and Andy quickly pulled the spark plugs to check for condition and a spark, cleaned & dried them off, then took their time to understand the wiring loom and how it routes to the MBE ignition from the coil pack. Having confirmed that all seemed to be in order, Andy hooked up a good battery and Bernie fired her up. Now running on at least 3 cylinders, Andy checked the exhaust temperatures with a laser guided gauge and found number three cylinder was still quite cool and so not firing; a quick tweak with a screwdriver to the carburettor idle mixture screw and suddenly the engine started to run on all 4 cylinders.
After carefully positioning the car on the lift, Bernie lowered the car down on to the corner weight scales, and it turns out that my Sylva is a bit of a fat boy - 655 kilos with a full (endurance sized) tank of fuel. I reckon there must be over 50 litres in there so my estimate of 620 seems about right, but shows how heavy that old Vauxhall/Cosworth XE is compared to a more modern 4 pot. Fury's with a K Series weigh in at about 525kilos and those with a Motorbike lump are well under 500. Only a Pinto is more of a boat anchor, but I must remember that the XE was the class of it's day, but that day is now nearly 20 years ago!
Next up - the dyno test. As you might have read in my previous blog posts, I had done some calculations based on actual drag race time slips and figured out that it must only make (a rather weedy) 165bhp at the rear wheels, equivalent to about 200bhp at the flywheel.
The engine is a lightly modified Vauxhall Cosworth XE "red top" - 2 litres in capacity, normal aspiration via 2 Weber 45 DCOE carburettors; SBD dry sump lubrication, and SBD airbox; QED cams of unknown profile; a hand built exhaust manifold with Caterham R500 silencer; and stock bottom end. In the road cars such as the Astra GTE or Calibra 16v with fuel injection these engines made 156bhp at the flywheel.
Bernie fired the Sylva up and made the first of several dyno pulls. It sounded really crisp as he ran it through the gears, and with a strong flapping from the carbs it sounded torquey as he accelerated from around 3000rpm up to the rev limiter. We had trouble reading rpm from the electronic rev counter so obviously still a few gremlins in the system but plugged in a laptop to the MBE ignition and used a timing light to determine actual rpm.
Spitting flames from the exhaust with a snap, crackle, and pop as Bernie backed off the gas, the dyno pull proved that the car was making 179lb ft torque @5,000 rpm and 197.9 flywheel bhp @7,000rpm (164.7bhp at the rear wheels). So my calculations were pretty much spot on...and even having sat in storage for several years this is still a 100bhp / litre carburettored engine. So power to mass ratio with fuel but without driver stands at 306bhp/ton or 267bhp / ton with driver. In metric that is 302bhp/tonne static or 263 bhp/tonne with driver; to put this perspective this sort of power to weight ratio is on a par with a Porsche 997 GT3. An oil change along with new oil filter and air filter will do the world of good and might release the last couple of horses to reach the 200 mark.
With so much weight to drag around the car is hardly going to be a front runner in the 750MC SS championship, but it will certainly be a lot of fun to drive. Here's looking forward to Brands Hatch at the end of April!
Massive thanks to Paul for his tow car skills, time, and for the ride in his awesome 30th Anniversary 4th Gen Camaro SS this morning!
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