Back in my January 2020 update post, I dropped some hints about my change in engine choice. 427 cubic inch, titanium rods and, the need for a dry-sump tank...
So if you hadn't already guessed, I am now planning on installing an LS7 engine instead of the LS3. My engine builder, Kyle, made me an offer I literally couldn't refuse. He also persuaded me to consider dry-sumping the motor to eek out a few extra horsepowers - hence the need to try and find a location in the confines of the AK for a remote oil tank.
So the revised engine specification looks a bit like this
LS7 Pistons - Mahle PowerPak Forged 4032 Alloy for low expansion with Grafal anti-friction skirt coating - modified wrist pins - hot washed and checked
Mahle High-Performance Piston Rings
Compression Ration approx 11.3:1
Competition Cams Camshaft (guaranteed to pass IVA / MOT)
LS7 Sump Pan with adaptor for -12 oil lines to remote tank
New LS7 Intake with 42 lb per hour Injectors
One Piece Manley Pushrods
New Gaskets
New Sensors
New Oil Seals
Fly-by-Wire Throttle Body
Custom Corvette Front End (Power Steering Pump, Alternator, Idler and Custom Tensioner)
Canems ECU and Wiring Loom modified to include immobiliser
Dyno Run and Set-up
Kyle started pulling together all the parts for the engine earlier this year but the Covid-19 pandemic caused a few delays with some of the parts coming from the States so final assembly did not begin until mid-June
LS7 Bare Aluminium Block with pressed in Steel Cylinder Liners
Cam installed and upper main bearings in place - note dowels to assist location of end caps
Forged Steel Crankshaft 2.559in dia Mains / 2.100in dia Rod Journals
Reluctor Wheel (24X) welded to Crankshaft
Pistons and Rods ready for assembly
Piston Ring Gapping
Short Block Assembly complete
Cylinder Heads - CNC Ported / 70cc Chambers - 2.205in dia Titanium Intake Valves & 1.610 in dia S/Steel Sodium Filled Exhaust Valves
Uprated Valvetrain
Fly-by-Wire Throttle Body
Sump Adaptor to connect to remote Oil Tank
Assembly almost complete - looking like an engine!
The LS7 was the largest displacement engine in the LS engine series. It was based on the C5-R engine used in the Le Mans racing Corvettes so is purpose-built for high performance. It found its way into a number of GM cars between 2006 and 2015 most notably the Corvette Z06.
The stock LS7 produced a respectable 505bhp at 6300rpm and 470lbft torque at 4800rpm. Kyle built the LS7 for Apple, the AK demonstrator, which put out around 630bhp and a shade under 600lbft torque, some serious gains over stock, and I would have been happy with similar numbers from my engine.
Kyle had the engine hooked up to his dyno at the beginning of July and spent a day checking over for leaks, before a session at fast idle to run in / bed in the engine. The plan was for Dave from Canems to come and assist with the set-up of the ECU before carrying out the power pulls proper.
On the dyno and ready to rumble...
About mid-day on the day that Kyle was hoping to do the power pulls, I got a phone call. "Are you sitting down?" he said. So down I sat, thinking the engine had blown up on the dyno or some other equally catastrophic scenario. Turned out the numbers on this beast exceeded even Kyle's expectations; 659bhp at 6300rpm and 603lbft at 4900rpm! He was over the moon and so was I!
Dyno output...
...peaking at 658.6bhp and 602.9lbft torque!
Torque exceeds 500lbft from around 3000rpm!
While the engine was still on the dyno I took the opportunity to pop up to Kyle's workshop and check it out in action. It also gave me the chance to familiarise myself with all the various connections from the ECU to the engine sensors and to get some guidance from Kyle for when I come to start up the engine myself.
The video above of the outside of the dyno room just does not convey the power of this engine - it was like a Force 8 gale blowing out of the exhaust pipes and the whole ground was shaking. Absolutely awesome piece of kit and I would recommend Kyle without a doubt to anybody wanting to get some serious bang for their buck on the engine front.
I should be picking engine up in a couple of weeks time so I guess I'd better crack on with getting the rolling chassis completed!!
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