To study and properly understand the Stage 3 gains, we must first study the torque and horsepower Monty produced (and where) when he was in Stage 2 tune, at this point I should stress Monty already produced excellent torque in Stage 2.
First let's look at the 4,000rpm - 6,000rpm window as this is where you're typically asking the engine to really deliver on the road, and specifically let's look really closely at what we've really added by changing the Newman Phase 2 cams for Newman Phase 3 cams, and changing the standard cylinder head for the A.L Developments ported head with 1mm larger inlet valves, 1mm larger exhaust valves, and the head's exhaust ports brought out from 38mm to 40mm?
Stage 2 HorsepowerIf look at the horsepower delivered over that 4,000rpm - 6,000rpm window, we see that Stage 2 Monty goes from 112hp to 170hp
Stage 3 Horsepower Over the same window, Stage 3 Monty actually goes from 145hp - 175hp, so yes by the time Monty reaches 6,000rpm Monty is only making 5hp more, but at 4,000rpm Monty is actually producing 33hp more than Stage 2 Monty, in percentage terms that's a huge 30% increase!!
Stage 2 TorqueWhile the peak of figure 158 lb/ft at 5,250rpm is impressive in itself, what stood out was the way Monty made 150 lbs/ft at 4,000rpm and held onto that number all the way out to 6,000rpm where Monty's Duratec was still making 150 lbs/ft! That wide 4,000rpm - 6,000rpm window of torque where the engine constantly served up 150 lbs/ft is what made the estimated 930kg Stage 2 Monty fast in the real world.
Stage 3 TorqueThe peak of figure has gone from 158 lb/ft at 5,250rpm to
170 lb/ft at 6,400rpm, in the 4,000rpm - 6,000rpm window Stage 3 Monty now starts out with same excellent Stage 2 figure of 150ft/lbs, but unlike Stage 2 Monty the torque line is now a rising line. At 6,000rpm rather than making 150 lbs/ft, Monty is now producing a full 18 lbs/ft more to give 168 lbs/ft, better still Monty holds onto that advantage all the way out to 6,400rpm where Stage 3 Monty is now making a very healthy
170 lb/ft .
If you look closely at the Stage 2 graph you'll see Monty's torque line falls off steeply after 5,250rpm, at this point Stage 3 Monty is now already making 10 lbs/ft more (160 lbs/ft). However, he doesn't give up there, Stage 3 Monty then goes on to pile in another 10 lbs/ft all the way out to 6,400rpm which is 1,150rpm more revs than where Stage 2 Monty complete gave up. Stage 3 Monty not only adds 10 lbs/ft at the same 5,250rpm where Stage 2 Monty's torque peaked, he now keeps piling on more and more torque all the way out to 6,400rpm where the new peak figure of
170 lb/ft arrives.
Back in the real world what this really means is under hard acceleration I can now hold onto the gear for a lot longer, a full 1,150rpm longer! Out on the road, and on the track where you can enjoy it safely, you really notice staying in gear longer. Monty is not only holding peak torque as before, he's actually pilling on more and more torque, which pushes you back in the seat and definitely puts a big grin on your face.
Dave.
