As you may recall I built a 4.2, with some head porting, D type cams and 9.5:1 compression ratio.
I’m running a pair of HS8’s with 100 thou jets from an early XJ6.
To get it to fuel properly he ended up using BCA needles. Any more would have required changing to 125 thou jets.
Peak power at the wheels was 136.3 HP at 4900 rpm.
Peak torque was 294.7 lbft at 3400 rpm.
To put the power in perspective a 5l V8 fuel injected Holden Commodore produces 140 HP on his dyno. The quoted engine power for the Commodore is 165kW, or about 221 HP and 284 ftlb . So I’m pretty happy with that.
He says a 3.4l engine makes about 90 HP, and 3.8 around 110 HP on his dyno.
That torque figure is awesome!
But there is something incorrect here. That torque figure equates to a HP of 191 or 140kw at 3400. And reading off your torque curve you would have 219hp at 4800rpm.
But just a note on dynos, yes some dynos read very low. Many years ago I had my 4.2 E type on the dyno at a well known race shop in Sydney. The engine had been rebuilt and was fitted with Webers. It rated 165hp and the dyno shop said this was quite good as XJS V12 were only making 180hp on the same dyno.
There are plenty of calculators on the net if you google “torque to hp”
The formula is HP = Torque (ft/lbs) x rpm / 5252
In your case 295x3400/5252 = 190.97hp
No idea why your dyno sheet shows figures that are nowhere near this.
I vaguely recall reading somewhere that the blueprinted engines used in the original press E Types produced around 220 real bhp. The 150mph target was only achieved by backing off the bearing torques to their minimum to reduce friction, removing the front overriders and motif bar etc. Apparently, the very last few mph were hard to coax, but, if the story is correct, the road testers were told not to come back until the magic 150 had been achieved. Don’t forget, 9600HP, on its original road test returned 650 mpg OF OIL, so a very loose engine.
I presume that would be engine dyno HP though, not rear wheel HP, which is reduced by the gearbox and diff (and whatever ancilliaries the engine is running)
I think we all have read that, but in 1962 German Auto, Motor & Sport tested “6162RW” in Germany and Italy and it ran an average of 256km/h = 159mph measured over 1 km both ways. With overriders and a glass rear window etc. The legends regarding the early cars are much exaggerated IMHO, I think they had used perspex simply because no safety glass had been made yet. YMMV.
Me too. I scanned and sent copies to a few fellow listers years ago. Copyright over here expires 50 years after the photos were taken and/or they were published.
I drove about 100 miles in the car today. The motor is fantastic.
With the front end rebuilt, uprated front springs and the new Koni shocks set hard it handles amazingly well. I was keeping up with the E types. The freshly rebuilt brakes are better than any of my E Types.
