Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) New Morgan imminent!

I'm utterly delighted! I was originally thinking of a 3.7 but I didn't like the PAS nor the width of the gearbox tunnel. This one is almost perfect.... if I was nit picking, I'd rather have the traditional studded hood and cream leather, but the navy looks nice.... better than black anyway!

My only plan is the remove the front bumper and fit a Wolf lower valance. Does anyone know when he'll be back working? I heard he is looking after elderly parents.

Delivery day today! The car should arrive home around 11.30 and I have the afternoon off! Both kids have requested collecting from school in it and glorious weather up in York too.

I woke at 4.00 am and was wide awake like a kid a Christmas.

Good luck today - I’m not at all envious!

Thanks for the pic - looks a lovely car, and a great colour too !

If you're desperate Williams do one, look on their web page or phone Mike Gardener.

Oh! and when the heavens open you'll love that hood!

The above figures seem low to me?

My naturally aspirated 4.0 Litre TVR Chimaera (3.9 Rover V8) made 198hp at the hubs, which is a calculated 233hp at the crank. This was running nothing more than a 'Stealth' cam from V8 Developments and a Canems ECU, and was also recorded on Lloyd Specialist Developments' hub dyno.

I would expect something around the 300hp mark from a bog standard 3.9 (Range Rover spec) Rover V8 fitted with a Sprintex S5-335 screw compressor, and running it to deliver 8psi of boost.



Looking at the above image there seems to be no intercooler? If that's the case I'd be inclined to keep boost at 6psi for safety, but as a minimum some sort of mappable 3D ignition system would be essential. Even something simple like a 123 Tune distributor could be configured to give a boost referenced ignition retard strategy.

However, if you're still trying to control your fueling with the 14CUX system I would strongly recommend something a bit more sophisticated, you really need a boost referenced 3D VE bastsed fuel table and an IAT sensor input allows you to pull timing as air temps rise. The 'EMU Black' ECU fron ECU Masters is an excellent stand alone engine management system that would give you all this, and so much more!

With no intercooler, and running a safe 6psi, I'd be expecting 270hp at the crank (230hp at the hubs) and 300 lbs/ft of torque from just 2,500rpm staying there to 4,500rpm. Either side of that peak torque window, right from almost idle engine speed to 2,500rpm and from 4,500rpm to 5,500rpm you should see 240 ft/lbs average, giving you a very flat traction breaking torque curve right off the line to 5,500rpm, this will give a 950kg Morgan massive thrust but will demand respect!

A big torqe V8 in a light car is a very different animal when compared with a high revving four banger in a light car, the latter delivers a very controlable linea power delivery while the former will have you facing the wrong way in the blink of an eye. In my extensive experience of both, and even if you believe you have the skills to cope, one day (probably a wet day) the big torque V8 in a light car recipe will eventually catch you out.

Have fun, but do resect all that early onset torque

Most I've read about superchargers is that they add around 20%. The performance is adequate (I'd always welcome a little more) as it is, and I certainly wont be spending any more on the engine. It feels like it could do with a different cam as it runs out of steam around 4000 rpm. From the 40 miles I've driven in it so far, it feels planted and I don't think it has enough to loose control unless I drove it like a complete di*k. In the wet it will be more fun, but the throttle travel is quite long and I'll drive it appropriate for the conditions.

A positive displacement Sprintex S5-335 screw type supercharger can take as much as 30 horsepower just to turn it when it's pumping hard, so if you are starting with a standard 180hp Range Rover spec 3.9 in good health, you're now down to 150hp. Of course, this before you've put any of the compressed air the blower makes back into the engine.

At this point you should keep in mind you'll need roughly 3psi of boost just to get you back to the original 180hp, at which point you would be better off with no compressor at all because you'll just be burning more fuel to turn it, and get you back to the same 180hp the naturally aspirated engine started out with.

If you don't have an intercooler or charge cooler then 6psi would be a likely safe boost ceiling, so that's 3psi to get you back to 180hp, plus whatever the remaining 3psi gives you above that. Common folklaw states you should enjoy roughly 10hp for every psi of boost, this is of course an over-simplification as it's actually a percentage increase not a fixed 10hp per psi.

None of this is easy to estimate as the percentage will change across different compressor types, diffent engines, different elevation levels above sea level, different temperatures etc etc etc. To asses the effciency of your setup you really do need to start with your engine's naturally aspirated power output before the blower was fitted, you then need to confirm exactly how much pressure over atmosphere (boist) you are forcing into the engine?

You may also find you actually only started out with 170hp, and you're getting more like 15psi per psi of boost, so at 6psi that would be 170 + 60 = 230hp, which wouldn't be far off your quoted 240hp

Montegue -- mechanical neophyte here: your write "I'd be expecting 270hp at the crank (230hp at the hubs)". Does this mean you lose literally 40hp between the engine and the wheels? Does it really take that much power just to turn the driveshaft and the axels?

It's not an exact science as there are many variables, but most tend to use something in the order of -18% for their drivetrain losses calculation.