[VintageLambo] Re: Turbo Charge/intercooling for the Jalpas

As you know boats and cars are somewhat different. From a cooling standpoint the difference is that boats have plenty of both cool air and cool (sea or lake) water available, while cars only have plenty of cool air available. The vast majority of automotive inter-cooling is done with air to air intercoolers, which is more direct that an air to water to air heat exchange. A coolant liquid intercooler cannot reduce the air temperature below about 180F. The name of the torque game (from the 2nd law of thermodynamics) is to cram as many n"s (= PV / (RT)) into the engine as possible before detonation, which is done with high pressure and low temperature. Currently I plan to use intercoolers and port (close to the intake valve) water injection for cooling. The phase transition from liquid water to steam takes a lot of calories and is particularly beneficial if it occurs during the combustion phase, essentially combining an IC and a steam engine. Too much water is not good. See here for more information and justification: http://www.aquamist.co.uk With respect to the engine location and inter-cooling, Porsche does a pretty good job with their 911 Turbo and GT2. The aerodynamics of the Jalpa (and others of similar design) is such that there is a low pressure behind the rear window (above the "bird-bath"), creating an upward airflow around the engine, which can be utilized by the intercooler(s) and it is also good for the down-force. Here is an important trick to consider: Imagine for a moment having a flow restriction at the intake valve (for example by using small intake valves and only one per cylinder) and having a turbocharger system that can deliver both high pressure and flow. The pressure and therefore the temperature before the valve could be very high, thus making it possible to extract a lot of calories with an intercooler (proportional to inside and outside temperature difference). If the intake valve provides enough of a restriction there will be a pressure drop and therefore a reduction in temperature on the path into the combustion chamber. This I believe is the reason that Porsche used only a 2-valve configuration for their early turbocharged engines. This unfortunately requires medium pressure and low flow (at low rpm) and high pressure high flow (at high rpm), witch is at odds with turbochargers characteristics. However this scheme would work extremely well with infinitely variable cam lift and timing. So here is a real project: Buy a BMW 745iL (or better, the yet to be release BMW 760iL), stick a couple of turbochargers and intercoolers on it, learn how to fully control the whole thing and set the cam lift (and timing) and waste-gates at WOT (Wide Open Throttle) according to above scheme. That would be a monster and could probably even run on regular gas. Laust --- In VintageLambo@yahoogroups.com, "docmirror " wrote: > Just a thought I was tossing around the other day. I know Laust has a > current turbo project going on, and I"ve heard rumblings about other > turbo projects too. Has anyone given any thought to using a liquid > charge cooler to improve the thermal efficiency of the pressurization > process? > > I did some PV=NRT crunching the other day, and it seems the value of > the charge cooler would be of great benefit. The only car I can think > of that uses one is the Lotus Esprit of some vintage. > > The increase in volumetric efficiency by turbocharging is partially > offset by the decrease in thermal effieciency. Since the Jalpa is a > mid engine car, a standard intercooler wouldn"t be very practical. > But, a liquid chargecooler with small fluid lines to a front mounted > radiator would be not only feasable, but fairly easy. the front > radiator wouldn"t need to be very big, and the circulation pump can be > any number of small 12V remote mounted uni