fraser_drinkwater

Think this should do... Engine Genetics Engine performance for the genetically curious or engine genetics for the performance curious ... Why is it that your cultivator engine plods along at a mind numbingly 3200 rev/min? Why does your average gasoline passenger car engine run to 6000 rev/min? Why are passenger car diesel engines restricted to 4500 rev/min? What's Montoya?s BMW engine got that gives him 19000 rev/min? Is there a link between all reciprocating engines and are they ?brothers under the skin?? The Eureka moment comes from an understanding of the relationship between mean piston speed and brake mean effective pressure (BMEP). If you don?t know what these terms are, open an engine textbook and find out. For the terminally lazy, consider that mean piston speed is the average speed of the piston as it travels from top dead centre to bottom dead centre. BMEP can be considered as specific power per unit swept volume per unit rotational speed. Plotting BMEP against mean piston speed we can see:- The Heavy Duty (HD) diesel engine is limited to a mean piston speed of about 11.5 m/s irrespective of bore and stroke. The data includes 400 kW on-highway truck engines and 4000 kW generating set prime movers. This is essentially a limitation on peak inlet port gas speed, characterised by mean piston speed. Air consumption is limited by the need to produce both an inlet swirl and flow, resulting in a mean inlet flow coefficient that is significantly worse than a gasoline engine. Since the diesel engine runs a significantly higher compression ratio, the peak cylinder pressures are higher than gasoline engines, the structures to support this loading are more robust. The diesel engine is, therefore limited to a lower mean piston speed than the gasoline counterpart by the ability to transfer air from the outside to the inside of the cylinder and by the higher friction losses associated with the higher mechanical loading. The Light Duty (LD) passenger car engine runs to 13 -14 m/s mean piston speed as the lighter structures and reduced load factors contrive to lower the parasitic losses. Electronic fuel systems are limited to 4500 rev/min by the speed of the control solenoids and the pressures required to inject fuel into the cylinder in a short time period. Development of the diesel engine proceeds parallel to the abscissa restrained by mechanical losses and to a lesser extent by air delivery issues. Ever higher boost ratios and mechanical loading limit the progress via material tribological and fuel system challenges. A gasoline passenger car engine doesn?t need swirl to mix fuel and air and runs to 18 m/s mean piston speed and slightly more in motorcycle configuration. The Honda S-2000 runs to 9000 rev/min, a staggering 23 m/s and would be the engine engineer?s choice for ?engine of the decade?. Formula 1 engines run to 26 m/s aided by a design brief to achieve an advantage irrespective of cost and aided by uncompromisingly expensive and light components to limit inertia loading and a 25 hour life. The Gasoline Direct Injection (GDI) engines run slightly higher mean piston speed than the port injected gasoline engine as the air consumption of the GDI is higher as the inlet system has only to pump air and not air + fuel. Development of the gasoline engine proceeds at 60 degrees to the abscissa limited by parasitic losses, thermal loading and in the case of F1 engines, by valve gear durability. It follows that: All engines are brothers, related by mean piston speed and BMEP. The Honda S-2000 is the engineer?s choice for engine of the decade but would your grandparents be happy with one? The diesel engine is capable of running faster than 4500 rev/min when fuel systems are capable. An engine speed of 10,000 rev/min is technically feasible. In the future, will turbocharging find favour on passenger car gasoline and will the gap between gasoline and diesel structures narrow? Answers: The limiting mean piston speed of industrial gasoline turf engines and passenger car engines are not dissimilar. The turf engine has a restrictive exhaust (higher parasitic loading) designed to minimise noise and keep the neighbours happy. The average gasoline runs to 6000 rev/min or 18 m/s mean piston speed as this is a happy balance between cost, rated speed power and the ability to sit at 70 mph at 2500 rev/min in top and still accelerate (just) with peak torque only some 1000 rev/min higher. The diesel engine is restricted to 4500 rev/min by the ability of the fuel system to deliver fuel at the correct quantity and at the correct rate to ensure complete combustion. Higher engine speeds are possible with continued fuel system development. Montoya?s racecar engine runs to 26 m/s or 19000 rev/min as the only mechanical development restraint on this engine is the ability of the valve gear to stay in one piece. ?Is there a common link between all engines?? ?... mean piston speed and BMEP. By Fraser MEng BSC

psmsl now thats entertainment lol gotta love the humour. You cant be serious about this now can ya!!!

rover metero 998cc van den plas thingy

Sad day I bet, what ya getting next Jamie???????

Everyone buy Jap Performance this month it has a section dedicated to this,and the truth will be told.

This is the harsh reality that we should keep in mind.

bttt

Is it sitting on dubs!!!! I know a bloke who has Gumball stickers!!!! And a Yorkie! Rubber duck there is a bear in the air. Nice.

Like them mate, are they bigger than standard rims, any handling improvements?

Morning all, might see ya the night in Edinburgh, need to test the zorst!!!!!

Nah but thats a mere technicality, all the American Highways are straight any how .lol

Do it yourself ma man these places are stealing your potential money for more mods!!!!!!!!!!!

Lets do it.

Thats Wullie away to Carlisle the night Gumball style. He said all is welcome, if not standby for his photos at about 4am!!!!!!!!!!!!!!!

Back and holy poo what a change,even before the map! Pick up is quicker with turbo lag no longer and the noise is nuts, pure rally car. It passed the noise testing zone with ease. now next part coming up, and by the way there IS 3 CATs on these trust me!!!!!!!!!lol

Get the h&S and do it yirsel nae bother!!!!

lol a like it ma man!!

The bits in the bin are now replaced by the shiney's!!!!!! Wednesday is going to be like Clarke Kent turning in to superman THE SWIGG......

That's me and Wullie (WRC NO1) just in after removing the up pipe and down pipe - it involved removing the turbo, intercooler, power steering lines, one half of the headers and turbo actuator.... The car is ready fot the Hayward and Scott install tomorrow Jigsaw shall be completed on wednesday... READY FOR THE GUMBALL......!!!!!!!! C'MOAN THE SCOOBS MAN

had a laugh at this and a good session on the pop..!!!! Im definately the fastest on the ring and Wilky saw it so there na na na na!!!!!! See ya later THE SWIGG..... And black is the fastest colour as of the 20th!!!!

This is a Subaru Imprezas drivers club the english speaks for itself. I dont worry about other clubs, just that ours is getting better. I dont care a lot about other clubs and I dont care if anyone agrees but thats life. We can do what ever Gumball etc we want but the main stuff is kept to the members section, as this is a public forum and we can log in anywhere ie Web cafe...and say what we want. If peeps have a stronger opinion they should attend a meet or contact the commitee and express their feelings. This would be better than venting our opinions on a public site....YES.. If anyone has suumin to say, dont make it public!!!!! There are too many keyboard warriors out there, you know who you are. PS. MOAN THE SCOOBS.

Got 3 licences but a mince motta still, trying to get it modded. Ill report back in a bit.

Give me the co-ordinates of these clowns!!!!!!! Wilky can you help?

Cheers bud ill give it a go.

boing...