Compound Turbo

[Anaema]

and yeah, back on topic.... diesels have more compression only because they have huge rods and a much larger stroke than any gasoline engine. but ill leave the math to the people that can do it correctly..

that isnt true. deisels have such high compression ratios because the high piston height and small dish in the pistons creates a 20:1 compression ratio. they use that because the higher compression ratio you have, the (relatively) more effecient engine you run. thats why two engines equally sized, one a deisel, one a gasoline, will get different fuel milages, in favor of the deisel.

 

[robertk515]

not every diesel engine has an "M" style dish piston like you are reffering to. a classic example is the 5.7L diesel engine in some chevy and oldsmobile cars that have a 23:1 compresion ratio with FLAT top pistons. because they have longer rods and most of the later versions have a larger stroke. i am a diesel mechanic and have been working with these engines for 6 years for 5 days a week for 48 weeks of the year, larger stroke and longer rods will give you much more compression on a diesel WITHOUT dished pistons.

efficiency of a diesel comes from the fact that they will always try to run lean because they do not need a throttle body to control the amount of air going into the engine. they always take as much air as possible, so the rpm is controlled by the amount of fuel delivered to each cylinder. these are precisley controlled by a mechanical or electronic fuel pump delivering a set amount of fuel measured in cc's to each cylinder. if these are even 1/10th of a cc off in amount it will destroy a diesel by scoring cylinders from uneven heat distribution inside the cylinder.

i will no longer be going off topic on this post.

 

[nookymonsta]

I wonder if anybody has tried twin compound turbochargers ?

 

[Anaema]

I wonder if anybody has tried twin compound turbochargers ?

i doubt it, since it really doesnt have any advantages over a single compound setup. its already an expensive and complex system, adding two more turbos would be a waste.

 

[Toysrme]

You can see it done on diesel & big drag cars. They just pair off cylinders.

 

[jdchmiel]

people do not do it in gasoline motors due to reaching the limits of the fuel octane. If you can reach the limits of pump gas with a single turbo now adays, why bother running more than one turbo? since diesel does not detonate, they have no such limitaiton in place, merely the challenge of getting as much air and fuel into the motor as possible while keeping EGT temps in check.