Cat diesel power!!!!

So what would U suggest as far as compression ratio.I planned on puttin 58 injectors,800hp marine cam,a B exhaust manifold,lose the twin turbo set up and go to a single Michigan stage 5 and a 6NZ ecm.Probably install a head from a 6NZ as well to get rid of the VIVA's.My goal is to have a reliable useable 1000hp at the flywheel without the Power Box.Maybe thats unrealistic in my application.Appreciate all the info

 

I think you will need 10R0959s to make that kinda power without a box, also an acert head is the same a late model 6NZ head anyway. I would think 16:1 (6NZ) would be suitable. To be honest I may not be the best person to answer this question, DDS has had a lot more experiance building high power C15s than me, also give PDI a call, they are supposed to know a lot about getting big power from a C15, Pittsburgh Powers web site also has a lot of interesting articles on building big horsepower cummins, the basic theory is the same for any high horsepower diesel.

 

I have read some researches that say everything over 16:1 is less efficient because of more internal friction. Over 16:1 is only used for NOX emissions, retarded timing needs more compression to get back some lost power.

 

I would think raising the compression does increase internal friction but the gain in power would out weigh increase in friction. The internal friction cant increase too much or the big-ends, little ends etc would suffer. In Cats 18:1 engine they still use the same big end as the old 14.6:1 B models.
Internal friction due to compression would be as a result of the pressure on top of the piston as the piston comes to the top on the compression stoke, when you increase the boost pressure you would get the same effect, more pressure on top of the piston and therfore more friction.
Just given my opinion, not necessarily proven fact, I'm a wrench not an engineer

 

It's about piston to cylinder wall friction, above 16:1 friction increase outweighs efficiency gains. There might be some tolerance up or down depending of rod/stroke ratio. Boost has same effect but most engines spend most of their time at low load. Turbocharging makes engines more efficient so that outweighs losses under boost.

More fuel also needs larger combustion chamber, that's why marine engines have lower compression. Marine injectors with marine pistons is not a bad choice.

 

It is all about cylinder pressure.The big question seems to be how the best way to make the pressue for the best performance.The higher compression pistons builds pressure by making the area between the piston (at TDC) and cylinder head smaller.In this configuration the engine has a higher static compression ratio and then you can add boost from a supercharger to a point before things go very wrong.IMO for performance a better way is to have a lower cylinder pressure created by the piston and make the rest of the cylinder pressure with nice cool air being forced into the cylinder by your turbo which will help burn the fuel being injected into the cylinder.FYI camshaft events can have an effect on cylinder pressure too.

 

550 that is amazing to hear about and to HEAR!!!!!

 

havent been on in awhile.but i tell you was a good thread to start back on.lol.nice numbers 550.

 

what upgrades are suggested for a air to air 3406b cat

 

Sorry, we'll have to agree to disagree on that one I just cant see a higher static compression decreasing efficiency, friction between the cylinder wall and piston is caused by pressure on top of the piston either from static compression or combustion, if that is the case then increasing combustion should also decrease efficiency, most trucks I know get better on fuel if you increase the horsepower and therfore cyinder pressure. I realise this is a topic far to complicated to explore properly on a forum, there are way too many other factors.

As for lowering compression for big horsepower, I agree, but too low can be detrimental, there are plenty of guys making big power with 16:1 C15s. Ideally 14.6:1 will make the power with a lot less stress on the engine and therfore allow room for even more power. Marine engines can get away with lower compression and big turbos because they need very little torque, a truck engine with too low compression and a big turbo would suffer when trying to pull at lower engine speeds.

Oh, and technically a turbo reduces and engines efficiency ( this will get some interesting comments ), a turbo is a form of supercharging and all supercharging takes some power to run ( you dont get anything for free ), in the case of a turbo the exhaust gas pressure powers the turbine to produce boost, this exhaust gas pressure in the manifold and cylinders caused by the the restriction of the turbine creates some load on the engine therfore reducing efficence. HOWEVER... what a turbo does is allow us to make a a given amont of horsepower from a much smaller engine and a smaller engine is alway more efficient than a larger one, lower internal mass etc. I'm only taking engine efficiency here not vehicle efficiency which is effected by many things.