Anyone every bored out a cummins 5.9 for more power?

[Bandit1]

just curious with all the race to get the highest horsepower why someone hasnt bored out the bseries motor unless everyone is trying to get the most out of a 5. 9L motor. If someone has tried boring this motor out who and what was the outcome.

 

[HoleshotHolset]

The naturally aspirated world often uses a few techniques to increase the displacement of their engines... . because they have to. All things equal... when you increase displacement alone... you have the capacity for a more powerful combustion event provided you maintain the same air/fuel ratio.



At 150psi of boost... . an engine is under a lot of stress. So much stress that pushing the 'bore' envelope with paper-thin cylinder walls isn't such a good idea.



We get by on a measly 359cid block that is built to the hilt and make up for the lack of displacement by force feeding it in a big way.



Matt

 

[Ncostello]

But if you did... you might end up with a 6. 0 Dodge!! Would you really want that??

 

[JDailey]

Matt, you're right 150psi is hard on any engine. But you can't make up displacement by feeding more air. It's alot of work... alot... . to make a big inch B. Maybe one of these days I'll get mine done. Look out!

 

[Forrest Nearing]

Originally posted by JDailey

Matt, you're right 150psi is hard on any engine. But you can't make up displacement by feeding more air.

you can if it's pressurized... or by spinning the hell out of it. that's how they were getting 1500hp out of a 1. 3 liter Indy engine at 40psi of boost... turning sick RPM.



if you stack 150psi on a 5. 9 liter Cummins, it's gonna make up for a little displacement, doncha think?



high power requires high cylinder pressures... high cylinder pressures require thick cylinder walls...



Forrest

 

[JDailey]

Forrest, 359ci is still 359ci... . whether it's at 20psi or 150psi. So I guess the answer to your question is, no, I don't think 150psi is gonna make up for a little displacement.

 

[SEmerson]

I only thing you gain by makeing more displacement is a larger amount of air and or fuel. By adding psi and fuel (#2) you gain the same thing.

 

[Vaughn MacKenzie]

JDailey, cramming 150psi boost into a 359 engine makes it act more like 3000 cubic inch engine, minus HP-robbing heat and pumping losses due to extreme boost.



CFM is another way to look at it. At 3000 rpm a naturally aspirated 359 sucks 311 CFM air at WOT (not counting pumping losses). Crank the boost to 15psi (double atmosphere) and you have a "718 CID" engine running 622 CFM. Go higher, 60psi, and you have 4 atmospheres and running 1244 CFM as if it were a 1436 CID engine.



Yeah displacement is nice but with a stout motor you can make up for it with boost. How else do you explain the fact a 7. 3L PSD can't even come close to a 5. 9L Cummins when it comes to shear HP-generating ability??



Vaughn

 

[Forrest Nearing]

Originally posted by JDailey

Forrest, 359ci is still 359ci... . whether it's at 20psi or 150psi. So I guess the answer to your question is, no, I don't think 150psi is gonna make up for a little displacement.

well... let's say at 150psi you're making 1,000hp, but if you bore the engine out to 6 liters, the block is only able to withstand 600hp. yeah, I'd say 150psi is gonna MAKE UP FOR a little displacement... didn't say it was going to magicly make the engine larger, but it's sure gonna make it ACT larger!



boost = the replacement for displacement

 

[Rman]

Originally posted by JDailey

Forrest, 359ci is still 359ci... . whether it's at 20psi or 150psi. So I guess the answer to your question is, no, I don't think 150psi is gonna make up for a little displacement.

I don't think you're understanding the idea of charged air. This was the basis for the discovery... they wanted more power but increasing the displacement just wasn't feasible. So they developed turbo and super chargers to force the same air and fuel of a large displacement engine into a smaller one. Thus making more horsepower from a smaller displacement.



I built and N/A gassers for a long time, and believe me nothing adds power like cubes, but when dealing with turbos and superchargers... views are totally different.

 

[RustyJC]

Basically, the amount of BHP an engine can make is directly proportional to the mass flow of air that the engine can handle. You can always add more fuel, but getting the air in and out is the challenge.



If you think of the engine as an air pump, displacement (bore & stroke) times volumetric efficiency (valve size and lift, porting, etc. ) times RPM gives you an idea of a naturally aspirated engine's BHP potential. I can take a smaller displacement engine, however, add a blower or turbo and move the same or more pounds of air per minute through the engine as a larger displacement naturally aspirated engine, thereby giving it the potential to make the same or more BHP as the larger engine.



Therefore, a boost increase (if it results in greater mass flow - a function of where the turbo is operating on its performance curve) will provide greater BHP potential (as more fuel can be burned) just like a displacement increase.



Rusty

 

[JDailey]

Well obviously you guys are way smarter than me. I guess I need to go to the library and read up so I can understand you guys. So I guess I am wasting my time with a 619ci Deere... . when a 466 would've been just as good?? Man, all the pulling tractors I've worked on(farm stock to diesel/alky supers) that had big inches wasn't even necessary! Damn I wish you guys would've told me sooner! BTW..... do any of of you guys actually have any experiance with big power diesels?

 

[Forrest Nearing]

did you bore that 466 out to 619!??!?!?! (remember, the topic is boring a 5. 9 for more power)



Forrest

 

[DavidGardner]

Jdaley

Why dont you go ahead and bore a 5. 9 and then let us all know how succesfull it was so we can decide whether to make this our next bomb project.



Dave G.

 

[FFL8N]

You guys also need to under stand surface area. Taking the same pressure at any given point on a piston head, as you make the head larger, you are also gaining in down force. If you have a piston that has a surface of 9 square inches at 150 psi, you will get 1350 lbs of force on the piston. Now increase the piston to 10 square inches with the same 150 psi and now you have 1500 lbs of down force. Now multiply that by 6 ( number of pistons), and you have an extra 900 lbs of downforce per revolution of the motor. That would be like adding 2/3 of an extra piston. This is about a simple as you can make it. I think I did all of that right. . ?

 

[TxDieselKid]

It's been done,..... by more then you might think.

 

[Forrest Nearing]

anyone know the average wall thickness on a standard bore 5. 9?



anyone know what the recomended wall thickness is on a diesel with 150psi of boost? (or however much you want to run)



that right there will dictate what size bore you can run...



have fun paying for your custom pistons!



Forrest

 

[FFL8N]

Didn't say I would want to do it... . LOL

 

[Rman]

Originally posted by JDailey

Well obviously you guys are way smarter than me. I guess I need to go to the library and read up so I can understand you guys. So I guess I am wasting my time with a 619ci Deere... . when a 466 would've been just as good?? Man, all the pulling tractors I've worked on(farm stock to diesel/alky supers) that had big inches wasn't even necessary! Damn I wish you guys would've told me sooner! BTW..... do any of of you guys actually have any experiance with big power diesels?

nice here comes the attitude on how great we are.



Well there smart guy, yeah on paper it's possible to make that 466 put out what a 619 does... but guess what, it probably wouldn't hold together or there isn't a turbo big enough. You said "359ci is still 359ci... . whether it's at 20psi or 150psi. So I guess the answer to your question is, no, I don't think 150psi is gonna make up for a little displacement. "



That is utterly wrong, maybe you should go back to wrenchin... or perhaps head back to school where thermodynamics is taught and they could point out why, because obviously we're all flawed????

 

[RustyJC]

Originally posted by JDailey

BTW..... do any of of you guys actually have any experiance with big power diesels?

Well, I've worked for Cooper Energy Services for over 30 years in various field service and technical management capacities. Our largest Cooper-designed diesel is the Cooper-Bessemer LSVB-20-T. It's a turbocharged, intercooled 4-cycle V-20 with 15. 5" bore and 22" stroke, rated at 6300 kWe (8620 BHP based on 98% generator efficiency) @ 400 RPM. Does that qualify as "big power"?



Edit: Nobody has said that there's anything wrong with cubic inches. I believe the common point is that more boost (and correspondingly, more fuel) is generally a cheaper route to additional BHP on a turbodiesel than more displacement. If you're pushing for that last BHP and cost is no object, then by all means do both (i. e. , more boost and more displacement. )



Rusty