Why do diesel's last longer then a gasser????

[Pcoz88]

Or is it just a myth?? Why should I buy a diesel?How about maintance?:jawdrop: :jawdrop:

 

[wood4heat]

They turn half the rpm's, hold three times the oil and are built far heavier but cost twice as much to replace or fix. With the price of diesel right now I'm not sure they're a bargain anyway, unless of course you have something substantial to pull.

 

[DarylB]

Maintenance costs are a bit higher due to that fact that you MUST change the fuel filter on a regular basis, unlike a gasser. They usually hold 2x or 3x as much oil per change, but you can go 2-3 times longer between changes so the oil change is a moot point for comparason reasons.

Diesel usually costs more up front on new vehicles but pay for themselves over time. I'm on my 2nd diesel pickup and will never go back to gasoline for a truck application - real world mileage for me is nearly 50% better with a diesel in a 7000lb pickup. Like Wood4Heat said above, they turn lower RPMS and are designed for Heavy Duty usage which is why their longevity is greater than a gasser.

 

[romeo]

Another reason is that they generate far less heat, even when turbo charged. Plus a slower explosion rate in the combustion chamber.


I often wonder why they don't have more diesel choices in cars.

 

[wood4heat]

Another reason is that they generate far less heat, even when turbo charged. Plus a slower explosion rate in the combustion chamber.

I thought diesel burned hot.

 

[Freakingstang]

I thought diesel burned hot.

The combustion temp is hot, as it has to ignite, because there is no secondary force to burn the fuel (spark), but overall they run cooler.

They also have a lot more material in the castings to disapate heat better. A typical 3/4 ton or 1 ton diesel engine weighs 800-1000lbs more than a gas counterpart.

They are built to work, the older powerstrokes and cummins don't like being baby'd around, they need worked to run efficiently.


The lower rpm applies to the older school diesels, but the newer stuff is turning more RPM than any diesels of older vintage. Look at the Duramax, it spins quite a bit higher (almost 2 times a cummins)

 

[Peacock]

Get ready for a diesel Honda Accord next year.

Diesels are for the most part quite a bit more fuel efficient than gassers. The newest wave of light duty diesels are saddled with some pretty invasive emission equipment. Particulate filters, EGR valves and coolers, oxygen sensors and cats.

 

[spacemule]

I often wonder why they don't have more diesel choices in cars.

Emissions. Also, I think Americans weren't formerly interested in diesels cause we've had cheap gas for so long. Efficiency was not a priority in the 90's.

 

[DarylB]

Emissions. Also, I think Americans weren't formerly interested in diesels cause we've had cheap gas for so long. Efficiency was not a priority in the 90's.

QFT. The new honda diesel will be nice. EGR valves on a diesel is just pure ignorance. It's just something to make you have to change your oil sooner b/c of the soot.

 

[DarylB]

The lower rpm applies to the older school diesels, but the newer stuff is turning more RPM than any diesels of older vintage. Look at the Duramax, it spins quite a bit higher (almost 2 times a cummins)

Not true necessarily. Most of the older cummins were goverend @2500rpms, but capable up to 4000 if you change the governor spring. Most of the ligh-truck diesels now spin up to +3k. The Kodiak's etc are still goverend @ aro9und 2500RPM's on the D-max. The Big cummins' and Semi-Tractor engines run at even less rpms since they have many, many more gears than a regular pickup.

 

[Peacock]

QFT. The new honda diesel will be nice. EGR valves on a diesel is just pure ignorance. It's just something to make you have to change your oil sooner b/c of the soot.

EGR is one of the only ways to get the NOX emissions down to a reasonable level. They even use EGR cooler to lower the temp of the inert gas further.

The soot levels of modern diesels are pretty low. As far as I know, all the current new diesels call for low ash oil and using anything else will clog the DPF in short order.

I've got a diesel myself, even if it isn't a truck. It uses far less fuel than the competitors gas engines and it's a Kubota, so it should be running for a long time.

 

[TDunk]

The combustion temp. is far hotter than a gasser because they use compression to ignite the fuel. Most gassers have a 8.5:1 comp. ratio, most "small block" diesels are anywhere from 17-22:1, that's alot of heat, but they HATE heat. Hence the larger radiator,large coolant passages,oil cooler,oil capcity,piston coolers,etc. With diesels, they really don't care about weight, so they over build them to take the abuse. If your pulling alot of weight or driving real far i might consider a diesel. But if you drive 5 min. to work then no i'd stay with a gasser. Diesels don't like short trips. Maintance defintely costs more. The filters cost more, the oil costs more and you have to do it just as often as a gasser. If you have the nead for a diesel, don't hesitate. If you not sure if you nead one, then i'd prolly stick with gas.

 

[TDunk]

Not true necessarily. Most of the older cummins were goverend @2500rpms, but capable up to 4000 if you change the governor spring.

When i was in college, a kid there had a pulling truck with a 5.9 24 valve. The engine block and internals were all stock and it could turn 6500 rpm. Now i admit it had a HUGE turbo on it, injectors etc. That thing sucked so much fuel at 5000 rpm + that he had to run two fuel pumps on it to keep it from starving under a pull.

 

[Peacock]

When i was in college, a kid there had a pulling truck with a 5.9 24 valve. The engine block and internals were all stock and it could turn 6500 rpm. Now i admit it had a HUGE turbo on it, injectors etc. That thing sucked so much fuel at 5000 rpm + that he had to run two fuel pumps on it to keep it from starving under a pull.

I'd be willing to bet it was pretty inefficient at that rpm. The biggest reason why diesels don't turn more rpm is because there simply enough time to heat the fuel to the point of combustion.

I've talked to a few of Honda's engineers and they are completely against diesels. It goes against Honda's long line of lightweight, high revving, quiet gassers. They spent quite awhile trying to get the things to rev beyond 5k with any efficiency, but they couldn't. I guess the gains in fuel economy are worth it though....

 

[wood4heat]

When i was in college, a kid there had a pulling truck with a 5.9 24 valve. The engine block and internals were all stock and it could turn 6500 rpm. Now i admit it had a HUGE turbo on it, injectors etc. That thing sucked so much fuel at 5000 rpm + that he had to run two fuel pumps on it to keep it from starving under a pull.

Holy cr@p!!! What sort of stroke has a cummins got? I wonder what the piston speed would be at 6500 rpm.

I have a buddy that built a Honda CRX drag car. He's running a Honda B-16 V-Tech four cylinder with 28lbs boost on a stock crank. Runs low 10's in the 1/4 at 140mph. He also runs two fuel pumps.

 

[wood4heat]

I'd be willing to bet it was pretty inefficient at that rpm. The biggest reason why diesels don't turn more rpm is because there simply enough time to heat the fuel to the point of combustion.

I've talked to a few of Honda's engineers and they are completely against diesels. It goes against Honda's long line of lightweight, high revving, quiet gassers. They spent quite awhile trying to get the things to rev beyond 5k with any efficiency, but they couldn't. I guess the gains in fuel economy are worth it though....

I wonder if multiple glow plugs or some sort of auxiliary ignition source would have improved things. How did you come to talk with Honda engineers?

edit: never mind that last part, I just looked at your profile.

 

[Peacock]

I wonder if multiple glow plugs or some sort of auxiliary ignition source would have improved things. How did you come to talk with Honda engineers?

edit: never mind that last part, I just looked at your profile.

I don't think glow plugs would help at all. The piston is likely hotter at that point than the glow plugs anyways. The problem is that the cool fuel is coming so fast that there just isn't time to heat the fuel to the point of combustion. You gotta figure that at 5000rpm each cylinder is firing at the rate of roughly 40 times per second.

 

[wood4heat]

I don't think glow plugs would help at all. The piston is likely hotter at that point than the glow plugs anyways. The problem is that the cool fuel is coming so fast that there just isn't time to heat the fuel to the point of combustion. You gotta figure that at 5000rpm each cylinder is firing at the rate of roughly 40 times per second.

Ok how about an inline preheater? I know Honda probably already figured all this out I'm just curious.

 

[Peacock]

Ok how about an inline preheater? I know Honda probably already figured all this out I'm just curious.

Like a fuel heater? Ford used these on the old 7.3 and 6.9. Only used for cold start. I guess the Big 3 never had a reason for a high revving diesel, so they never tried it.

Most diesels have no reason to rev high. They produce so much torque at low rpm that they don't need to rev high. Most pullers only run so much rpm to build as much energy before releasing the clutch. I've got friends that tractor pull with a small block Deere and they leave the line a good 2,000 rpm more than the run during the pull.

 

[DarylB]

When i was in college, a kid there had a pulling truck with a 5.9 24 valve. The engine block and internals were all stock and it could turn 6500 rpm. Now i admit it had a HUGE turbo on it, injectors etc. That thing sucked so much fuel at 5000 rpm + that he had to run two fuel pumps on it to keep it from starving under a pull.

I'll buy the 5k and dual pumps, but not 6500rpms... Stock internals? I dont think so Tim.