Wide Open Throttle

[SkyPup]

We rev all our turbodiesels up to 5,000 rpms every day and after 10years still no problems.

VW 1.9L TDI

 

[N80]

Off topic content.​

Charles I love your quote:

"Meetings: If more than two people are there, at least one's time is being wasted."

Here's another (and my favorite because it is painfully true):

Meetings: None of us is as dumb as all of us.
(ref: Despair, Inc.)

 

[Soundguy]

A lot of that will depend on the displacement of each cylinder. Smaller pistons can fly up and down faster than bigger ones just like small people make better gymnasts than big ones.

Now don't go injecting any logical reasoning into this conversation.. when unqualified non-contextual statements are doing just fine!

( most tractor diesel engines I see are of the lower rpm variety.. turbo or not, vs the average truck diesel engine. There are exceptions.. etc )

Soundguy

 

[Opti-Mist]

The above two posts are quite right. Breaking in on a dyno helps to seat the rings, which is the same as breaking in under load. These things are designed to operate under load at high speeds. The only exception is to achieve PTO speed, which varies from brand to brand.

 

[N80]

Why do many owner's manuals recommend not running at full throttle during the first 50 hours? (Innocent question, I'm not arguing, just wondering).

Aside from that question I don't know how it can be completely avoided if you actually intend to get work done during the first 50 hours. No problem while mowing or pulling the box blade but I'd guess that the throttle pedal got pegged on my tractor many times in 1 or 2 low while shoving the bucket into a pile of dirt or gravel.

 

[Opti-Mist]

Having authored some of that stuff (so long ago I don't remember the specifics) it does provide an "out" if an engine blows up during the warranty period. That said, it still makes sense to vary operating speeds during a break-in period just to allow component to "run-in" or "seat". Thats how I treat engines like outboards as well (the ecm will out you if you don't).

 

[cp1969]

Break In Secrets--How To Break In New Motorcycle and Car Engines For More Power

I offer that link for some interesting reading about break in.

 

[Doc_Bob]

Break In Secrets--How To Break In New Motorcycle and Car Engines For More Power

I offer that link for some interesting reading about break in.

Here's How To Do It:
There are 3 ways you can break in an engine:

1) on a dyno
2) on the street, or off road (Motocross or Snowmobile.)
3) on the racetrack​

 

[sandman2234]

To each his own, but I try to avoid overreving my engine. I don't baby it either, but if I need to run just a little bit faster, I go to a higher gear. If I need the cutter to turn a little bit faster, then I am mowing too fast, time to drop a gear lower.
Check the hp/torque curve of your engine, and see what making it turn those last few rpm's actually gains. Most engines don't gain much in the higher rpm range above the torque curve, but I guess somewhere, some might. Never owned one that did...although I still mash the throttle a little more to try to make it work harder!
David from jax

 

[KICK]

since they govern engines at a maximum safe conservative engine sped, you generaly cant hurt them runing them there.

question would be why run it there if you don't need to?
.
generally you get the most power at peak torque rpm and you just run it somewhere above that speed range and use the corect gear to allow you to do the work required. get the best fuel economy while being able to do the work required.

 

[john_bud]

Check the hp/torque curve of your engine, and see what making it turn those last few rpm's actually gains. Most engines don't gain much in the higher rpm range above the torque curve, but I guess somewhere, some might. Never owned one that did...although I still mash the throttle a little more to try to make it work harder!
David from jax

I use a higher RPM (2600 vs 2200) for heavy loader work. The pump puts out more volume which makes the loader operations faster. A gain of 4 seconds on each end might not seem like much, but if you have a 58 second round trip time from load to dump locations, that's 15% or more improvement. It adds up when you have to make several thousand trips. Yes, fuel costs will be slightly higher, but time is money too.

jb

 

[Soundguy]

4 seconds on each end?? How fast ( or should i say slow ) is your loader lift time? My old ford 660 with a 4gpm pump lifts the loader to full lift in about 4 seconds ....

Soundguy

 

[Doc_Bob]

generally you get the most power at peak torque rpm and you just run it somewhere above that speed range and use the corect gear to allow you to do the work required. get the best fuel economy while being able to do the work required.

Unless you run an HST.
Bob

 

[daTeacha]

I was waiting for someone to bring up HSTs here.

I'm pretty sure an HST will use more fuel than a gear model to do the same work simply because most of us just set and forget the throttle on an HST but use the foot throttle on a gear model. Of course, the argument could be made that a diesel running at constant rpm will use less fuel than the same engine running up and down through the rev range, but I doubt that anyone has done the work needed to answer that one.

Of course now that I've said that someone will find some arcane reference to some small tractor test long ago that shows I'm wrong, but that would be a good thing.

 

[Soundguy]

Perhaps a HST may use more fuel due to more ineficiencies in the drive train, between piston and wheel.. etc.

Soundguy

 

[Doc_Bob]

I was waiting for someone to bring up HSTs here.

My pleasure
Bob

 

[Doc_Bob]

Of course, the argument could be made that a diesel running at constant rpm will use less fuel than the same engine running up and down through the rev range, but I doubt that anyone has done the work needed to answer that one.

I can carry a bucket full of whatever up a hill in 5th gear at 1300 RPM. My neighbor has a HST and in the same situation, must keep his tractor at 2400 RPM. The minute I get to where I am going to dump the load, my RPM drops to 700 RPM and I dump the load. He is at 2300 RPM while dumping his load. I back up in 5th gear at 1200 RPM, he backs up at 2300 RPM. I go down the hill in 6th gear with an empty bucket at 1100 rpm and so on and so on.

I have 70HP and he has 40HP, so not exactly apples to apples comparison, but you get the idea.

Now, get us in a tight area with us both doing pallet work and I prefer his machine every time. And his 4 cyl is so much quieter than my 3 cyl turbo.
Bob

 

[Soundguy]

You may find a point where a given amount of work, uses a given amount of fuel.. even if the tractor is slightly different.. or one has more hp. For instance. it takes about 5g's of diesel for me to mow my 10ac pasture. Don't matter if it is my ford 5000 and 10' mower ( 72 hp ) or my Nh 7610s and 10' mower.. 90+ hp ). The cut with the 10' mower takes about 2.25 or so hours.. I can also cut it with my 7610s and 15' mower and it drops to 1hr 45m .. but still uses that same 5g of diesel to cut the 10 ac.

Both tractors are similar in weight and size.. though the 7610s is a tad bigger.. etc. Again.. not completely apples to apples either.. etc.

Soundguy

 

[Doc_Bob]

You may find a point where a given amount of work, uses a given amount of fuel.. even if the tractor is slightly different.. or one has more hp. For instance. it takes about 5g's of diesel for me to mow my 10ac pasture.

Agreed, if I have to run at PTO speed, I see no avantage to a gear vs HST. It is the "other" situations where there might exist some advantage.
Bob

 

[Soundguy]

Yep.. a constant pto load of say.. 30 hp on a 45 hp machine, may use very similar fuel to a 30hp pto load on a 50 hp machine.. etc.

It's that non constant load that throws a wrench in there..

Soundguy