[DarylB]

Anyone got a stock run or info on the HP/TQ at around 3200rpm on the 4BT? I'm thinking since they're goverened down they might actually have a little more power than 105hp as they rev just a wee bit more.

 

[JimmieD]

Interesting thought, DarylB. I know on a gasser the hp/tq both supposedly peak or converge at 5252 rpm, not sure on a diesel where the peak overlap is.

 

[mooktank]

Interesting thought, DarylB. I know on a gasser the hp/tq both supposedly peak or converge at 5252 rpm, not sure on a diesel where the peak overlap is.

I don't see many diesels running that kind of RPM...

 

[DarylB]

Well, the reason I asked was a guy over on thedieselpage.com asked why the 4500 series had less HP than the 2500/3500 series chevrolet. They're governed at 2500rpms vs 3200 for the 2500/3500. I think the difference was 330hp @ 2500 vs 360hp @ 3200.

My thinking was our 4BT's with the 366 spring actually have a few more horses. Maybe 120 on the non-intercooled versions w/ a spring. I'm thinking a 4BT, intercooled, with the 366 spring will put out around 125-135hp stock at 3200rpms. I remember hearing some stuff about dyno'ing the motor so I thought I'd throw this out there.

 

[JimmieD]

I don't see many diesels running that kind of RPM...

Don't know as that has anything to do with the question. True, few run there, but that doesn't say anything about what the potential power is. The one and only reason for governors is to protect the engine and extend service life. They have no other purpose. Diesel engines are not governed for the purpose of extracting maximum performance.

 

[Machman]

Interesting thought, DarylB. I know on a gasser the hp/tq both supposedly peak or converge at 5252 rpm, not sure on a diesel where the peak overlap is.

The formula for Horsepower (in our application) is:

(torque x RPM)/5252 = Horsepower

Horsepower is a measurement of work done in a given timeframe. Torque is simply an applied force, with no time element.

It comes down to where your torque peaks and how rapidly it falls off as you increase RPM. Diesels tend to have their torque peak at relatively low RPM (and don't usually turn high RPM) so will show low horsepower ratings.

Gassers normally have their torque peak at higher RPM. So they tend to have a higher peak horsepower rating, and horsepower and torque numbers are typically pretty close to one another because of it. (And right around that magic 5252 RPM.....)

Why the 5252? Well, that's a simplification of a lot of other things in the equations. More info can be found here:

http://auto.howstuffworks.com/question622.htm

That all said, remember the old saying: Horsepower sells cars. Torque wins races.

 

[LincTex]

(torque x RPM)/5252 = Horsepower

http://auto.howstuffworks.com/question622.htm

Wow...I have known the formula for years, but never knew the explanation behind the 5252 number. Very interesting math theory.

Only way to increase the HP number is to increase the torque at that RPM.
If torque goes waaaay down after 2200 RPMS then you just won't get good HP numbers, even if spun to 3200 RPM

 

[mooktank]

Torque will be higher at higher RPMS with the spring due to the pump defueling later. There will be HP gained by the spring I think.

 

[Machman]

Ok.. Question, and mebby a stoooopid one.

Where does the 366 spring go? I mean, between what 2 things does it hook? I've not found 366 spring install how-to articles that have any pictures.. (Have I just missed those??)

I *think* it links the control lever (where our accelerator cables attach) to the tensioning lever that moves the fuel delivery control collar. If that is the case, then I assume that the 366 spring a higher rate spring than the stock one, right?

 

[DarylB]

I believe it's inside the pump. Not a throttle cable spring like on an old Q-jet.

 

[BobS]

Ok.. Question, and mebby a stoooopid one.

Where does the 366 spring go? I mean, between what 2 things does it hook? I've not found 366 spring install how-to articles that have any pictures.. (Have I just missed those??)

I *think* it links the control lever (where our accelerator cables attach) to the tensioning lever that moves the fuel delivery control collar. If that is the case, then I assume that the 366 spring a higher rate spring than the stock one, right?

From Den's First Gen Dodge Tech Info site:
http://dens-site.net/Dodge_CTD/Governor_Spring/index.html

 

[Machman]

Thank you, BobS!!

That's exactly where I thought it went / connected. It wasn't in the pump rebuild photos I found because those were for a VW version of the pump, which uses a spring assembly in a frame to do the job of that spring.

And, if I'm looking at it right, the 366 spring has fewer turns of thicker wire than the stock one, so should be a higher rate spring (which makes sense for what it's doing and what happens when it's swapped in for the stocker).

 

[mrector]

I would think that with the extra rpms it would make more power. In reference to your queshtion: about two years ago my 97 12v(p-pumped)dodge, made 380-ish rwhp, with NO OTHER CHANGES except 3k governor springs, I netted 441 rwhp on the same dyno-same day.

So, yes, it will make more power. At least, that is what I believe.....:beer:

Mikey