What determines HP rating for a specific engine (DT 466 / DT 360 for example)

[dzl_]

I'm trying to soak up as much knowledge as I can before making a purchase, one thing that I don't really understand is the different HP ratings for a particular (mechanical) engine.


Taking the DT360 as an example:

DT-360-160 = HP 160 @ 3000 RPM, Torque 375 @ 1800 RPM
DT-360-180 = HP 180 @ 3000 RPM, Torque 420 @ 1800 RPM
DTA-360-190 = HP 190 @ 3000 RPM, Torque 475 @ 1800 RPM
DTA-360-210 = HP 210 @ 3000 RPM, Torque 485 @ 1800 RPM

What determines these different ratings/presets? Are the actual engines physically different (higher HP versions being more robust or newer)? Are there physical differences but only with peripheral or upgradeable parts? Or are the higher HP ratings achieved through some combination of tweaking the timing, fuel delivery, and governor?


The TL;DR is that I'm trying to understand whether a low HP engine can be easily and safely be converted to its higher HP specs without adversely affecting durability/longevity.

[dzl_]

Followup to my OP:
Its possible those HP/Torque numbers are not correct. I found them posted to another forum (here) but upon further googling I can't find other references to a 210hp DT 360.


And this source which is a little unclear but seems more reputable appears to list all the different DT360 engine variants variants as being between 170 and 190 hp.


If someone with more knowledge could chime in that would be helpful.


This doesn't change the nature of my original questions, I just don't want to be passing along incorrect information.

[cadillackid]

ive never seen a 210 DTA360.. they may have made one..



on some engines the turbo, injectors, and such are different.. on mechanical engines in the lower family.. ie there were no "high torque" versions of the mechanical 360 sold.. though there were AG versions and a marine version from what I was told...



on those it amounted to timing and injection pump adjustment anbd whether it was after-cooled or not.. ie DT360 had no charge cair cooler.. DTA360 (most common ) are after-cooled..



DT466s were made in standard and high torque models.. turbos and internals were different on some of them..


in the electronic ones (DT-466E,T-444E) you could gain some power if you reprogram the computer...


omn the mechanicals you can gain power by advancing the timing and adjusting your pump.. DT360s mostly used Bosch A pumps with a fuel later ones using MWs... DT466s esp the later mechanicals used P-pumps. earlier ones (post-rotary) used MW pumps...

[dzl_]

Originally Posted by cadillackid

on mechanical engines in the lower family.. ie there were no "high torque" versions of the mechanical 360 sold.. though there were AG versions and a marine version from what I was told...

on those it amounted to timing and injection pump adjustment and whether it was after-cooled or not.. ie DT360 had no charge air cooler.. DTA360 (most common ) are after-cooled..

DT466s were made in standard and high torque models.. turbos and internals were different on some of them..

So if I understand what you are saying correctly for the DT(A) 360s found in buses, the only physical differences between different HP spec'd versions is whether or not it has an aftercooler/intercooler, and beyond that differences in HP rating are due to adjustable parameters with the injection pump/timing. Put another way, apart from the DT / DTA distinction, the horsepower spec is more like "how the engine came preset from the factory" rather than an indication of what the engine can safely handle. So a lower HP aftercooled version could be turned up to match its higher HP aftercooled counterpart with no adverse affects (specifically in terms of the DT(A) 360).

[WIbluebird]

On newer (late 90s >) buses with electronic engines the power rating is usually determined by whatever is on the ECM as well as possibly larger injectors.

Cummins is the king of this, they sold the 5.9 ISB in all sorts of power ratings ranging from 195 hp to 250 hp. Same thing with its bigger sibling the 8.3 ISC. Motorhomes and fire trucks get 350 hp while school buses like mine are usually in the 275 range.

[magnakansas]

internals may be very close to the same parts, fuel injectors, intercooling, amount of fuel that can be injected, pistons, all may or may not be part of the power adjustments. any time you increase the power output you will decrease the longevity.... the question becomes will it last 400,000 miles of in town driving or 200,000 miles of in town driving or 75,000 miles of in town driving.


I think sometimes, the reduced power rating is for the transmission. Some times the reduced power rating is for fuel mileage. some times I think reduced power rating is for an accountant type cheap @33 school board.

I am changing power output from 225 hp to 400 hp on my 5.9 cummins.... It will not last as long as a 195hp rated bus engine. I will be on the highway more than most buses. I expect 20 years and 200,000 to 400,000 miles.

dt360 intercooler add more fuel maybe more turbo maybe add two or three degrees of timing bigger out let for the turbo exhaust...... yea you can do things.... make sure the drive line can take the additional torque.

william

[EastCoastCB]

Originally Posted by WIbluebird

On newer (late 90s >) buses with electronic engines the power rating is usually determined by whatever is on the ECM as well as possibly larger injectors.

Cummins is the king of this, they sold the 5.9 ISB in all sorts of power ratings ranging from 195 hp to 250 hp. Same thing with its bigger sibling the 8.3 ISC. Motorhomes and fire trucks get 350 hp while school buses like mine are usually in the 275 range.

Yep they all do this. The 3126 in my bus is available in 175-330 HP configurations. After 210 hp the injectors, turbo, and other things are different.

[cadillackid]

magna is correct.. some engines have different internals for different power ratings..



from everything I can see is that the HP for the same year in a DT360 the internals are the same..



the internals DID change from year to year.. there are different turbos and later years different pumps in the DT360.. Id have to get my books out again to remember the exacts but not all years offered all HP ratings...


on the electronic engines , international is what im mosrt familiar with, there are hardware breaks on ratings and again some of it is year-based... so the T444E for instance had standard torque levels of 175-190-210, all the hardware was identical in a particular year.. then they had High torque models of 210-230-250, those all had the same hardware.. the differences between group 1 and group 2 were group 2 had a Smaller wastegated turbo and different injectors.. yes you read that right a smaller turbo... the design was to spool up the turbo faster at lower RPM.. thus being able to shoot more fuel into the cylinder with earlier timing.. this allowed higher torque levels and keeping EGTs in check.. of course the computer programming is different..



the DT466E's got their higher torque ratings by computer programming, injectors, turbo, and I believe different crank / pistons / sleeves...



which is interesting because there are guys crankinfg up the smoke on the stabdard toque variants of the 466 with stock bottom ends way beyond these ratings and they live.. of course IH / CAT / cummins, and others builds Medium duty engines for longevity, not for winning races... turning up the power comes with its risks as you are putting more pressure on components... whether you blow it. up or not depends on alot of factors..



ive been turning up hotrod engines for years.. and I can homestly say ive definitely broken more stuff on Highly cranked up engines vs stock, but oh well.. when I break one it gives me an incentive to build me a new and better one,
-Christopher

[dzl_]

Thanks guys, I'm a lot more informed on the subject, though it seems the subject is not quite as clear cut and simple as I had hoped. But I appreciate all the new information.


Sounds like the moral of the story is when at all possible get a bus with an engine that meets your needs Re: HP/Torque specs and don't expect to squeeze too much extra power out of a lower HP model without swapping out injectors, etc?


I have 2 follow up questions:


First,

Where do you guys get all your information? I have been doing a ton of googling and researching here lately, but I'm finding it a lot harder to find good sources of information, specs, etc for skoolies and medium duty engines than the mass market and enthusiast vehicles I'm used to dealing with.


Second is for CadillacKid
Are you satisfied with the power you get from your Engine/Trans combo? What HP spec is your engine. I'm considering a similar bus to yours with the same engine (unknown trans, likely at545). Non sure what HP spec it is, its a 1990 international 3800.

[cadillackid]

I get a lot of information from my service books and from looking up parts.. so for instance if I look up a turbo for a 190HP T444E and a 230HP T444E they are different.. the spec sheet shows the turbos and injectors are different..


when navistar sold the 466E (pre maxxforce) documents existed on their website that showed differences between the 2 engines.. as does lookimng up ordering in-frame rebuold kits as they name a different kit for the HO vs SO engine..



my DTA360 is a 185HP, remanuifactured jasper engine that was put in 2004... my trans was an AT545 and now is an MT643.. its a short-but rather heavy bus... I dont win any races but i travel 60-65 on flat ground easily.. and slow down on the hills..



my T444E is a bastard in a way... it is a standard output 190HP with my computer punched up to the 250 setting.. its in a 6 window short bus.. to be frank, it Hauls Ass.. I drive it at 65 because im not in a hurry in a bus.. it holds 65 up Jellico mountain on I75 in tennesee but my EGTs run up.. a new turbo will fix that.. and the new injectors im about to put in.. I should be able to throttle curve it in such a way i dont run such high EGTs... it has an Allison 1000 6 speed i swapped in a couple years ago in place of an AT545

-Christopher

[FamilyCircus]

I have a 215hp/620tq classified as a high torque engine with a shorter stroke than the regular engine, go figure.

I cant help myself and have played with my engine. Ive got larger injectors from the I530 and a larger intercooler with a GT3782BD turbo from the 250hp DT466e planned for the near future.

My current EGT's run 1200-1250 on long grades, Ill be putting in a water/meth injection kit to keep those egt's down on long grades in summer.

It moves for a bus , loads of torque which makes getting off the stop lights kind of fun.

[EastCoastCB]

Originally Posted by FamilyCircus

I have a 215hp/620tq classified as a high torque engine with a shorter stroke than the regular engine, go figure.

I cant help myself and have played with my engine. Ive got larger injectors from the I530 and a larger intercooler with a GT3782BD turbo from the 250hp DT466e planned for the near future.

My current EGT's run 1200-1250 on long grades, Ill be putting in a water/meth injection kit to keep those egt's down on long grades in summer.

It moves for a bus , loads of torque which makes getting off the stop lights kind of fun.

What year are you talking?

According to this chart The DT466e in both standard and high torque both share the same bore and stroke.
http://www.astleford.com/pdf/dt466dt530brochure.pdf

[Dirtdoctor]

Like was said before 466 block and different bits and pieces, larger turbos, stronger Conrods, different pistons etc. I’ve run 195hp 466 and a 350hp 466. My recommendation is Go with the larger. The lower hp unit gets crappy mileage. Works hard and drinks lots of fuel, my 350 hp drank the same amount of fuel but had the beans to haul 35,000 pounds all over the place. My bus is 175hp and I’m planning on installing a 300hp in it and will get an easy 10mpg or higher. Right now it gets 5-6mpg. Buy big or swap out with a larger hp engine it’s cheaper than rebuilding with all the new bots and pieces.
Cheers

[cadillackid]

Originally Posted by Dirtdoctor

Like was said before 466 block and different bits and pieces, larger turbos, stronger Conrods, different pistons etc. I’ve run 195hp 466 and a 350hp 466. My recommendation is Go with the larger. The lower hp unit gets crappy mileage. Works hard and drinks lots of fuel, my 350 hp drank the same amount of fuel but had the beans to haul 35,000 pounds all over the place. My bus is 175hp and I’m planning on installing a 300hp in it and will get an easy 10mpg or higher. Right now it gets 5-6mpg. Buy big or swap out with a larger hp engine it’s cheaper than rebuilding with all the new bots and pieces.
Cheers

**THIS**
ever since I pumped up the power on my T-444E, my MPG have gone UP.. I dont have to floor it and run out every gear to Max RPM to get up to speed.. and i dont have to kick-down a gear on every little incline like i previously did.. im sure the transmission is much happier with less down and upshifts. and the engine gets in a groove and stays there.. sure if you use your extra HP to drive faster you will burn more fuel because of wind resistance.. but in general letting a diesel engine get in a groove nets good efficiency.. running it in an RPM band its happy vs up and down all the time usiong gears for lack of power..


-Christopher

[Bon Voyage]

A good source of info on a engine’s upgradability can be giving a phone call to the manufacturer. My 8.3 Cummins is rated at the lowest power/torque setting it came in. I called Cummins about programming it up; I was hoping I could get up to at least the next power level and they seemed quite willing to do it but the guy there looked it up for me and said it would require a lot of upgraded parts to do it.

Also to consider is the extra power output on the transmission can ware it out faster. A call to transmission dealer might help with that info too. With any luck you could end up with fuel savings and reduced transmission shifting like Cadillackid. I increased the power on one of my old Ford 6.0 power stroke’s and loved it but shortly after the transmission stared to show mild signs of fatigue so personally I wouldn’t increase power without checking everything first as they’re just so expensive to fix engines and transmissions like these. more power is nice but so is longevity.

[PNW_Steve]

Originally Posted by magnakansas

internals may be very close to the same parts, fuel injectors, intercooling, amount of fuel that can be injected, pistons, all may or may not be part of the power adjustments. any time you increase the power output you will decrease the longevity.... the question becomes will it last 400,000 miles of in town driving or 200,000 miles of in town driving or 75,000 miles of in town driving.


I think sometimes, the reduced power rating is for the transmission. Some times the reduced power rating is for fuel mileage. some times I think reduced power rating is for an accountant type cheap @33 school board.

I am changing power output from 225 hp to 400 hp on my 5.9 cummins.... It will not last as long as a 195hp rated bus engine. I will be on the highway more than most buses. I expect 20 years and 200,000 to 400,000 miles.

dt360 intercooler add more fuel maybe more turbo maybe add two or three degrees of timing bigger out let for the turbo exhaust...... yea you can do things.... make sure the drive line can take the additional torque.

william

I am curious as to which Cummins 5.9 you are starting with and what your plan is to accomplish 400 horsepower?

I have done it on the Dodge version of the ISB but have not seen the pieces that would give you that kind of horsepower on the MD Cummins 5.9.

Thanks.

[More Power]

I don't know anything about specs for mechanical engines. But with electronic engines there are a range of ratings available for any engine. If you want to change from a lower rating to a higher one, some ratings are achievable with only programming, but other ratings would take programming and hard parts (possibly trans/clutch, inj, pistons, hp pump...). Most people looking at a skoolie project with an International electronic engine would be looking for 1994-2003 model years. Navistar no longer supports horsepower increases for 1994-1997 engines (engines with 3 control modules). So for those years, what you buy is what you get - unless you know how to tune them aftermarket (this can require replacing one of the 3 engine modules as well as reprogramming one of the other modules...and that requires a higher programming access level than comes standard with the software).
As for the 1998-2003 engines, Navistar still supports hp increases. Some of those can be turned up with programming only, and some require programming and hard parts (possibly including trans/clutch, inj, pistons, heads, turbos...)
Also, Navistar does not give hp quotes to the general public - they only provide them to dealers. So you would have to add dealer fees into any hp change that you are considering on an electronic engine.
As others have said, it's always better to buy a bus that is already rated for the hp/tq that you want.

[cadillackid]

I’ve turned a couple 3 box engines up to the top notch in their rating family. It appears they took..
Plus one on transmissions. In my case I had my trans built and for much higher power than what I’m pushing out of the engine.
Christopher

[concrete]

Originally Posted by dzl_

What determines these different ratings/presets? Are the actual engines physically different (higher HP versions being more robust or newer)? Are there physical differences but only with peripheral or upgradeable parts? Or are the higher HP ratings achieved through some combination of tweaking the timing, fuel delivery, and governor?


The TL;DR is that I'm trying to understand whether a low HP engine can be easily and safely be converted to its higher HP specs without adversely affecting durability/longevity.

With a dta360 it will be relatively easy and inexpensive to safely bump a lower hp model beyond a stock high hp model.
1) install a pyrometer. It tells you when you’re cooking internals by over-fueling or improper injection timing.
2) adjust the injection pump. Get to know your pump. Perhaps even more than the rest of the engine, research your pump. You may not need to do anything beyond this to meet your goals. And this step is virtually free (not counting time).

At this point, As long as your egt’s are in check I wouldn’t be overly concerned about durability. Is the engine in good condition NOW? Then it’ll take a bumped pump. Watch the egt’s! If your tranny is an at545, then install a large tranny cooler.

If you need/want more power but are getting high egt’s/black smoke, then look for ways to get more air in. Consider a freer flowing exhaust or upgraded turbo. Turbos! There’s a rabbit hole of info!
Your current injectors do have a hp threshold, but you may never hit it; or it may be perfectly satisfactory. Do the (almost) free pump mods first and see how you like it. It wouldn’t surprise me if you got 230+ just with the pump. NOTE! This is assuming you do have a charge air cooler, i.e.-after-cooler/intercooler (there are technical differences...).
You’ll max your egt’s, and thus your hp, way sooner without a charge air cooler.