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Message |
Earl-8-Ky (209.42.188.102)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 18, 2002 - 11:01 am: | |
I have a 8V71 non turbo. If I installed a turbo on the 8V71 would it be worth the trouble? The engine is standard timed with C60 injectors. What are the pros and cons on this. |
RJ Long (Rjlong) (24.127.74.29)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 18, 2002 - 11:58 am: | |
Not unless you tear the engine down and make all the other necessary changes required by the turbo engine - different pistons, cams, injectors, etc.
Slapping a turbo on a non-turbo engine will work, you just won't get any life out of it w/o the correct internal parts, too.
HTH,
RJ
PD4106-2784
Fresno CA |
Stan (64.154.136.237)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 18, 2002 - 2:51 pm: | |
RJ, that is an interesting comment. What do you consider getting any life out of a Detroit in a conversion. Very few people put 100 K miles on a motorhome (converted bus). Would slapping a turbo on a non-turbo engine last that long? |
Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 18, 2002 - 6:43 pm: | |
You can put a turbo on a non turboed Detroit and it will work, it just will not work as well nor will it last as long as one done properly.
Properly? Yea, you need to AT LEAST change the pistons to lower compression and increase the injector size to what you want.
The rest is NOT absolutely necessary. The mill will start and run and put out the beans. You do NOT absolutely NEED the blower bypass....
Or the timing changed... Or the "proper" cams. Or the exact proper turbo. Or a huge intercooler.
An opened up exhuast and intake system (less back pressure) is also a very good idea and rates with the pistons and injector size.
Properly done, a turboed converted Detroit will last just as long as a non turboed mill (maybe longer) and will really perform.
A low budjet turboed Detroit will start and run and pull just fine only it will not probably last as long nor will it have the same fuel mileage.
However, in a coach application, it may not make all that much difference. It depends upon the mileage the bus sees and the expectations of the owner. Good luck. |
JMAXWELL (66.42.92.3)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 18, 2002 - 11:08 pm: | |
Seems that if u do the cheapo change you might get the same results as putting a 4 brl. carb on a 2 brl. manifold--just doesn't work right. I can't go along with any suggestion that DD engineered all those differences for no good reason and especially lowering the compression ratio by 2 points, which in turn brings about a need for changing cam angles and timing. If you're not going to do it right, then why bother? |
Gary Carter (66.82.48.1)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 18, 2002 - 11:19 pm: | |
First you do not need change timing or compression. But you do need to do some blower work.
As to why? If you travel out west you soon know why. It's called keeping power at altitude. It is amazing how much power the 8V71 loses at 5000 feet. |
RJ Long (Rjlong) (24.127.74.29)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, November 18, 2002 - 11:48 pm: | |
Gary - And that 8V71 loses even MORE at 7000 feet crossing the Sierras, let alone the Eisenhower tunnel on I-70 in CO. . .
According to the 8V71 manual I've got here, there IS a difference between N and T engine pistons. . . different part numbers, too! Same with camshafts. . .
Stan - you're right, most folk don't put that many miles on their coach, and what's really the difference between 100K and 400K anyway, at least from that perspective. . .
I'd just hate to have a fellow busnut have his coach go down at oh dark thirty on a snowy winter night at 6,000 feet on I-80 pulling the 6% grade going to Reno because he slapped a turbo on a non-turbo engine and it punched holes in a piston. . .
Guess I'm just one of those folk who feel that it's awfully hard to second-guess the factory sometimes. . .
OTOH, I'd LOVE to have a 370 hp, Jake-equipped, LH 8V71TA in the engine compartment of my 4106 - and that's definitely second-guessin' GM!!!
Ahhhhh, the joys of hod-rodding. . . 8^)
RJ
PD4106-2784
Fresno CA |
FAST FRED (209.26.115.99)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 19, 2002 - 6:03 am: | |
RJ , Those $1750 , 400HP new rebuilt tank engines await your instalation of a Jake!!
OH yea , they might have to be made to spin the other way too.
FAST FRED |
Earl-8-Ky (209.250.62.216)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 19, 2002 - 10:07 am: | |
Boy did I open a can of worms. |
Mallie (65.38.24.116)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 19, 2002 - 10:29 am: | |
This question comes up pretty often, and I doubt there will ever be a uniformly accepted answer. Over the years I have seen DD, and other diesels turboed with, and without modification, And I am pretty familiar with the DD manual. I will offer my opinion,, take it for what it is worth.
The factory turbos all have a lower compression ratio, about 17:1. The non turbos have a compression ratio of about 19:1.
There are companies like Banks that produce after market trubo kits for non turbo engines, like the ford/international and Chevrolet v8 diesel, that recommend just bolting them on. The Problem is your final compression ratio is going to be greatly increased with a 15 pound boost. And as we all know, too much compression ratio will kill any compression device, especially an internal combustion type.
With a boost pressure gage, and a pyro, and soft footing, you can make it work, but it is very easy to blow it up in a matter of minute if you leave you foot in it!
With the right kind of control, it may be possible to keep the boost to acceptable levels, but you would never get safe hp above the sea level ratings. This can get pretty complicated too.
If you are going to over haul the engine, it is pretty simple to use turbo pistons and sleeves.
The blower is supposed to have a different drive gear too,, it actually slows the blower down, I suspect it further limits max final compression ratio.
According our resident DD expert who I trust, an after cooler reduces engine failures considerable. And it boost Hp another 20. The Turbo use std timing, while the n with 65 or above injectors uses advanced.
Now if you consider putting a turbo on a conventional configured 8v71n, just lower the compression ratio has to be an improvement.
But I know,, there are people,, supposedly DD people who say they use high compression pistons even in the turbo models. You have to decide if this makes any sense to you.
IMHO,If you want to put a turbo on a conventional high compression 8v71n, you are going to have to drive it like you are sitting on eggs to make it last, and yes it can be done.
But if you want to tie into a hill in 3 gear and run at max power of 2100, full throttle, then build it according to DDs proven specs.
Mallie |
Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 19, 2002 - 10:40 am: | |
Just FYI....
No DD here, but same problems... I'm adding a turbo to my stock normally aspirated Cummins 743, and I'm doing it without any other mods. BUT for this job I've purchased a waste-gated turbo that is purposely a bit small, that will automatically limit the boost to 7 PSI.
I'm doing this solely to get sea-level performance at altitudes and hot days. Not to gain additional horsepower, but instead to keep from loosing what horsepower I have while driving in the mountains or high desert. I've been told by a lot of people, a number of diesel shops including the one I bought the turbo from, and a diesel school, that this is a totally acceptable addition to my engine. As long as I don't go much higher than 10psi, it seems to be universal opinion that there will be no problems with the stock pistons, etc.
So evidently this is one way to do it that is safe and will not harm the motor, without changing pistons, injectors, timing, etc. Turbos of this type are mentioned in my engine manual... when used in this configuration it's called a "smoke turbo" or an "altitiude compensation" turbo....
Cheers
Gary |
Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 19, 2002 - 8:37 pm: | |
My dream is to turn my Big Cam Cummins 250 HP non turboed 855 mill into a Big Cam Cummins 444 HP turboed-intercooled 855 mill.
To do so requires a bunch of changes inside the engine including much lower compression pistons, retarded injector and cam timing, larger injectors,
A recalabrated fuel injection pump, a larger fuel pump, a larger crank balancer, the correct turbo and intercooler, larger fuel lines and filtures....
And opened up exhaust and intake systems. The point is that there is a big difference between what I want to do power wise and what Gary wants to do power wise.
In a coach application one MAY be able to get away with minor changes with a Detroit with a Turbo and live to tell the tale. How the driver operates the bus makes a difference too. Thanks. |
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