Powerstroked162
On Da Juice
A 38/42 combo is a waste of time.
38R and injector size???
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A 38/42 combo is a waste of time.
swamp_ratt
New member
Unless youve made some changes, you dont have much smoke at all
Thats may be your opinion
Powerstroked162
On Da Juice
It's an opinion based off fact. Trust me. You would be better off running the 42 as a single then attempting to make compounds with it.
UPINSMOKE
New member
238/100 and a 38r is quick spooling and makes good power, but you are also towards the upper end of that turbo's limits. Egt's become an issue as well, especially if you aren't intercooled.
I personally think the 238's (when use to full potential) are too much for the 38r... But that is just my opinion. Lots of people swear by the combo.
I personally think the 238's (when use to full potential) are too much for the 38r... But that is just my opinion. Lots of people swear by the combo.
Diezel Dawg
New member
bruce
Active member
There is no way I would upgrade an obs to run a 38r. After the cost of turbo, up pipes, ext you could have an s366 sittin on irates t4 mount and have a superior design with tons of turbo options
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swamp_ratt
New member
Whos fact? Yours? A 38r is similar to a stock duramax turbo and there are quite a few people with a 42 under their gt37s on the duramax. A 42 is good for 1200 rwhp! So please tell me why "you" say its not worth it!
swamp_ratt
New member
Why upgrade? You could go to a junkyard and get the driver manifold up-pipe and pedistal off a sd for around 50-75 bucks high
lincolnlocker
Well-known member
I want it to be smoke free at 500 HP range... I'm thinking of buying my brothers truck to build and beat on anyway... save mine for DD only...
What's the set up Charles is running? I thought a 42/38r but don't remember!
What's the set up Charles is running? I thought a 42/38r but don't remember!
SDS97_7.3
Active member
I thought Charles was running the 55
UPINSMOKE
New member
It simply doesn't work that way... We have a different injection system than a duramax who can more closely control fuel delivery, a duramax turbo is vgt, and we have larger displacement motors...
There are many reasons we can't get the same power put of turbos that cummins, duramaxes, or even our 6.4 friends can...
I have a friend with a cummins that dynod 905 with just a 66... Does that mean a 7.3 can do the same? Dream on.
We are handicapped more than you think.
Steve is right. I wouldnt go any smaller than a gt47 if you are using a 38r as a high pressure turbo. You will be pushing both turbos extremely hard to make the same power you would with a 38/47 combo...
That is what Charles started with, but then moved to the gt55.
Lots of guys run 42r's without issue as singles.
swamp_ratt
New member
Charles was running 38r/47. I think he now is running 38r/55
swamp_ratt
New member
Regardless of fuel system, a 38r/42 combo is actually a decent setup. Compounds is not ALWAYS about power. Compound setups are also about clearing smoke as well as lowering egts! Also not all duramax turbos are vgt! I have one sitting in my garage that isnt as well as 2 trucks that dont have em
UPINSMOKE
New member
Lbz turbos which I believe are a 2.54 inducer are closest to a 38r... I realize the lb7's were not vgt turbos... But they still have smaller displacement and better injection systems...
UPINSMOKE
New member
It might be a decent setup on a duramax, but on a 7.3 it will not perform equally as it would on a duramax.
And honestly I think most duramax compound setups are made using a factory turbo and an s475... Maybe I'm wrong but I am pretty sure at least the mpi kits are designed that way.
And honestly I think most duramax compound setups are made using a factory turbo and an s475... Maybe I'm wrong but I am pretty sure at least the mpi kits are designed that way.
UPINSMOKE
New member
I guess my question to you is if you are only wanting the power a 42 can produce (which is why it is your atmosphere)... Why do you need the 38r? Do you think the 42 is that slow to spool?
smokedout250
New member
Idk if this helps but I looked into swapping a 38r into my obs but I wanted to do bellowed up pipes by the time I got a turbo, pedestal, and all the other stuff I went with the t4 and s366 for almost the same price
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Powerstroked162
On Da Juice
I'm gonna stop you right there. You have great enthusiasm and I can appreciate that, BUT im thinking you lack the proper understanding of compounds and singles on a 7.3 to grasp what I'm trying to tell you. What you said above really proves that. No way in hell will a 7.3 ever do 1200 on a gt42 without some sort of power adders involved, PERIOD. Now, I have a hair of Duramax in my blood and I'm friends with some very talented engine builders ad developers of that platform and I'll be straight with you, I asked a few of them what they thought of your turbo scenario and so far nobody seems to think its a good idea even on that engine, so unless you are referring to a backyardagain project I'm unaware of, its not heard of in the dmax world. So in the end, its still a bad idea that is gonna leave the end user wishing for somebody to put him out of his misery.
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Hotrodtractor
Moderator
I run a modified VGT turbo and a hybrid GT42 on my Dmax. Its a nice little set of towing compounds - but truth be told if you mess around with it enough you find that the GT42 is holding the setup back for the same reasons that Charles upgraded from the GT47 to the GT55 - the turbine wheel of the 42 is the restriction in the system. Going to a more efficient turbine wheel will improve spool up and top end capabilities. I've been on the verge of installing tachs on both turbos just to see where they fall in the maps at all times - I keep hesitating because I fear I know the answer already based on experience of myself and others - just because it can "work" doesn't mean it works ideally. doing it over again - I would probably have a GT55 for an atmosphere and I would just keep on towing my 36' gooseneck trailer down the road with low EGTs and no spool up troubles, but then what the hell do I know - I've only been rocking compounds on a trailer towing Dmax for 80Kish miles.
swamp_ratt
New member
I wgree a 7.3 wont see 1200! Anr i understand the handicap of them, hence my cummins. I tow too heavy for the 7.3 in my eyes. But i do know at times the 42 can be laggy. Hence the compound setup with the 42 as the atmosphere. Is it too laggy in all applicatiions, no. But can it be in some where as a high pressure over it wpuld benefit, yes. Would i personally run the setup, doubtful. Have i put that setup together for someone, you bet. And im doing it again soon. the simple fact of the matter here is that everyones tastes are different. So everyone will go how they feel. My personal setup will probably be a gt4094r/gt55. Havent given it reasonable thought yet. But then again i as well am only in the where abouts of 363ci on 6 cylinders! i do agree with all of you to certain extents but disagree to others. In a roundabout way hrt said it best. Makes a decent setup but restricts potential. But not everyone wants that potential
