Fueling my set of twins

TheSh111t

TheSh111t

That one guy
Joined
Sep 30, 2008
Messages
68
Hello everyone. I have a few questions about my set of compound turbos. A little background on my truck. I have a 1981 Chevrolet short bed 2 wheel drive pickup. I converted the entire front suspension over to 1 ton componants, I also swapped rearend in favor of a full floating 14 bolt diff (10.5" ring gear) with a set of 3.42 gears and a Detroit Locker. The engine is a 1995 Cummins 160 horse engine. I installed a set of 5x12 injectors (370 horse) with the CORRECT spray patters, not the marine injectors, I have a #5 fuel plate, 181 delivery valves, a 3200 rpm gov spring kit and it's all backed by an NV4500 5 speed manual transmission and Southbend single disk clutch. My question has to do with the fuel requirements of my compound turbo set. I ordered a set of compounds, the top side turbo is an S300 with a 57mm inducer (Also knows as a S357) and the bottom turbo is an S400 measuring 75mm (S475). I know that with a larger turbos, sometimes a lack of fuel is almost as bad as too much fuel, simply because the turbo will never light ot take forever to do so. So my question is will I have enough fuel to spool this set up? I really don't have a horsepower goal, I just want a peppy truck that gets decent fuel mileage and can tow my 8000 pound toy hauler every once in a while without having to worry about EGTs getting too high. The reason I went with a compound rather then a single larger turbo is that I want to try to keep smoke to a minimum. I know that it's a diesel and by it's nature will smoke some, but I don't want something that will smoke out the whole left hand side of the freeway. I know that the AFC housing, starwheel and fuel plate selection/placement can to some extent control the smoke these engine put out, but in my opinion the more air, the cleaner the thing will burn. I will be installing the turbo set as soon as it arrives, just to get the thing back up and running, but I know that in the next month or 2 (I work off shore so I'm gone for 4 weeks at a time) I'll be removing the head to have the head o-ringed and install head studs. ANY SUGGESTIONS would be great. I have considered perhaps installing a set of 435 injectors, but it I can get away with the 370's (And I can keep the horsepower bug from biting me) I would like to just run the 370's I have. Thanks for everyones time. I look forward to hearing from some some guys more knowledgable then myself.
 
Don't go real big on the injecters. Take your pump off and send it Brad Ponci(Ponci's Diesel in Fortuna) Have it maxed out and re-balanced. It costs about as much as a set of injecters and reaps many more rewards. This way you will be able to stay clean on the bottom end and have power on top.
 
I have thought about having the pump worked on, but I was not (I'm still not) sure exactly what the purpose of this is. I quess I just don't understand what they do differantly then Cummins did from the factory. By maxxing out I guess you mean to increase the fueling to the maxamum capability of the the pump, but what about balancing it? Lets say for examle I was not turning up the pump but insead only balancing it. Does Cummins do that bad of a job balancing? Ok so pump work is definatly an option, I will look into it. I'll call Monday morning to get a price and perhaps a better explination of what is involved in it as well as the benifits/drawbacks. As far as the fueling goes, my main concern is that I may not be able to spool the turbos well enough to keep the EGTs down. Does anyone have any experiance wih a set of twins like I have? They are a fairly large set of turbo and the last thing I want to do is install them and have them perform poorly. Thanks for the help and advice, I'll call the shop you mentioned Monday morning. Any more input would be greatly appreciated.
 
I'll have to agree with Ron. Your 5x.012 injectors is enough fuel for 800hp.
The problem you have right now is your 160 pump needs to be bench tuned.
Bosch/Cummins dont do a bad job at tuning and balancing the pump they just set them up very conservatively, its just that a good pump guy can get twice the amount of fuel out of it, and Brad Ponci knows these pumps. If you arent to far from him, it might be worth it to get it running, and just drive down to him. He can do some amazing things to a p-pump with it still on the truck. He will also be able to set it up so you will have zero to minimal smoke at take off and zero at WOT.


Otherwise it will be a GREAT setup. It should put you in the high 500 to low 600 hp, tow like a raped ape, and cool the EGTs. This is a real common setup for towing twins.
 
who makes a 8k# toy hauler?

think mines says 8k on the sticker

but for some reason every time i roll the scales i am 20k+

more like 22 or 23k

(they lie)

anyways, what are the rest of the specs on your primary?

those suckas are avail in a bunch of diff combos
 
DTanklage said:
who makes a 8k# toy hauler?

think mines says 8k on the sticker

but for some reason every time i roll the scales i am 20k+

more like 22 or 23k

(they lie)

anyways, what are the rest of the specs on your primary?

those suckas are avail in a bunch of diff combos
Click to expand...

Specs for the s400 are:

Compressor wheel OD - 3.94"
Compressor inducer - 2.94" (75mm)
Turbine wheel OD - 3.768"
Turbine exducer - 3.476: (88mm)
Turbine A/R - 1.32

What other info can I provide to give a better idea of what I have?
The toy hauler was build by a good friend of mine, it is more of an enclosed twin axle car trailer with a couple small tool boxes and a fuel can holder. No generator or anything like that. Last time I crossed the scales with it, it weighed 7750 but I have since added another tool box so I figure it now weighes around 8000 pounds or so.
 
most rec the 96mm turbine

and a 71mm comp to match the 57 up top

be sure to report back
 
DTanklage said:
most rec the 96mm turbine

and a 71mm comp to match the 57 up top

be sure to report back
Click to expand...

I'm not arguing with you, I'm asking you to clarify because I don't fully understand what your saying.

My turbine measures 3.768" (95.7mm) with an exducer of 3.476" (88mm) so when you said that most people recommend a turbine measuring 96mm I think your saying that me primary turbos turbine is about right. My compressor wheel measures 3.94" (100mm) with an inducer of 2.94" (75mm) so I guess your saying that my primary turbos compressor may be 4mm too large. Do I understand this correctly? Once again, not agruing, just trying to learn a little something myself. This is not the first and won't be the last time I have been taught by someone more knowledgable them myself. If my turbo is in fact slightly mismatched, what should I expect the outcome to be? Would you expect this setup to surge, or lag more then it should or what other ill effects may I see when I get this think up and running?
 
i dont beleive there is an s400 with a 96mm turbine exducer. the 96 inducer wheel is the 88mm exducer like you said
 
TheSh111t said:
Specs for the s400 are:

Compressor wheel OD - 3.94"
Compressor inducer - 2.94" (75mm)
Turbine wheel OD - 3.768"
Turbine exducer - 3.476: (88mm)
Turbine A/R - 1.32
Click to expand...

Rollin Coal said:
i dont beleive there is an s400 with a 96mm turbine exducer. the 96 inducer wheel is the 88mm exducer like you said
Click to expand...

I don't think I ever said that there was a 96mm turbine exducer available for the s400. The 96mm is the overall diameter of the wheel.
Here is a link to the specs of my turbo.

Borg Warner S400

I'm not trying to cause an argument, so please don't take it that way. I'm honestly trying to learn all I can about the setup. Thanks for the input, please keep the info comming.
 
TheSh111t said:
I don't think I ever said that there was a 96mm turbine exducer available for the s400. The 96mm is the overall diameter of the wheel.
Here is a link to the specs of my turbo.

Borg Warner S400

I'm not trying to cause an argument, so please don't take it that way. I'm honestly trying to learn all I can about the setup. Thanks for the input, please keep the info comming.
Click to expand...

i was just clarifying the sizes, as far as saying a 71mm wheel goes w/ the 57mm turbo, thats an ignorant statement. the s300g (57/65/14 or possibly 12) is a 57mm compressor wheel, but it out flows an hx40 and he351 which are 60mm turbos that people pair up all the time with an s475, and have great results with.

the s300g/s475 will be a great combo, the 1.32ar T6 housing and 88mm wheel are going to make it a little harder to light, but will come on very hard. the s300g is probably the best all around top turbo for less than 700 horse.

it can be paired up w/ an s465 (65/74/0.90) like the BD tow twins, or all the way up to 75/88/1.32, maybe even bigger.

Hope this helps
 
57/71

62/75

64 or 66/80

so on and so forth...

i have not tested any of these combos but karls suggestions sound right to me

says ya gotta match the turbos

guess it sounds wacked to some of you

thats okay

cant make all the people happy all the time

plz report back

don

ps - if ya could swap a 62 in for comparison sake would be great cuz as of now thats the combo i plan on running 62/65/13<75/96/1.32

not trying to change the earths rotation or anything just want something in the middle of tow twins and race twins
 
DTanklage said:
57/71

62/75

64 or 66/80

so on and so forth...

i have not tested any of these combos but karls suggestions sound right to me

says ya gotta match the turbos

guess it sounds wacked to some of you

thats okay

cant make all the people happy all the time

plz report back

don

ps - if ya could swap a 62 in for comparison sake would be great cuz as of now thats the combo i plan on running 62/65/13<75/96/1.32

not trying to change the earths rotation or anything just want something in the middle of tow twins and race twins
Click to expand...

No offense taken. I gusse I'll hve to look into it further. I will report back as to how things work, and if there are issues I'll post them. From there I'll take suggestions and swap out parts as needed. The money is already spent so you can bet I'm going to give it a shot. Thanks for the assistance.
 
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