Mild-build Compounds

Hey, guys... been doing alot of research up to this point so I'm pretty clear on how it works. What I'm a bit more at a loss for is what would make a good atmosphere. I've got a vague idea of what I'm supposed to look at in the maps, but still not sure how to utilize them completely. I turn wrenches for a living so I have no doubt that I could understand it... unless I either don't have the information I need or I can't afford the tools to do the job (alignments and tire work lol LOL ), I do it myself.

What I'm building is a 500HP daily driver and tow rig. I know most guys who build compounds are looking for high-hp numbers and while that would be fun, my truck has to stay reliable. I am going to be running AC-codes with 100% nozzles for injectors. My reason for this is because AC-codes are brand new NEVER-been-touched injectors and are very consistent and reliable. My reason for the nozzles is because they can empty an AC in that 2.5-3ms window, or so I've been told by injector builders. I would think that this injector should be capable of putting me at 500HP since an S366 alone can get these trucks up in the 475HP area with these injectors. I might be wrong, but I know I've seen a few OBS trucks with this setup that supposedly dynoed 475HP.

Which brings me to what I'm planning for my high-pressure, a waste-gated S366... as for the wastegate size, I'm not sure. I wouldn't think I'd need to run as large as some think. I've heard guys running one close in size to what the area of the two up-pipes is, but being that 100% of my back pressure will never have to be bypassed, I don't see why any larger than a 44mm like Irate uses should be necessary. That's just me, tell why I might be wrong.

But for my atmosphere, I'm not sure... I'm not versed enough to know how to pick a good atmosphere using math and maps. I've been under the impression that in general I need to pick something that would make a good single turbo where top-end is desired, maybe a little larger? I know alot of the guys that are running much larger injectors are using 45R and bigger turbos in their compound setups. I'm thinking along the lines of an S475/GT4202? An S475 running a 77mm turbine wheel with the 1.10 T6 housing (the GT4202 is virtually the same)... I can get transition flanges that transition 3-3.5" tubing to a T6 flange, perfect for going from the outlet of the S366's outlet to the inlet of the s475 and should flow really nice.

If I go a little smaller, I might do an S471/GT4294 (T6 as well). Truck will also have the appropriate supporting mods: twin oil, studs, valve springs, etc. I understand that this is alot of work and money for a mild build, but I'd love to build a really efficient, cool-running, virtually smokeless truck. I've done alot with the new 6.4's and am pretty hooked and I'd love to see my old 7.3l do the same. The old girl has been good to me and I'd love to see her go another 350K.

What do you guys think? Am I on the right track? Is there any more light some of you could shed on the subject? I appreciate it, guys!

I personally would just run a s366 an 250/100 from full force, that would be reliably and make a good tow vehicle. You may also want to do comp 910 valve springs and smith brothers push rods. That's just me tho, you could also do something like this guy did
http://powerstrokenation.com/forums/showthread.php?t=283562&highlight=

Alot of guys also like the 38r/gt45 setup or te 38r/gt47

I'm all about cool stuff that is different but with a goal of 500 why not just run a 366 single with a gate, it'll get you there and spool quick. You're about to spend more on just a turbo setup than what it'll cost to have a rock solid 500hp setup. I would also go to a bigger injector. A 160/100 probably won't hit 500hp, I only know one guy that has hit that high of hp with a small sized injector like that. You are looking at to much turbo and to little injector for a good combo.

S362 with a 4202 sounds pretty appealing but I wouldn't run less than a 250/200, at 500 horse they would have to be cleaner than 160/100's

The 160/100's might be a little small, but I'm pretty sure they'd spool the S366 just fine... guys are making more than 40lbs on the S366 alone and more than 5lbs just cruising with 160/100's. The only thing I'm a little concerned about is the atmosphere. I don't know if the 475/4202 would be about right or a little big.

Honestly, I wouldn't necessarily object to a larger injector if it was necessary to get 500HP, but I'm just not convinced that 160/100's couldn't be made to work with an appropriately-compound setup. If upper 400's can be had with the S366 alone, then I don't think it'd take much more to break 500HP with a setup like this.

There used to be a guy around here with an obs with 160/100 and compounds. Pretty sure it was an s366 with a 4202

Seems like that'd really make a good combo... honestly, an S475/4202 isn't that much bigger than an S366. I would entertain a larger injector, though. Maybe some 200/100's?

I would run 200/100s with a Brute 66 or 38r w/ ww2 and see how you like it. If you think you need atmosphere turbos then do it but you will find it will be fine just with a good single.

I have doubts that a 160/100 will get 500hp. Its honestly not enough fuel to run a compound setup and be reliable, tow, etc...

For responsiveness and reliable I also would look at a brute 66 drop in for 500hp. 238/100 hybrids, with a single hpop for that power level.

Im not trying to talk you out of something you want to do. However, there are A LOT of guys on here that have run that setup and been happy.

If you're for sure not going over 500hp it just keeps it simple, and easily serviceable. IMO.

why such a small turbine?

Small turbine because of the smaller injector size that I was considering, however I might consider something larger.

co04cobra: I have my doubts as well, but I have to wonder at some of the numbers I've seen. I'm wondering what I good set of 200/100's would do? I know a good single will work, but I love compounds. Higher cruising boost levels, alot less lag, overall more efficient, cooler egt's, and higher overall boost levels per the HP if done right.

So on a different note, 200's, 238's, or 250's? 100% or 200% nozzles?

Injectors too small. I would question anyone that can make 160cc of fuel make 500hp. Regardless of nozzle. A stock ad is 150cc. A stock ad with a 30 or 80% nozzle will make 375ish. Runs out of fuel.

A 160 is a 400hp injector. Maybe another 25 on a good day. 80 or 100% nozzle.

Op-I too toyed with running a 200/200 but the 250 is the same price so unless you floor your truck every time you apply throttle there wont be much difference besides peak hp. A 200% nozzle should make cooler power over a 100%.

I like your idea but having run a slightly larger injector my self with a 38r, the pw required to.make power above 400hp makes shti too hot and noisy. If you could ignore your horsepower goal and just build a compound setup to make a ac/100% run well you'd be happier. Otherwise larger injectors and larger atmosphere. Maddiesel had really good results out of a 250/100 s366&s482 set. Buuuut he blew the bottom out of the block. So a billet rodded motor might be ideal.

Charles ran his compounds as a gt4718 over a 38r and ran several different injectors all while tuning it himself. But he doesnt come out of the cave much anymore. And probably wont.

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TyCorr said:

Injectors too small. I would question anyone that can make 160cc of fuel make 500hp. Regardless of nozzle. A stock ad is 150cc. A stock ad with a 30 or 80% nozzle will make 375ish. Runs out of fuel.

A 160 is a 400hp injector. Maybe another 25 on a good day. 80 or 100% nozzle.

Op-I too toyed with running a 200/200 but the 250 is the same price so unless you floor your truck every time you apply throttle there wont be much difference besides peak hp. A 200% nozzle should make cooler power over a 100%.

I like your idea but having run a slightly larger injector my self with a 38r, the pw required to.make power above 400hp makes shti too hot and noisy. If you could ignore your horsepower goal and just build a compound setup to make a ac/100% run well you'd be happier. Otherwise larger injectors and larger atmosphere. Maddiesel had really good results out of a 250/100 s366&s482 set. Buuuut he blew the bottom out of the block. So a billet rodded motor might be ideal.

Charles ran his compounds as a gt4718 over a 38r and ran several different injectors all while tuning it himself. But he doesnt come out of the cave much anymore. And probably wont.

Click to expand...

I've been readin compound threads on psn for an hour. Man I'd like to sit down with Charles and talk powerstrokes, dude is a genius.

IMO. 250/200s at minimum for compounds. There are just too many good single turbo options available to do it with anything less.



A properly setup single, with anything up to a 238/100, can be tuned to spool and run just as efficient up to the power levels you want to be in.

Exactly! Its almost foolhardy to do them under a 250/200 simply related to the amount of fuel.

Buuut if the guy wants to run some small charger like an s362 and a s 480 let him if it makes his ac powered truck run how.he wants. It would be an expensive way to make 410hp, no doubt.

I was sold on the 250/200 simply because a hybrid.with 200% nozzle is like adding another power level, to put it in simpler terms for people reading along, compared to say a 238/100. It will do.what they will.and have more up its sleeve. Or a more dynamic throttle if you drive in the hottest tune all the time,lol.

I get the low boost, responsive/no smoke thing that's associated with twins, but a 160/100 with just a 38R would work pretty good. I want to see more from the guy that recently put 6.4 turbos on the 7.3. Cheap, compact package that should run good and be very responsive with a small injector once its vgt controls are dialed in. Still seems like a lot of work over a decent single though...

I understand that nozzles have to be large enough to empty the injector in that window to keep CP's down, I just wouldn't have thought that going to a 200-250 from a 160 would require a 200%. But then again, going from a 160 to a 200 is more of a flow increase than going from the stock AD to an AC... Makes sense.

TyCorr, I don't necessarily have to hit 500hp, that was just my guess for HP seeing that some guys had made upper 400's with Stage-2's and a single S366. I know there are a lot of good singles out there, but I don't see why a matched set of compounds isn't a good idea for a more mild application. The 6.4's are 350HP at the crank and come with compounds, that's less HP than I'd be making with Stage-2's

I agree, but translating that result to a 7.3 is pointless.

An s366 will make over 700hp on a duramax but on a 7.3 its a 500hp charger IF its gated otherwise its a dead turbo.

Anyway, I think you could make compounds work on a smaller scale. Its no doubt doable. Several people have agreed. Its just there are too many singles that are perfectly tuned up to 500hp to really piss with a set of compounds. I ran 175/80s and it was a few stomps over 400rwhp. With a 100% nozzle and several different tuners the smoke would vary but 425 hp seemed to be about it. But it ran.great. I just was humbled by the peak hp #s. I fully expected more. To be over 450.

But that wasnt pushing my 38r to its limits or even close. So a small hybrid and 38r could get to the 500hp mark as well as in positions 4&5(you know, if you use one of those old 6pos ts chips) you'd have stage 2 like performance levels. Going to a medium sized injector it seems you'd have all of that and even more naughty!

But yea, if you grab you a set of ac's and have some.nice.new.nozzles put on and throw a set of smaller chargers on you could change the powerband of the 7.3. A small high pressure and then a charger that would be.considered "too large" for a single with your injector choice and let er rip.

Just off the cuff a s 362 being driven by a s475 or something maybe a hair.smaller. Spool quick.and give you clean power with those stage 2's, as people call them.

So you'd go with a 362, not a 366? A 362 is basically an H2E with a 366 being the modded version. And yeah, that about sums up my goals... really smooth and clean power, higher boost pressures while cruising, really responsive bottom end, awesome top end, cooler egt's, better mileage, etc. Yeah, there's alot of good singles out there, but I like to be different. Plus, I can do it too... not everybody can work on their stuff and I love to work on my own stuff. It's what I do for a living. Thanks for all the input.

Now what'd really be great would be a chart with alot of the different injector sizes and how large of a nozzle it takes to empty each size withing that 2-3ms window that keeps egt's and CP's down. That was what I asked when I looked into the AC's was what nozzle would I have to run if I wanted them to empty within that window. According to Full Force, 100% nozzles on an AC empties it in 2.5-3ms... not too horrible. I'm guessing any larger than an AC/180cc a guy would want a 200% nozzle since there really isn't anything in between?