Cost vs. Benefit of twins? Chime in

[Matt400]

When you guys are talking about more maint. on a set of twins what are you referring to, name a few.

That is an excellent question, some time ago a friend of mine and I were talking about doing twins on my 03 when he said. . One thing for sure is the hood will be up more often



I said why? and he said because they are finicky with clamps and mountings always needing tightening and adjustments and such.

That to me sounds more like a poor kit than the fact they are twins. Sometimes I just hate the quality of aftermarket garbage, wouldn't it be slick if Cummins offered a twin kit!

 

[SRadke]

To directly address your questions Mr. Malone... .



"Is it feasable to fab a set of "mini-twins" where you have a real small top turbo and a 66 class bottom? Would such a setup provide very fast spool and still support 50-55 psi or am I just dreaming?"



The first question is not really. The second question is absolutely.



Twins are just compound turbocharging. Compress the air once in a large charger then run it through another and compress it again. You could even use two chargers of the same size if you want but you're limited to the amount of air that the primary charger can collect. If you used two stock turbos you'd get as much air as your stock turbo but at a higher pressure. If you use a SP66 on the bottom with a stock turbo on top you'd get quick spool but you wouldn't get any more air than it will give you as a single.



The reason we use diffrent size turbos is because we need one that can be spooled quickly and get the engine to consuming the large amount of air that it takes to make a big turbo roll. You really want as big of a bottom (primary) turbo as it takes to provide the air you need then choose the top turbo that is a good match to it. Too small and it becomes congestion, too big and it spools slow. Using a SP66 on the bottom doesn't make sense because it doesn't move enough air to support 500 hp anyhow. What are your egt's at 500 hp output? Too high to maintain I'm willing to bet. You cold use HTB2 or HX 40 on top of a HT3B and get more, cooler, higher pressure air with faster spool up.



-Scott

 

[Fishin Guide]

I agree with Scott. Proven turbo combo. 35/3B and the 40/3B.



It all comes down to what you really want your truck to do. If daily driving, towing and occasional drag racing is you thing, a 35/3B is hard to beat. If you don't mind some more lag to gain more power, 40 on top.



And the reason the 3B is so popular is that is is relatively inexpensive for what it does. Yes there are tougher, bigger, meater turbos out there. Just be honest with what your needs are.



500 sustainable horsepower is a tall order out of any compound set. I'm not talking about a blast down the quarter or a 5 second dyno run. Real world, 90 degree heat, 65% humidity, 10K trailer out back, pulling a steep grade.



Even if EGTs were in check, other things start getting the brunt of the power and heat. Ask lots of questions and take everything with a grain of salt. And, if possible, drive a truck equiped like you want it and hook a trailer or whatever it is you are looking to do. Then go for a ride. Ask the owner to stretch the trucks legs. Watch the gauges. That'll answer a ton of questions and allow you to see/ feel real world performance!



Dave

 

[BDR]

Hey SRadke~

If you don't mind me asking, what turbos are you runnin in your set-up?

 

[BrandonF]

That is an excellent question, some time ago a friend of mine and I were talking about doing twins on my 03 when he said. . One thing for sure is the hood will be up more often



I said why? and he said because they are finicky with clamps and mountings always needing tightening and adjustments and such.

That to me sounds more like a poor kit than the fact they are twins. Sometimes I just hate the quality of aftermarket garbage, wouldn't it be slick if Cummins offered a twin kit!

not if you install them right. . They are on my wish list for my 05. . However I must keep my horses on all fours when hauling down the road..... So I take them off my wish list.....



Matt are you having twin issues???

 

[rubberneck]

not if you install them right. . They are on my wish list for my 05. . However I must keep my horses on all fours when hauling down the road..... So I take them off my wish list.....



Matt are you having twin issues???

You're choosing the safety of your horses over twins?? I knew you horse people were nuts.

 

[BrandonF]

hey, Brandon told me you were up all hours of the night... He still thinks I want twins. I didn't tell him about the horse thing... I just know I couldn't keep my foot out of it. Maybe I need a new mega cab to put twins on and dubs. Then my dually could just stay hooked up to my truck..... lol

 

[BPonci]

Keep in mind that the cooling system is the factor as well as egts. If you can keep the egt low at a 400 to 500hp levels you still cant hold it there all day due to the cooling system soaks up the thermo energy. I beleve 300 to 350 is a more reasonable horsepower level for towing. What do you guys think?

 

[RonA]

That would be a good question for BPine. Blair has tried a number of combinations. I think 350 to 400 continuous would be possible. But I don't think you are going to get much life out of any transmission. My '02 5600 transmission makes unpleasant sounds if I push the boost up high on a hill or passing with a trailer.

 

[jabird]

What about gas mileage for a set of twins while your towing? Would it be about the same as a single? Better than a stocker? Worse? I guess it all depends on your right foot. But is there any noticeable increase or decrease?

 

[Matt400]

not if you install them right. . They are on my wish list for my 05. . However I must keep my horses on all fours when hauling down the road..... So I take them off my wish list.....



Matt are you having twin issues???

:-laf :-laf :-laf Danelle this is so funny I can't hardly stand it :-laf :-laf :-laf and you are now probably wondering why??. . Ask Brandon and say... Honey- who would have told Matt his hood will be up more often with twins?



I think you should put them back on your wish list cuz Brandon will make sure they are done right the first time so the hood won't be up more often, that way I can copy your set



I think I will always have twin issues.

I don't need twins but would like a set for sure as long as they are super nice looking, spool just as well with the boxes off in the winter and no more maintenance than a single.

 

[rubberneck]

I keep telling myself, buy a new one and drive it. Just think about how nice it would be to just drive and never wrench. Dont mod anything. but I know i am fooling myself, cause i have to have a box. Couldn't stand the lack of power with a stock truck, then i would need the transferflow, oh yeah, cant live without the air compressor, or the lift, or the gauges, or the wheels. No matter what i buy, the hoods gonna be up a lot. i guess im my own worst enemy. Oh well, its either work on the truck or listen to the wife nag. truck wins.

 

[rubberneck]

Oh yeah, matt400, the secret to reliable twins is bailing wire and hair spray, just ask brandon he'll tell ya

 

[Matt400]

the secret to reliable twins is bailing wire and hair spray

Shhh, you mean safety wire and boost boot super stick!

 

[SRadke]

Brad is right, 300-350 is a good towing number. Peticularly if you take transmission life into account. No transmission is going to live towing at that kind of power unless you spend the bulk of your time in direct. They simply don't have the cooling.



BDR, I'm using a HTT "Killer B2" which is a 64mm compressor and 14cm housing over a City Diesel S400. The Killer B2 flows a little better than a HX40 and the S400 flows similar to a 3b but spools quicker. It's a nice setup but can be a touch laggy for a daily driver. Pictures in my readers rigs.



Matt, since I put the twins on about two months ago I've had the hood up a lot! Not to fix them though. Tweeking, modifying, showing people, tuning... ... you get the idea. Once I get them where I want them the hood can stay down. Unfortunately, I doubt that will ever happen



-Scott

 

[BrandonF]

I can give you a reference number of an 03 with twins. Probably first few sets ever put on. They live in Lockeford (of course they are auto-impaired) {opps u r 2}... After they got their transmission set up right. The truck is fool proof. I kid you not. This guy pulls a 37 foot big azz trailer. He does drives it like he didn't pay for it. It is AWESOME. He did undue the strait pipe due to the airplane jet engine sound. I can't tell you how awesome his truck is. They have been on about 20 months. I always ask what are peoples (fords, dodges, duramax's and hemi's) faces doing when he is pulling the biggest baddest azz trailer up all the major grades in California and Oregon. He just smiles... ... ... . cause he walks all over them



Heck I get excited thinking about it!!!! Just call Piers he will hook you up!!



Maybe on my megacab. I have some money vested in my horses and they don't perform as well after being laid out in the trailer... ... ... ...



you should get them, you only live once and you won't be sorry... I promise!!! Your wife will probably like your truck more than you after she drives it... Its a girl thang...

 

[BrandonF]

I keep telling myself, buy a new one and drive it. Just think about how nice it would be to just drive and never wrench. Dont mod anything. but I know i am fooling myself, cause i have to have a box. Couldn't stand the lack of power with a stock truck, then i would need the transferflow, oh yeah, cant live without the air compressor, or the lift, or the gauges, or the wheels. No matter what i buy, the hoods gonna be up a lot. i guess im my own worst enemy. Oh well, its either work on the truck or listen to the wife nag. truck wins.

Come on Rubber just twin it and be done



:-laf :-laf

 

[Matt400]

(of course they are auto-impaired) {opps u r 2}

I probably always will be, I got better things to do than put my latte down just to grab another gear.

Just call Piers he will hook you up!!

They are pretty good people from what I hear. Piers and I had a few emails going on my 03.

Maybe on my megacab.

Another new truck in the making???

you should get them, you only live once and you won't be sorry... I promise!!! Your wife will probably like your truck more than you after she drives it... Its a girl thang...

I will try that out on her and see what happens.

 

[Matt400]

I've had the hood up a lot! Not to fix them though. Tweeking, modifying, showing people, tuning... ... you get the idea.

Guess I am just lazy. . no its really because I don't have the time to tweak, mod and tune. Having the truck down for a weekend to get them on is one thing but to make more time for the aftermath is just not in my schedule. I want to bolt them on and go. .

 

[SRadke]

Bolt on and go is very doable if you buy the right kit. I'm a rookie that just fabbed my own so you can expect I had a couple bugs that I needed to work out on my first set. Nothing major, just stuff that I skipped over in the initial fab work in the interest of time. If I wasn't always pushing it an looking for improovment it could be a set and and forget it setup.



-Scott