Putting a set of Twins on this week

[Sled Puller]

Originally posted by TxDieselKid

Gene,



When you got your twins, you also added a TON of fuel from where you were.

Andrew

That is incorrect, Andrew.

I broke it in with the exact same fuel. Do a search, I talked about about having no smoke at all, the twins cleared it up etc.



After that, I only added a set of bigger d valves, same inejector.





Jr, I think you thread was worded strange to get your point across, but oh well.

An edit before you posted the bigger housing bit would clear things up, but if it doesn't bother you to have incorrect information posted, it does not bother me.







TDK,

It takes the air longer to reach the cylinder???????

Explain that one, please.

 

[therabbittree]

i am planning on using a external wasegate . . plumbed back into the secondary feed etc... also running the thickest marine head gasket. . etc... i was going to get a h3tb from a N14 but i found the hx55 cheap and Brand new... so how much bigger is a h3tb from a hx55? ... also on the small turbo i see the diesel dragster of Sbentz's in Colorado runs a hy35 9cm housing and a hx55 with a 22cm housing . . works good for him but he weighs ALOT! less then my truck... . so if i stick with the hx55 22 cm for now and the h1c 18. 5 how do you think those would work?... latter on i could swap for other turbos etc when i get more $ but as i start i'd like to try what i have... . i think if i swapped to the hy35 9cm as the small turbo it would have a lot of drive pressure or restrict the setup. . what to you guys think? plus the hy35 9 is set aside as the secondary turvbo for my twin turbo vw tdi project hehe!

thanks for any ideas and experiences!!!

Deo

\x/ hillfolk!

 

[TxDieselKid]

Originally posted by Sled Puller

TDK,

It takes the air longer to reach the cylinder???????

Explain that one, please.

Gene,

I never claimed that this was THE cause of the nano-second of lag, but just how does the pipeing go, is it longer in twins?



As for the fuel, I believe you, no one knows better what happen to your truck then you, and being a year an a half ago, I can't recall that well.



Andrew

 

[Sled Puller]

The air comes into the big charger from the air cleaner, then stuffs through the small one, then into the intercooler.



But there is not a switch, air/no air, I mean there is always air in your pipes.

Bascially, with no way to measure it, SOPM my HX-40 twin set up has about the same lag as the old 35/16 single charger.

Obviously, going to bigger chargers and housings will make the twins more and more laggy, same as a single.



But I believe there is a point there, where the twins have LESS lag than a single, that is one of the sweet things about them.



It is a pity all the twin guys go for broke, none of the trailer haulers post about them. Probably becuase they have jobs, and aren't selling Cummins parts.

We are missing a lot of good info, seems like we are bypassing street, and going right to comp.



A lot of combos "will work" but twins are something that almost need to be custom tuned to every truck,(and driver) to be perfect.



I think it pretty much goes, if you have a big charger and a small charger, cheap, go for it!LOL

 

[24VChev]

Daily Driver

The only competition I use my truck for was a couple of drag races at the local strip. I used the stock HX35/12 with a turbo from a 15L Cat engine. I have no idea of the housing size on the Cat turbo although it is comparablr to HT3B. The only change was the turbos and a drag comp from a regular comp. On the same dyno I went from 368 hp to 439 hp.

I drive this truck daily but minimal towing 5000 lb boat once in a while. I notice no increase in lag but now I can keep my foot in it and EGT never goes about 1250 or so. I am not using a external waste gate just a modified stock gate. The stock gate opens at stock boost pressue (21 psi). Total boost is about 52 psi.



I basicaly had a couple of turbos and "went for it" That is good advise!



I am not running alot of fuel as some but I am very happy with my twins!!





Malcolm

 

[TxDieselKid]

Originally posted by Sled Puller

I mean there is always air in your pipes.

Right, but it takes a second, and creates a vacuum in the pipe untill air gets into the big charger, and around into the small one.

It is a pity all the twin guys go for broke, none of the trailer haulers post about them. Probably becuase they have jobs, and aren't selling Cummins parts.

We are missing a lot of good info, seems like we are bypassing street, and going right to comp.



A lot of combos "will work" but twins are something that almost need to be custom tuned to every truck,(and driver) to be perfect.

I agree with both points 100%. There are a LOT of twins combos out there not in the internet at all, that we will never hear of, that actually WORK, not compete.



Andrew

 

[Hammer]

Somewhere in my wheel job of Sleddy's truck I missed the lag time. Upon my stomp of the loud pedal and the boost guage going TILT Gene was sent smashing into the seat deeply, begging for me to stop as his phone number was on the truck not mine. Missed his comment about it as I rowed the stick and fogged out half of York county. Lag... what lag.



TDK. .

Length of piping has nothing to do with lag time. Air will flow in a straight line,no matter what the length,at the same speeds. Harsh bends,twists and bends following bends disturb air flow and could have the effect on spool up time. Another that will is superheating the air which will slow up flow rates. Of the many twins being built here how many actually use them to tow in a extended session or up long progressive grades and can say they have no inherent problems with them. I'll tell the they are full of bunk. Heated air is heavy and doesnt flow as well and when extra chargers are added air is heated faster.



Mark. .

Guess I'll never understand your newest set of chargers and their piping. There are things in them that defy most anything learned by a flow bench. Only time will tell.....



J. R.

You ask Ol Sleddy a good question. You kinda remind me of P/S racer Warren Johnson with a comment like that. He is quick to point out who in his sport BUYS their power instead of building it and he has a problem with guys who do it. Kinda like you with Gene since he went to a viable source and got what he felt was right for him. Could it be a hint of envy maybe?????



Huff n Puff. .

Congrats on doing well at MIR and the bouncing baby twins... . Andy

 

[BRI7070]

If I Understand twins correctly. (This is concerning the fresh side of the twins. )



The Fresh air enters the intake side of the larger turbo and exits to the intake of the smaller turbo. From there to the intercooler and finally into the engine. If this is correct, when you frist start out the smaller turbo will spool up faster than the big turbo and will suck air thru the big turbo until the big turbo can take over. When the big turbo starts to move it mass of air what keeps the small turbo from over speeding?



I would like to make a set of twins and was thinking of using my HY-35-9 as the small and a HX-40-16 of 18 for the large. I am not looking for ungodly amount of power but lower egt and very quick spool up. (Plus I would like to be able to say " Yeah I have Twins")

 

[Gizmo 007]

Brian, yep, you pretty much nailed the operation of the twins. Little one spools on the low end, then the big one stages in, then the little one drops out (via wastegate).



Wastegate configurations vary from setup to setup... Some guys have a wastegate on both turbos, some guys have only one wastegate (on the small turbo) and others aren't even running a wastegate. I tried the no wastegate route and lost a turbo . I only have one on my small turbo now, set to 25 psi. I regulate the big one with my right foot . I try to keep it below 75psi :-laf I love it!

 

[BRI7070]

Gizmo 007,



The way I understand it is the wastegate controls the engine exhust pressure and where it goes based on the boost level on the fresh side.



What I dont understand is, (all number are hypothetical)



If the small turbo is capible of 300 CFM of airflow and the large turbo is capible of 600 CFM what keeps the large turbo from overspeeding the small turbo on the fresh air side?



Even if the wastegate is dumping all exhuast pressure around the turbine impeller the air flow from the large turbo compresser impeller should spin the small turbo compresser impeller as it pass its 600 CFM thru the small turbo.



Thanks for the reply

 

[Mark_Kendrick]

Originally posted by Hammer

Mark. .

Guess I'll never understand your newest set of chargers and their piping. There are things in them that defy most anything learned by a flow bench. Only time will tell.....

What don't you understand and what doesn't make sense on the flow bench????

 

[Mark_Kendrick]

Originally posted by BRI7070

Gizmo 007,

... If the small turbo is capible of 300 CFM of airflow and the large turbo is capible of 600 CFM what keeps the large turbo from overspeeding the small turbo on the fresh air side?



Even if the wastegate is dumping all exhuast pressure around the turbine impeller the air flow from the large turbo compresser impeller should spin the small turbo compresser impeller as it pass its 600 CFM thru the small turbo.



Thanks for the reply

The turbos work really work on factors of input pressure. It takes x amount of drive pressure to give a resultant increase in pressure ratio ie from 1:1 to 3:1



at 40 psi a single charger is making a 4:1 pressure ratio. to make a set of twins do the same each chager only has to make 2:1. the first charger sends 14psi of boost (28 psi absolute pressure) to the second then it mutiplies that times 2 for 56psi absolute -14psi abient to get 42psi of gauge(boost) pressure. Subtract the last 2 psi to losses due to inefficiency.



The small turbo is going to be spinning faster than a single turbo at 2:1 but not anwhere near the speed of a single at 4:1. turbo speed gets to increasing almost exponentially above 4:1.



Now, lets look at drive pressure. it takes much less drive energy to make 2:1 than 4:1 because turbos are generally much more efficient at lower PRs. The single turbo will have 50-60 psi of drive at 40-45psi of boost where a proper compund setup should need 38-47 psi of drive pressure. A single charger will see skyrocketing exit temps and drive pressures above 3-4: PRs where a set of compounds will see a near linear and equal drive pressure to boost pressure ratio(1:1) until well past 60psi of boost.



If you take my statements to heart you see why a lot of people see close to 60 or 80+ hp improvements when going to compounds.



Later,

Mark

 

[rubberneck]

Question for Mark

Ok, here is what i want. I want a better than stock bottom end with the top end my B1 gives me. I really dont need much more up top. I love driving the truck empty with the B1 (standard not quick spool), however, it isn't the greatest for towing. I tow a 14k trailer and i run the stock charger if i am going to be towing alot. EGT's stay cooler on the hard hills. So will the HY35/9 Ht3b combo be a good choice for what i want to do?? I have a set of super mentals ordered, other than that power is as stated in my sig.

 

[Mark_Kendrick]

An hx35-12 ht3b26 would definitely work well there. I have not put the hy on a 24v to check egts yet but I expect them to be very low.



The good news is the hy and hx will interchange w/o modification.



Mentals should work fine with either even when towing. just keep a little rpm so you carry some boost. Low boost still gives a abit of smoke if you lug it.

 

[rubberneck]

Hey Mark, Do you happen to know if the piping you sell for the above mentioned combo will clear my onboard air system. I have the york compressor mounted with a kilby bracket?? If not want somebody to do a test fit

 

[Mark_Kendrick]

I have that bracket Too ... i'll check

 

[Huff N Puff]

The twins are in,a tough install but they are

everything, Mark Hendricks said they were. A little lagy on the bottom end,but I'm still playing with the wastegate ,but after 10lbs it can peg my 60psi gauge almost instantly. The waste gate system is very touchy you can vary the pressure from 40lbs to at least 60psi can't monitor it after that. Whats really amazing you can play with the amount of lag,with how you adjust the wastegate. Whats best of all my EGT's dropped from 1400deg to about 1000deg floored. Thanks Mark. Merv

 

[KennyM]

You gonna have it at the track Sunday? I want to here and see this run.

 

[Mark_Kendrick]

I'm waiting to see the ETs,



Merv was already running a 13. 4 on DD3s... very impressive!!!

 

[rubberneck]

Maybe i missed it in the earlier posts, but if you dont mind me asking, which turbos did you decide on??