Parallel turbo's??

[RCone]

I honestly don't know if this a stupid question or not. If it is, don't laugh hard enough to hurt yourself. My feelings won't be hurt. I just want to know.



I know that most with twin turbo setups run them in series. Can you, or is anyone running to small turbos parallel? I am asking because it strikes me that there are a lot of smaller used turbos available for a good price.

 

[John]

Great idea! I have a friend and vendor on the TDR BB here that has had this exact idea for more than several years now. He thinks this will be the trick, kick a$$ turbo setup for all but the most insane of power requirements.



HeberRam...



is he still working on this concept?

 

[Idaho CTD]

Originally posted by John

Great idea! I have a friend and vendor on the TDR BB here that has had this exact idea for more than several years now. He thinks this will be the trick, kick a$$ turbo setup for all but the most insane of power requirements.



HeberRam...



is he still working on this concept?

He is still working on it John. I talked to him about it last week.

 

[TxDieselKid]

The high cost would come in the manifold.

 

[rkubicki]

Its not unusual at all to have smaller twin turbos in a tandem (parallel) configuration, but this is almost exclusively used in V-engines where it makes more sense to have one smaller turbo for each bank than to have one large one and a plumbing nightmare



If you used two smaller turbos on your inline Cummins engine I think you would lose some efficiency since the exhaust energy leaving the engine would be split to drive two turbine/compressor shafts that would likely weigh more than one larger turbo in a single-unit setup - this means more lag and slower spool-up.



Also two smaller turbos may increase your overall back-pressure before producing the same output pressure-ratio that your old turbo gave you.



Rob

 

[Jim Fulmer]

All it would take is a couple of small turbo to spool quickly and a good fabricator to build a custom header and a spare cracked head as the mock up for the bench!



Jim

 

[willyslover]

Besides. . Steve thinks that Cows fly and that he has a pretty truck , and he is a chick magnet LOL

 

[TxDieselKid]

I hear HY35's work nicely.

 

[esommer2500]

The Liberty Belle, a big rig puller that is owned by Metzger Trucking, which is only 5 minutes from home, has 4 turbos on thier Cummins. They have split the manifold to two manifolds of 3 cylinders each, and each 'bank' of cylinders is running a set of twins, for a total of 4 turbos. So, they are really running a 'series' of turbos in 'paralell', right?



Either way, it looks cool as he11. And you really should hear them on spool up. Oo.



Eric

 

[HVAC]

Parrallel

I've been building twins for a couple years now and along the way I've considered just about all the options. The problem with parrallel turbos is you lose the compounding effect. Typically we are in need of the higher boost numbers to drop our egts. IMO the only reason to go to parrallel turbos would be if it were not possible to find a single big enough to do the job.

 

[CMNS PWR]

Originally posted by esommer2500

The Liberty Belle, a big rig puller that is owned by Metzger Trucking, which is only 5 minutes from home, has 4 turbos on thier Cummins. They have split the manifold to two manifolds of 3 cylinders each, and each 'bank' of cylinders is running a set of twins, for a total of 4 turbos. So, they are really running a 'series' of turbos in 'paralell', right?



Either way, it looks cool as he11. And you really should hear them on spool up. Oo.



Eric

Here is the Liberty Belle's charger setup:

#ad

 

[Forrest]

hello wallpaper

right click ... set as background Oo.

 

[nickleinonen]

#ad
i like turbo...

 

[Rams-n-Hogs]

Forrest,



Thanks, didn't know I could do that so easily. Now if I could fit something like that under the hood of my truck.



Jim

 

[RICHIE 2]

Re: Parrallel

Originally posted by HVAC

I've been building twins for a couple years now and along the way I've considered just about all the options. The problem with parrallel turbos is you lose the compounding effect. Typically we are in need of the higher boost numbers to drop our egts. IMO the only reason to go to parrallel turbos would be if it were not possible to find a single big enough to do the job.

What do you mean by compounding effect???

 

[HVAC]

That's easy Richie

Richie, I run 90 psi of boost with my current twin system. I need a lot of boost to keep my EGT's at bay. I'm running over 650 horswpower at the wheels with diesel only. That means a bunch of heat. I run a low pressure turbo into my high pressure turbo back to back. That means the low pressure turbo makes say 15 psi and feeds the high pressure turbo whichs then takes the 15 and jacks it up to say 90 psi. This is compounding cause we are using the aggregate of the two turbos. Say 15x times 6x (pressure ratio of second turbo) = 90 psi.



With parrallel turbos you get a max pressure of whatever either of the two turbos will create alone. No multiplication of pressure. No single turbo is going to give you the max boost of a compound system. It follows that no parrallel system is going to give you the pressure of a compound system. With a parrallel system you get twice the volume at the same pressure of a single.



Make any sense?

 

[EOliver]

I think the Toyota Supra could be a good example for us to follow. It also is an inline six with twin turbos from the factory. I believe they are in parallel also.

 

[RICHIE 2]

Re: That's easy Richie

Originally posted by HVAC





Make any sense?

Yes it did. I only had to read it once!







kris

 

[Idaho CTD]

HVAC,



Is it boost pressure that creates egt relief or cfm? To a degree it makes sense that it's the volume of air first until you have a restriction then pressure is increased to try and force more air through correct? So if a person could run parrallel hx35's with a combined cfm of say 1200 @25psi vs. a hx40 with a cfm of 750 @35psi (these values are guesses) which would you consider is better? IMO parrallels are a good idea if you aren't looking for super high hp and providing only 1 turbo is used up to 5-10psi utilizing some form of gating. Another benefit of parrallels is not double heating the air as compounded twins do.



Nathan

 

[HVAC]

Good Question

Nathan, I can't wait to visit with you at May Madness! That's a excellent question you have posed. Right now I have a pizza in the oven which is drawing all my virually awake attention. Then I go into a coma till daylight.



Truth is your too smart, I may have to dodge your question (kidding)



Quick answer is both volume and pressure are important.