The New Yellow Kitties are running twins.. from the factory...
12.5L, 13L, 15L, 15.2L..
http://ohe.cat.com/cda/layout?m=85523&x=7

 

Even the ol' reliable 425 cat had compounded (series) twins.

You'll find the overwhelming majority of high output diesel gen sets and medium to large marine diesels have multiple chargers as well.

You also wont find any high speed centrifugal air or natural gas compressors over 25 Psi in a single configuration either. We have a 2,500 HP 250 Psi centrifugal air compressor at the plant that has four compressors in series. The primary compressor wheel is about 18" in diameter and the final stage (forth compressor) isnt much biger than an HT3B wheel. Turns at 43,000 RPM too, its a very cool machine, i will have to take a picture of it..... anyway lots to learn about how they stage those compressors, and its done for a very good reason.....



KP

 

This blanket statement is basically what I'm arguing with. I admit, I don't know everything about twins versus singles, other than what I've read on this board. I didn't take into acount the compound compression advantage of twins.

"And twins have nothing to do with covering RPM ranges."

600mw, I am not trying to pick your post apart........there was alot of good information there, but I thought one reason for twins other than reducing egt's during heavy engine labor was quick spoolup at low rpm?

 

You're right walexa, the low-end spool is indeed a great advantage of twins.

When you said about each turbo covering RPM ranges, and I commented on that, I thought you were refering to the incorrect notion that in twins one turbo covers a certain RPM band, and the other turbo covers a different RPM band. Thats all I meant by saying that was not the case at all. Some guys on here have said that is how twins worked but this is not at all true, and I thought perhaps you were saying the same. Sorry for the mix up if there was one.



KP

 

Surprise, I agree with Kev

Unfortunately, a lot of us don't have the tools or knowledge neeed to fab twins-- like me, for example.

The only downside to twins, imo, is complexity. They're more involved, and require some tuning to make work well. But you can make them or have them made for not too much, using your stock turbo.

Take your stock charger, get a larger 14Cm housing for it, and have it thermal coated to hold heat in.

Then hang a nice charger underneath it: a GT42 or T88 or something. Heck, even twins with a dinosaur HT3B will STILL work better than any single!

 

K31

 

Sure, works for me

 

And they boot you up to the Super Street or Pro Mod pulling class.

 

And they boot you up to the Super Street or Pro Mod pulling class.

Very true!