6.7L Cummins Turbos on eBay

JGTurbo

JGTurbo

Well-known member
Glad to see some action on here lately!

Have you guys seen the 6.7 Cummins turbos on eBay? People are almost giving them away. Most of them I think are taken off by dealers when the VNT nozzle sticks. Just clean it and it is as good as new! Here's an example: Buy It Now for $150

eBay link



I have been looking into these pretty hard lately and I think they would be ideal for our inline sixes with a few modifications. Here's why:

1) COMPRESSOR FLOW:
Best of both worlds.

The compressor is very similar to the HX35 and HY35 that has been used in the 5.9 Cummins for years. This compressor can support over 450hp, and it is capable of boosting a 250 cubic inch engine to 18psi at 1500rpm WITHOUT SURGING and will also support high RPM/HP levels. This combination of high hp support and low rpm-high boost capability is unheard of in turbos designed for gas motors.

2) VNT EXHAUST TURBINE:
Tunable A/R ratio.

There is always a lot of talk around here about which A/R ratio is correct for our sixes. A small A/R spools up quick, but is a restriction at high rpm. A large A/R takes higher rpm to spool, but revs out without restriction. Wouldn't it be nice to be able to have both? That's what VNT does.

Unlike the movable vanes on Duramax Diesels, the Cummins uses a sliding nozzle to vary the area of the turbine that is exposed to exhaust. This has the same effect as varying A/R ratios continuously. Also, when it is all the way open, it takes the place of a wastegate. It is also used as an exhaust brake when it is all the way closed.

Constantly varying the position of the nozzle in relation to engine demands gets kind of complicated and this is the reason for the electronic box in between the housings. I think this is what scares most people off. They think that a computer is required to make the VNT function. I have found this to not be the case...

While looking at PDFs from Holset with cutaways and schematics of the turbo, I saw what was under the electronics box. What was it? Why, a mechanical arm that looks just like the one used on normal wastegates. This got me thinking...

If you took off the electronics and connected a normal wastegate actuator to this arm, the VNT would work! Of course, it would't be constantly variable like it is with the electronics, rather it would either be "open" or "closed". EDIT: On second thought,I think it would be sort of continuously variable...hmm

The advantage of this set up would be that you could alter the "closed" position using a threaded rod on the actuator. This would allow you to choose whether the turbo spooled up early or late. Also, as long as the linkage was right, the actuator would slide the nozzle out once full boost was reached and boost would be limited, just like a wastegate.

If that system doesn't work, simply lock the nozzle in place with a threaded rod and no actuator and run an external wastegate. This would still allow lots of tuneability.

Import guys have been using 98.5 and newer Dodge Cummins 5.9 (360cu.in.) turbos for years and they claim the spool is around 3000rpm on their 2.0L-2.5L motors. Just looking at this seems to show that the exhaust side of these 6.7 (408 cu.in.) turbos would be a perfect match for our sixes.

3) THEY'RE CHEAP!

SUMMARY:
So the compressor is sized just right... The exhaust is the perfect size and TUNEABLE... They are going for pennys on eBay...

These turbos have been on my mind a lot lately but I don't claim to know claim to know everything about them. What do you guys think?
 
I have worked on these in the dodge trucks, if you take the electronic actuator off the side it drains the coolant out of it also, just saying you will need to find a way of sealing it up
 
If you could find out what the actuator was it might be possible to make a remote trim control that would be dash mountable. With an ECU monitoring A/F you could dial in boost level electronically with a potentiometer.

Shopower, have you any idea what resides under the cover? If you give me some info I may be able to find or build a controller that could make use of the factory actuator.
 
pretty sure all that actuator is is an actuator that moves the lever back and forth and a position sensor, I will look at one when I go to work on monday and see how it works, actually I am kind of interested in where these ones on ebay are coming from because those turbos have like a 4,000 dollar core charge from mopar
 
I have heard of import guys using the stock actuator with some electronics hooked up. I'm not sure what is required to do it.
 
if you take the electronic actuator off the side it drains the coolant out of it also
Click to expand...

Are these water cooled as well? Or does it drain the oil when the actuator comes off? Could it be sealed with a machined flange?
 
What interests me is that it may just take a variable voltage to actuate an armature in the unit itself. That could be accomplished with less than $25 in parts. It depends on the actuator and the control signal.
It may use a stepper motor which would require a more sophisticated setup. That might put control out of reach as these drivers are expensive.
If you could determine if there is a "motor" or a "plunger" that would answer a lot of questions.
 
TCIC 300ci superbeast":3l1ibqmv said:
from what i know all dodges trucks use holsets.
Click to expand...

Correct, but that does not answer the question as what they are for sale as they may be an aftermarket version made by another company.
 
I went to check these again and they are gone. No word from ebay as I was watching them. Any one make contact and have the info?
 
but do you know if these will work for our motors with the electronic actuator or not? Just curiouse in case I run across one in the junkyard!! so you say these are about perfect for a 250?Just in case I find one!
 
I have been doing research on these for quite a while and I think I am going
to buy one. I am planning on bidding on one of the two that end on
December 6th. So don't bid against me...you will lose! :x Haha, just
kidding. No but seriously...


I'll tear it down and figure out how everything works. I'm planning on
looking into either replacing the electronic actuator with a mechanical one,
or rigging up some wiring and seeing what it takes to run the electronic one
properly. I'll post pictures if you guys are interested. Anyone?
 
not sure what I am looking at on the graph.Ok I read a little so its mainly done by power points in the rpm range of our motors?So the hx35 on my map looks really good if the top flat line is supposed to be in the center opening of the graph and the line at the bottom that goes up should be inside the left line( also in the center on its way to top).Is that right?
 
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