Holset Turbos on LB7's

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NeilLB7

Supporter of Diesel Power
Joined
Dec 5, 2008
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76
I want to install a Holset HX series turbocharger on my LB7 Duramax. I know there are easier ways to get a performance turbo on the truck...but this is the way I'm going for various reasons. In essence I'm just switching brands of turbo and not looking for some huge HP gain etc.

I guess my main question is who sells a decent turbine pedestal first? I've seen some from PPE and know that Garrett, ATS and ??? must make pedestals since they offer kits to mount theirs. But I dont think I can call ATS and just buy their pedestal.

Then I need to figure which Holset I should use. This is a stock truck...and will remain as such with the expection of this swap, 5" exhaust and cold air intake. IE: No electronic mods, boxes, chips, handhelds etc.

I suppose I need to figure out which Holset and with what housings, wheels etc will meet/exceed the OEM IHI turbo. Any suggestions or whom should I talk to?? Thanks!!
 
NeilLB7 said:
I want to install a Holset HX series turbocharger on my LB7 Duramax. I know there are easier ways to get a performance turbo on the truck...but this is the way I'm going for various reasons. In essence I'm just switching brands of turbo and not looking for some huge HP gain etc.

I guess my main question is who sells a decent turbine pedestal first? I've seen some from PPE and know that Garrett, ATS and ??? must make pedestals since they offer kits to mount theirs. But I dont think I can call ATS and just buy their pedestal.

Then I need to figure which Holset I should use. This is a stock truck...and will remain as such with the expection of this swap, 5" exhaust and cold air intake. IE: No electronic mods, boxes, chips, handhelds etc.

I suppose I need to figure out which Holset and with what housings, wheels etc will meet/exceed the OEM IHI turbo. Any suggestions or whom should I talk to?? Thanks!!
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wait so why do you want to put a different turbo on if you are going to leave the tune stock. Thats completely pointless. What are you expecting to gain?

ben
 
I believe that Garrett makes a bolt on replacement for the Lb7, I believe its the gt3788
 
BullfrogJohnson said:
I believe that Garrett makes a bolt on replacement for the Lb7, I believe its the gt3788
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even then abouthte onlything you get is quicker spool time and lower egts...


but doing that ona truck that has a stock tranny... is not very smart IMO
 
BullfrogJohnson said:
I believe that Garrett makes a bolt on replacement for the Lb7, I believe its the gt3788
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yeah the GT3788 is the biggest waste of money ever. A couple guys on DP have decided to "upgrade" to it, against mine and everyone elses recommendations, and later on, they come back and say "yeah...you guys were right...this GT3788 is a POS"

A stock LB7 turbo with a good engine tune will outspool any stock-tuned GT3788 and blow its doors off any day.

ben
 
I am finding it increasingly impossible to gather data regarding Holset turbo specs and configurations. Garrett on the other hand makes it fairly simple in all respects...including tips and calculations on how to size for the proper choice.

HX50's for example had many different applications. If I choose the wrong one...it could be an expensive mistake. But I seem to be unable to avoid this.

Which is pushing me more towards Garrett so as to make an informed decision. But this completely ruins my initial plan. :(
 
Oh forgot. I like to tinker with my trucks. Just to be different. Experiment.

If I ever need new injectors which I may...I may go with something such as honed and balanced 50HP units. Maybe. The cost is not much more.

Plus...the sound from Holsets are music to my ears. My stock IHI sounds like...well nothing at all. Idle is silent. Mid is silent. High end is somewhat audible. Sounds like a non turbo 3208 Cat.
 
An HX50 with the right specs should be close. I guess you'd be looking for something in the 62-65mm range on the compressor side to be comparable to stock.

If I were you, Id be looking for an HX50 with 65mm compressor wheel, and a 65mm exhaust wheel with a 17cm T-3 exhaust housing.

My HX40 whistles pretty darn good. I sure like the sound of it. It would probably spool good and run pretty good on a duramax too, but im not sure if it would run as good as the stock turbo does or not since it is a little smaller than the stock IHI on the compressor side. An HX40 with the most desirable specs is a 60/65/16.
 
Thanks. I've had a couple folks elsewhere tell me that the HX40 would be too small for this engine. Of course I've seen 330HP Cummins ISC 8.3L engines with HX40's. So I'm not sure how the math works out that its too small for a 300HP 6.6L Duramax. But thats what experience has told some.

Its been difficult for me to find the stock IHI specs. Exhaust housing size, wheel sizes etc etc. Just as difficult to find Holset data in my experience. But I'll keep pluggin away!!
 
If you are going to leave the tuning stock, an HX40 would be fine. Im just not sure if it will flow as good as the dmax charger in the upper HP's.
 
I went to one of the local big rig truck yards to look at take off turbos. Had my hands on a Holset HX55...which I think is similar to a HX50. Just from physically holding it...it looks TOO BIG!!!. Of course the housings make alot of difference for the application. But this thing was monsterous. I think it was off a big Cummins cause it was all red. At this time...I'm really leaning toward a correctly setup HX40.
 
An HX50 is just a little smaller than the HX55. They are fairly big turbo's though. I really think a 60mm HX40 with a 16cm exhaust housing will be pretty close in performance to the stock turbo.
 
Cummins Driver said:
An HX50 is just a little smaller than the HX55. They are fairly big turbo's though. I really think a 60mm HX40 with a 16cm exhaust housing will be pretty close in performance to the stock turbo.
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I still can't figure out why to swap a turbo and gain nothing other than experience. Especially on a Duramax...my 12v I can swap a stocker on in less than 45 minutes...and most aftermarkets go on in under 2 hours.

Chris
 
Turbo swaps on a Dmax are a gigantic pain in the ass. Topside creeper was helpful, and still was a nightmare. I would NOT do this just for sound without the performance aspect, doesn't make much sense, but it's no skin off of my nuts, because I won't be doing it, so good luck.
 
Signature600 said:
I still can't figure out why to swap a turbo and gain nothing other than experience. Especially on a Duramax...my 12v I can swap a stocker on in less than 45 minutes...and most aftermarkets go on in under 2 hours.

Chris
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Dont preach to me, im not the one doing it:hehe:

Im just helping him with some specs. I sure wouldnt do it.
 
NeilLB7 said:
I went to one of the local big rig truck yards to look at take off turbos. Had my hands on a Holset HX55...which I think is similar to a HX50. Just from physically holding it...it looks TOO BIG!!!. Of course the housings make alot of difference for the application. But this thing was monsterous. I think it was off a big Cummins cause it was all red. At this time...I'm really leaning toward a correctly setup HX40.
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you asked for advice, so why are you not listening to us?? This isnt a freaking dodge where everyone and their brother runs non-stock turbos/housings/whatever, swapping turbos in the dmax world is like #10 on the "to do mod list".

A bigger turbo is going to suck on a duramax if you leave the "chip" (tune) STOCK. You need to tune it/increase fueling to see any gain at all. If you put a bigger turbo on and leave the tune stock, the lag and everything is going to drive you insane. And finally, how do you expect to install the turbo? Unbolt the stock one and bolt the new one on? Have you looked at how the dmax turbo is mounted? No, its not just any old T3 flange, you need to buy (500$) or make your own custom pedestal mount.

So you like to tinker on your truck, well thats great, so do I. Go build your tranny, put a big tune on, make 525rwhp and run 12's in the 1/4 and THEN maybe think about upgrading the turbo. Because a stock turbo will do all of that no problems.

And as far as injectors to. Again, THIS IS NOT A DODGE. Are you below 700rwhp? YES. Stock injectors work fine until you are above that horsepower level.

And if you do change injectors but still insist on leaving the tune stock and not "chipping it" it will run like ****.

Ben
 
I am listening. And I am learning. I've owned a 2nd Gen 24V Cummins 5spd and still own my 91.5 Intercooled D250. I've played with turbos on them and injectors. The Duramax LB7 is new to me. I know a few folks with them and have always liked them. From the experience of others...I've been told the ATS Aurora 4000 on a stock tune LB7 performs great and provides better response than the IHI.

I know its not easy swapping the LB7 turbo. I have a topside creeper, a nice garage, lots of tools and plenty of time. So having to get the pedestal (PPE) and do some time consuming wrenching doesn't bother me in the least. I'm fully prepared to have the truck down for a week or two or whatever I need. I'm fully aware its not like bolting up one to the flange of a Cummins manifold. And I've know just about every inch and detail of my Duramax block. I have a BS degree in engineering and absolutely love to experiment and fool with things. Thats just the way I am. Its easier for me to change this turbo than change myself :).

I realize what I'm talking about doing isn't popular and makes no sense to those wanting big HP performance. I know it isn't going to gain me much at all. And I know the Duramax injectors don't have an aftermarket alternative like Cummins injectors.

I'm just asking for advise on doing the turbo swap and I greatly appreciate the responses I've received.
 
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