Turbo upgrade

[Deere65]

So I’ve finally got my truck starting good, running good and shifting good for a mostly stock truck. I think the Teds trucks optimizer is going to last me a long time. I’ve got about 1500 miles on it and the oil is still clean and no blow by so I think it’s time to get it to where I need it. I originally bought this truck to have a cheaper, easier to repair diesel to drive whenever and pull a camper or car hauler when I need it but honestly I think my 2011 1500 with a 5.3 does a better job so I’ve been looking at turbos and thinking that the hx35 should fit my needs for mostly empty driving but being about to pull up to 10,000 lbs when I need it but the issue I’m having is it seems there are different size turbines and housing for a hx35/40ii and the 40 so I’m lost on that. I would like a little info on what would be the best for what I’m doing. Also I plan on a tune to go with whichever turbo I decide on but I just need help deciding what the best turbo option is

 

[JayTheCPA]

The 'best' idea is a myth.

Aftermarket turbos are good, but each has its trade-off.

Holset / CKO is a definite DIY with social media as its support. Overall drive-ability is noted as good, pulls good, and has no notable lag. But runs higher psi that really should have better head studs and pushes IAT's into the territory of needing an intercooler.

ATT has vendor support. Overall drive-ablity is good, pulls great, has some lag, less complex (no wastegate, so getting rid of the entire vacuum system is possible) and makes the same power as other turbo's with a *lot* less psi or worry over EGT's. Seeing as the truck is already running a turbo master, am suspecting that the vacuum pump is already gone.


In looking over the signature, might consider swapping the exhaust (post downpipe) to 4". Also, wrap the downpipe as it will help with A/C and other components.

 

[Twisted Steel Performance]

Budget will come into play. What's yours for this project.

 

[Deere65]

Jay, I forgot to put in the signature that this is a vin S truck so it does still have the vac pump to keep the egr happy although all it has is the solenoids and map sensor. I am currently only running the turbo master at around 10 psi peak to keep from getting any codes.

I have heard the ATT is the way to go so yes @Twisted Steel Performance budget is a big factor since I have replace the engine and rebuilt the trans. Even though I have done all the work myself and saved a lot of $$. I’m still cheap. It seems as though I could do CKO turbo for around $400 and still have the cash for a tune where as the ATT looks to run me around $1200 but ultimately I don’t want to be disappointed if I cheap out so that’s why I have come for advice and opinions

 

[ak diesel driver]

which turbo you'll like depends alot on your driving habits, towing, cruising the freeway, etc. There is no one turbo that shines in every application. For instance most people at higher elevations don't like the ATT as it takes to long to spool, but if you do alot of towing it might be for you. Me, I'm at sea level so the ATT works great for me. Also if your the kind of person who lopes along trying to get better mileage by keeping the engine rpm down then any bigger turbo may not work for you.

 

[Will L.]

Also pay attention to where is your rpm. The rpm range in a 6.5 is pretty decent. There is a guy with a hummer (which has way lower gearing) that said he has never hit 2300 rpm. And never hit 45mph. So for him the gm turbo is perfect.

War wagon comments on the use of a 2,000 rpm stall converter, but that takes away a lot of my offroading capacity. So as much as I love the ATT, and I onow it would be wonderful for all my freeway use, I am leaning towards a 35/40.

 

[JayTheCPA]

Pricing for the ATT through Leroy is a complete kit.


Holset prices do not include additional parts that you will probably need to fabricate or replace. If the plans are to get the most power out of the Holset, it will likely need head studs which in turn call for new valve covers. Maybe an intercooler too, but not an absolute requirement.


Point is, the cost of one turbo over the other does not account for the all-in cost of one turbo over the other.


AK has a good point about elevation. From experience, pulled 8K over the Apalachains (~15.5K combined), so it is capable with the Eastern Continental Divide. We did need to limit power as the motor could not shed heat well enough to stay at highway speed.


Bringing this full-circle, each path is a trade-off. So just pick whichever way is best for the personal tastes and plan the path forward.

 

[WarWagon]

The GM turbo is an asthma attack over 2200 RPM. Towing I don't see under that RPM except when getting going from a stop.

Unless you go too small you can't do worse than a GM turbo.

Towing turbo's specifically the ATT more or less throw away the RPM below 2000. So first gear you gots LAG because it won't spool until the RPM hits 2000, period. After that it's a fright train till past the 3600 RPM redline. How often after 1st gear is anything over 2000 RPM not available with the TCC unlocking or a gear change? Yeah the GM 4L80E programming keeps you in the GM turbo GAG high RPM zone with any throttle. For DD I tossed in a High Stall converter. With the constant grades out here and 4.10's out back this setup works for me.

If you want a tighter turbo to run lower RPM there are a few out there. The turbo is literally another engine under the hood and selection of what matches what you want is more important than budget. Case in point the fuel savings over a GM turbo at 7.5 MPG towing paid for both the ATT (10 MPG towing) AND the Yank converter. Low RPM with the GM3 wasn't possible towing and it sure as #ell didn't save fuel.

10,000 Lbs towing depending on your truck and options is, frankly, beyond the limits of most of the 6.5 truck's tow ratings. Only a 454 with a GN or 5er has a 11,000 tow rating. The 6.5 is way less. My truck can do it: until the lawyers get involved and your insurance refuses to pay due to overloaded vehicle. The door sticker and published tow ratings are the limits as far as lawyers and Arizona's "Stupid Law" is concerned. Yeah, the law that says you pay for your rescue for driving into a flooded wash. - Just saying and that is you just got it put together and now you want to work it beyond the limits and tear it up again...

 

[Deere65]

@WarWagon i don’t want to push it beyond its limits. I would say I exaggerated that number. Honestly I’ll probably only be pulling more like 7-8k and it won’t be frequent but I don’t want to be that guy with the hazards on pulling a hill. This part of Arkansas is nothing but hills.

So I am gathering that the att is probably the best choice for the 6.5 and honestly I should probably just save my money and get the att but the hx turbos are also a good option or basically anything other than the factory turbo.

I would still be interested in knowing what’s up with the different housing sizes and turbines for the hx turbos. Also would it be an absolute waste to get a tune without changing the turbo I mean will I be totally disappointed if I just went that route or would I see a noticeable gain

 

[WarWagon]

Again best choice only applies to your situation and use. Frankly how do you feel about keeping the engine above 2000 RPM most of the time? That is only a 1600 RPM range between 2000 and 3600 redline? (Ok 4K RPM if you roll the bad odds dice on old valve springs not breaking. Another discussion of IDI's don't like overspeed. ) Hot weather with the AC on and fan locked in from a light simply sucks to get going: in trade for power to climb the hills when towing. Unless you spend another $1100 to stall it with a converter.

The *your* 3.42 isn't a high RPM ratio to begin with. The 3.73 I had on the 1995 burb was more of a dog with the ATT vs the 4.10 Patch has. Precups also hurt me being 6.2 NA on the 1995, but, gearing kept me out of the happy RPM range longer with the 1995.

Today, unlike 2011, there are several other turbos that have been tried and have results on a 6.5. I can really only speak to the two turbo's I have used the HX40II and the ATT. I have built my rig around Towing, high RPM, and grades that go for miles. Over stock I love the ATT and don't mind the high RPM it needs because that comes with low back pressure. For example at 75 MPH off the top of my head 2500 RPM the GM3 would produce 6 psi of boost with no throttle. The ATT was zero: the engine isn't spooling the turbo from airflow alone. Hammer the throttle and 15 PSI of boost, NOW.

The HX40II dyno'd near the same HP/TQ but at 24PSI of boost on the 1995 burb (Vs. ATT @ 15 PSI). AKA HX40II backpressure and intake air heating was using up the boost. IMO they spooled at the same 2000 RPM. BD Spool valve (We are collectively and absolutely 6.5 NUTS.) on the ATT was something else getting 10 PSI vs, 2PSI passing 2000 RPM, but, IMO the converter is quicker with instant boost RPM. Watch the video of ATT with a Spool Valve and, yes, guilty as charged. https://www.thetruckstop.us/forum/threads/att-videos.39789/#post-452501

Look at @n8in8or build for example. His 6.5 will run door handles in the 1/4 with a Trailblazer SS factory powered by a Corvette LS2.

Many choices now and doesn't hurt to explore them.

 

[Deere65]

The gearing of my truck is a good point I didn’t really consider. So it’s not really a simple stick a different turbo on it tune it and go. I’m going to need something that brings the boost in low because of the higher gears and keeps it “available” at cruising speeds for when I get to hill. Does that sound about right?

That sounds like a tall order for any better flowing turbo. There’s always got to be a give and take somewhere I guess

 

[JayTheCPA]

No, you really are not going to need something that brings the boost in low RPM's. The shift lever is good at keeping RPM's where the system needs them Seeing as there is no mention of rock-crawling, low RPM torque is not a factor here.

And, No, it really is not entirely as simple as plop a turbo + tune and go. But, it is possible to do the upgrades in steps that are more budget friendly.


Power to pull up a grade and ability to do so are two different things.

With the Burb's configuration, I had plenty of power. The cooling stack needed more help so I had to cut the speed and was one of those over in the right lane with the semi's that crawled up the 6% grade when I had the RV in tow.

Unloaded, the Burb would fly up the same grade and rarely drop out of OD (when it still had the slushbox).

Point here is that no matter which turbo, if you want to maintain highway speed up grades for any distance, the overhaul needs a holistic approach and not simply picking one component.


In the end, each of the turbo's is known to make about the same power, so it is just a matter of what else needs to happen around the turbo.

Toward controlling RPM's and managing the ATT's desire for 2K RPM's, this is really not a big deal as that is what the shift lever is for You are way smarter than this generation of PCM, so driving the truck does call for a little more operator involvement to stay ahead of road conditions. Especially while towing.


One thing that will make a bigger difference than a turbo is the tranny. Ditching the slushbox was the best thing that happened to the Burb. Seeing as you are already planning to pull the motor and tranny, now is a good time to consider a swap.


Yes, a tune now will definitely make a difference as the tuner can lock the TCC a lot more than what GM did. It is really tough to tell what GM had in mind with its logic. Some comment that it was for fuel economy, but leaving the TCC unlocked in all the situations that unlocks it actually does the opposite.

 

[WarWagon]

What RPM do you run when towing? Do you have the budget to swap the turbo, tune, re-gear and/or different stall? You have DD gears in it now. Not a show stopper, but, affects starting from a stop and you are running a lower gear a lot more towing.

Now if you are towing and have the RPM over 2200 or are willing to rev up when towing with lower gears... This is a major surprise to some ATT owners in the past and the entire warning I point out. However it has power when you need it on grades towing. It will walk all over a GMx turbo including less fan and lower ECT pulling a grade. The flip side is you are going from GMx that spooled before the starter quit spinning aka stoplight till 2200 RPM is snappy and then it bogs, bogs more, and you just can't make it past what 62MPH? (62MPH was my max speed with a GM 3 some days.) http://www.maxxtorque.com/2012/07/the-65l-diesel-factory-equipped-asthma.html

I say Yank because it delivered without excessive heating of the trans oil. I had the transmission shift sooner and release the TCC sooner with load to lower smoke when the grades crept up on me. I also lock it at 35 MPH - something the OEM converter is not strong enough to do without slipping on some grades. When the TCC locks you don't know you have a stall in it. The Yank made Daily Driving a lot of fun with the big towing turbo.

The Yank can overcome the 4L80E's somewhat wide gears. You have more fuel than I am running in this video with a small maxed out 6.2 pump. One day soon I will remake it with a 6.5 Moose pump.

 

[Deere65]

What RPM do you run when towing? Do you have the budget to swap the turbo, tune, re-gear and/or different stall?

At this point the budget really could only do either the turbo and tune or maybe gears and converter not sure about those two as I haven’t really priced those parts. Since it’s 4wd I’d be looking at 2 sets of gears and a lot of work and I’d hate to by another converter right away since I just bought one when I rebuilt the trans. I’m really leaning towards turbo and a tune to start with and see how the truck reacts to towing before I change the stall and then I think gears would be last. Also I always try to keep rpm up while towing with a diesel. I guess I’m use to running the Deere equipment where the only way to work a machine is at or near full throttle because that’s how it was designed although I’m not going to keep my truck at full throttle I believe in keeping it in peak rpm range if it’s going to be under a load so I can get the most out of it and from what I’ve read in the past the 6.5 peak seems now to be a bit higher rpm than what the stock turbo is good for.

I with you @JayTheCPA about using the shifter while towing. I’m use to it from driving gm trucks with 4l60s and 700r4’s. You really got to baby those when towing.

Also @WarWagon thanks for sending me that link. I enjoyed reading that. We’ve got the steep grades but they’re generally not miles long.

 

[Deere65]

Another thought. I suppose with any turbo I choose I’m going to need to install head studs? From what I’m understanding to make the most out of an upgraded turbo I’d probably be wanting to see closer to 20 psi boost right? As the att doesn’t use a wastegate there’s no way to really keep its boost low enough other than the throttle pedal to keep from stretching the tty bolts.

 

[WarWagon]

As the 6.2 is one step above a Olds diesel hand grenade and a 6.5 is just a punched out 6.2... Head studs are a good idea on even a stock engine. In context the factory turbo runs around 14 PSI (it chokes above that making more boost by heat alone) of boost on a DS4. DB2's were 6 PSI. HG life on a stock 6.5 is average 200K with TTY bolts factored in. Not bad really. You appear to have newer TTY bolts in it now...

Unless you go nuts on fueling (tune) you are not going to be much over 15-18 PSI with the ATT. Well even going nuts the DS4 runs out of fuel and you don't get much over 18 PSI... Keep in mind this is with very low backpressure. So head studs are not required as the ATT is not only in the factory turbo boost range, but, in it with a lot less backpressure on the exhaust side. Don't make a special project for 'just head studs'. However if you are there (heads off): there isn't any reason to use TTY bolts again.

If you use a different turbo that hits 24 PSI...

 

[royunion]

I will watch this thread. I was thinking all the things Deere65 is until I got a decent reliable Sure Cure Lift Pump on mine, to keep 9 psi at the IP like the Stanadyne spec says - and fixed vacuum leaks and put on a new stronger vacuum pump so the waste gate would work properly. It was a night and day engine at that one change.

Then there is the aspect of crappy low cetane fuel, and religious use of a decent additive - and use of decent initial cetane fuel like Chevron changed the thing into running like a 400 c.i. gas motor with boost at even initial low speed take off from a light with no mods as a stock motor.

I barely have to touch the accelerator.

I do have an "F" motor and not the "S"; however today's diesel fuel blend is made to burn cooler and thus has less heat and velocity to spin a turbo - so I will watch to see if more boost really does anything

I bi-fuel (fumigate) mine on the highway with true pure Hydrogen made on the fly (not HHO) and can do CNG - or a Hydrogen - CNG mix; and that made way more performance and mileage difference - even with a stock turbo than can mechanically changing parts - except the lift pump as previously said.

And my EGT's do not go much above 600 degrees F with my additive in it - and with straight pump diesel they barely get over 500 and almost no boost either. So fuel is junk out of the pump - at least where I am. Completely stock I get about 3 to 5 psi boost and poor performance and with additive - I get above 5 to 7 psi and it runs smooth and quiet )little diesel rattle as there is little ignition delay.

A stock 6.5 engine is not meant to go over 10 psi in a factory config or the ECM /PCM will step in and open the waste gate anyway and should throw and over boost error code.

You cannot get performance out of low BTU content and low Cetane fuel - as the ignition delay will just always be there - no matter what. It does not light fast enough to give power when you wanted it.

The first thing I would do if I were Deere65 is check the actual inlet lift pump pressures at the IP when actually driving. This would mean installing usually an electronic fuel pressure sensor just before the IP and an electronic readout gauge of some type in the cab.

If it does not have OVER 5 psi at all times to the IP inlet - more like better off 9 psi at idle or WOT - then that is a performance problem no turbo size will fix. The IP simply cannot perform with low or not inlet pressure under 5 psi by how it is designed by Stanadyne

Having spent quite a bit of time at a work bench rebuilding the Stanadyne IP's and seeing the reasons they need rebuilding and testing them on a test bench - low inlet fuel pressure is always the culprit at the IP is its demise and it needs it for the fuel oil to act as immersion lubrication and cooling the IP and PMD on the side by the re-circulation of fuel back to the tank is what makes the system work properly and the injectors inject strongly and evenly. Anything else results in a dog of an engine lots of people try to band aid with mods and slow death to the IP.

While one can mod a mechanical DB2 IP engine - and not suffer retribution from the engine - the DS4 is not as forgiving because of how the PCM / ECU is going to react depending on the year of the engine and programming code the ECM has.

For instance to remove the waste gate solenoid from the DS4's circuit is known to cause the KOKO timing procedure to no longer work - and there is a list that goes on and on and on for other mods. Admittedly the OBDl engines (93-95) are different than the OBDll engines (96-02) and ECM's but that is why I will watch and see what happens here

 

[WarWagon]

@royunion Welcome!

Night and day of running properly literally goes to "Another Planet" when you swap out for a turbo that will pull hard all the way to redline vs. fight the engine.

 

[Will L.]

@royunion another welcome to the forum. Love to bear others sing the song of fuel preyat the ip. SO MASSIVE an impact, I say it is the most important gauge missing on the dash. Way more than boost, egt, etc. i value it over the voltmeter wether ds4 or a db pump. Between that and a clear ip return line, a person is buying life for the ip and engine.

Although it sounds like you are a proponent of keeping the pmd on the pump (which I disagree) the proper fuel flow helps there too if a person chooses that route. Unfortunately we saw too many pmd failures from heatsoak after the engine is off in the fleets.

 

[Deere65]

Yes welcome @royunion. I have heard over and over that the gm turbo has a choke hold on this engine and after reading warwagons provided link in this thread along with other threads related to this subject I firmly believe it and that is why I am here asking for more info.

I feel that I have gone through this truck thoroughly to make sure I am getting the most out of the stock configuration before I move on to trying to unlock what it is capable of. I am able to maintain 7 psi to the injection pump under hard acceleration. I have completed the ftb mod to make sure it is getting the flow. The injection pump is new as are the injectors. I don’t have a permanent gauge in the cab but I do test fuel pressure regularly as I don’t want to have to purchase another pump if I can help it.

I have had the keep my vac pump in place (which is another load on the engine that’s not needed) to keep the non existent egr system thinking it working along with the solenoids. I do have the turbo master set to peak at 11 psi which does help as the stock programming seems to want to cut boost when I need it. The solenoid is still there to once again keep the pcm happy. Now I have no idea what the pcm does when it try’s to run egr but if it’s anything like the engines I work on it does it under certain loads and reduces the amount of fuel entering the cylinder to lean the mixture which increases combustion temp to help reburn the recirculated gas so I’m sure I’m losing power because of that. So I kind of have multiple reasons I’m interested in changing the turbo because doing so really requires new programming which can eliminate a lot of unwanted systems that my truck possess.

I do agree with you that most of the fuel is crap and the proper additives should be used to make the fuel worthy of being used by our beloved trucks. Some of the worst fuel I see is off road although we are safe from using for the legal reasons. I have had a lot of customers stop using off road fuel because it has trashed the entire fuel system only to have the green stuff do the same thing to them and at absolutely no fault of theirs.

Take a look at warwagons link a few post up. It a good comparison of the differences in the stock turbo vs the a-team turbo