Turbo Thread links - aka choosing a turbo

[Will L.]

My intent is to link together the most useful turbo threads for people trying to determine turbo comparisons into one thread rather for reference. Kind of a turbo sub thread in the performance section. If you come across any comparison threads you feel relevant, please add the link.

A picture request is made - attach any you open as full size pic instead of thumbnail whenever possible even if you post it separately as we have lost many pics through the years in updates and many small images get where they can’t be opened later.

 

[Will L.]

This link is to the HX40ii kit @racedaymechanic created.

HX40II Turbo Install

Im gonna throw a few pics out here to show what I have had to do to make this happen, The first is the downpipe, I wanted to make this a clean install and this is the most difficult part, it not only has to go from 2 1/2 inch to 3 inch it is also off center, I have about 2 hours into the...

www.thetruckstop.us

His kit works well with the cko as well as authentic hx40. I never owned one but seen one in use. Any current input on how long these turbos lived, regrets of the cko vs authentic or happy to have saved the $ and rebuild-ability would be great info from folks.

There is discussion of this HX40

 

[Will L.]

The last link a comparison of ATT to HX40ii was spoken of but not shown.
Here is @WarWagon doing a dyno comparison of the two.

ATT run vs. HX40II

Statistically the power output on the 1986 6.2 Military engine is the same for both turbo's. There is bragging rights if I was selling an air filter. Except one turbo wins torque while the other wins HP. Yet, the numbers are so close - less than 5% there isn't a clear power winner IMO. Driving...

www.thetruckstop.us

If my friend from Az still has these files in his computer- a request to repost the dyno numbers in a modern pic at full image please at the end of your thread please.

With the ATT- I’m not sure who currently (if anyone) is still selling it. Still a very serious contender of a choice imo. Years ago I spoke to Dennis aka @Slim Shady about using my Hummer as the test mule for fitting the ATT but it never happened due to my chaos in life. Hummers/hmmwvs are incredibly tight fitting. As centermount a custom dog house would be required, possibly using the banks sidewinder exhaust manifold could work as its in use on a couple hummers with hx35 turbos I have seen. With respect to that, I haven’t found threads on that in hummers yet but the results in hummers is similar to pickups- just account for the 37” tires and the 5:13 gear final ratio. Do the math on the pickup threads found for comparison. If someone knows of a goof thread on hx35 options, please post the links faster than I can.

Back on ATT - I am still hung up on wanting to add an external waste gate as an option because offroading there are times you want to force boost for torque — think butterfly valve in the pipe st the turbo to narrow flow like a twin scroll vs open one. When open it would allow the normal non wastegate operation of the turbo there by negating any argued low rpm side affects of the turbo. Controlling it magically makes it become a variable turbo… so not the easy diy project. My uses of it would be crude therefore a choke cable could do it for me in the rare instances I would use it.
I absolutely love the free flowing, minimal heat inducing activity of this turbo. Hummers/ hmmwvs are far worse for fighting heat than square bodies or gmt400. So the ability to outperform the gm6&7 center of turbos and reduce the iat would be a massive win for hiway use. The same tunes in pickups works in hummers.

Any db2/db4 thread links with ATT would be awesome if you see any.

 

[Will L.]

No link but side note for centermount - myself and several others have often thought a t4 twin scroll centermount very similar to the ATT would have been the ideal stock turbo for the 6.5. Magically finding it- well we didn’t have searchable data bases that might exist now.

 

[Rockabillyrat]

BW s300SX-E 62/74 was my choice. I went with a twin scroll .83 A/R T4 Gated turbine housing that will have a fully divided 2" hot side. I really think the S300 is a great turbo option for these. Could even go with a smaller s354.

 

[dbrannon79]

Something that might also be of good info is a comparison on them for the different use cases. for the casual every day driver vs the towing or hauling. something that points out which ones spool up at lower rpms and higher.

for myself, I like to hear the spooling but have no need for one in the towing or hauling section. My only reason for not trying to get into anything larger than the factory GMx. it's funny how I can't hear the turbo on my 95 with the 4" exhaust, but I can with the 93 which is all stock exhaust.

 

[Will L.]

Here is an old, long one from yonder site.

Turbo upgrade

www.dieselplace.com

 

[dbrannon79]

I also read somewhere that supposedly turbo blankets also help their performance aside from insulating them for things around them in the power barn.

 

[Will L.]

BW s300SX-E 62/74 was my choice. I went with a twin scroll .83 A/R T4 Gated turbine housing that will have a fully divided 2" hot side. I really think the S300 is a great turbo option for these. Could even go with a smaller s354.

If you can elaborate on this please. I understand basics of turbos, and see details like t4, twin, etc but rather than my 2c on them - I prefer your explanation and experience with it for my better understanding as well as others.
Draw backs besides physical size (request for dimensions of it) like gmx fits easier.

More or less compatibility with db pumps, stick vs auto, etc. obviously the ds4 having tune-ability helps when you can get them tuned just right. Db- not an option so we play with androids (puff limiter). I know you (like me) run db pumps -
So what fueling range limits do you see with this turbo- smoke before spooling, only supporting up to Xcc of fuel/ power.

 

[Rockabillyrat]

Either pump can be tuned to handle similar turbos. The DB2 just takes more work to limit the lower end fueling and still have enough in the upper end. The aneroid can help with that. Stick vs auto I would normally run a small turbine housing on a stick since you have to spool it every gear change.

The way I see it the 6.5 makes 3-3.5 hp per 1cc of fuel. A 110cc (at peak hp) pump should be good for 350hpish. You need to find the right turbo that supports your HP goals and match the turbine housing to you application and rpm range. You want to keep the turbo in its efficiency zone.

For me my HP goal is 400hp, I calculated the CFM of air and CC of fuel needed to reach my goal. The sx362 fits what I'm trying to do. BW has compressor maps that are helpful. The turbine housing you have to figure out on you own. I'm running a NV4500 so i when with the smallest T4 twin scroll i could find. Keeping it divided should help it spool, and I'm running stock heads. No need to port these heads in my opinion. Air velocity is more important that volume to a certain point. our heads can support 400hp NA. no need to open them up.

 

[WarWagon]

ATT, CKO HX40II, and something off a 4 banger ... oh wait that's a GM3 Asthma Attack turbo.




I believe the ATT kit isn't made anymore. The Mitsubishi TD-07 turbo and knock-offs without mods to fit a 6.5TD still is.

It was a hellva stigma to break "use a better bigger turbo" Neither the ATT or the HX40II would leave the line like the GM3. However once the engine chokes it's way past 2000 RPM it would run the GM3 down and then run it over. Esp loaded. The ATT once lit would pull hard till redline. The HX40II was building more backpressure and using higher boost numbers for the same power. The MPG loaded towing was MISERABLE SINGLE DIGITS (7MPG) with the GM3 loaded towing grades and couldn't maintain the speed limit or 20 under. The ATT turbo put me into double digit 10.4 MPG towing at the speed limit.

Don't forget being like 1 of 2 (Well at least the 2nd to have done it) that put a spool valve on this engine with an ATT.







And the first crazy SOB to put a Yank behind a 6.5TD to overcome the ATT big turbo no boost below 2000 RPM. I get a phone call about that once in a blue moon.



On a budget I would do a big turbo and a Yank stall converter skipping the spool valve. Today there are better turbo choices available than around 2013.

Don't forget the discontinued Peninsular Engines towing turbo. Said to be a Schwitzer s300 series turbo.

Peninsular Engines towing turbo?

Looks like something I have under the hood... Anyone know anything about it? As many times as I have been to their site I have not run across it before. Peninsular Engines » Vehicles » 6.5L Diesel Truck/Motorhome » Turbos and Exhuast System T6500751 Turbo, Truck with Welded Elbow...

www.thetruckstop.us

(DB2 small plunger 6.2L pump.) Dyno run with a DB2 and the ATT.

1993 DB2 Dyno run with ATT

1993 DB2 Dyno run with ATT, 108 degrees Fahrenheit out. The fan running made a difference with some runs having the same peak back to back numbers. This was a 'sane' run with the smoke completely clearing and EGT at 1000 MAX. Room to turn up the fuel. Boost was 14-15 PSI. It will generate more...

www.thetruckstop.us

Videos including what member 6.5L did with a spool valve.

ATT videos

Someone was saying there wasn't enough ATT video's so I decided to upload some. Because I had that kind of free time yesterday, and because any excuse to drive my truck and make videos is worth it. So here ya go. The first one is a 0-80mph run with max fueling. Don't mind the shaky camera, it...

www.thetruckstop.us

After throwing a Yank behind a 1993 DB2 with an ATT. This was a 6.2/6.5L hybrid 6.2L longblock small precups and all including a 6.2L small DB2. More fuel and bigger precups would have made a big difference. Fun as it was with minimal smoke.