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Holset HE 351 6.5 Potential?

Sand

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Thread starter #1
I just picked this up (for Free!) And was considering it for my 6.5 TD.
Im definitely foido a turbo update and likely a 4" exhaust in my Hummer. And a intercooler is coming into play.

My question is - what is this turbo in relation to the HX 35 snd HX 40?
I like free! Im opening it up tomorrow. EWha should I measure inside? Im new to turbos in detail. The outside of the intake is stamped 14mm.
Sand
 

FellowTraveler

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#2
I just picked this up (for Free!) And was considering it for my 6.5 TD.
Im definitely foido a turbo update and likely a 4" exhaust in my Hummer. And a intercooler is coming into play.

My question is - what is this turbo in relation to the HX 35 snd HX 40?
I like free! Im opening it up tomorrow. EWha should I measure inside? Im new to turbos in detail. The outside of the intake is stamped 14mm.
Sand
If it is stamped 14 on the inside of the turbine housing then it is a 14cm2 and far better than the stock HE351CW 9cm2 used on Ram Cummins @ 325 HP level or the GM8 9cm2, as other specs go search the part number and HE351.....general rule of thumb is that a very large CAC/IC is needed to cool down the air charge produced by any Holset turbo that has a 9cm2 turbine......
 

Sand

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Thread starter #4
Nice to hear. Mine is the pressure pod actuated wastegate that is looped to the charge side. Ill see if it looks like I could vacuum actuate it. I have a DS4 and like how my Leroy Supertune controls boost.
The variable vane is amazing. I've been watching them. There are a few stand alone controllers out there. The one I like the *least* you have you send back and pay for every adjustment you want.
20180325_193016.jpg
 

THEFERMANATOR

FRANKENBURBAN
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You say you have a hummer? Good luck fitting the turbo in there if that's what you have. To date, I don't think anybody has successfully done any turbo upgrades to one other than what is available for the gm-x series of turbos. The hummer uses a completely different turbo arrangement from the pickups, and is going to be a challenge to fit a different turbo into.
 

Will L.

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#7
There has been a few hummers done with other turbos. The s300/s400 fits, but requires a body lift over the gm turbo.

There were some done with the banks sidewinder. One hx40w11 iirc done as a sidemount that required some drastic changes.

If you are willing to push the turbo into the cabin more than the gm turbo is, and do some custom oil feed$ drain then a bigger turbo like the 351 could fit.

Obviously a new doghouse cover is needed, not sure about the interior piece staying original.
Mine got destroyed by the thief ripping out the lockbox inplace of the glovebox, so it is gone anyway.

I am way convinced the ATT is a perfect turbo for a hummer. Pickups don’t have the crazy gearing we do that can spool a big turbo much easier. And the few pickups that I know of that run 2800-3000 rpm sustained did amazing.

I am as far from a “turbo guy” as one can get. No clue how close the ATT and the HE 351 compare.
Can anyone explain the differences?
 

THEFERMANATOR

FRANKENBURBAN
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I should have been more specific, last I heard nobody had found an easy bolt in turbo replacement. I suggested on a facebook post that maybe somebody should look into possibly adapting the duramax turbo base in as a way upgrading the hummer/humvees turbo. It's readily available to keep costs down, and is available in t3 and t4 flanges. If one could adapt the 6.5's center mount up pipes to one of those bases, it may make the swap feasible. I could have sworn that Leroy at 1 time said he was looking into a base to adapt the att to a hummer, wonder if anything came of it.
 

Sand

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Im sitting on a tig welder and have a CNC mill and lathe in play. Its definitely not bolt in.
Im more concerned with viability of the turbo itself as opposed to fitting it. I pulled it mostly apart to measure the turbine wheels today. Getting the center section away from the cast Iron exhaust side is proving difficult. I pulled off the V band but the two sections are really stuck....its soaking in ATF overnight.
 

WarWagon

Well it hits on 7 of 8...
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#10
Im sitting on a tig welder and have a CNC mill and lathe in play. Its definitely not bolt in.
Im more concerned with viability of the turbo itself as opposed to fitting it. I pulled it mostly apart to measure the turbine wheels today. Getting the center section away from the cast Iron exhaust side is proving difficult. I pulled off the V band but the two sections are really stuck....its soaking in ATF overnight.
Make a kit. Seriously it will sell and will sell for some serious cash. Locate the turbo anywhere it will fit including behind the engine under the frame. Before and after 1/4 mile runs would sell it.

IMO that's still an awful small turbo for a pig heavy H1. An improvement I suggest one should look at is a ball bearing turbo because they spool up at a lower RPM for the same size due to 3-4 less shaft HP in bearing friction loss.

ATT, HX40II, GM3 Asthma Attack:

largemedsmall.jpg

You don't need a complicated variable turbo: just wind the damned "high speed diesel" up with a large turbo and leave it above 2000 RPM. Want to lug a diesel? Get a long stroke Cummins or a 180 RPM boat engine out of a shipping barge. With a heavy Hummer H1 you really need a large turbo for power and one that will get out of the way for cruise. This would be a low backpressure type that doesn't have a wastegate because again you are over it's 2000 RPM spool up.

Spool valves are a cheat to get variable type turbo performance, but the Yank stall I put in will walk all over that setup. The Spool valve keeps heat in the engine to the point of engine oil failure. Does the engine at any point from a standing stop stay under 2000 RPM? If so replace the weak OEM converter and stall it higher. Oldsmobile did this with the gutless 5.7 Diesel. So high converter stalling a under powered diesel is true "Old School". Locking the converter for high MPG cruise is the best of both worlds as my MPG hasn't changed with a high stall. The engine smokes less as it isn't lugging up to the turbo light off RPM.

Keep the boost low enough and forget the complexity and additional cost of an intercooler. Lack of backpressure is as important if not more important than the actual boost number.
 

Twisted Steel Performance

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#11
If the motor was at high rpms from a stand still maybe a big turbo would work. But that isn't the case is it, a vgt with a top of the line controller would serve better. Going from a 9cm to 22cm turbine as conditions required just seems better in my mind. But my mind is somewhat out of the box.
 

FellowTraveler

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#12
Aside the GM/IHI series turbos 9cm2 is most commonly used on Ram Cummin's applications and requires a CAC/IC to cool the air-charge when cranking the boost. Commonly those early turbo GM/CUMMIN'S diesels were de-fuled while GM/IHI used 9 cm2 the Cummin's was running 18 & 20+ cm2 w/o CAC/IC.....in the industrial world big turbine housings were common as were low rpm diesel's.

Bank's has done perhaps the most turbo/CAC/IC development on the 6.5td HMMWV....

Keep in mind that because a turbo may be identified as an HX40 or a TDO7 there are many configurations of those turbo's available w/different compressors/turbines and a wide spread of stock & after market parts and turbine housing options "in all cases for a DD you need to drive at peak torque output for best results."

SEE: http://www.myholsetturbo.com/images/holsetpartnumbers_2008.pdf
 

WarWagon

Well it hits on 7 of 8...
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#13
If the motor was at high rpms from a stand still maybe a big turbo would work. But that isn't the case is it, a vgt with a top of the line controller would serve better. Going from a 9cm to 22cm turbine as conditions required just seems better in my mind. But my mind is somewhat out of the box.
Absolutely this is completely "out of the box". No wrong answers. Merely suggestions as to what can be done and what I have done.

Offroad you may not want to rev it up all the time. Complexity vs. simple. The controller will have to be dunk proof for extreme offroading. Both methods are used today with constant velocity transmissions and complex turbo's that deliver power the entire engine RPM range.

Again I encourage *someone* to make a H1 turbo kit.

Personally I believe the entire RPM range of a 6.2 / 6.5 under 2000 RPM is wasted. Sure it's for economy and all, but, a 3/4 ton and H1 isn't exactly about economy. I have been disappointed in the RPM where the GM3 works in all but a unloaded DD configuration. Even then the gearing at freeway speeds generated a wasted 6 PSI of boost off engine airflow alone without the fuel on: May as well have a power robbing belt drive SC on the thing. The Spool Valve still didn't bring it to life like I had hoped. Getting the engine to a power band *now* is more fun.

Here is high RPMs from a standstill with the Yank. Even with a 6.2 IP I feel it would out run a DS4 with a spool valve because *lag* waiting for the lower stall DS4 engine to get up to speed and light everything in it's power band. If I brake stand and punch it the engine jumps to 2000+ RPM and then there is a delay as the turbo lights off followed by the rear tires lighting off.


So cost is something to look at and why not combine things. IMO a better TCC clutch than OEM is not a bad idea. Yank is $1100 plus labor to get there. Spool Valve is $800+. Variable turbo and controller? But what works best at any reasonable cost is what one should offer. After all it's between a all out Cummins conversion and stock. Me being frugal with performance stuff vs. all out.
 
Last edited:

Will L.

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#14
Depending about type of offroading that is done, the stall can effect control at slow speeds. Best teaching of hummer off road is described as a fat ballerina. It’s ability to tip toe is amazingly useful, so I wouldn’t be willing to give that up. I also focus on being able to submerge the entire engine compartment in water.

But not all, hell, almost none of other hummer owners think the way I do or enjoy theirs the same way.

VVT if controlled proper will always outperform a counterpart. $ is the question.

I’ve done a little bit of reading and it seems the he351 can be heavily modified into an ok turbo. Even when done though still lacking for a 6.5L, especially higher rpm.

If you want to build up for a bigger turbo,option 1. sell that one and do the large housing 35/40 hybrid or go ATT. Even, An hx40 if you run the freeway a lot.
2. Build it leaving room to upgrade it to a larger turbo still. I don’t think you would loose any performance compared to GM choke monster. But your gains will be limited.
 

Will L.

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#16
Just what i was reading on it from a few forums of people that did comparisons from swaps. I am definitely not the guy on turbos. From what I read the 351 is a smaller housing than the 40 and held more backpressure than most hx35 even.

All that is pushing me toward ATT on hummers had been pickups and suburbans with it, and seeing the ones loaded to similar weight or heavier and seeing thre gearing differences of otherwise identical trucks- then guestimating from there.
 

Sand

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Thread starter #17
Im still in the game but my 4L80e just started acting up....
No codes. Works fine cold. When warm looses OD, then third. Then starts slipping in first and second...
Fluid is fresh one year ago. 100 000 miles.
Dipstick is showing fluid. Strangely there is loads of rust at the top of the dipstick....thats new since I last checked it but its been a really wet damp winter.
Ill start a new thread after work. If I make it home....lol
 

Twisted Steel Performance

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#20
The one sand is using may have a smaller hsw, the vgt's are a different animal, the he351ve weights a little over 40lbs, it's twice the size of the one he posted pics of, the vgt part & controller will provide anywhere from a 9cm to a 22cm size hsw.

The blades however are the same, in essence I can make my turbine what ever size I need whenever I need to all by turning a knob on the controller, the controller uses 5 censors that allow it to be as oem would be ...

Yes it's not a perfect turbo for every situation but me thinks it will be close for what I need...
 
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