cheap turbo upgrade

[ENafziger]

I think we're saying the same thing. Opening the WG drops DP. Opening the waste gate reduces boost (obviously, because DP dropped). Opening the waste gate lowers turbine speed (obviously, because DP dropped).

To control DP you need to match the turbine flow to the existing exhuast flow. You can control DP by also matching instead of opening the WG.

Are you referring to port matching the exhaust manifold T3 flange and the turbine inlet?

If you are, sure, that helps flow some, but I don't think that eliminates the need for a WG.

You don't really need to open up the WG port as the stock port will limit boost and DP just fine when it opens.

Maybe I'm looking at things wrong, but I disagree with this too. On a 3rd gen at 350 - 375 rear-wheel hp, it's easy to push the HE351 out of it's efficiency range. Even with the WG working as intended! This little turbo can (and often is) oversped to the point that it's operating at horrible efficiency (1. 4:1 or worse drive:boost) and making 45+ psi of boost! ... and it does this with a waste gate that is designed to limit boost to around 35 psi!

As you know, the 3rd gens are more tolerant of inefficient air, and can handle higher boost and hotter temperatures than 1st gens by design. Thus, unless you are studded and/or fire ringed and/or willing to take the risk of hot 45 psi+ boost with your 1st gen, it is beneficial to open up the waste gate port to allow boost to truly be controlled to the desired setpoint.

 

[cerberusiam]

On a 3rd gen at 350 - 375 rear-wheel hp, it's easy to push the HE351 out of it's efficiency range. Even with the WG working as intended!

Nope, that is not going to happen on a 3rd gen either. Once the WG opens boost and DP are dropping right along with power. It doesn't really matter how large the WG port is the effect is the same, given fueling is in a manageable realm for the turbo.



Now, if you override the stock programming the EGT's go nuts about then also where with the stock controls, the truck just noses over and finds a new balance.



I think your trying to attribute too many functions to what a WG is and actually does. The WG only function is too control turbine speed on a small housing, nothing else. If the WG opens it is working as intended, irregardless of the port size becuase at even 450-500 hp the stock port size is way more than adequate to provide turbine speed control.



Trying to use or attribute DP control to the WG is self defeating. Routing exhaust flow away from the trubine is going to limit the speed and ultimately the boost as the primary reaction. Yes, DP will drop but it is a secondary effect by adding additional flow capacity. Ultimately, DP need sto be controlled by turbine and housing design, not WG operation.



While it is entirely possible to spin the HE351's over 40 psi, thats simply using it way outside its design parameters with massive fueling, or, way too much leverage. Any turbo, even a Silver 66 can be made to do that but its not a normal condition.



At 300-350 HP in a 1st gen with timing bumped and in a higher gear its hard to push these turbos much beyond 38-40 psi. The DP gets high enough at that point it starts limiting the spool capability so boost just slows down.



What you were talking about originally, opening the WG port up to control DP, is what I am saying has no effect. When you start talking about DP and controlling it that is entirely a function of turbine cross sectional area and flow relationships. The WG has an entriely different operational use. You cannot partially open the WG to control anything becuase the turbo will just crash. The 3rd gen control system is 5 volt PWM signal that is opening and closing the WG in quick small increments to keep boost in an 8-10 psi range.



DP and EGT's in 3rd gen are something that doesn't exist in the 1st gens in normal use. The 3rd event and retarded timing of a CR artificially create these conditions for emissions reasons. When you remove these drivers DP is quite good for a cheap production run turbo, around 1:1. 1 to 1:1. 2 for the most part. DP really only starts getting wild under heavy throttle and 3rd event activation that is literally creating combustion event in the exhaust manifold.



When you get to that point with 1st gen you are so far beyond the operational range of an HE351 its not even open to discussion.

 

[ENafziger]

DP and EGT's in 3rd gen are something that doesn't exist in the 1st gens in normal use. The 3rd event and retarded timing of a CR artificially create these conditions for emissions reasons. When you remove these drivers DP is quite good for a cheap production run turbo, around 1:1. 1 to 1:1. 2 for the most part. DP really only starts getting wild under heavy throttle and 3rd event activation that is literally creating combustion event in the exhaust manifold

I'm not trying to argue, but I simply don't think this is right... at least from what I've seen. Have you seen OEM fueling maps for the 3rd gens? From everything I've seen, the post injection event disappears at high load and high rpm... but yet this is exactly where high DP occurs! It becomes more a factor of burn rate and heat release at high engine speed... and even with a first gen single shot injection system with timing advanced, the burn duration is huge. On my brother's mildly modded 1st gen with PODs, there is a constant flame out the hood stack at more than 3/4 throttle. Larger injectors, MUCH lower injection pressures, poorer atomization, etc of the 1st gen design simply do not allow combustion to occur as quickly in the 1st gen engines as it does on the commom rail ISBs.

Now, if you override the stock programming the EGT's go nuts about then also where with the stock controls,

This is true... and that's why I said a 3rd gen with 350 - 375 rear-wheel hp. That means they've bumped things up 75 hp from OEM with a programming change, etc. One of those people was me. EGTs get out of control quickly, and so does drive pressure. The WG design was to control boost to ~ 35 psi max. The WG can't do that anymore because it can't bypass enough exhaust energy around the turbine.

While it is entirely possible to spin the HE351's over 40 psi, thats simply using it way outside its design parameters with massive fueling, or, way too much leverage.

Yes!!! Exactly!!! But the truth is, it's not that hard to spin the HE351 past 40! I saw it myself... and the OEM wastegate could just not control boost to the 35 psi range!

It's a very common thing to need more waste gate capacity than is offered stock. On a good high hp twin setup, it's almost impossible to get by with just an internally gated charger... thus, the need for external wastegates! No waste gate is worst. OEM internal gate is better, a modified enlarged internal wastegate is even better, and an external gate is best!

You cannot partially open the WG to control anything becuase the turbo will just crash.

I know this is not true. Have you played around with a mechanical boost elbow? That's what I put on my HE351 on my '91. 5. I spent 30 minutes with a regulated air supply and the turbo on the bench. The wastegate doesn't just "pop" open. Rather, it's a gradual opening from 0 to about 60° over an 8 - 10 psi range! And the turbo doesn't just crash. Sure, it may not give the preciseness of an OEM designed PID controlled solenoid, but it actually works remarkably well for the simplicity of design.

My comment about enlarging the WG, was made to the original poster... who says he wants to add performance to his truck. Obviously, he has/will be adjusting the pump, fuel pin, etc and pushing more fuel than stock. Thus, I don't see a downside to enlarging the WG, and I do see benefit of doing so.

P. S. I definitely don't mean to argue for arguments sake, nor do I mean to come across as haughty or rude. I've learned alot from your past posts, and no doubt will continue to do so. I'm just discussing and learning.

--Eric

 

[TFaucette]

well, back to the original topic of a cheap turbo upgrade i got my hands on my buddy's hx35 off of his 01 6speed and i think that this would be a great upgrade but remember that the shaft is broken so i've seen a rebuild kit cheap on ebay and also a new compressor wheel for around 60$ and i guess i could use the stock h1c shaft and turbine wheel, so i would have a good hx35 for around 110$ right?

 

[cerberusiam]

I definitely don't mean to argue for arguments sake, nor do I mean to come across as haughty or rude.

No offense taken, none meant. Discussion forums are just that. Even if both of us walk away still believing what we started that is just fine. If I didn't think you were worth discussing things with I would never answer back. I have no time for trolls.

From everything I've seen, the post injection event disappears at high load and high rpm... but yet this is exactly where high DP occurs!

Stop and think about what you just said there. The 3rd event is gone but drive pressure is high. Given the 3rd event is a key part of the in-cylinder EGR, the EGR is designed to limit NOX emissions which are created in high load high temp scenarios, you have to ask yourself WHY would an event explicitly designed to limit emissions be absent in the very scenarios where it is needed?



Fueling map? Just find an actual fueling map that shows you the parameters involved in the injection timing, duration, and events overlayed with a MAP reading and load calculation created on a quality scope. You will get that about the same time you get a rpm map of the injection head pressures, case pressures, injector head pressures of a VE pump. When you go pry it out of Cummins engineerings hands is when you will get it. :-laf



Lets just say a Fluke and free revving an engine in the garage does not valid proof make, and leave it at that.

This is true... and that's why I said a 3rd gen with 350 - 375 rear-wheel hp. That means they've bumped things up 75 hp from OEM with a programming change, etc. One of those people was me. EGTs get out of control quickly, and so does drive pressure. The WG design was to control boost to ~ 35 psi max. The WG can't do that anymore because it can't bypass enough exhaust energy around the turbine.

I routinely hit 35-38 psi at 65-70% load with no EGT or DP problems. My truck will hammer out a 1000 ft\lbs TQ at 2100-220 rpms so it ain't short on the fuel. DP stays quite manageable at around 1:1. 2. thats is not too bad a trade off for the spool capabilities of this turbo. Try running your tests and doing your driving while staying under 2500 rpms. You will surprised at the results.



There are a couple things you forgot to factor in when comparing a CR to a 1st gen. Cam profile design makes a hug impact on the numbers you see. The CR emissions cams create an unnatural condition that is not present with a 6bt.



Tuning a boost elbow is a pain. Yes, I am well aware of the fun trying to find a setting that works well as I have not found it yet. Your tests on the WG are valid but they don't take into account the 45 psi of DP when that gate starts to open. Depending on your spring tension in the WG the turbo crashes under too high a load and barks like crazy. Under lighter loads boost just flattens and drops along with the power. I got mad and crimped the hose closed again and just control things with my right foot.



The other thing you need to consider is a single event has a massive spike in cylinder pressures early in the event then a sharp downward turn at the end. Feed it enough timing and your DP is way lower with way more fuel than a CR. Combustion event speed and spikes is the main reason to use multiple events in a diesel. You get more efficient use of the fuel plus a lot quieter engine in the process but stretching that burn time also carries much more of the pressure later into the cycle. Couple that with a cam profile that is designed to use it and DP is simply not an issue in a lot of cases.



As for the flame out the stack, thats pretty normal for any short exhaust diesel. doesn't mean you have combustion or excess fuel there. The transition into an oxygen rich environment will create the flame effect simply off the hot soot.



The need for an external or larger waste demonstrates exactly what I said, using the turbo way beyond its means. Its not that the turbo is not funtioning correctly but rather it is operating beyond its capacities. With the OP doing what he said to get some more perfromance he won't stress the turbo's capacity at all.

 

[cerberusiam]

i got my hands on my buddy's hx35 off of his 01 6speed and i think that this would be a great upgrade but remember that the shaft is broken so i've seen a rebuild kit cheap on ebay and also a new compressor wheel for around 60$ and i guess i could use the stock h1c shaft and turbine wheel, so i would have a good hx35 for around 110$ right?

If the compressor wheel is bad the compressor housing is messed up. If the H1C shaft would fit then it might work but you would need to keep the turbine wheel with the housing I think. It would be a slight upgrade but not much. Even a stock HX35 was anemic and needed a larger compressor to actually perform better.

 

[TFaucette]

If the compressor wheel is bad the compressor housing is messed up. If the H1C shaft would fit then it might work but you would need to keep the turbine wheel with the housing I think. It would be a slight upgrade but not much. Even a stock HX35 was anemic and needed a larger compressor to actually perform better.

then an hx35/40 hybrid by larger compressor? so the easiest way is to throw a 16cm housing on it, i just want it to spool quick without sacraficing egt's especially when towing . but from the shaft/turbine wheel i saw for sale was listed for both h1c and hx35, are you saying the turbine wheels are different?





Holset HX35 HX35W H1C Turbocharger Turbine Wheel & Shaft 3519336 | eBay



that is why i was thinking both the shaft and turbine wheel from the h1c could be used to repair the hx35

 

[cerberusiam]

that is why i was thinking both the shaft and turbine wheel from the h1c could be used to repair the hx35

Not positive as I never tried that exact thing. I thought there were differences in the turbine wheel across housing but maybe there aren't or they are minor.



The compressor side is where you will gain performance and that almost needs at least 1 58 mm wheel and housing change. The turbine side will give you the spool with its design. It is tough to beat the 12cm housings, or even the 9 cm on the HE351's as the single volute flows about the same as a 12 double volute.



Uou can spend lots of time and money on trubos.

 

[TFaucette]

i found this locally but trying to figure out anything about it, the tag is missing but there are some numbers that are on it and mabey some one would recognize it from the pics or description



Schwitzer Turbo (cummins)



the numbers i got are;

316952e

313830

100268sc1

and the said the compressor wheel is about 2. 25" which is about 57mm and that the exhaust wheel is about 2. 5" which is = 63. 5mm if anybody could tell me anything about where to find info on it that would be great

 

[TFaucette]

i guess the only way to know if it would be benefical is to just try it?

 

[cerberusiam]

i guess the only way to know if it would be benefical is to just try it?

Pretty much. Without knowing the exact model and specslit is tough to tell. Sometimes the only to know how it will work is try it.