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More boost ?s

O

Orange Bomber

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So I finally ditched the supercharger and got a HX40wII turbo on my truck, and man what a difference. But I got a couple questions now.

With a banks or 6.5 set up, what rpm does the turbo spool at?
At what rpm do you guys see max boost at?
And is between 700 and 800 egt normal for cruising 65-70 in 5th gear?

Thanks. I'm just kinda curious how the hx40wII preforms compared to a turbo that's supposed to be put on a 6.2.
 
Curious as well, any pictures? any issues with plumbing the exhaust? How is the low end with the hx40?
 
The down pipe was a piece of cake and the cross over pipe took a bit of work to get made but all in all not that bad to do. I'll take some pics and get them up tonight.

As far as low end, that's one thing I'm a little iffy on. My turbo doesn't spool till 1900 rpm, but it takes off from there pretty good. It feels a bit faster down low but that may be because I haven't driven it in such a long time.

Up top this thing scoots, during a test run to see what the turbo would do, with just the fuel turned up a 1/4 turn I pushed 16lbs with egts never above 900. Then I took the silencer ring out and ran it again and I got 18lbs about same egts.

So that being said if I turned up my fuel screw more, would the turbo spool faster? It seems like I want the boost to come on sooner than it does.
 
Fuel, exhaust size, gearing/ tire size there are a whole bunch of factors. do you have a stock pump and injectors? my Gm8 turbo showed about 3pounds of boost at idle.
 
HX40 is a pretty big turbo for that engine. Holset hx40s is about a 60mm compressor inducer. I'm not surprised is laggy down low. that being said 1900 light isn't too terrible.

To answer a couple of your questions, The more fuel you put to it the sooner it will light. And the more boost you can make. There is no peak rpm for max boost. Turbochargers on diesels are demand devices. based on throttle input and engine load. so there can never be an RPM for max boost. as its constantly variable. You will only ever see maximum boost at full throttle and full load IE the governor is giving full fuel. Then the turbo can make potentially all the boost is can possibly make. Up to the wastegate setting or max output ungated.

Where is your EGT probe drilled? Is it wastegated? is the gate disabled? what size is the turbine housing?
 
Its actually an hx40wII, I've read that its a size between the hx35 and a true 40. The specs from the manufacturer, not sure what much of it means though.
Compressor: 8blades
Ind 2.36"
Ext 3.27"
Trim 54.8
Turbine: 12 blade
Ind 2.99
Ext 2.52

My egt probe is drilled a couple inches below where the turbo attaches to the manifold. The waste gate is hooked up but set to open at 20lbs. Here are some pics of my set up.

DSCN2331.jpg

DSCN2332.jpg
 
Ya bubba, 2.36" is 60mm. That is an hx40 no matter what variant it is. The 8 blade compressor wheel is a newer design.

So is the probe pre turbo or post turbo is what I'm curious about. I don't follow your description.
 
The probe is pre turbo, sorry about the bad description.
Man I almost got the hx35 instead of the 40 but I read a bunch of stuff saying the hx35 was going to be to small for the 6.2.

Any thoughts on egts in fifth? I dunno if 700-800 seems a bit high? If I add much more throttle to get past cruising rpm, the egts just go up from there.
 
7 or 800 degrees at cruising speed isn't terrible. But what psi is that at cruising speed at that temperature? If its around 6-9 psi I think that's right in the ballpark of average. Operating temperature is just fine in the 1250-1400* range, you just don't want to sustain temps there or over. that's just my professional opinion.

I'm not sure how an hx35 would be too small for a 6.2. I'm sure its bigger than or at the very least equal to that gm8 or whatever guys are usually using off the 6.5.

IMO its not the displacment of the engine that's most important in sizing a turbo for a diesel, but the volume of fuel injected per cycle.
 
I don't think I'm pushing that much boost at cruising speed. I think I'm somewhere between 3-5 maybe. I always thought that you didn't want to get your egts past 1100*?

I'm new to the turbo game, so I did a bunch of reading on the diesel page and found a bunch of them trying out the hx40 and the hx40wII with good results. Quite a few people asked about the hx35 and the general thought was that it'd be on the small side for the 6.2 especially if you wanted to tow much. They had a bunch of reasons why they thought it was going to be to small but at the moment I can't remember exactly what they were. It is from what I remember a bit bigger than the gm8 turbo but not by a huge amount.
 
I just bought a hx35. I am hoping it will be fine. Most guys with the gm8 say up top (above 2300ish) it starts to become a restriction and the hx35 won't. I saw lots of guys running hx40ii and hx40s so I think they all work it just depends on the amount of boost lag. I think with my manual and low gears the 35 maybe a little small but right now I am N/a so it has to make a difference. Thanks for posting the pics I wondered how it would sit with the banks manifold.
 
After playing with the hx40wII, I think the hx35 should be a pretty good fit. When you get it on, you should defiantly post up your results, I'd be really interested to see how it does.
I'm going to try turn up my injection pump a bit and see what happens, hopefully I can get boost more quickly. I don't really like revving my motor as high as I did to get the 16-18lbs.
 
I will most likely limit my boost to 12ish but I hope it will work well. Mine actually governs out at 4000 but I think towing that high might be pushing it.
 
Been thinking about that a little. Just seems really backwards to upgrade to a big turbo, crank the fuel up, then try to neuter the crap out of it by wastegating it down to 8 or 12 or 15 psi or whatever it'll be.

Seems like a colossal waste of time money and effort.
 
DEMON44 said:
Been thinking about that a little. Just seems really backwards to upgrade to a big turbo, crank the fuel up, then try to neuter the crap out of it by wastegating it down to 8 or 12 or 15 psi or whatever it'll be.

Seems like a colossal waste of time money and effort.
Click to expand...

You know it could be. These engines are n/a engines converted to turbo charged. The won't handle alot of boost and the banks kits were only 8-10 on the high end. I was hoping for boost by 1500 and to hold the boost till 3800 or so. It has to be better than what I have now and honestly I am not sure what else I should be doing to get more power and keep the mpg. A cummins swap would be alot more and I would have to OD it to be useable.
 
1500 is pretty low and 3800 is pretty high for full boost. but a hx35 should lite up by then and do what you need. depending on the turbine housing size its got. theres 5 or 6 different sizes floating around.

I know 6.2s are N/A stock. thats doesn't really matter. all the turbo is doing is increasing thermal efficiency of the engine.

Oh right, couple other things IMO, over drive and lockup converter should be a given. its 2012, get with the times.
 
My converter locks up fine every time my foot lifts off the pedal.
 
80' 427 said:
My converter locks up fine every time my foot lifts off the pedal.
Click to expand...

I know.you have a.stick. I'm saying in general, not.you specificly.

So, I'll rephrase. IMHO, A lockup converter ......Or a clutch....... and an overdrive. Should be part of any diesel program, before that person breathes the words economy or mileage. Or the battle has already been lost.
 
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Ok so I will agree. I don't have the money for a OD yet. I like the 465 so it will have a ranger or a GV someday. For now it will get a turbo to help it some. I am only afraid to push the boost from what others have said about the limits of the engine (plus it is 30 years old). 10-12 lbs of boost will make a difference and mine may get more at some point. From what I understand the specific HX35 I have will push well above 20lbs of boost. I think it will work good even boost limited because of 2 reasons. The Banks turbo is wastegateless so it just builds boost as you gain rpms which can make the bottomend soggy. The "best" gm turbo tends to build boost at a lower rpm but then stall out and just create high EGTs. The HX35 seems to "light" at a low enough rpm but not create a restriction up top. I am not looking for crazy power but like I said if it would make 250hp and 450lbs or torque I would be happy. It is just a old pile of crap truck, I am not looking for modern diesel power just better than what I have. On the farm where I only drive around at 40-50 mph it actually does great on mpg getting 18+.
 
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