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Replacement turbo options

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79 views 11 replies 6 participants last post by  Russ McLean  
#1 ·
I have a '90 4bt and my turbo started making an awful sound. I had a feeling it was next to go. So what are my options for replacement? I saw discussion about an upgrade to HX30 but there were additional things needed. What is the general thought? Is there an OE replacement? Do I need to swap it for the HX? This is my RV, not a hot rod. Thanks for any input on this.
 
#2 ·
I would bet that finding a replacement OEM turbo like the h1c would be a real PITA and quite costly compared to a hx30, using a hx30 in place of the OEM unit
with the same setup and more or less similar fueling should not affect things adversely. The hx30 has a smaller exhaust housing with a waste gate so your down pipe would move rearward about 1.5" and you will likely see boost a bit earlier and increased drivability, and I would expect your fueling and AFC settings to change some. I don't see any downside
to the change should you not find a OEM unit...$.02
 
#3 ·
I have a H1C you could have for $200. I also have a slightly smaller exhaust housing For slightly quicker spooling. It even has a ceramic coated exhaust housing. I want to say it cost over $200 just to get it coated.

After saying all that, I would tell you don’t buy it because the HX30W is so much better.
 
#4 ·
I assume you have the old H1C turbo. No waste gate. The HX30W came in 4 sizes. There is a 40mm, 42mm, 44mm, and 46mm. The 40mm was on commercial engines and tends to be rather expensive. The 42mm came in 2 versions. One had a 6cm2 turbine which came on the P pump 4bt. The other had a 12cm2 turbine which came on a low powered 6bt. You wouldn't want that one. The one most common in todays swaps is the 44mm. Has the 6cm2 turbine and does very good. It is only made in China but is a genuine Holset unit. The last is the 46mm Super HX30W. This one never came on a Cummins but is an excellent unit. Now, the first 3 units would be a direct replacement for you H1C. Same size intake, 3", same exhaust output, same exhaust manifold mount, and same oil line. The main difference will be the fact it is about 1.5" longer so some exhaust work may be needed. If you do not have one you will need an intercooler. That is a must. One difference in the 42mm and 44mm will be the air output connection. You will need an exhaust elbow which will feed the air system. Piping to the intercooler will be 2.5". Now the 46mm has some differences. Its air intake is 4", the exhaust output is the same as the others, exhaust manifold mount is also the same, the oil line is different, and the air outlet will use an elbow that is 3.0" instead of 2.5". It will also be a bit more expensive. Your old H1C likely has a boost output that dies off around 18-20 PSI. The HX30W can do a bit beyond 30 PSI. Of course, that means you have to turn up the fuel to get more boost and also adjust the boost control on the turbo. Boost on any of these will be almost instant compared to your old turbo. Here is what the 44mm HX30W will look like.
Image

And here is what the exhaust elbow looks like. If you need part numbers I can get them for you.
Image
 
#5 ·
So I would need to add an intercooler, too? There was another thread talking about a boost gauge and a pyrometer gauge as well.

I don't suppose there is a write up somewhere with a list of what's needed and where it might go.

I guess the idea of a bolt on swap was a dream.
 
#6 ·
So I would need to add an intercooler, too? There was another thread talking about a boost gauge and a pyrometer gauge as well.

I don't suppose there is a write up somewhere with a list of what's needed and where it might go.

I guess the idea of a bolt on swap was a dream.
If you do not need to increase the power output I doubt the intercooler would be required, without one you will not be able to utilize the full potential of the hx30
but I would think it would still be superior to the h1c. However a boost and EGT gauge will be required to tune it correctly and IMO just for peace of mind and the intercooler
is a worthy upgrade at any power level as it will increase the overall efficiency of your engine and if I were doing it I would do what was needed to add one.
 
#8 ·
I'm seeing H1C turbos from Fab Heavy for $300. Would it really be worth the effort to swap it? I'm not lacking in power or drivability.

I'm not against doing the work, but I'm trying to keep the costs down and it seems like adding an intercooler and additional gauges puts this over a grand easy.
 
#11 ·
I'm seeing H1C turbos from Fab Heavy for $300. Would it really be worth the effort to swap it? I'm not lacking in power or drivability.

I'm not against doing the work, but I'm trying to keep the costs down and it seems like adding an intercooler and additional gauges puts this over a grand easy.
It does by the time you figure it all in. I was fortunate enough to do my own aluminum work. My H1C was originally on my 4bt as a Skytrac engine rated at 100 to 110 hp. It was still working but it wasn’t putting out much over 6 to 7 lbs of boost. Pretty sure it could be rebuilt easy enough if it needed bearings, which I don’t think it did. Pay the postage and you can have it.
 
#9 ·
As long as you are happy with it as it is probably not worth it, however looking at the big picture should towing a car or trailer ever be something you could see yourself doing or should you move to a state where the speed limits are higher than where you are now then that could change things. In that case now would be the easiest and most cost effective time to do it, IMHO the intercooler is worth the time and coin as it will make your engine more efficient what ever the power level...$.02
 
#12 ·
Since I got the new lift pump, my top speed is 65-70 and to be honest, you don't want to go much faster than that in a big box. :D

View attachment 139358

I will price out what it looks like and see what my options are for placement of the intercooler. Thanks for the feedback, real world experience is key.
15years ago, I intercooled my Grumman van (aka The Twinkie Truck) and drove it for about a year.

This is my intercooler thread


The 4bt was swapped in a F150. And the Twinkie Truck is now a heavy duty storage shed.

Russ
 
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