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Discussion Starter · #1 ·
Has anyone tried an hx35 on a 4bd1t? I am running an hx30 now but feel I hit a wall with my 30% over injectors,colt cam,maxed out injection pump, and air dog fuel pump...
 

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An HX30 with a HX35 would be good, especially with your mods. An HX35 by itself wouldn’t be. You’re missing two litres. What size HX30 do you have?
 

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As a single it's far too big.

Have you dyno'd your engine or bench tested your pump to see what fuel you've currently got?
 

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Discussion Starter · #4 ·
No I have done neither.. I maxed the fuel screw, removed the boost limiter rod, and screw in the rack bolt on the front of the pump.. boost 28 to 30 psi and around 1200 or a little over when I am in it fairly hard.That is factory timing setting. I think it is fairly cool from what it had been and taking it is pushing a full size suburban along.When I advanced the pump the egt goes down around 100. Advancing the timing does wonders for egt I found. You dont have as much low end but gain it up top.. Right now I have the timing at factory.intercooler is very big.. Any thoughts?
 

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I think if you look back through the early threads, you’ll see guys experimenting and having bigger turbos like that and some bigger housing H1C’s, HY35’s etc and they had lots of lag, lots of smoke, and high temps. You’ll end up with that with the HX35. That was before all the work that some did on here to find the turbos that are suited to this engine.

If you already have an HX35, can you go duals? That engine bay is decent size.
 

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No I have done neither.. I maxed the fuel screw, removed the boost limiter rod, and screw in the rack bolt on the front of the pump.. boost 28 to 30 psi and around 1200 or a little over when I am in it fairly hard.That is factory timing setting. I think it is fairly cool from what it had been and taking it is pushing a full size suburban along.When I advanced the pump the egt goes down around 100. Advancing the timing does wonders for egt I found. You dont have as much low end but gain it up top.. Right now I have the timing at factory.intercooler is very big.. Any thoughts?
Doesn't sound like the turbo is holding you up at all. If it was you'd see boost fall and EGT climb really sharply as rpm rises.
 

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Discussion Starter · #8 ·
Well I just unhooked the wastegate and it is better. Has anyone tried the hx30 super on a 4bd1t?
 

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Well I just unhooked the wastegate and it is better. Has anyone tried the hx30 super on a 4bd1t?
Yes people have fitted the HX30 Super to a 4BD1T. Not sure if they are current members here though. It's a good match.
You need the wastegate working for good performance. Excess boost can create a lot of drive pressure and suck a lot of power up top.
 

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He has it tuned conservatively. He pushes about 25psi, but I think he had it up in the 30’s and brought it back down.

This thread may help figure out which one you have...

 

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Discussion Starter · #13 ·
I just talked to Benzforce. He sells Holset turbos. He says the new he250 turbo is a nice upgrade from the hx30. It has a 47mm compressor and 10cm exhaust housing and a t3 flange,with new design and better wheels. He says it’s fairly new with not a lot of reviews yet. He told me I could be a guinea Pig and give him some feed back for a 6 month trial and if I don’t like it he will switch it out.I originally reach out to him for an hx30 super which he carries .
 

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I bet Dougal will chime in, he’ll know a lot more. But 10cm is a pretty big housing. You’ll prob get worse lag. 6cm is what most end up running. Those that ran a 7cm tdo4hl over a 6cm noticed quite a difference in performance, not for the better.
 

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I just talked to Benzforce. He sells Holset turbos. He says the new he250 turbo is a nice upgrade from the hx30. It has a 47mm compressor and 10cm exhaust housing and a t3 flange,with new design and better wheels. He says it’s fairly new with not a lot of reviews yet. He told me I could be a guinea Pig and give him some feed back for a 6 month trial and if I don’t like it he will switch it out.I originally reach out to him for an hx30 super which he carries .
I've not heard of that one before. What is this turbo factory fitted to? 10cm is a huge housing.

I found it. It's for a Cummins BSIII which is a 6BT used by Tata and Dong Feng until 2017. Only 130hp: Tata Motors City Bus Starbus 54,57 seater BS III features

We don't have enough cubes to spool that. Better than an HX35 for low end but not enough for our usage.

BSIV is the Indian emissions reg which replaced that in 2017.
 

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Discussion Starter · #16 ·
I have an exhaust back pressure gauge I plan to hook up and see just what is going on. Will be in touch.
 
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