HX35 Installed - Lost 6# Max Boost

[KEENO]

Hey First Gen Brothers... ...



I've been away from the forum for awhile and thought I would drop in w/ a question.



I installed a used, low mileage HX35 on the Old Girl yesterday in place of the slowly fading H1C. All went well and the installation was straight forward w/ just the compressor having to be 'clocked' for our application.



Question: I lost 6# of Max Boost w/ the installation of the HX35. I went from 32# max w/ the old H1C and only see 26# from the HX35. Does this parallel what others have noticed that have installed a HX35 on a First Gen?



I've been told by Lawrence at Diesel Dynamics that this is actually a desirable condition and that it's due to the HX35 being more efficient over the H1C. The truck has great power and more of an 'electric' feel during spool up. I'm running the 12cm3 from my H1C on the HX35 and initially thought I would see a gain in boost of 1# or 2#'s.



Any thoughts from those that have made this swap?



TIA... ... . Tim "KEENO" Keen

 

[formula]

Did you go from a non-wastegated turbine housing to a wastegated one? If so, that easily explains the loss of max boost due to the wastegate opening. FWIW, when I installed my HX35, using the same turbine housing as the H1C, I did not loose any boost. Think it went up about 1psi or so.



Sean

 

[KEENO]

Thanks Sean... ...



It's a wastegate eliminated 12cm3 that I knurled/plugged & welded up. It's a great housing on a First Gen...



It's the same exact housing I was using on the H1C... . I just swapped it over to the HX35.



The used turbo seems fine, I just wasn't expecting to loose boost.



KEENO

 

[dpuckett]

KEENO-



Double check your connections, esp where the impellar housing flange conntect to the elbow- you have to get it perfectly, and may have to tap on it with a hammer to get it to seat right. WHen I did the 21 to 18 hsg swap on Mom's I noticed a lot more noise; more than should have come from an 18 with near stock fuelling. I checked, and the elbow had not seated as well as I had previously thought. Couple bumps with a hammer, and all was as it should be. Now, had she had guages on her truck (rebuilt pump and injectors, but no pyro or boost after 3 yrs ), one of us would have noticed it right away.



And... . what are your EGTs like? If your EGTs dropped, then that is a good thing. I would still venture to guess that you have a loose connection, or the HX wasnt in as good a shape as you thought.



Daniel

 

[CDegner]

Keep in mind that I installed a PDR HX-35 but when I did my install using the same 16cm2 housing, I went from 22# boost to 29# with no other changes. Spoolup is much quicker. My boost needle literally jumps for 8 to 20 psi in the blink of an eye when I get on it.



To me, it sounds like a coupl epotential problems:

1) Did not get the housing reseated after clocking,

2) leak in the o-ring on the outlet of the housing, or

3) Your boots are not sealing up correctly.



I concur with Daniel ... check your connections.



Carl

 

[KEENO]

Thanks for the tips guys!



I'll check a few things as soon as it stops raining... ... .



Carl:



When you say: "1) Did not get the housing reseated after clocking"



Are you speaking of the compressor side to the exhaust housing or the actual compressor rotation around the cartridge (Impeller assembly) & Backing plate?



I had to squeeze the huge snap ring (on the back of the Compressor Housing) w/ a pair of Channel Locks and rotate the compressor housing around the Impeller Assembly. The Compressor Housing had to be rotated from approx. the 11:00 position down to the 7:00 position with the turbo asm. attached to the exh. manifold. What seals the Compressor Housing to Backing plate that holds the huge snap ring. Could I of tore an O-ring or something?



I'll also check my connections once again... ... .



Thanks... ... KEENO

 

[KEENO]

I rechecked all of my connections and re-seated the Compressor Housing to the Backing plate. I had fun getting the large snap ring back into place.



Will drive soon & report back to I found my lost boost!



Thanks..... KEENO