Engine/Transmission (1994 - 1998) pros and cons of the hx40...

[STripp]

Hello again fellow TDR bombers... :-laf

I have the opportunity to get an HX-40 from an 8. 3 liter CTD for cheap. ( read FREE!!!) The catch is it needs to be rebuilt, which I can do no problem. The question is what benefits/tradeoffs am I going to experience from the stock HX-35? Also, obviously the exhaust housing will not fit my manifold, but can I get an adapter / new housing to make it fit? I am really looking for more boost. My stock 35 is getting approximately 30 to 35psi, but from what I understand that is about max. I want more boost without sacrificing depedability.



let's hear it from the gurus...

 

[WDimig]

stock hx-40

the stock hx-40 had the same size shaft as the hx-35's do. the hx-40 uses a larger compressor wheel, which creates more rotating mass, and at higher boost pressures, if the turbo is barked, has been known to snap the shaft, due to the larger compressor wheel. from what ive read, pdr hx40s are modified and significantly more reliable than stock hx-40's. it up to you. if you can get it free, go for it and rebuild the cartridge.



wes

 

[fox]

A bigger turbo won't give you more boost. It takes more fuel to get more boost. The benefit of the bigger turbo will be cooler air, and more of it.

you will see slower spool-up with the bigger turbo. And a little more top end charge.

 

[Cooker]

There are quite a few HX40 exhaust housings that will bolt directly to the stock manifold.



All other things being constant, you will have less boost with the HX40 but as stated you will have cooler, denser air, at a lower drive pressure and therefore more HP.



The PDR HX40 has the same shaft as a stock unit but it is zero balanced with better bearings.

 

[STripp]

HX-40 follow-up

I should have mentioned, I installed a TST#11 recently and have a lot of adjustment left on it to get more fueling, I just haven't done so because my EGT readings are approximately 1200 to 1300 deg @ 35psi which is (from what I understand) full boost for my stocker HX-35. The plate is in the stock position with light gray smoke under full throttle. Good power, but definitely not all that this plate has. My stocker transmission and converter are protesting, but still hanging in there. (I take it pretty easy on it. ) If I had to guess I'd say I am sitting at around 240hp and around 650-700ftlbs tq. Anybody with experience with this setup I'd like to hear from you.

 

[Bob4x4]

I think you may be a bit optimistic on your power estimate and wouldn't step up to a 40 untill at about 350hp.



Bob

 

[bmoeller]

I think you may be a bit optimistic on your power estimate

Hate to burst your bubble, but I'm with Bob. You have the smaller 160hp pump. Chart from Piers- http://piersdiesel.com/CamPlate.htm

wouldn't step up to a 40 untill at about 350hp.

Yep. even if it was PDR modifed HX-40, I think you'd regret it. At this point, I would just put a 14 or 16 housing on your current turbo, assuming it is in good shape. Will bring the EGTs down some, and still allow you ro slide the plate later if you want. The boost will come down some, but it will be breatheing easier.

 

[Forrest]

I should have mentioned, I installed a TST#11 recently and have a lot of adjustment left on it to get more fueling, I just haven't done so because my EGT readings are approximately 1200 to 1300 deg @ 35psi which is (from what I understand) full boost for my stocker HX-35. The plate is in the stock position with light gray smoke under full throttle. Good power, but definitely not all that this plate has. My stocker transmission and converter are protesting, but still hanging in there. (I take it pretty easy on it. ) If I had to guess I'd say I am sitting at around 240hp and around 650-700ftlbs tq. Anybody with experience with this setup I'd like to hear from you.

I had that setup. I put in a stock HX40-16 & EGT dropped significantly.

I ran that turbo for at least 5 years. It dropped max boost to the upper 20's & EGT down around 1000 from 1500. It spooled slower, of course, but not objectionable. Spooling started @ 1700rpm with the #11 slid 3/4 forward.



Finally sent it up to PDR for rebuilding, didn't need it, into the PDR40. On top of all the other tweaks PDR does, it's set up as the top turbo for twins. Oo.



My stock 40 had the 16cm wastegated exhaust housing. Hopefully, the one you have a lead on has that housing.





Forrest

 

[JPittinger]

STripp- Get rid of the drop in K&N... I mothballed my drop in afe for a BHAF and WOT EGT's dropped 250 degrees when climbing hills. I don't have a heat shield, so it picks up a little underhood temp when idling, but once you get moving I think there's plenty of fresh air.