Hx35

[McGivern]

Hello everyone,

I ran across a deal on an HX35. I'm wondering if any first gen guys have upgraded from their H1C to an HX35. The main benefit looks like getting the waste gate for quicker spool-up. I'd like to hear anybody's opinion. Also, does anyone know if the intercooler on the 2nd gens is any larger?

Mark

 

[R.E. Miller]

McGivern,

I am going to try to help you out here as best I can. The HX-35 does have differences like the way the compressor housing attaches to the bearing housing, and other small variations. All things considered, the HX-35 that is built to the newer dodges specs is almost identical in performance characteristics to the WH-1C.



NOW, before I get flamed for not spewing all of the details, the next topic... . wastegates. If the HX-35 that you are looking at came off a say 1994 dodge, then it probably had the 12cm^2 exhaust housing that has a wastegate on it. Note: individual models of turbos can be configured in numerous ways. This is where the "Hot Rodding" begins here with turbos and the first gens. On your existing WH-1C, you could switch from the large 18-21. 5cm^2 exhaust housing to a smaller housing like the 16cm^2, 14cm^2, 14cm^2 wastegated, or the 12cm^2 wastegated... . and I am sure there are even others. The idea here is by reducing the volume of the turbo housing, and still pushing the same relative amount of exhaust gases through it, you will "spool" the turbo up quicker, and will make your diesel accelerate quicker



Now for the wastegate, it is along the lines of a headgasket, a fuse, and a tuning device. For example, say you change from the 18cm^2 housing to the 12cm^2 housing, and your fueling stays the same (that is a whole different issue. ) Not only will your turbo lag be less, you will actually be able to spin the turbo faster>>>=more boost on tap. Well, that really for all purposes does increase HP as much as many think, and actually induces more stress on the internals of your engine for a nominal HP gain. That is the beauty of a wastegate, you can adjust it so that once a certian boost pressure is reached, the wastegate will open bleeding off exhaust gas thus reducing the speed of the turbo, and the amount of boost that it can produce. Now you have the same HP, at less boost, with less stress on the engine .



There are however many other things that people are "tinkering" with here, and in the diesel performance arena. Like the PDR HX-35... . it is an aception to the rules above, because above I have talked mainly about the results of changing the exhaust housing. The PDR HX-35 has a modified compressor wheel and housing which again benifits many of the same things, but in a different way. One point that I am trying to make here is that if your WH-1C is in good shape, and you are not planning to modify the compressor housing, you can make affordable modifications to your existing turbo, that will be great, and if you go out and buy a HX-35 that is stock, and do the same modifications, you have just spent more money.



Finally, I am not totally sure, but I think that the second gen intercoolers are larger then ours, and I also think that one of the first genners here has adapted one on our style trucks, but I can't remember. I know that this was long winded, and may not be totally complete, so let me know if I can help you out, and I hope that sheds some light on this topic for you.



Russell

 

[McGivern]

Russel,

I think you answered my questions well. I do have a non-gate 16cm on the truck now, and the turbo is on good shape. Therefore, unless I can get the whole HX35 for the price of a waste gated exhaust housing (the HX35 is gated), then I'll pass it up. I checked with a friend, and the overall width and height of the old/newer intercoolers are the same, so I think us first geners could make one work. If I can get it and install it, I'll let you know.

Mark

 

[Lil' Dog]

The second gen intercoolers are about twice the size of the first gens and has 3. 5" inlet/outlets as opposed to our 3". The turbo outlet on the HX is 3. 5 I think on the compressor side as well.



I think your conclusion is good, no benefit really realized by switching unless there are alot of other mods in store. .



J-eh

 

[Paul Herioux]

HX35W and 2nd gen cooler

I have both of these on my 89 and like it. If you have A/C the second gen cooler won't fit without using it as a grill . It does spool up very fast, to the point of making winter driving a little exciting at my current fueling levels. The other issue with the 35 is that in its stock outlet position the elbow won't clear the frame rail on the first gen. I had to clock mine up to about the 10 o'clock position for clearance putting the pipe to the cooler about 1/2" off of the inner splash shield and tight against the air inlet hose. I would not do this to a three speed equipped truck as this is not a good setup for a high rpm application. If I leave the OD off the truck seems to run out of breath at about 60 mph. OD on I can run it till I'm to scared to hold on anymore .