Engine/Transmission (1994 - 1998) Which is better - turbine housing ?

[Matthug]

For some reason I cannot find it, my friend Denny (denviola on turbododge.com) did the test but I did a search for all threads started by him and it wasn't there. Here's a few links for feedback-

http://www.turbododge.com/forums/showthread.php?t=74870&highlight=ported+manifold

http://www.turbododge.com/forums/showthread.php?t=79585&highlight=moparzrule+ported+manifold

http://www.turbododge.com/forums/showthread.php?t=78669&highlight=moparzrule+ported+manifold

http://www.turbododge.com/forums/showthread.php?t=81624&highlight=moparzrule+ported+manifold

 

[Matthug]

Well I got it on the other day, it's quite less than satisfactory. I have about 2 PSI more boost while doing 65 MPH, not much improvement maybe 50 degrees EGT reduction. Top end seems to be all there though, so I guess thats a plus. The other downside is that for some reason it spools slower than the 16 housing. With the 16 it would light at 1500 RPMs and now it's 1600 with the ported 12. I think I should have just ported the wastegate and port matched the housing and left it alone there. Should not have ground out the divider. I'm thinking about sliding my AFC housing back a little, because it seems like the engine is just flogging out now when I floor it at low RPM's. Anybody else have these issues with a ported 12 housing?

 

[moparguy]

I didn't have any negative issues with mine. However I drilled through the divider, did not remove it and just did a port match with small bit of porting.

 

[pwerwagn]

I didnt have any spool issues with mine. All I have done is grind the divider out about an inch or so, havent even port matched it yet. Are you sure the wasteagate is closed all the way? Maybe its bleeding off some pressure at lower rpm...

Maybe the little bit of extra volume from porting it made the difference??

 

[Matthug]

No the wastegate is shut, the boost was set to 30 PSI when I first put it on but I cranked it up to 37 PSI. I think the extra volume did hurt, because I completely port matched it which took about 3/8'' of material off of both sides and 1/8'' off the top and bottom each. I had enough metal to fill my palm twice after I was done with everything including cutting out the divider. But this turbine housing was on my truck before, and I used the soot as a guide to show me how much the housing was necking down at the outlet of the manifold. Personally I believe my truck pulls better up top now, but that is obviously a seat of the pants feeling and is not 100% accurate I'm aware of that. But that sure would explain the loss in the low end. Like I said in my post before it seems like it's getting flogged out at low RPM WOT so I may try backing up my afc housing a tad. I have the smoke screw in the whole way and AFC housing full forward so it really dumps the fuel at initial WOT.

 

[PKirby]

My take is a bit different from Wes'. I ran a 16 for a few years, never really liked the slow spool when pulling a load (backhoe, loaded horse or hay trailer) and trying to start off on a hill.



A few months ago I gasket matched the 12cm housing, porting back a 1" or so into the housing. I then drilled the divider out to 1 1/16". I found a 1. 25" exhaust valve out of a junkyard engine to replace the stock wastegate valve.



Last I tightend (shortened) the waste gate adj. rod a bit.



Now I have better spool, boost doesn't exceed 35lbs. (with the 16 would hit 45+) and egt's are down 100+ degs. Still can go above 1250, but it's much slower.



I'd recommend the above, takes a bit of time, but no cash and if it dosen't work try something else.



Good luck, RR

I don't have much experience building turbos and I have an HX35 that I am going to modify and replace the WH1C that is on my truck so I have a question.



Wouldn't drilling the wastegate and installing a larger valve lower the boost instead of building it more, unless the port job would completely overpower the stock wastegate at high rpms?

 

[pwerwagn]

I don't have much experience building turbos and I have an HX35 that I am going to modify and replace the WH1C that is on my truck so I have a question.



Wouldn't drilling the wastegate and installing a larger valve lower the boost instead of building it more, unless the port job would completely overpower the stock wastegate at high rpms?

I actually just replaced a H1C/18. 5 wiht a HX35/16 monday night for a friend. nice difference in spool.

Drilling the wastegate and installing a larger valve will allow the wastegate to vent excess pressure better. If you set up the wastegate right (ideally with a hobbs switch. . ), the wastegate will make absolutely no difference in spool up, or max boost. It just has the ability to vent boost off easier.

Look at it this way: My truck has waaaay to much fuel for a 12cm WG housing. Even if I set the wastegate to open at 30psi, it will make 35 or so just because the wastegate isnt large enough to vent that much volume. But if it were larger, I would have more control over it, thus reducing drive pressure. And increasing power if setup right.



hope that sheds a little light on it...



Matt,

I have a few 12cm's. I will port another kinda like your and replace my other 12 and see how much diff I notice.





--Jeff

 

[moparguy]

PK, what PW said. The problem with these little 35s is building too much boost. At one time I was running near 50lbs when pulling a load on a big hill if I just stayed in it. Not good.



My goal was better flow through the exhaust housing and the ability to dump more of the hot gasses while keeping boost in the most efficient range, (32 to 35lbs max).



It's working so far.



My guess is that Matt has actually increased the volume of his 12 to something greater than a 16. Hense the slower spool, but better top end.

 

[PKirby]

I have never seen my WH1C get over 18psi even with a boost elbow. I am thinking about installing a larger wheel and housing on the fresh air side on the HX35. I will probably have to use the exhaust housing from my WH1C on the HX35 because it is different on my non-Dodge engine.

 

[pwerwagn]

If you only have enough fuel to make 18psi with the H1C, I dont think you need to upgrade to the bigger wheel. I will probably not make enough difference to be noticeable.

when you are up in the mid 30's for boost #'s, then its benificial to change wheels.



--Jeff