Why not to go with smaller than 16cm housings

[sparks57]

Why???



I have noticed that most people say that on first gens we shouldn't use anything smaller than a 16cm housing. Why is this?



I'm sure some people here use smaller housings very succesfully, but why do people say smaller housings are a no-no for our trucks?





PS: My truck is hauling some seriouse tail, I stomped a 2000 Power Joke, a v-8 Chevy, and a 2001 Dodge 24v all in the last 24 hours.



They thought they should get cocky with me just because I had an old truck... taught them a lesson.



I was surprized I got that 24ver.

 

[dpuckett]

CB,

COngrats on the smokings. I have to shift my old Gutbag too slow into 3rd to keep up with the autos everyone round here runs. But if I do a 3rd gear start, I can keep up ok.



I think the reason everyone disses the <16 housings is due to a lack of airflow out of the engine in stock trim (no porting). I did ok with a 12 and a set of 3. 54s, but I wouldnt recommend it for a set of 4. 10s and serious hauling. At 65mph, I NEVER run less than 10 psi on the flat empty. Going into a headwind, I can make 20 easily, just to keep speed. i think a WG 14 may be a good compromise, if the 16 isnt fast enough for you; just make sure to hook it up. Most of the mechanical stuff has some sort of trade off. After porting the manifold and housing, my turbo spools QUICK. Now I need to mutilate the AFC pin. : I have a choice between superfast takeoff + smoke, or just fast take off + slight haze. Hmmmm... ... decisions, decisions.



Daniel

 

[CAROLINA CUMMINS]

I haven't heard that you shouldn't use smaller than a 16cm, just that things get a little warm when your towing. My 16 works pretty good, but I think that It needs a PDR Hx35 to go with it.



I think if I race much, the ol Getrag is gonna go. Good excuse for a Nv4500



Steve

 

[cerberusiam]

You can go with a smaller housing but you tend to limit the use of the truck. Drag racing and draggin' a load tend to effect different parts of the rpm range. The hot side of the turbo is a good deal like the exhaust system, the expansion of the hot gasses is what drives the turbo so at some point there is a diminishing return to how much fuel and air you can add before the drive pressures on the exhaust side start balancing the boost pressures. The closer together the higher the EGT's and the potential damage to the engine. Since our trucks are mechanical we don't have a computer to overide the engine killing conditions that could come about so the 16 is a good tradeoff for spool up and towing. The 18. 5 would even be better if you were doing a lot of towing cuz you could put more fuel thru it without the EGT problem. What we need is a VGT turbo to really make things usable. Cummins uses them on their bigger engines and they are used in a lot of gas applications also so I do not see why they would not work just fine on our engines. The new PS and/or Duramax (I forget which) is using one to help make the engines more responsive and pass emissions.



Lessee, when I have a couple of grand that is just sitting around I will start that project.





Yeah, like that is going to happen in this economy.

 

[Bob Beauchaine]

C B

I have run a waste-gated 14cm2 for close to 10 years not and it seems to produce enough power to get me to 353. 7 RWHP. Future plans do not call for a different hot side unless I see a need for a change. I like the relative lack of turbo lag and when towing my current combination does quite well.



Bob

 

[JMorrow]

I have a 12 and a set of 3. 54s on my truck and tow a 29 foot Holiday Rambler and I have had no ill effects. I love the instant spool-up.



John

 

[Doug Czaja]

12cm / Getrag / 3.07 ?

So, is anybody running a 12cm / Getrag / 3. 07 combination? If so how do you like it? I have been considering this for a while, but haven't seen anybody experimenting with this combo.



Wonder how it would work, I don't tow much any more. Maybe 5k lb five or six times a year.



Doug

 

[Greenleaf]

16 'cause I may pull sumten sometime... . also with the pump mods I'm verrrrry happy with the spool-up and I WANT lot-o-lots of smoke if I call upon it.



Resale too. The truck is more diversified with the 16 than say a 14/12 housing. Somebody else my want to tow with it when I sell it in 30+ years. The engine should be broken in by then



Greenleaf; I have a 1st gen addiction ..... and I admit it.

 

[Mgrant]

I went from a 16 to a gated 12 on my truck and I'm very happy with the setup. I don't drag race or stretch the rubberband beyond the stock governor, but I do tow very heavy loads up steep secondary roads in the woods. With the added low end torque given by the 12 over the 16, there is no need to wind it tight. The first thing I noticed was the instantanous boost and power, which is nice for gear changes, with much less smoke. The second thing I noticed was lower EGTs at peak torque ~1500-2000 rpm. The third thing I noticed is the engine oil stayed much cleaner for a lot longer between oil changes. I did loose a little on the very top end, but after hooking up adjusting the wastegate and adjust for 25 psi, I doubt that I can feel much difference up there when compared to the 16.



I feel with stock or PW injectors, the 12cm is great. With PODs and higher RPMs, 16 or larger is the only way to go. I prefer to tune my CTD for low end torque rather than high RPM horsepower. But for high RPM horsepower, I'm a fan RB 440 with B1s and tunnel ram. That'll make a V8 Chev look awfully sick!

 

[Mgrant]

I went from a 16 to a gated 12 on my truck and I'm very happy with the setup. I don't drag race or stretch the rubberband beyond the stock governor, but I do tow very heavy loads up steep secondary roads in the woods. With the added low end torque given by the 12 over the 16, there is no need to wind it tight. The first thing I noticed was the instantanous boost and power, which is nice for gear changes, with much less smoke. The second thing I noticed was lower EGTs at peak torque ~1500-2000 rpm. The third thing I noticed is the engine oil stayed much cleaner for a lot longer between oil changes. I did loose a little on the very top end, but after hooking up adjusting the wastegate and adjust for 25 psi, I doubt that I can feel much difference up there when compared to the 16.



I feel with stock or PW injectors, the 12cm is great. With PODs and higher RPMs, 16 or larger is the only way to go. I prefer to tune my CTD for low end torque rather than high RPM horsepower. But for high RPM horsepower, I'm a fan RB 440 with B1s and tunnel ram. That'll make a V8 Chev look awfully sick!