I have had my truck about two years now. 91 3/4 ton 2wd, getrag, 3.54, 203,000. I have seen a lot of referance to the 16cm exhaust housing. Is this the best do-it-all size? Why is it so popular? What sizes were factory for our trucks? Are the housings marked for size anywhere? I assume the number refers to the internal volume of the turbine housing? Is this a good, bang for the buck mod? Looking for inexpensive upgrades that I can do myself. Only thing done to the truck so far is straight pipe exhaust into dual 5 inch stacks. I love the feeling when passing a victom in 5th gear, but I am sure it can be improved upon. I have lots of experience with gas, but haven't touched a diesel.

 

Basically the small the turbine the quicker the spool up. But before you go to a small housing its recomended to turn your pump up a bit, youll need gagues when you do this. I believe yours is a 21cm housing, but it might even be a 18.5 you can look its on the housing. as for cheap mods ive got the 16cm housing (160) 3200 rpm spring, (20), Htt stage 3 (230) everything else ive dont is free mods, like turing up the fuel, grinding the fuel pin. BTW is yours intercooled? Im sure the wiser first geners will post here before to long.

 

Yes, my truck has the factory intercooler. The previous owner said he had a local diesel guru work the pump. I think it smokes a little more than a stocker.

 

The housing is marked on the bottom firewall side towards the exhaust manifold. With an extendable mirror and flashlight you maybe able to read it, if its not all rusty and such. I think its just a money maker for vendors the 16cm housing. I am not a fan of it. I didn't feel the difference or should I say $150 worth from going from the stock 18.5 to the 16. You have a 18.5cm. 21cm's are found on 92's. I suggest taking that $150 and putting it towards a hx35 turbo or HTT vendor upgrade/hybrid as FTD did. Then run it with your 18.5cm exhaust housing.

 

Yea i forgot to mention if you do upgrade or even get a new turbo, i would keep your stock housing, otherwise youll build a lot of boost pretty quick and bad things will happen. Speaking from experience, course i dont kno how you drive but i got a heavy foot.

 

I believe the 16 CM housing is the best all around housing. I tryed a 14 and it worked good till I started making lots of power than it was to restrictive. I ended up with a Hytech turbo hybrid. and I still use the 16CM with that turbo. I have seen 44 PSI boost out of this combo and it spools nicely. Last 16cm housing i bought was $140 delivered to my door. Both my 92s have the 16cm housing.
From 21 to a 16 is a nice change, I never went from an 18.5 to a 16 so I cant tell you how much difference it would make.

 

Personally I dont care for the non-wastegated housings, with them the only way to adjust your boost level is to change housing sizes. Not the best if you plan on turning up the fuel later on down the road. Im not sure how much power youre looking for, but If you plan to keep it somewhat mild I would recomend a 12cm wastegated housing. You will have lightning fast spoolup and be able to adjust your boost to any number you want, via the wastegate. Your best bet would probably be to upgrade to an HX-35 from a 12valve, as it is a better turbo and has a 12cm wastegated housing. Look in the classifieds.

 

The measurement refers to the area the exhaust has to flow through at the turbine. A 16 cm housing has 16 a square cm opening around the turbine. The smaller the number, the less area there is for exhaust to flow. This causes higher velocity flow, which spins the turbine faster.

Housing selection really depends on what the truck is used for. A truck with a stock motor that's used a lot in town will really wake up with a 12 cm, but the same housing will choke a turned up truck very badly on the top end. Tell us how you use your truck and we can make recommendations from there. The 16 cm is a nice "do it all" housing. The 21 cm housing makes a good doorstop, but that's about all. The 18.5 is very useful in some situations, though.

 

Hey Dave, kind of a related thought...you had a 16 for a while then switched to the 14 w/g, right? Was it because a 14 with the w/g open will flow more than the 16, or is there something I'm missing? I'm trying to decide which way to go when I get my HTT housing. Ok, hijack over

 

I couldn't keep the boost low enough without a wastegate . I saw 50 psi on water/meth, and that was before I ground the foot off the AFC lever. More timing might have gotten it low enough, but I doubt it.

 

Thanks for all the great responses. This is my nice truck, I have a beater S-10 to drive to work. I get the dodge out on weekends when its nice. Not looking to make a race truck out of it and would like to keep factory turbo for now. Maybe I should have asked the question this way. If you had, let's say $500 to spend on improvements, what would you spend it on? I saw that a lot of people had the 16cm housing, so I thought that might be a good place to start. The first thing I need to invest in is some gauges.

 

I just read a thread about the 3200 governer spring. That sounds like a good mod with no negatives. Right when my truck starts pulling hard, then its time to shift, seems like it runs out of rpm's really fast, through 3rd gear.

 

with 500 dollars i would get some guages, then do some of the free mods to the pump (fuel screw, star wheel, fuel pin grinding and turning). then 3200 spring(wish i would have done mine sooner).while you are in there its a good idea to grind the afc lever. if it is not strait piped i would do that(cooler egts and soudns good). then probally a 16cm housing. i dont beleive that even adds up to 500. guages are first but other than that the order is pretty much up to you. if you do all of that your truck would move, it would have a good amount of power and be pretty quick.

 

peyton, i just bought my second truck.. a 5-speed with 4.10 gears and i agree, i run out of rpm REALLY fast. i plan on putting the spring in both trucks when i build the confidence to got into the pump! when i put gauges in my truck is ran $373 for pyro, boost, and tach along with the dual a-pillar pod... all made by autometer
2-5/8" tach part # 2888
2" boost part # 2617
2" pyro part # 2654
Dual gauge pod # 15198 (specific to 86-93 dodge ram)

there are pics of my setup in my gallery.

EDIT: pyro is the only one you really NEED if you are gonna mess with fuel, but i like to know all that is going on in the truck.

 

If you have the 21 cm housing, ditch it ASAP! That thing is the reason why you run out of RPM as soon as it starts pulling - it's because it takes dang near forever to spool up.

IHpower is pointing you in the right direction. Do your homework before you grind the AFC lever, though. That mod is free, but it's not for everyone.