Pro's and Con's of 12 cm turbine housing

[J DeMaio]

Hey Guys:



I'm wanting the pros and cons of the 12 cm turbine housing. Wirenut, KEENO, Matt S, and all others who have used this setup/are using this setup let me know how they work. What is the approximate horsepower and what kind of boost are you getting.



Is anyone out there running a 12 with stock injectors? What type of fueling enhancements are required? I was thinking of 1 1/2 turns on the full power screw providing my pyrometer reads low enough on the fuel rate.



Anyone know if 1994 and newer injectors will fit in our trucks?



Thanks,

John

 

[Forrest Nearing]

take this with a grain of salt as I'm FAR from a diesel guru... and FAR from a Cummins guru...



but... 1. I am under the impression that the later injectors aren't a direct swap... the Lucas marine injectors seem to be the ticket for the 1st gen engines...



and 2. you can swap in a turbine housing with no other changes... all it's going to to is bring in the boost quicker, and if your old housing was flat out HUGE for the amount of fuel you were giving the engine, it MAY increase the total boost level by a hair, but the main thing is that it's going to bring in the boost quicker



giving the thing more fuel will simply be a double whamy!



I have what could be considered NO experience with these engines, but based on my generaly automotive and turbo experience and my very limited experience with my truck, I'm gonna go out on a limb here and say that a smaller turbine housing will probably offer the most bang for the buck when it comes to drivability... sure, uncork the exhaust (cheap... just replace the muffler with a quality high-flow), tweak the pump (free), but your NEXT mod should be a turbine housing...



a smaller turbine housing is gonna REALLY wake up the part throttle on these babies and help get them moving off the line.



take care,



Forrest

 

[BushWakr - RIP]

I've read here that if you change to any housing other than the 16cm you'll have to adjust your down-pipe length about 1- 1 1/2".

I went from the stock 18. 5 cm housing down to the 16 and saw faster spool-up, about 2psi more boost and less smoke for same fueling. Next time I'd spend the extra and go for the 14cm. If you really Bomb the truck you may find the 12cm housing a little small at WOT top end according to those 'in the know'.



Regards, Bob

 

[Forrest Nearing]

absolutely... a small turbine housing will limit top end HP but you'll gain more oomph down low...



horsepower numbers look neat on paper, but it's all about area under the curve... in the real world, average HP beats peak HP any day...



if you can utilize the top end power, the bigger housing will be better, but for something that is driven around town, the lower end power will be more appreciated...



I'm going to be stock pump and stock injectors, and low RPM, so the smaller housing is just fine by me...



on one of our turbo gas drag cars, we dyno'd more power with a larger turbine housing, but the car was quicker down the track with a smaller housing because it was making more average power under the curve on the way down... now, if we'd cammed and gear'd the car to make power in the upper rev range, the bigger housing would have made more average power, but that was not our combo...



these trucks don't rev like the later trucks...



Forrest

 

[JMorrow]

I have a 12cm wastgated housing on my 93 and it is greaaaat. The other day I was passing another vehicle and I was up to 92 mph and still going strong. And in town it is nice to beat the socks off of the powerstrokes.



Thanks John

 

[KEENO]

Hey "J"!



My views & opinions about the 12cm2 (and 14 & 16) have been 'mentioned' on this BB over the last year or so. They haven't changed... . I'm one of those "First Gen'ers" in favor of the 12's & 14's!



Spend some money... Have some fun!



Remember though... . It's FUEL +- AIR that equals POWER! If you twist that MAX FUEL Screw too much w/o upgraded injectors you will shorten it's life. Proven Fact... If your truck is @ 178,000 miles and is still on the OEM pump... She might already be 'tired' & no amount of "Tweaking" will net much. Sorry!



KEENO



$20. 00 Shipping & I'll send you my 21cm2 to trade for your buddy's 12! That would make for an incredibly inexpensive 12cm2...

 

[Forrest Nearing]

KEENO,



yeah, I'm kinda wary of turning up my pump with a hair under 200k on it, but I know my buddy isn't going to let me leave his house without tweaking it a LITTLE...



perhaps deep down I'm looking for an excuse to buy a 230 pump?



Forrest

 

[J DeMaio]

Well guys:



I'm almost absolutely sure that the pump/injectors have been previously rebuilt. I like that somewhat but if it went out now I would have the excuse/need for a set of Power Wagons and a 230 horse pump But since that's not needed then I'll be saving money.



Thanks for that offer KEENO but I don't think I'm going ot trade now. I don't know what to do, I feel that turbo might be gettin a littel tired, max boost is about 10 pounds. I might just wait till Christmas and purchase a Piers Super Turbo with a 14 or 16 cm non-wastegated housing. I feel that's the safest bet. I also won't have to fool with trying to get the housing off, hurting the turbo, or the turbo being worn and the blades contacting the housing Is that possible? I just don't want parts in the intake side I'll let you guys know what I decide after I do more decifering. Also, it doesn't hurt the pumps unless you go over 2 full turns right?



Thanks,

John

 

[KEENO]

trade...

I understand John!



If your buddy still wants the 21cm2... . I'll send it to him directly for the same $20. 00. At the moment the only use I can think of for a 21 is for a really cool door stopper!



Better yet... I'll trade him directly for the 12cm2 and pay shipping for both. Having a 12cm2 around is always a good option.



Still runnin' the wastegate eliminated 12 on my truck.



KEENO

 

[Matt S]

Sorry I'm late into the action

I thought I'd still jump in here. I have yet to tow anything with the 12 cm2 housing. I don't know what the max EGT's will be. Right now, at a WOT acceleration from stop (ok, a toll booth) in 5th, I see around 1200 EGT's. On 15 Dec, I will be hitting the dyno again. The only difference will be the housing swap from 16 to 12. No pump adjustments, same dyno, but different day. I'll report my findings when I get them.

 

[Power Wagon]

Originally posted by J DeMaio

Well guys:



I'm almost absolutely sure that the pump/injectors have been previously rebuilt. I like that somewhat but if it went out now I would have the excuse/need for a set of Power Wagons and a 230 horse pump But since that's not needed then I'll be saving money.



Thanks for that offer KEENO but I don't think I'm going ot trade now. I don't know what to do, I feel that turbo might be gettin a littel tired, max boost is about 10 pounds. I might just wait till Christmas and purchase a Piers Super Turbo with a 14 or 16 cm non-wastegated housing. I feel that's the safest bet. I also won't have to fool with trying to get the housing off, hurting the turbo, or the turbo being worn and the blades contacting the housing Is that possible? I just don't want parts in the intake side I'll let you guys know what I decide after I do more decifering. Also, it doesn't hurt the pumps unless you go over 2 full turns right?



Thanks,

John

If I understand you correctly, you're saying that taking the turbo apart is not necessary with a non-wastegated housing. Not true.



As far as the turbo goes, it's an equal amount of work. BUT, putting in wastegated housing results in the exhaust pipe being wrong, as the outlet is soemwhere around an inch and a half farther back from where it used to be. Your downpipe will hit the heat shield and heater. I'm a glutton, though... so if I do the job, i'll use a wastegated housing. You need only as much boost as is required to keep down the smoke and EGT to safe levels.