12cm turbo housings

[Jim Curry]

Hey Fastmark;

I have been of the opinion,(based on what I have learned on the TDR), that the best place for the pyro probe is pre turbo in the exhaust mannifold to get true reading of exhaust temps coming directly from engine. After exhaust goes through turbo it is cooled down a great deal. Also not sure that the probe being in the exhaust brake elbow may not be restricting air flow a bit to much. I am not an expert and maybe someone else can jump in here with another opinion but ,if it were me, I would relocate the pyro probe to the exhaust mannifold and put a treaded plug in the brake elbow. Much more accurate readings that way and less restrictions to air flow out of turbo through brake. Just MHO.

As to only having 16 #'s of boost I think you should have much more than that. How many turns on the fuel screw have you done and can I assume that the restrictor as been removed from th fuel screw to allow full range of adjustment? Have you adjusted the star weel or the fuel pin positions to allow for more fuel delivery. I would try these before going to the expense of having the fuel pump checked out. Also check to make sure you do not have any leaks in any of your tubo lines . Do not remember weather you said your truck was intercooled or not but if so there are lots of places a leak may develope on its way back to the manifold. Check for leaks in either case,(intercooled or not) .



Hope this helps and is not to long winded.



Jim Curry

 

[fastmark]

Jim, I don't think I have any leaks. The starwheel is all the way down, the diaphram is in the 5:00 position(almost all the way) and the full power is 1 turn in. I tried 2 but could see no improvement other than the abilitly to kill more mosquitos( it smoked more). When I floor the truck, the boost goes up. As soon as it gets to speed and the load is removed, it drops back down in boost to around 4 or 5. The turbo is used, do you think it may be bad? I think maybe part of my problem is that I expected too much. You see, the other manual transmission vehicle in my garage is an AAR cuda. It has a built 340 with a six pack. I have had a little more experience with three Holleys than with desiels. When I put it on floor, it hauls butt!

 

[Jim Curry]

Well Fastmark ;



If your housing is waste-gated have you tried adjusting the waste gate? Maybe the gate threshold is set to low and once you reach your 16 #'s of boost it is opening and bleedding off pressure. Try adjusting it or blocking it off and see if that helps.



Jim

 

[fastmark]

I pulled the wategate vacuum sol off and made a brace to bolt it shut. I have been wondering if it is leaking some. I might pull it off and see if I can spot the problem .

 

[BillyKidd]

Turbo's, ETC.

Hey Gang:

Here's my $. 02 worth. The 12cm2 is "Quicker" but you get higher EGT's. I like the 14cm2, almost as quick and no EGT problems,wastegates are easily blocked off or set high enough as to be non operational. Injectors are the real secret to power and boost, as without bigger ones your not going to get optimum boost. Turning up fuel screw is questionable after about one turn and could be harmful to life of pump. (mine is turned up about 1/3 turn) Again injectors give you more fuel /better. Pump timing also has effect and mine is at 1. 75. I made my mods with performance in mind but longivity as the more important factor. I get 25 lbs. boost and 1250 max. EGT's towing or climbing hill in hot weather(100+). Don't forget free flowing exhaust as this will also increase boost and lower EGT's( a little, but some). One reason I don't have an exhaust brake is I believe it really disrupts flow just being in system. I believe power is a PACKAGE deal!

Billy

 

[fastmark]

Your right about the exhaust brake. I have had too much trouble in stopping on long grades in Colorado. Wolf Creek Pass gets steep in a hurry!

 

[RDusch]

I've been running my 12cm banks housing for over 3 years now with alot of playing around and trying this and that,

i have found that i get the best of both worlds, really fast boost of the line, and cooler EGT's by setting my waste gate to dump at 25 psi and adjusting the star wheel to get what ever fuel i need

when the waste gate opens you keep the 25psi but double the size of the exhaust path (double is just a guess maybe more maybe less but still quit abit bigger) thus lowering top end EGT's.

and still have all the power i've had all along.



Rick D

 

[Power Wagon]

Originally posted by fastmark

Jim, I don't think I have any leaks. The starwheel is all the way down, the diaphram is in the 5:00 position(almost all the way) and the full power is 1 turn in. I tried 2 but could see no improvement other than the abilitly to kill more mosquitos( it smoked more). When I floor the truck, the boost goes up. As soon as it gets to speed and the load is removed, it drops back down in boost to around 4 or 5. The turbo is used, do you think it may be bad? I think maybe part of my problem is that I expected too much. You see, the other manual transmission vehicle in my garage is an AAR cuda. It has a built 340 with a six pack. I have had a little more experience with three Holleys than with desiels. When I put it on floor, it hauls butt!

Please don't consider me the final word on the subject, BUT... .



You need to change out the 215 injectors. They make EXCELLENT replacement injectors for going to high altitude and preventing smoke, IF you don't want more power.



However, in your case, you want more power, and the pump simply isn't capable of the pressure needed to mash the fuel through them. Instead, the injection cycle is just getting longer and longer - which means the end of injection is delayed farther and farther. Late injected fuel makes smoke, doesn't make power, and increases EGT's signficantly.



Here is what I would suggest you do... Change the housing to a wastegated 12, and set the actuator to get about 25-28 PSI. Adjust your injection pump timing to 1. 3 to 1. 6 MM @ TDC. Trial and error will get you the best setting for the way you use the engine. Replace your injectors with the PW's. . (someone can get you the part number, I don't remember it off the top of my head), and then turn the fuel screw DOWN to stock or 1/2 turn less than stock. Return your diaphragm and and spring tension settings in the AFC to stock values. This will easily get you at least 210 HP (and i'm more inclined to believe it's more like 220-230), if we can believe performance numbers VS a stock 180 HP engine. If you're adventureous, you can crank the fuel screw up a little from stock, but make sure you watch teh smoke and egt if you do that.



Where I used to work, we set a number of trucks up that way, and the performance is good, the smoke is low when pulling, and the milage is usually as good or better than before.



If you are lacking green stamps at the moment, you could start with advancing your injection timing to at least 1. 4 MM @ TDC. This, in addition to VERIFYING the TDC timing pin should get you improved performance, along with reducing the temperatures and improving your milage.



The 215 injectors have more holes, but smaller ones, and they do well in places where you are at high altitudes (5000 and up), where smoke is a problem. On the 2nd gen engines, the pump can generate a lot more pressure, and so it shoves the fuel through to produce the power desired. High pressure + lots of small holes = good atomizing and distrubution which = good power and economy + low smoke.



You, on the other hand, can't generate the pressures needed, so instead, you're just making injection long and slow, which is not good. The PW injectors (bosch) and the lucas injectors have larger holes to let the fuel go in fast. While injector efficiency is not as good, I believe it is made up for with better timing characteristics.

 

[AlK]

Power Wagon injectors (bosch part # 0432133875)

 

[Jim Curry]

Hey Power wagon;



I assume you are talking to me since I am the only one listing 215 injectors that I am aware of. Are the old blue and the PW's one and the same and might it be less expensive to just buy the new tips as opposed to the entire injector or is the cost differance negligable. If the tips are much less expensive and I have a shop that will set them up for me,does anybody have the part number for the tips alone?

As to the 12 cm2 housing, (waste-gated),would a 12 cm2 non-gated housing due or is the waste gated version a big advantage. What about finding a used turbo set up off of a 94 to 97 truck and do i have to cut and reweld the down pipe or can the piping be easily moved with out going to that much trouble?



Thanks Jim

 

[Jim Curry]

P. S.



Does anybody have a set of these injectors they want to part with. Funds are very low since I am not working right now and I am about to start back to school for computer programing,(2 year course). At 46, the thought of going back to school to train for a new career is a little nerve racking to say the least, but the situation does not leave me much in the way of boming funds and for someone that has caught the bug that is not a good position to be in.



Thanks Jim

 

[Power Wagon]

Originally posted by Jim Curry

P. S.



Does anybody have a set of these injectors they want to part with. Funds are very low since I am not working right now and I am about to start back to school for computer programing,(2 year course). At 46, the thought of going back to school to train for a new career is a little nerve racking to say the least, but the situation does not leave me much in the way of boming funds and for someone that has caught the bug that is not a good position to be in.



Thanks Jim

Jim, you may be right about the 215's. I read the thread through and decided to respond to fastmark's posts. I am doing the school thing myself, so I understand how things are without money.



About the cost... Last I knew, the cost of putting tips in your old injectors was MORE than buying the whole thing new.



I have no idea what "ol blue" injectors were made from, sorry.

 

[Big Don]

Jim,



The ol blue specials are the Lucas 300hp marine injectors. These are the best injector we've found for the first gen trucks. Alot of people run the PW's. The PW's are an upgrade for the intercooled trucks (91. 5-93) but do not give increased performance for the early nonintercooled trucks (89-91). I run a 14 cm wastegated housing and like it. I feel that the 12 cm housing is too small for what I use my truck for. If you want excellent lowend boost, the 12 is fine, but the 12 is so small the truck runs out of breathe on the high end. Can't force enough air thru it to feed these trucks if you're gonna spin it fast. I tow and use mine for a daily driver. I also have a 99 and after some upgrades on it I got rid of the 12 cm housing cause it was too restrictive. I went to a 14 on it and now it pulls strong all the way to governor cutoff. I recommend the 16 for those with 4. 10 gears in the first gen trucks. I recomend the 14 for 3. 55 gears. This is how we set alot of local trucks up and the owners are very happy. A friend of mine did not want to spend the moey for a 14 on his 93, 5 speed, 3. 55 gears and now he wishes he had. The 16's are very popular becasue they are so cheap. Best thing to do is to look at how you use/drive your truck and then you can make a better decision on what is best. If money is the factor that dictates, then just save up till you can buy what you feel is best. If you jump into something you may not be happy with it.

I think you would be very pleased with the Lucas marine injectors. They make awesome hp and give good economy.



Good luck

Don