Ok! I'm new at diesel performance, but I do understand the basics! I have what I believe to be a stock 91.5 CTD 1 ton auto. I tried to veiw #'s with a mirror on the backside of my turbo but nothing jived with info that I have found here. If I were to purchase and install a HX-35 would I benefit from it or not.? If so how much?As it sits now I haul a skidloader with it and it weighs in with the trailer at about 7500 lbs. + what ever else I'm carrying. I've been backed down some inclines and loaded up the truck and trailer and when I tried to go, I put it to the mat and I just sat there for about 6-10 secs.(Turbo Lag!??) then the duals just broke loose like I threw a nitrous switch. So I have to put it in 4wd and it pulls right out like nothing.(I still have that 6 sec. delay, but my tires don't brake loose) It's a hell of a truck and it's not often I'm in this type of situation, so would I benefit from the turbo swap in overall performance. I can't seem to get a crystal clear answer looking thru these forums.I'm willing to do other things to this truck, but a little at a time, I don't want to dump 1or2 grand all at once. Let me know what your thinking? (Hey wannadiesel you seem up on this type of game! Help a guy out here!)

 

There are plenty of guys who know more than me, I just post a lot. If you want real details from somebody who understands this stuff, ask Asilitch.

If you have an automatic trans there's really nothing to be gained by swapping in an HX-35 over just changing the turbine housing on the current turbo. The HX-35 is more desireable for manual trans guys because we get turbo flutter at low rpm when we change the turbine housing. The automatic trans won't load the engine hard enough at low RPM to cause the flutter, so save your money and just change the housing. I would bet you have the truly awful 21 cm housing, so going to a smaller housing would make a huge difference for you. A housing swap will cost less than $200 for a 16 cm. If you're not going to add injectors or turn the pump up a lot, a used 12 cm off a 2nd gen gives near instant spool up (that's what I'm running ) and you can find them for less than $100. You do have to move or shorten the downpipe to use the 12 cm housing, the 16 cm is a bolt-on.

 

I'm a new comer to the CTD, and this is my first time making a post but I am an industrial engine Mech. Do you think you could be having wastegate problems? I would just like to add I am learning alot about the gen 1 trucks, I thank you all.

 

seanb the first gen trucks were non waste gated turbos,,unless it has been changed.

bumpytruck theres an incredible differance between the stock housing and a 16 which im running,,soon to be a 12. mines a 89 and i also had the lag problem till the smaller housing was put on.
and if your making any mods on your truck get gauges if you dont have them, in my opinion no mods should ever be made without them,no need to trash a nice truck because you couldnt monitor your engine.

and have fun here but be warned hide your wallet, theres to many toys that you find on here.

 

loch thanks for the info, thats why I come here so I can get the info I need. Thanks

 

Dave didn't tell you that when I first changed to a 12cm turbo housing, I thought that the turbo surge was a problem with my waste-gate -- luckily Lil' Dog (who has since left our ranks to own a 2nd gen) pointed me in the right direction.


I agree with his recommendations. If you aren't planning on cranking the hp too high, I would get a used 12cm housing, which will be most helpful with your start-out problem. At higher engine rpms, though, say towing on the highway at 70 with an auto transmission, the 12cm housing might be too restrictive for you if you turn up the fuel.

If you really aren't interested in bombing your truck at all, you could probably get away with swapping turbo housings without running gauges BUT I would highly recommend getting a tachometer and transmission temperature, pyro, and boost guages.

I think what is happening with your loaded truck on the inclines is as follows:

The stock trucks have a torque curve that increases abruptly at about 1700 rpm -- the turbo doesn't even really spool up below that speed. So, on take-off, the converter is stalled until you get the engine up to about 1700rpm, and then suddenly everything takes off.

Putting a smaller housing on the turbo will make the turbo spool up more at lower speeds, and increase the torque produced at lower speeds (the boost produced by the turbo is determined by the mass quantity of gas flowing and the temperature of that gas, at low speeds there simply isn't enough air flowing to drive the turbo -- using a smaller housing is similar to increasing the air flow. As boost goes up, more fuel is added by the AFC, the increased boost allows this fuel to be burned, and the torque goes up).

By the way -- have you ever been in a situation where putting it in low range wouldn't let you pull out smoothly?

 

I just had an interesting talk with the owner of Desert Diesel here in Tucson. I asked him about changing the housing on my 156,000 stock turbo. He said he wouldn't recomend it on a turbo with my mileage. He said the change would present issues to the turbo seals that would 9 times out of ten cause oil consumption. As Martha says that is not a good thing. Swaping a low mileage turbo and changing the housing presented little risk of creating problems. The references I got on this guy from other truck owners lead me to believe that he knows what he is talking about.

 

I had 215k on my truck when I swapped the housing, no leaks. I have never heard of anyone having this sort of problem. Between this post and the one on the ticking noise, I don't think this guy at Desert Diesel knows what he's talking about.

 

160k on this one here when I made the swap to the 16. 218k now and it does not use a lick of oil. I can possibly see how going from an 18 or 21 that you have to a wastegated housing on a high mileage truck COULD cause problems.

This is due in part to the wastegate design. When the wastegate opens, for an instant, this leaves one side of the turbine wheel with almost zero resistance from exhaust, while the other side still has as much resistance as it did before the wastegate opens (closest side to the manifold). This puts side stress on the shaft as well as the bearings. This is why engine mfg's such as Detroit have gone to billet shafts and wheels to aid the stress caused by side loading the wheel. Most are only putting them on there bigger engines such as the 60 series 12.7ltr because they see more boost than our little engines do. However, when you start playing with performance, you start to get up in the number to where every little thing is critical.

Anyway, I feel that the 16 non wastegated housing is the best all around housing especially for towing. As for the HX35, I dont feel that you see enough gains to justify the cost of going to a stock HX35. IMO, a modified HX35 with the housing milled to fit an HX40 wheel is your best choice if you plan on playing around with the pump.

 

There is a very reputible diesel shop (Hucksdorf) here in Milwaukee WI. and I have seen trucks that they have changed housings on with only + results. I can only beleive that if it would create oil problems 9 out of 10 times!, they would not recommend doing such a swap.The last truck I seen was about 20,000 miles ago, it had 192,00 on it at that time with no problems.However I do like to hear all sides of the story,thats why I'm here, to learn and spend money!I mean ,get all I can out of my truck

 

I suspect that he is leary of backing up the swap should the swap fail. It is also a possibility that he has so much business he doesn't want to mess with it. The guy is backloged for two weeks. He also may not know what he is talking about. Finding a good shop is like findig a good doctor you go through a lot of bad ones before you find a good one. IN my case I am the third owner on a truck that has all of its mileage towing a 27 foot and a 30 foot fifth wheel. From some of the things I found on the truck I suspect the maintance was less than it should have been. I live in the RV world and it amazeses me how many guys break down on the road and most of the time it was due to poor maintainance.

 

Just how much boost should I be getting with a stock turbo. The best I ever see is arround 15 psi. The other day with a empty truck that is the best I could get with my foot in the pump.