thumbs

I know we have talked about this a million times but I need some no frills answers.

The way my truck is set up I can only at best get 17 lbs of boost at 1200* at 2600 rpm(@ gov).

Now is this "normal" is this with in the range I should be getting? I am runnin about 19k gross weight with my camper. I have more throttle available but the themps go up to high on a long pull. I rarely have to shift below fourth here in Pa. or on the interstates up through New England. I can usually keep my speed around 55 or 60 pullin the interstate grades after I shift. The temps will run about 1000 to 1100* after I shift to fourth. I still have to watch the egt's even in fourth but most if the time it just runs to about 1100 and stays there. If I had more boost I would figure my temps to be lower. I am always runnin on a pull in the 1100's and have to watch to be sure I don't go over 1200*. I could do it very easily. I have to drive by my pyro not the tac.

Ok is this "normal" stuff or can I improve on this with some adjustments. If it ain't broke I don't want to fix it but if I can do somethin to get the egt's down and still keep the power it would be great!!!

Thanks guy's

wannadiesel

Have you pressure tested your intercooler and plumbing yet? Everything can look OK but still have a leak when you put 15 psi in it. Hit the plumbing section at Home Depot and get pieces to plug the boost hose at the intake manifold and plug the turbo intake, then put a valve stem in one end and pump it up to 15 psi to look for leaks. With any luck it's just a boost hose, but you might have a leaky intercooler.

nascar mark

Hey Gary,

Your lacking air allright!! I've done some testing for the 1st gen engines at PDR and have tried different setups trying to get the most power for towing. You should be able to run at 28psi @ 1200 while pulling that load safely. I would suggest stepping up to a more efficent turbo to have more usable towing power.

thumbs

Ok you think I'm doin the best I can with what I have to work with huh? Ok I'll check for leaks in the IC system. I just wanted to know if this is about right. Remember I did get that new 16 housing and it did make a difference over the old 21 for sure. I sure was hopeing for more though.

thumbs

Mark

I forgot to ask. What are we talkin about here? Do I need a compleatly new turbo or another housing? Are my numbers right for what I have? I want to make sure I have done all I can before I have to change turbo's again. Not that its such a tough job but I want to make sure it will give me the performance I am looking for. Is there anything else I may be overlooking? Is this a common problem even after switching from the 21 to the 16?

I want to get this straightened out so I can get the power I need and get those temps down. I know I am still in the safe range but I am pushin the limits.

carl20320

Gary,
PDR sells the HX35 that has been modified. There are others out there as well that are similiar. It makes a significant difference with no other changes. When I installed mine, I went from 22psig to 29psig with no other mods. That was witht he 16cm housing. After I had some porting and polishing done to the intake and exhaust, I'm now at 35psig. I'm to the point that I need to open my exhaust up in order to do much more.

Carl

Tommy93w350

Does your truck have an exhaust brake?? If so, it could be restricting exhaust flow if it is malfunctioning a little.

thumbs

Yep but I have a gauge on it to measure the back pressure. Wait a minute. I did boost up the pressure at idle. That may effect the flow. I'll bring it back down and check it out. Yea I put it up to the max at idle. I'll drop it back five pounds and see what happens. Good though

Bushy

How bout a bit of reality check here too.....
19K is overloaded, period.
With that in mind you're doing pretty good actually. The trick, as mark alluded to is to have enough boost, and only enough boost to burn the fuel you're supplying.
Any more than that and it very quickly begins to work against you.
The modified HX35's have an extended efficiency map which basically means you can push it a bit harder and still have decent boost pressure which is cooler, comes on faster and is more usable.
A stock h1c/wh1c/hx35 have their map limits at about 26 psi + or -.
The hybrid 35 extends that up into the 35 psi range quite nicely.

pastor bob...

thumbs

P Bob

I do notice that is running pretty clean when pullin even when the temps are up there. Of course before the turbo spools up it gets pretty dark behind me but after the rpm and turbo boost comes in it cleans up to almost not being able to see any smoke at all.

So what you are saying is that 17lbs isn't that bad.

Does the above make sense to you?

Alec

I think that you have a boost leak.

1200 degrees at 2600rpm with a 16cm housing should give you more than 17 pounds of boost.

This means that you either have a clogged air intake (doubt it, cause you have the AFE filter), or a restricted exhaust (looks as though you did some work there, but maybe the muffler is more restrictive than you think or there is some other problem), or you have a clogged or leaking aftercooler.

I would take all of the piping and hoses off, clean everything, inspect the hoses, and gaskets, check out the inside of the cooler with a light, and if nothing else appears as a problem, pressurize the cooler up to about 10psi and see how long she will hold. As Dave said, you can get the hardeware you need to do the pressure check from a good hardware store without busting the bank.

A new turbo would help, but I was getting pretty close to your current performance with my 21cm housing.

thumbs

Yep I think I should be doin a lot better. I have been trying to get around the intercooler check but I guess it's down to it. I don't think the exhause is a big problem or like you said the intake. I did lower the idle pressure in the exaust brake and will check it out in the morning.

I guess I will have to find out how to do the IC check.

Thanks

wannadiesel

Gary-

Once you find the proper plumbing bits to cap off the system, here's the abridged procedure out of the Cummins book:

Apply 30 PSI to the intercooler and shut off the air supply. Monitor the pressure gauge and determine the rate of pressure drop with a stopwatch. If the drop is 7 psi or less in 15 seconds, the CAC is OK. If the drop is more than 7 psi in 15 seconds, check all connections with soapy water and watch for bubbles.

Before you get freaked out that it leaks some, here are some reassuring words straight from Mother Cummins:

wannadiesel

Looking at that procedure again I don't know if I'd go for the whole 30 psi, you might find some new leaks. I'd go for 25 psi since you should be able to get that much out of the turbo. Maybe allow 7 psi in 12 seconds to compensate for the lower pressure...

thumbs

Ok thanks. I am goin to get this done in the next couple of days. If I can get into the 20's I'll be happy. I think it will be a big help to get some more air in there while pullin.