If I am not mistaken the boost elbow is just a small oriface in a brass elbow. My flow control is the same thing, but the oriface is now adjustable for my liking. The elbow is just a way to delay the rate of air pushing on the diaphram to push open the wastegate. My setup is likewise, but it is an adjustable oriface spliced inline between the stock elbow and the wastegate. I may be wrong, but weather you have a boost elbow or not, the wastegate will eventually open all the way, the small oriface is just delaying the rate of opening.

 

Correct, the boost elbow will bleed off some pressure so that the wastegate doesn't see it.
You say that the wastegate will eventually open fully. I'd say hopefully. With the elbow on mine the wastegate will start opening a little @ 30# and be fully open @ 45#.
I'd look into your wastegate mechanism to see whether it can close fully.
The boost elbow works like this: There's a small orifice coming from the turbo going into the elbow- then there is a Y split in it- one leg goes to the wastegate and the other to another really small orifice that is open to ambient air.
If there is boost in the turbo only a small amount of air will pass through the orifice into the elbow, and some of that air will be bled off into the ambient air- the result is less pressure going to the wastegate. This doesn't make for a time delay in opening the wastegate, it will just open the wastegate at higher boost levels than before.
As far as I understand your setup you regulate flow betwen the elbow and the wastegate- but there is no flow, it's just stagnant air under changing pressures. (The DC factory air will just be shoved back and fore in the line)

AlpineRAM

 

Thanks Alpine. As you can see I had the concept of the boost elbow all wrong. I didn't know that it let air bypass. Hence the title noobie. I will take my flow control out and get an elbow. Maybe this will help anser my question on my other string "How much RWHP am I making?"

 

I hope that you'll get some boost then- where are you EGT-wise? (And is your pyro pre or post turbo?
As far as I read your other posts about this guy doing the work on yor truck and the wire not to be pierced.... I'd say you should look around for a second opinion. I'm running mine with the wire pierced for a little more than 100 000 kms and had no issue yet. Also any reputable speedshop would have told you the same thing on your "boost contraption".
Where did you buy your 80hp injectors?

AlpineRAM

 

These mods were done by Performance Diesel in the Dallas Ft.Worth area. I think they are DD2's.

 

OK, DD2s and a small box. Plus low boost. This sounds like a truely HOT combo.
I think it would be rather interesting to see your EGTs on a pull or when accelerating.

Edit: I saw that you run 1400 or 1500F- on this site this is considered to be quite high.
The rquestion that remains is pre or post turbo?

AlpineRAM

 

This is post turbo, and I only reached 1500 1 time this summer while pulling a hill with about 17000# in 5th gear and the petal to the metal. Unloaded I find it impossible to reach 1300 even in hard acceleration. I sure do get lots of smoke at the beginning of each gear. I have 4:10's so I rarely use first, and it spinns in 2nd, and breaks loose in 3rd. This is with almost 305 Durango Mud and Snows. 4th is my favorite though. It shoots out like a rocket between 1800rpm and 2200 rpm.

 

All trucks from 1994 came with HX-35's with a 12cm WasteGated exhaust housing. Until '01 the Auto trucks recieved an HY-35 which sports a tiny 9cm wastegated housing.

There aren't only two turbo's. Just two turbo's that came OE on the 2nd Gens. HX-35 and HY-35
An HX-40 is a good upgrade, but is laggy.
An HX-50 is a huge turbo, and takes some work to get it on our trucks.
An HX-55 is just and takes alot of work just ot get it to bolt up on the manifold. It CAN be used for the Primary turbo on a twin turbo, but it is too small. It doesn't really fit in any class. Too big for a secondary, to small for a primary.
An HX-60? Can be used for a primary in twin turbo setups. I don't have experiance with this turbo.

45PSI on an HX-35? That's pushing it into critical overspeed.
After 36PSI, the turbo is useless except for a huge hairdryer, because it's making a great deal of heat, and a crazy amount of backpressure.

The WasteGate Actuator is opened by air pressure, and is closed by a Spring. Even with the Wastegate line completely blocked, with enough backpressure the Wastegate will open anyway.

The common way to control boost (The OE way) is to apply boost pressure to the diagphram, and that will open the wastegate. The other way is to moniter how much backpressure the motor is seeing, and relieve that. You don't want more backpressure than boost. You might make more power, but efficiency will only diminish from there. Your EGT has only one choice at that time, and that's to go up.

To get more power you need to go bigger on the exhaust housing, exhaust wheel, the compressor housing, and compressor wheel. The trade off with bigger housings, and bigger wheels? More turbo lag. You will have to find your happy medium on where you are ok with the lag.
I was happy with an HX-40 with an 18cm housing for 20,000 miles and 457RWHP.

Hope this helps.
Merrick

 

Hmm, Blutic... if your pyro reads correctly you can be very glad that you didn't melt your engine. A temperature difference of about 300F across the turbo translates to 1800F pre-turbo EGT. (Hint: ISSPRO lets the red arc start at 1250F for the pre turbo pyro)
I know that your EGT differential will be a tad lower due to the open wastegate (post turbo) but nevertheless I feel that you are playing with fire in that setup.

It seems that your truck runs well, but I'd definitely look into your EGTs.

AlpineRAM

 

I read somewhere that WTTD was working on a HX35/HX40 hybrid and was having good success with the spool up time. That would take care of the HX40 lag.

 

I'm sorry my thermocouple is pre turbo not post. I had to go look. I hope that clears things up. Sorry! I think I will still send my guage in to have it checked. You scared the wizz out of me there for a second. Thanks for the help.

 

Yah. 1700* post would be :-* your motor good bye.

I know where you can pick up a used DodgeZilla 35/40 Hybrid turbo. If you are willing to drop the money, a B-1 might be a better bet.

Drop me a PM.

Merrick

 

Well, 1500 with your setup and low boost seem reasonable. Personally I'd see to it that pre turbo shouldn't go over 1250F. Racers do go above this mark, but they do so for just some seconds and are prepared to pay some money for the extra 1/10ths of a second they get out of it.
I'd go and look for the elbow and see what it does for you and then for maybe a bigger turbo. You'll need to sort out your clutch stuff first. I wouldn't go for propane for a daily driver. (detonation, headgasket etc)

AlpineRAM

 

I tore into my guage today. What I found was the boost needle was actualy touching the egt needle and raising it. This guage is a combo guage that has two needles crossing eachother. Wne needle sets out a little further than the other. Now I can barely reach 1050 preturbo. I haven't pulled a load since these findings, but I already feel better.
Maybe a boost elbow will drop it even more. So scratch all of the BS I stated previously.

 

Well that's some good news- maybe you were reading wrong boost numbers too?

I'd try to check the gauge with an external heat source and a second pyro. If there is something amiss in there you won't know what your real egt and boost are.
You'll also have to be careful not to go for too much boost on the stock charger. It will work fine 'til about 33# but this will be the ragged edge of its efficiency map. Over 45# you risk throwing blades and the like.

Just my 2c

AlpineRAM