Engine/Transmission (1998.5 - 2002) Boost Elbow and Boost questions

[jeepit]

I have a boost elbow I have never installed but after yesterdays trip I think it needs to be done. Against a 35-40 mph wind towing trailer with Jeep on it and Lance in truck bed I was easily seeing egts at 900 to 1000. Uphill I would have 1100-1200. Boost was 20-21 max.

It is my understanding the boost elbow and the Smarty will allow a higher level of boost and lower egts.

Do I need to put any sealant on the threads of elbow when I install it?

Elbow seems to be tourqed on tight. Can I use any penetrant to loosen it or will that be bad for turbo?

 

[MAllen1]

I am presuming that you are talking about the elbow between the turbo and the downpipe. If you are, here is what I can tell you about it. It'll leave your egt's about the same (they did in my case), again presuming the smarty will up the boost. I have a 99 2500, 4x4 with oversized tires, rv injectors, and an upgraded computer from Cummins that up my 99 to 00 specs (505 lbs. /ft. vs. 460 lbs. /ft. ), and a 4 in. throughout. My egts. mirror yours right now, and I haven't seen it go over 1200 pulling an 8000 pound trailer. Difference is I bought a boost fooler to allow the turbo to spool up to as high as 30 psi. I am assuming the Smarty will allow your turbo to spool up that high once it is installed, based on the stock levels you gave.

 

[MVieira]

You should be talking about the little elbow on the intake side of the turbo. That has a hose that goes to your waste gate. I would definitely install the boost elbow and adjust it to around 30 to 35 psi on an HX35. Your Smarty should take care of the boost fooling. I would use the Teflon sealant in the tube, that loctite sells, on the threads. One of the first things I did to my truck, after gauges, was install an Edge- EZ. I got better mid range and bottom end (quicker fueling & timing ) but I noticed my EGT's were higher and I had to watch them and back off the throttle. My truck is an Auto and I originally had the HY35 with the hard boost line, so I couldn't install the boost elbow. So I made my own "J-Hook" and adjusted it to dump around 30 to 32 psi. That really helped cool my EGT's down, mainly while towing. Now I have the HTT 62/12 and with the Mach 1. 2 injectors, I've adjusted the allan down on the boost elbow to dump around 38 to 40 psi. The truck really runs good there and no EGT issues. Regards, Mike.

 

[champspa]

the boost elbows from tst are already set for 32psi . I thought the boost elbow was for p7100 pumps not Vp44 ones . check with tstproducts.com

 

[RustyJC]

the boost elbows from tst are already set for 32psi . I thought the boost elbow was for p7100 pumps not Vp44 ones.

The Edge EZ for my 2002 ETH/DEE (HO/6-speed) came with a boost elbow. The EZ acted as a boost fooler. Stock, maximum boost was 20-22 PSIG, but the boost elbow kicked that up to ~32 PSIG with the stock HX35W-12 turbo.



If you're running additional fueling, you definitely need the additional airflow you'll gain with a boost elbow to burn the fuel efficiently, thus cutting the black smoke and lowering EGTs.



Rusty

 

[jeepit]

The Edge EZ for my 2002 ETH/DEE (HO/6-speed) came with a boost elbow. The EZ acted as a boost fooler. Stock, maximum boost was 20-22 PSIG, but the boost elbow kicked that up to ~32 PSIG with the stock HX35W-12 turbo.



If you're running additional fueling, you definitely need the additional airflow you'll gain with a boost elbow to burn the fuel efficiently, thus cutting the black smoke and lowering EGTs.



Rusty

The fitting that is currently in there (that the boost elbow will replace) is very tight. How can I loosen it up? Can I use penetrating oil to get it loosened up? or will that get in the turbo?

What is the max boost the stock turbo can handle?

 

[RustyJC]

You can certainly try some penetrating oil on the threads. Mine was snug, but not THAT snug. Of course, I installed my boost elbow when the truck was only a few months old, so the stock boost elbow didn't have a chance to "set up" in the compressor discharge housing.



32 PSIG is really about all you want to run on the stock HX35W. Once you get to 35 PSIG and above, you're so far out of the turbo's design envelope that efficiency has gone to pot, and all you're really doing is heating the air beyond that point.



Rusty

 

[jeepit]

Ok, elbow is installed.

Now where should I set it at. Right now set screw is closed. Do I start at 1/2 open or what?

 

[MVieira]

You are going to have to adjust it by your boost gauge. Hook up to a trailer and find a hill or get on your truck real hard and see what your max boost is. Somehow, you are going to have to put a load on it. When I adjusted my boost elbow on my HTT turbo, I hooked up to my 5th wheel early one Sunday morning and drove it from Dixon down to Vallejo on Hwy-80. It is about a 30 to 40 minute drive one way and there are some nice long step grades in both directions. If anyone has been through here to San Francisco, you know what I'm talking about. The boost elbow set screw was screwed all the way in, so I started with it backed out 1/2 turn. I would get on my truck pretty hard and watch my boost gauge until my boost psi peaked and held steady. It started around 32 to 34 psi and I adjusted it in a couple times until I got a consistent 38 to 40 psi on my HTT turbo. With my modifications, this setting has worked well for me. I think you could start about the same and back out the set screw 1/2 turn. If your boost comes up real quick and looks like it is going to fly past 35 psi, back out of the throttle real quick. Use your throttle pedal as the safety valve. Pull over and adjust it out a little bit more. If you only see 20 to 25 psi, pull over and adjust it in until you get it around 30 to 32 psi on your stock turbo. To make a long story short, there is no exact adjustment, you are going to have to do it by feel. Regards, Mike.

 

[jeepit]

Thanks M Vieira. I just needed a starting point as to where the set screw should be. I plan to load trailer with the CJ7 on it and get up on the highway to check.

 

[jeepit]

Ok, so I took truck out on highway with a 5500lb load. Boost will not go over25-26. I have the set screw all the way closed. Is this because the load was not heavy enough that the boost did not go any higher? I hammered on it pretty good going uphill also... same reading. Or is the elbow the problem? I was expecting a higher boost reading.

 

[MVieira]

Jeepit, You could have a boost leak somewhere, or there may be a possibility that you are only putting out enough fuel to get 25 to 26 psi. I was able to easily hit 30 psi, when I turn-buckled the waste gate completely closed on my HY35, and all I had was an Edge EZ on an otherwise stock truck. You should have a HX35 and you should be able to see 30 to 35 with the Smarty loaded on the fueling settings. Where is your Smarty down load at. I assume you have it on 3 or up for fueling. Boost is related to fuel, the faster and more fuel you give it - the hotter/bigger the burn - the higher the exhaust flow - the faster/quicker the turbo spins - the more boost you get, UP TO A CERTAIN POINT ! You possibly could not be fueling the engine enough, but you may have a boost leak. Check the 4 bolts on the intake horn/elbow, they are notorious for loosening, torque should be 18 ft lbs. Also check all the bolts on the intake plate and check the tightness on all the after-cooler hose clamps. There are several ways to plug the intake and pressurize the system with compressed air and spray soapy water around all the joints to look for bubbles & leaks. I would check the 4 bolts first on the intake horn, because I had the same thing happen on my truck. I hope this helps some. Let us know what you find. Regards, Mike.

 

[jeepit]

Mike,

Smarty is on level 5 which is fuel and timing. The even numbers are just fuel. Maybe go up to 7?

I will check for leaks as you said... ... Thanks for da the suggestions at what to look at first.

Randy

 

[MVieira]

Jeepit, I think setting 5 is fine. I don't own a Smarty, but my buddy has one on his '02 and the higher numbers don't give you more fuel, it just gives it fuel faster/more aggressively. I would check around for boost leaks. You are seeing more than the stock 20 to 21 psi. , but it has been so long since my truck has been stock, that my memory could be a little clouded. I honestly think you should see higher than 25 to 26 psi on your HX35 with the boost elbow screw turned all the way in, with your Smarty on a 5. Maybe someone else here will chime in and back me up, or correct me if I'm wrong. I would really suggest checking the torque on your intake horn and intake pale bolts. If you have never checked them, I'll bet they're loose. It wouldn't hurt to check all the hose clamps either. If you find anything loose and tightened them up, then recheck your boost to see if that was the problem. Regards, Mike.