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So this was going to be my only mod this year, until I read about the 6.7 harmonic damper. Anyhow, I truly think I am about done with power mods at this point, thou I have said that before. I will be playing with the Smarty UDC, and possibly going to a Smarty Sr but nothing crazy. Anyhow.. I purchased a GDP Air Boss and it's awaiting install. It really is a pretty piece of equipment! This mod is supposed to improve airflow thru the intake manifold, which helps spool (not really an issue with a BB charger) and EGT's. I don't have an EGT problem persay, but wouldn't mind a slight reduction when towing at 6K feet plus, and with the new TT being 2-3K lbs heavier I am going to be using more of my power. I have heard several claims of 100-150° EGT reductions from this plenum with grid heater delete. One of the features I like is that Richard (GDP) has an all seasons kit for it, which allows use of either the OEM grid heater or grid heater delete. I plan to run the grid heater Oct-Mar, and deleted the rest of the year. I have been "bypassing" the grid heater on some cold days this winter, and have had zero issues starting even into the teens. I could probably get away without it year-round, but I don't want to risk it. I am hoping by starting this thread today it will motivate me to find the time to do the swap this weekend.

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Yes, it's the plate under the rail.

I have his MK2+ kit, and intake horn on the truck as well.

--- Update to the previous post...

Well I got the install done this afternoon, probably no more than 2-3 hours of honest work. I started about 5 and finished about 8:15, and that included a dinner break, chasing the kids, helping with the kids bath, and a glass or two of vino...

It's pretty darn simple, thou I'll admit I didn't follow the instructions too close. The instructions tell you to remove each injector line, and then the rail. I didn't want to break that many leak-free connections, so all I did was remove the line at the head on 1-4, and at the rail on 5-6, then the supply and return lines and pulled the OEM plenum out with the rail attached via the line clamps. I then swapped the rail to the new plenum, and reversed the removal.

The only PITA part was trying to torque the injector lines. I borrowed, and broke :banghead:, a 12 pt crows foot from work and the other one I had was all but impossible to get on there. 22 ft/lbs isn't too much thou, and I just used the "arm-o-meter", so far no leaks.

I installed the grid delete, and will put the heater back in around Sep-Oct. It should only be a 15-20 minute job to swap it. Even with the grid installed I think the flow will improve as the grid will be about 0.5"s higher, and give more room for the air to move foreword/aft.

After installing it I hooked up all the connections but the injectors. I ran the LP for a few 25 second cycles, and then used the starter for 3-4 5 second cranks. I did this to get the pressure up in the rail (saw 17K for a second, then held steady at 6K) to check for leaks, and to get the return flow back to the tank. I wanted to flush the rail/lines of any debris that may have gotten into the lines while working on the system. I think I moved enough fuel to clean anything out.

I will have to drive it to work this week, need to use the receiver as a vice to adjust my equalizer hitch for my new TT, and will report back. First tow should be in the upcoming weeks.

It sure is shiny and purdy!!

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--- Update to the previous post...

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One thing I noticed, that I was expecting, is that the new cam has more overlap (if the OEM had any) on the intake/exhaust valves. Right after doing the cam install I noticed that my IAT's would go up about 10° with the exhaust brake on, where they didn't with the OEM cam. Looking at the OEM plenum I can see that I am pushing a little soot into the intake, but no where near as much as I thought. Cylinder 4 is the shortest, and most direct shot and nearly all the soot is around it. If it was a huge amount of air moving back thru I would have more soot in the intake than that, and it's been nearly 20K miles.

Seeing that the overlap really is there, and wasn't in my head, makes me even more happy I swapped the turbo as now 28-30 psi of boost only has 22-24 psi of drive, where with the stock turbo it was 40-50 psi of drive. I am certain I am moving a LOT more air at 30 psi than the OEM setup was ever capable of at 30 psi.

--- Update to the previous post...

I also found it interesting that there is rust on the inside aft intake horn bolt, and rust lines from about that location to the back cylinders. I have zero idea how any liquid would get up there to work thru the bolt, especially since when the motor is running there is positive pressure in the manifold 99.99% of the time..

My only thought is that maybe the bolt wasn't as tight as it could be, and when I would rinse the motor (maybe twice in the last 3 years, and low pressure) water would seep down the bolt hole and into the plenum.

I wonder if it was enough of a boost leak that I will see more boost or anything else? Or maybe I am off base, any thoughts?

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A loose bolt will also cause fretting which will have a rusty look.The other question I have is that the threaded holes for the rail hold down bolts are blind holes in the OEM piece, and through holes in the aftermarket piece. What steps if any did you have to take to seal those?

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I put a little liquid pipe dope on the threads. The mounting holes on the head are thru as well, and there was a slight amount of sealant on the stock bolts, I put a little dope on them too. The stuff is good for 100 psi instantly, and 300 psi after 48 hours, I should be good :lol:

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Empty there is more throttle response and cruise EGT's appear a little lower. Towing the puff of smoke at the shift, if I shift at 2K rpms or so, is MUCH smaller and shorter. EGT's appear to climb slower and stabilize a little lower as well (especially in 2-4th gears). I can't do a 100% comparison as I sold the trailer I have been towing for the last 4 years, but I am quite happy. My new trailer is 7' longer, 8" taller, and 1,500 lbs heavier (had dumped water by this point, and drank most the beer :-)). I generally pulled grades at the same EGT as the old trailer, and more power! The big grade I pulled this weekend is about 2 miles at an average of 5.7% grade, with sections of 7-8%. The last 1.5 miles averages 6.7%. I was in 5th gear, at 55 mph, 2250 rpms. The truck was at 60-65% load for the majority of the hill, and about 26 psi of boost. I started at 1050° and finished about 1125-1150°. My old trailer pulled the hill at 50-55% load, 24 psi and 1125°-1150° peak so I think the air flow from the airboss must be increased! I do have the grid heater delete installed right now, fired up at 29° like it was 100° outside.There is a short, 1/3 mile, stretch on the way home that is a 10% average grade. It's my 6th gear test stretch. 94%-WOT, 1210°, 1700 rpms and ~28-30 psi, down from 1250° with the old trailer/intake.

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