Boost #'s and egt's

Mr. Magoo

Mr. Magoo

huh?
Joined
Mar 27, 2012
Messages
243
This is regarding the truck in my sig.

With the mods that i have can anyone tell me what boost #'s i should be seeing? Under WOT boost will peg at 50 until the tranny shifts into the last gear and it will build about 55-57 then. EGT's climb to 1400-1500 very fast until it shifts and builds more boost, and then the temps cool a little bit. I feel like I should be seeing higher boost numbers to keep it from running so hot. Just built a leak tester today and found a few leaks, sealed them up, problem remains... Im lost. Running sw7 rp2 tq3 injection2. Also have been getting pretty bad mileage, around 410miles per tank
 
How is your rail pressure? I would check and make sure your waste gate is sealing closed and is set correctly. Try pinching off the boost line on the top turbo to see if the boost goes up drastically. Sounds to me like you have a waste gate that is not closing and/or not sealing and it is bypassing.

Joe
 
Have the injectors been tested? How many miles on the injector bodies?
 
I tried plugging the wastegate at all that did was make my primary not work so hard, but total boost didn't increase. As for the injectors I'm not sure how many miles are on them as they were on the truck when I got it. Rail pressure seems good. It will hit 25k but only at higher rpm's. Is that normal? It steadily increases as rpm's do.
 
BD tow twins are pretty small, I had them with a little more fuel (Flux 3s) and I gated them at 55ish. I think that's about as hard as I would run them without a DP gauge.
I had the same issue and that's how I ended up with a larger set of MPI twins :doh:, should have gone the MPI route the first time.
 
Yes i do have a primary boost gauge. With the wastgate connected and adjusted as tight as it will go, total boost was 50, primary was 35. Wastegate plugged off, total boost 50, primary between 20-25.

I know they are rather small but i figured with 90hp injectors i wouldnt run into any problems with high egts.

BD assures me, as well as other posts ive read, that the tow twins are efficient up to 65#'s. I feel like just a few more #'s of boost would keep me cool enough to be happy.

What would adding an MP8 do for my current setup?
 
Well ive spent a few hours today working on the truck. removed my secondary and all piping. Made sure all clamps/boots/hoses/piping/everything was the way it needed to be and was good and tight. Took the truck out for a test drive. similar to before but maybe a tad better. I took a video of a run I did. to the floor from less than 5mph.

[ame="http://www.youtube.com/watch?v=v0zQNpxUZWY&feature=plcp"]http://www.youtube.com/watch?v=v0zQNpxUZWY&feature=plcp[/ame]

I also found if I roll into the throttle slowly all the way to WOT from 30mph it will build around 55-59#'s immediately instead of stopping at 50#'s and egt's wont go over 1200*
 
Sounds to me like your cp3 isn't keeping up. If your rail pressure isn't up to par then it will have low boost, high egt, smiley, and lack performance. If you roll into it slowly the cp3 will keep up better and you won't drain the rail as bad. Try dropping the rail pressure setting default on the smarty and maybe even try running it on a lower setting like 5. Also the higher you run your torque management on the smarty the harder it will fuel on the bottom and it will drain your rail worse
 
You might be onto something about the rail pressure. I dropped tq and rail to setting 2 and did this test drive.
[ame="http://www.youtube.com/watch?v=X4_YkG0Ww1Q"]http://www.youtube.com/watch?v=X4_YkG0Ww1Q[/ame]

[ame="http://www.youtube.com/watch?v=xw4rBJsgG2s"]http://www.youtube.com/watch?v=xw4rBJsgG2s[/ame]

Did about 4 pulls and rail psi was inconsistent on each. I assume this means the cp3 is struggling.

Can a pressure box help this, like an MP8, or is an upgraded cp3 needed?
 
What he was trying to steer you to was the the smarty RP settings does the same thing that the MP-8 would do... only smarty doesn't do it as aggressively as you were thinking. Or in other words, the smarty isn't your problem and the mp8 won't solve it either.

IF the problem really is with the rail pressure, then a better cp3 is your only answer. However, your sig says a floor it stage 2 which should be able to keep up under normal circumstances. and the FASS is plenty too. How old is the cp3?
 
I would suggest CP3 as well. But I'd call Todd @T&C to see his suggestion. He's rather smart.
 
Yeah. Either your cp3 is getting old and loose and not keeping up or maybe you have some injector issue that is causing to much return. When I had johns 3.5 and flux 3.3 as soon as I hammered the throttle it would max out the rail pressure and would not drop a bit until I let off the throttle. Maybe tired pump or failing injectors would be where I would look.
 
I appreciate everyone's help with this! We have a diesel perfoance shop in town and I'm going to get with them about testing the injectors. The cp3 has been on for a few years and it's very possible it's getting tired, damn it. Haha! Maybe duals are in my future
 
Does that shop actually have a test bench for the injectors? Most shops don't. A fuel injection shop is what you need to test them. Around $25-30 each most places.
 
Im going to call tomorrow when they open and ask them. If they dont they should be able to recommend a place.
 
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