oaborbag

So I put in my injectors I aquired from a member on here, and took it out for the first "official" test drive since putting them in. Overall I am impressed with how they drive around town, the truck feels smoother in acceleration and overall driving, and surprisingly while cruising I believe my EGT's are actually lower than they were with my DDIII's.

After testing some full throttle accelerations these are my observations:
With the comp on 1X1 max boost was about 36 psi, although it seemd to flutter quite a bit 2+/- psi each way, haven't seen that before.

with comp on 2X5 about same results, maybe 1-2psi more than before.

So I decided to really open her up with the comp on 5X5. the boost ran up to 50psi this time and since I'm still running the stock HG I left off after sitting there for about 2 seconds. truck runs fine so nothing happened! other than after I looked back and couldn't see behind me...good thing no cars were behind

So I've come to the conclusion I should probably adjust my WG on my turbo, question is, how exactly? do I make it go in or out? I have also thought of maybe these injectors are a tad too big, and maybe I can trade someone somewhere for some mach 4's (I might not do this afterall) I'm also wondering how much exactly a head studs/gasket/O-ring would be for someone to do it, with me aquiring all the parts of course.

Overall I'm happy with the injectors, I'm a little afraid of boosting that high with the stock HG although I know I've read people running higher than that with the stocker and no problems. Since my turbo is somewhat on the larger side my drive pressure might not be too bad so maybe I'm worrying over nothing.

Sorry in advance for the essay, but some comments, criticism, concerns, and recommendations are much appreciated. Thanks for reading.

Mods in sig are current (other than the injectors going to change that now)

DMcPherson

what kind of egt's were you seeing with the comp up? I see you have the super b special, Im looking at one for a similar setup

JIT

Im running Mach 5's looking to go up a size. Pm me if you decide to drop one size!

Josh

JP-4.5

Couldn't you do the Studs leaving your current HG in place? I have read that this is better than leaving the stock head bolts and allows higher boost without problems. I have thought about doing this for my current setup.

oaborbag

I have also read on leaving the head on and only replacing the bolts, would like to hear from someone that has done this on reliability, I did not look at the egts, wish I did, my eyes were glued to the boost gauge. I'm going to take it out again tomorrow for another run and see what the egts go up too, but with such a short run I'm sure they aren't that high.

Mike D

If you have black smoke at 50 psi of boost, you have a major boost leak. That charger should all but clear up those injectors, kind of a brownish haze should be what comes out.

I would wastegate the charger at 50 and leave it, should flash to a tad over 50 psi on the gauge then come back down once the wastegates open.

oaborbag

I think the majority of the smoke was from the charger coming up to boost, like I said I only held the boost at 50 for maybe 2 seconds. Tomorrow when I take it out again I'll look at the mirror at full boost and see what kind of smoke I'm getting. At low rpm it smokes like a freight train, but I guess that is a given since they are a very large injector. I'm happy with my fuel psi though, stays pretty steady no matter the throttle.

Mike D

Yeah, no boost = big smoke signal. Launch around 18 psi and see how it does, assuming you have shafts of course. Even rolling into it on the highway you shouldn't see too much smoke. Can't drive these things like gas powered rigs and expect to get good driving results.

oaborbag

Yeah, no boost with these things it just pillow's out. I don't have an input, when I bought the transmission a billet input was not offered from ATS, I do have the output. so launching at high boost makes me sceptical. But I'll take it out tomorrow and have some fun. Then I think I'll order some studs and put them in to make me feel a little better about the needle hitting 50 psi.

Erska

How's your fuel pressure with the walbro? I have lost an interest with the walbro and the stock fuel filter. My fuel pressure drops from 15to 5psi with full throttle with the mach 6's. And it starts struggling right away.

I'm waiting my airdog to arrive with the ½inch line. I have only the 3/8" line now.

Mike Holmen

What elevation you at? The mach 6'rs injectors at sea level should clean up around 50ish boost. You might need a cam as it occurs sooner. I'm driving some of Don's early ones, back when he just cared about making power, smoke output was a third or second issue. Drove a set of big power dynomite sticks, they are egt's and smokey. Make tons of power, more than the 6's. Hows the injection pump handle the wot pulls? Just keep you're foot in it or the truck will run out of fuel. They are really twin only sticks, to really get them to work right. The more air you give them, the faster the truck gets. I'm around the 70-80ish area. Hard on parts.

oaborbag

Back from the real test drive, and overall I'm impressed with the results, but I'm no expert, keep in mind the test drive was not on a public road!

Anyway on with the results, they were all done from a 60-65mph to 100-105mph roll on, changing the comp settings each time.
Test1: Comp=1x1
max boost=36psi
fuel psi=18
egt=1050

Test2: Comp=2x5
max boost=36psi
fuel psi=18
egt=1050

Test3: Comp=3x5
boost=41psi
fuel psi=17
egt=1200

Test4: Comp=4x5
boost=46psi
fuel psi=16
egt=1350

Test5: Comp 5x5
boost=52-53psi
fuel psi=16
egt=1500

From the results, I think until I get studs, o-rings and a gasket I think I'll put the comp on max 4x5 just to keep it a little more on the safe side, as for smoke, was only a haze after the turbo spooled, so I was happy about that. the egt's as well seem okay to me, I could be wrong. The truck has definitely never pulled as hard as it did with the comp on kill, and it felt good, can't wait to launch like that after I get the hg taken care of, which leads me to my next question: Can someone pm me telling me how much I should expect to pay to have studs/gasket/hg done? I don't know of any shops around here that work on diesels, and I don't want some random mechanic taking the head off my truck.

Any suggestions? Please advise, thanks for reading. I am definitely happy with how it's running right now though.

Mike Holmen

I have about 100000 miles on a set of mach 6's. I would worry more about tranny, clutches, t-cases, tires, and small import cars. Head gaskets are fun times. I've only replace 3 this year. Still working on #4, the year is winding down so my record is at 3. I got off easy.

JIT

I would run it till the gasket goes. My neighbor ran BD twins putting out 70psi for over 2yrs on the stock HG. (35k miles) In the mean time get studs and either install them or retorque your factory head bolts. Then find someone that does good work, get your pricing and start saving some money. If you start now and the HG lasts 1-2yrs you'll be in good shape when it goes.

Mountaineer

OMG Mike that is just awesome.
That made my night.