i took off my cat back exhaust today, and mounted a 4" turbo back with no cat.

with NO change in tuning, i dont get nearly as much smoke as i did, as a matter of fact there is almost no black smoke anymore, and it used to flood the street before, has anyone else noticed this..

only thing i could think of is that the turbo is operating more efficiently now, and is burning more fuel, resulting in less unburnt fuel ie: black smoke

but i've also noticed now that i reinstalled my boost gauge, i am only hitting about 20-22 psi.

before i could hit 28-30 with old exhaust, but i was also using the edge then, and i am using SCT now..

any thoughts ?

 

Do a "simple" test. Reinstall the edge and see if you still get the same boost you did before. That would answer one question anyway. Less back pressure is supposed to be good for a turbo engine, but I'd think you should still be hitting 28-32 with the SCT.
If not then you might have sticking turbo veins.

 

i've been suspecting sticking veins for many months now, so i dont think that anything has changed since i had the edge, i had a LOT of lag, and lots of boost so i assume they are stuck open at least. i dont think i can bring myself to hook the edge back up, but maybe i will put it back on and put it on level 0 and see if the boost gauge on it reads the same as my isspro.
reason i took the edge off is because it doesnt work right anymore, and wont make the boost it used to, and keeps turning itself down to lower power settings automatically when i crank it up. it runs like crap on every setting and i dont want to damage my motor by putting it back on.
i was suspecting maybe a boost leak somewhere, but then i would actually have A LOT more black smoke with all that fuel and less boost wouldn't i ?

 

I was just thinking from electronics standpoint--IF your edge put you back to 28-32 then I would think it was a programming problem. If not then it's in the turbo or you have a leak, but a leak should be relatively easy to spot from soot on the hot side and eyes on the cold side.

 

did your Edge turn off the EGR?

 

LV,
I experienced the exact same phenomenon. I even wrote an article about my MBRP cat delete after I performed it in my driveway last winter (not sure if FTE ever posted it anywhere). I do not recall seeing my attitude monitor show over 30 psi boost since, and I sometimes run Edge/SCT stacked (yeah, I know). But as the edge is set to limit boost to 30 PSI, I guess boost would stay under 30. I can't remember what max boost was before the programming enhancements or before the cat delete. Nor have I paid attention to see where boost tops out with just one system running at a time. Since I don't have studs/o-ringed heads, I'm limiting the boost to 30 - not that that guarantees anything.
Perhaps the EBP sensor has some effect on max boost after a cat delete mod? My dealer even told me that if I went ahead and deleted the cat and muffler, my truck would not run well (if at all), and would quickly blow up the turbo. He looked very serious as he made these claims, so I knew it would probably be safe to do and even beneficial!
52K on the ODO and no related problems yet...

 

the problem with that is : the edge doesnt work like it used to, when i put it on 5 it will only hit about 24psi, then it will put itself on level 3 automatically, it wont stay on 5, like it knows there is something wrong, and it's going into limp mode. it did this when i first got it and was running the pryo in the downpipe, once i switched the pyro to manifold, it started acting right. now there is something wrong again, and not sure what it is. if i had a boost leak i would think that i'd have more smoke and high egt due to all the fuel not having o2 to burn. i've checked my boots they all seem good. didnt see any excessive soot marks either.

 

no but i have my egr unplugged. it was never unplugged when i had the edge, i've only recently unplugged it. i believe my SCT disables the egr anyway now.

 

no but i have my egr unplugged. it was never unplugged when i had the edge, i've only recently unplugged it. i believe my SCT disables the egr anyway now.

 

what boost are you running currently, can you still hit 30 easily ? i wonder if there is a difference between the boost reading on the edge monitor and the boost reading on a manual boost gauge, as i was using edge to monitor boost previously, and now an manual to monitor boost with the sct.

can i take to dealer and say that it seems to be lower boost now for some reason ( i wont mention it was right when i took off the cat )

 

When I first got my Banks, I had the EGR plugged in and the Cat on. I hit 30-35 pretty easily on Level 7, and it smoked pretty hard too.
Then I got rid of the Cat and no change to smoke or boost, but sounded better and maybe a bit more power.
Then I unplugged the EGR, got the CEL, turned the CEL off everytime I started the truck with the Banks PDA. Registered less boost on average. Observed much less smoke at WOT. Noticed a slight decrease in power.
If I remember the truck goes into some sort of safe mode with the EGR wires dangling thus resulting in lower boost and slightly decreased performance.
The SCT disables the EGR electronically and keeps the truck from going into "safe" mode allowing lotsa boost. And a big ole
But answering part of your initial question...my digital gauge seems to read a bit higher than the dash gauge does during quick spooling, but cruising, they both measure pretty close..

 

My manual gauge and my Attitude monitor show very close readings under average driving conditions. Unfortunately, when you need to know the most, neither is positioned in the right place to be able to see the numbers safely.
Badbrad may be right about the lag with the factory gauge; can't say for sure since my eyes are on the road at full throttle. He may also be right about the unplugging of the EGR. I think with the Sneaky Pipe blocking the EGR and the SCT turning it off, it should prevent any "safe" mode nonsense and improve overall function.

I would avoid going to the dealer unless things are really bad; like severely sticking turbo vanes. Just gives them an opportunity to snoop and find reasons to red flag you the next time (eg. My tailgate used to pop open at speed, and the dealer denied a warranty claim because I had a spray-on bedliner. And all it needed was a pin adjustment. Had nothing to do with the bedliner. But seeing the modded bedliner pissed them off enough to deny service. Your cat-delete could have a similar effect. Get to know your dealer/mechanics first. Some dealers are normal, others are not).
Someone on this forum is more likely to give you the best answers than the average dealer anyway.
I need to get that Heads-Up display for my gauge functions, so I can keep my eyes on the road. Or a telltale, that records high settings for later review. The edge will only show my max RPM and backdown% since last reset. Not very useful.
I feel there is still quite a bit of turbo lag, even though I often see numbers around 20 PSI. Can't say exactly how much past 20 they go, or how "easily" (quickly). I did see 30 once or twice, but rarely look down at speed.

 

okay guys here is an update :


i took it out on the freeway just now after it had sat for a while. i didnt really get on after the exhaust/gauge install earlier. well tonight cruising down the freeway i can say that i do have about a 200-250degree drop in egt's.

crusing boost seems to be lower than what i used to see on the edge. but once on the freeway in higher gears where i could load up the engine , it would shoot up to 30psi with no problem. i didnt have enough open road in front of me to stay on it, so not sure if it would go over 30psi will have to try that another night.

i have not installed the egr delete /block off yet, but i will go and plug my egr back in. i cannot say that i ever really noticed a difference anyway with it unplugged, however i'm not sure the computer knows it is unplugged, because it never threw a code (no cel, no code either, i looked with sct)

von , your edge should also tell you max psi, max egt, max backdown and max rpm, at least mine did, so i could go back and see how much boost it hit.

basically i jumped the gun little complaining about the boost, but i still have to say that i have lost A LOT of smoke, used to be black enough to block traffic, now i get a little grey, but not enough to even draw attention, and no black ??

 

I would say your cat was getting plugged and causing a restriction... If you're getting tons of power and very little smoke I'd say the boys at Spartan are doing a good job

The only time I can really make mine smoke is from a dead stop and I mat the throttle... Take it about 2-3 sec to clear and then I'm looking at the headliner

 

ya so does it make more smoke with the EGT plugged in or out? Bc i have a cat delete and it didnt seem to make much difference