Low boost & black smoke with ATT

[Detroit Dan]

This weekend was the big test, towed the big camper up to the mountains. First couple of small hills I was impressed, first pretty big hill I was extremely impressed, I took a hill from a dead stop at the bottom got up to 45-50 and held it there. I stayed in the right lane but nobody got by me. I was actually laughing out loud. But I was a little less impressed on the biggest hill, it didn't exactly fall on it's face, but it seemed to be stuck in 4th at only 2200 rpm. Couldn't downshift to get more rpm without slowing up, so I stayed at about 40-45 at 2200-ish. Next big hill I tried keeping it in third, but it was the same speed with more rpm. (all my mph numbers are estimated, my speedo is off.) This is still an improvement over the old turbo, because I'd have been going about 35 and worried about cooking the motor. But I was really hoping to blow right up and over the hills with little effort. Just seems like I can't get rpms and can't get much boost, maxed at like 7 psi, but normally even on hard pull I was only seeing about 5.
Forgot to mention, the first big pull where I started from a stopsign dead stop, the temp got up to 235 and skeert me pretty good. It came right back down after letting up though. I had just added a bottle of redline water-wetter. The other big hills I only saw 210-215, I cranked the heat to try and help it out.

Took a different route home, lots of small sharp hills, but only one long uphill highway climb. Held 52 mph according to wife behind me, which was pretty good. On the other hills it was very impressive as long as I saw it coming and got enough of a run at it to get into the right gear. Still got a tremendous amount of black smoke under quick acceleration. Standing stops pulling out into traffic on level ground is vastly improved. Vastly.
Overall I'd guess maybe a 15-20% improvement over stock turbo. Driving empty it's slower from a stop, but loaded it's faster taking off.
All that's left I guess is to time it and save up for the Heath ECM. Don't know of anything else I can do to get more out of it.

 

[Turbine Doc]

Dan hope you don't mind I borrowed your thread from the 1 year later thread, something is not quite right here you should be making more boost, since you have smoke I don't think it's a under fuel issue, it's lack of air, you do have stock PCM which is going to limit you to 10 psi of fueling ability once we get this resolved. Reflash which improves shifting-max fuel & timing will get maximum power gain from the ATT, works okay with stock program but really "comes alive" with the Heath reflash.

Do you have ability to read your IAT, it would be interesting to know what temp you are seeing there, what kind of muffler comes with the Diamond eye system, it it cross flow or through flow, I had issue with my original Banks Stinger system circa 2000 when truck was new to me, their muffler reversed flow and caused some issues with my GM-8 (minor but still there) issues were corrected with the Heath exhaust, IIRC Buddy had issues with his ATT install & a Banks muffler, low boost and heavy smoke.

Is it possible for a test you straight pipe the exhaust remove the muffler and see if it makes a difference?

 

[Slim Shady]

Detroit Dan

I think Buddy may be able to shed light on this. If you have an exhaust that has a muffler that is not flow through that will limit the exhaust flow and cause a restriction. I would try a straight pipe if the muffler is not a flow through. Some exhausts don't flow as much as they say they will, The free flowing exhaust is a must with the ATT to get the full benefits. CAll me if you have questions , you have my personal cell number, we can figure this out.

Maybe Buddy will comment on his experience and fix. I ran a stock chip with a Jardine straight through exhaust and could get 10 psi before I used up all of the fuel. Heath now has a chip that is tweaked a little for a larger turbo (ATT). I think we just need to figure out the hickup here. Do you have your TDC offset set at negative 1.50 to 1.94? This also makes a difference.

 

[mrbucbuck]

Detroit Dan

Sounds to me like ypu're having a intake air flow problem, due to some type of restriction, or even charge air pressure loss @ turbo/intake manifold area...check that the intake hose clamps are tight and that the boot itself is sealed up tightly. I ran into that problem last night as I had heavy black smoke @ 1-2-3 gears....intake air hose clamp was tight but had a small contact gap....

 

[packratt]

The one time I ran into extreme IAT's I couldn't build boost and I believed defueled. I do know I had thrown a code. Sorry, can't recall the #.

I'm running stock chip and I believe I'd maxed out the fuel rate at the time.

 

[Acesneights1]

Also exhaust leaks in the crossover or restricted(factory) crossover possibly ? Some of the factory crossovers that vintage are pretty restricted. I know you have the diamond eye but I'm not familiar with it and don't know if it includes a new crossover so I thought I'd mention it. when the crossover on my 2000 started leaking I lost alot of power. Of course my crossover argued with a large rock.

 

[dracor85]

I had one of my donuts that seal the cross over turn sideways on me once cause the PO didnt tighten the bolts down all the way. Any way I went from 10psi max to 18psi max with only fixing the donut and no other changes. This is the stock turbo on my 95.

Justin

 

[mrbucbuck]

One thing that I noticed is that with stock programing the ATT is sensitive to throttle positioning. WOT gives you the fuel but not the air demand. I had to totally relearn how to drive this truck with ATT and stock chip. I'll be adding a heath chip as this will truly compliment the ATT. As for lack of air....I need a 'Hi-Flow' intake system. Any ideas?

 

[Acesneights1]

The 94 Airbox is not as good as the later ones.

 

[Acesneights1]

Detroit Dan

Sounds to me like ypu're having a intake air flow problem, due to some type of restriction, or even charge air pressure loss @ turbo/intake manifold area...check that the intake hose clamps are tight and that the boot itself is sealed up tightly. I ran into that problem last night as I had heavy black smoke @ 1-2-3 gears....intake air hose clamp was tight but had a small contact gap....

Hmm...air filter ? Sounds stupid but it always is the stupid things we miss.

 

[96 OILBURNER]

Dan, did you install the muffler with the louvers catching the exhaust or turned to the rear?

 

[Slim Shady]

One thing that I noticed is that with stock programing the ATT is sensitive to throttle positioning. WOT gives you the fuel but not the air demand. I had to totally relearn how to drive this truck with ATT and stock chip. I'll be adding a heath chip as this will truly compliment the ATT. As for lack of air....I need a 'Hi-Flow' intake system. Any ideas?

Welcome to the ATT club glad to here that you like the turbo, I have been wanting to get input from everybody regarding their experiences with the turbo. I take it the UPS man was nice to the package. Did the packaging make it intact without damage? I miss talking with every purchaser, especially the ones that purchase through the web site. My number is on the installation instructions. cal if you have questions or kust want to shoot the BS about the turbo.

Slim

 

[mrbucbuck]

Slim,
First off, you the man!!! Package arrived intact with no damage, perfect. Installation was straight foward and exact! I still can't get over how much better performance is overall....I can tow 34,000lbs gcvw with a head wind and cruise 60 mph+...no problem.
Man, thats what I'm talkin about!!!

 

[Veg_Out]

One thing that I noticed is that with stock programing the ATT is sensitive to throttle positioning. WOT gives you the fuel but not the air demand. I had to totally relearn how to drive this truck with ATT and stock chip. I'll be adding a heath chip as this will truly compliment the ATT. As for lack of air....I need a 'Hi-Flow' intake system. Any ideas?

If you can find an airbox off a junker from a 97 or newer, you will have better flow. That said, Slim is running the stock airbox and his will pull a house down.

 

[Detroit Dan]

Well, to try to answer all the questions at once, I have a 6 month old DiamondEye 4 inch system, included new downpipe. I had been running without a muffler, so I was tempted to leave the new muffler off, but I ended up installing it. It is a straight-thru design, with spiral louvers to catch some of the flow. I reversed the muffler so the flow would go straight thru and not waste time sitting in the muffler doing nothing. It sounds great, a little less raw than the old 3.5 straight pipe, but better in that it lets the v8 sound really rumble. I think it sounds like a big block chevy at the tailpipe, if you could block out the clatter coming from up front. And under a heavy loud when it's catching a gear and accelerating, it sounds absolutely beautiful.
The crossover pipe was replaced a few years ago when the original rotted out. Just bought an oem style replacement from Robbins Auto Parts. Also, I recently noticed a little exhaust leak at the turbo clamp, couldn't get it straightened out enough to seal tightly, it has about a 1/4 by 1/4 inch space where the clamp bolt is. But that's after the turbo so I didn't think it could hurt anything.

I haven't got the IP timed yet, asked around a couple local shops, no one has the wrenches or seemed real interested in it. I will check the intake air connections over carefully tomorrow to see if maybe I'm sucking air. My air filter is ok, I went back to paper last time I changed it, I ran a K&N for years but finally gave it up after reading too many negatives.

I have the stock 97 airbox, which...wait a second, I'm having a thought. When I changed the turbo I also replaced the right fender because of a rust hole. My airbox mated up to the inside of the new fender, but to be honest I don't remember looking closely into the fender to see if it's restricted. I can try to check that out too.

For a long time I've been seeing oil push from the hose that connects back to the egr or cdr or whatever it's called. No idea what thats about, but it doesn't seem like it could hurt anything to feed a little oil mist to the turbo.

 

[ak diesel driver]

My vote is for the IP timing. Get car code and do it yourself.

 

[Slim Shady]

Slim,
First off, you the man!!! Package arrived intact with no damage, perfect. Installation was straight foward and exact! I still can't get over how much better performance is overall....I can tow 34,000lbs gcvw with a head wind and cruise 60 mph+...no problem.
Man, thats what I'm talkin about!!!

That is why I think, the problem with the the smoking on this truck and the ATT turbo is related to the exhaust or some other problem, not the turbo.

If you get a notion call and talk I love talking to people from different parts of the country. I am glad you like the turbo, it definitely a turbo made for heavy towing

 

[Matt Bachand]

Dan, I also had a tough time getting my Diamond eye DP to seal on the flange. It doesn't leak, unless I block the tailpipe (which now takes a pillow instaed of a rag ) , and I can hear a little escape. I took it off and on 3-5 times, and finally said, I'll deal with it again when I install the ATT next year

IF that helps at all.

My Diamond Eye muffler had straight thru honey comb lookin, with no directional change either way.

 

[Matt Bachand]

Where do you live Dan? I know your handle is obvoius, but somereason I thought you were near me by previous posts... (Mass) ((Ass))

I hope you by me, as a bunch of us here need to get -1.5 TDCO... just no scanner

 

[Brooklyn Tow]

I thought if that V clamp was on there good, that the DP was mated up against the turbo, otherwise the Clamp would be skechy (not straight, hard to close, etc)?