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I have now deleted a wastegate. Welcome to the world of ATT

Slim Shady said:
The turbo bearings are tight when first out of the box as the bearings get burnished in and the pcm does some adaptive learn (they do that and GM notes it in the manual) the truck will drive better. The exhaust is a crucial part of the package, any small 3 inch system will affect the pressure differential across the turbo. The freer flowing the exhaust, on the turbo exit, the faster the turbo will spool up. I recommend a straight through muffler if possible. I have had (Buddy was one, he can explain) two people that replaced their Banks exhaust and the truck ran much much better. ED If you are not happy pm me and let me know, but I am sure after towing you will see what your truck is really capable of.
Click to expand...

So far I am quite impressed. In time I may get a towing tune from heaths, The Coquihalla hill will determine that. I got to play with the truck a bit today in the the daytime with dry weather. I was stopped at a light and first in line with some kid playing loud music one car back to my right side. I don't know why some people play non english music loud with their windows open. I mean I kinda think East Indian music sounds neat, just don't get the words. Anyhow I says to my wife, Watch this. She knows me well enough that "watch this" means something's gonna happen. I says watch for BLACK smoke. and I punched it hard. She started laughing cause the guy is frantically rolling his window up. She also says ya know when you do that to people they really can't take it as you did it intentionally. You can always say you didn't see the open window. Anyhow, off the line it does shoot more BLACK smoke, I don't know that it is that much slower off the line that the gm8. It still takes off pretty quick and does pull harder. I would say a definite improvement over the gm8. later in the day it rained and off the line I had the tires on the dually spinning in O/D just to see if it would do it. That it never did pre ATT. Says me, once that turbo spools there is more power. Keeping in mind I have the 4.10 rear end I can put more torque to my rear end than say a 3.42 or whatever it is. I sacrifice top end for pulling. Ed
 
And my muffler. It has like an 8 inch diameter and it is straight in straight out. I could slide a baseball bat through it or drop a 4 inch bowling ball through it as there is no restrictions on it. I asked about that before I bought the muffler. It's there but don't see it as doing much muffling.
 
When you wipe the grin :D off and start driving normally again I would like to know what your before and after MPGs are.
 
Edzzed said:
x2 on that. It'll also shoot some black smoke when I punch it from legal road speeds.
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You now have a diesel engine that can and will tow much better. Your truck will change, and get more responsive over a few weeks to a month of driving. A real good tow will break everything in well. Once your exhaust manifolds clear out of the diesel soot that is in them and the piston crowns clean up the whole motor will start to breath like it was supposed to. Keep us posted, like I told you before, my concern is your satisfaction with the turbo nothing less.
 
I've had mine for a couple years now, at first I thought I noticed a difference but I'm so used to it now I don't know. It certainly doesn't feel fast to me, and the dragstrip proved that. Even running it hard at stoplight to stoplight it feels kind of slow. Not saying it's the ATT, it's more than likely the oversize tires sucking the life out of it. Which is discouraging because they're much smaller than tires I've run on gassers without such ill effect. The only place I can really feel a big difference with the ATT is pulling the camper up the big hills. It makes all the difference in the world. A combination of things has improved that immensely. I went from struggling over the top at 35 mph in stock form, to blowing across at 58 mph with the same trailer. That's with ATT, 4 inch exhaust, KOJO, FTB, and Walbro. If I went back down to the 235/85s, which are only a little bigger than stock, I bet it would pull like a locomotive.
I wouldn't buy the ATT with racing in mind, it's a towing mod in my opinion. My bone stock 94 Sub feels quicker, if it isn't faster it would certainly run with it. But I'm sure hooked to the camper it would fall on it's face just like the stock 97 did. We'll find out this summer. Sadly, all these mods are leaving. I'm finally selling my 97, and I'm leaving all the mods on it. So if I want to go that route again with the Sub, I'll be spending some more money buying the same stuff again.
On another note, what's the difference between the older gm turbo and the newer one? I've got presumably the stock one on my 94, but I still have the takeoff from my 97. Would that be in any way a worthwhile swap?
 
Just tuning in as I'm considering doing the same thing with mine.:agreed: Selling the GM8 and upgrading to an ATT. I have to replace the replace my crossover first as I just found a pin hole starting in it. 2.5"er on the way though.
 
Slim Shady said:
You now have a diesel engine that can and will tow much better. Your truck will change, and get more responsive over a few weeks to a month of driving. A real good tow will break everything in well. Once your exhaust manifolds clear out of the diesel soot that is in them and the piston crowns clean up the whole motor will start to breath like it was supposed to. Keep us posted, like I told you before, my concern is your satisfaction with the turbo nothing less.
Click to expand...

w/m might clean up the soot too. Now that it has been on there a week I have yet to really drive it this week. Loaned my wife the truck till her ride gets built. She ordered a ford escape and sold hers privately. Been putting some miles on the M/C. I did have the truck today and punched it off the line. I see what Detroit Dan says about "I wouldn't buy the ATT with racing in mind" I'm thinking or wondering if with the thunder cloud it shoots out of the pipe being unburnt fuel then yes it must have some lag off the line, I can get over that as it doesn't take much time to spool the ATT. I want to get a video of how much soot I can spray out of the pipe soon, I also want to do another 0-70 mph or maybe even 80mph. so you can all compare with the vid in my sig. Copy and paste into your browser. Ed
 
ED I had the HP4 from heath originally (still have the chip, want to buy it) and my hp4 smoked as well. You may want to ask Mr Heath if he can re-tune your PCM if the smoke doesn't clear up. I have a five speed so I can make mine smoke if I want to at anytime. (MY NEW TUNES YEP MULTIPLE ) are better designed for my application, course I have some blackop modifications that I like so far but not sure how they are for everyday driving. Might just be for that race truck everyone wants.

Try disconnecting your battery for a minute so that your PCM will re-learn, and also what TDC offset are you running. If you are NOT happy contact me, I will make it right.
 
Edzzed said:
w/m might clean up the soot too. Now that it has been on there a week I have yet to really drive it this week. Loaned my wife the truck till her ride gets built. She ordered a ford escape and sold hers privately. Been putting some miles on the M/C. I did have the truck today and punched it off the line. I see what Detroit Dan says about "I wouldn't buy the ATT with racing in mind" I'm thinking or wondering if with the thunder cloud it shoots out of the pipe being unburnt fuel then yes it must have some lag off the line, I can get over that as it doesn't take much time to spool the ATT. I want to get a video of how much soot I can spray out of the pipe soon, I also want to do another 0-70 mph or maybe even 80mph. so you can all compare with the vid in my sig. Copy and paste into your browser. Ed
Click to expand...

I started with HP4 at 1st, now have a ATT adapted tune from Bill, a lot of work between HP4 and the current tune I'm running, I suggest you spend some time on phone with Bill and let him know what you are after in way of a tune, since he's in house tuning now vs. 3rd party tuning to his specs, he can custom tune to your specifications/desires now.
 
Slim Shady said:
The turbo bearings are tight when first out of the box as the bearings get burnished in and the pcm does some adaptive learn (they do that and GM notes it in the manual) the truck will drive better. The exhaust is a crucial part of the package, any small 3 inch system will affect the pressure differential across the turbo. The freer flowing the exhaust, on the turbo exit, the faster the turbo will spool up. I recommend a straight through muffler if possible. I have had (Buddy was one, he can explain) two people that replaced their Banks exhaust and the truck ran much much better. ED If you are not happy pm me and let me know, but I am sure after towing you will see what your truck is really capable of.
Click to expand...

Banks is a crush bend system. Even w/o a kitty it is restrictive. So add the 3rd person dumping this system. Must admit it is a fairly quiet exhaust though even with a straight through muffler.
 
Slim Shady said:
what TDC offset are you running. If you are NOT happy contact me, I will make it right.
Click to expand...
I don't know the answer to that, I do know that when Bill Heath installed the hp4 he hooked up the truck to his tech 2. I'll try the battery disconnect and see what happens. Hopefully I'll know more about how the truck tows next month when I get my spring vacation.
 
Disconnecting battery won't do anything for OBD-II if you want to relearn you'll have to initiate it with a KO/KO APP to floor otherwise the TDCO in there now will stay indefinitely just like theft deterrent code does. Swapped in a PCM out of my truck that had been on shelf for over a year TDCO was same as when it was removed as was theft deterrent code.

HP4 was designed around the GM-X turbo and mine was over fueling on bottom end if I got into it hard, Bill tweaked fuel & timing for less bottom end smoke and added more to middle & top end, if I stomp it now it will puff healthy cloud but not for long then clears up. If I drive sanely no smoke, and acceleration is on par with what I had on my GM-8 turbo and far superior top end.

3 tunes ago Bill set me up with one that was a LOT of smoke even if you lightly rolled into it, folks in Albany NY when I was in steam turbine school didn't care for that one, as if I stayed in throttle with that tune 3 lanes of traffic would be smoked over.
 
I think he meant to remove battery for the supposed "adaptive learning"

Glad to hear you agree fuel and timing has to be adjusted to deal with slower builup of boost. And you have had the ability to smoke out an entire interstate with it.
 
Looks good Ed

I think your 0-70 is every bit as quick as the old vid. Smoke only lasts for a couple seconds
 
Pretty respectable, a little more advance in that tune and it will be real respectable.
 
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