S475 won't clean up smoke

Cknight199

New member
Aug 23, 2012
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Salt Lake City, Utah
I could really use some help.

Okay so I recently got my motor back together, and I was thinking that my 40% injectors would be my limiting factor. After watching a couple of these dyno pulls, something else is either fueling too hard or not allowing it to clean up. Thought it was my MAF reading 80g/s at idle but I swapped it with a working maf and it still read the same. (Could be tuning related so I'm getting it rescaled)

So here goes my situation:

S475/83/.90, 40% injectors, stock dual pumps, and I my tunes are 1800us, 2100us, 2400us, 2600us, and 2800us. My 2600 and 2800 tunes build around 50 psi of boost.

I had a retune done by another tuner and it made around 750 on the dyno, but the second we got on the street it had a terrible timing rattle and it smoked grey because there was so much fuel. Would kill my turbo when I'm at WOT if I didn't help it get spooled. He said he couldn't find anything in the tune that would add timing like that since it was at way more timing than what it commanded in the tune. With the same tunes, if I unplugged my MAF sensor it would jump instantly to 25* timing once I passed a certain throttle position.

Changed back to my original tunes (in the dyno video) and they make power, but don't really clean up on the street or dyno. They still have a bad timing rattle but not as bad as my other tunes.

My question is am I just asking too much out of this turbo, or is there another issue I'm overlooking.

First 3 runs I hit a speed limiter and didn't find out till the last run, so the last run goes through a better rpm curve. (3000-4600)

https://www.facebook.com/story.php?story_fbid=10206804619659931&id=100006760412374

Did 667hp today, and have had a couple 750hp dyno's in the past week or so. Maybe I am expecting too much out of my truck but comparing the dyno numbers to other similar trucks (friends lbz did 750ish on the same dyno with 30% overs and a 2650 us tune, but even smaller turbo, and it cleans up the fuel.)


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S Phinney

Active member
Aug 15, 2008
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Quncy, Fl
You just did this build right? Piston selection will determined how you approach the timing as well. Those injectors and turbo combo should not have a problem with smoke levels if the tuning is right. Bad injectors could cause this issue but would most likely occur from contamination destroying them. There would have to be a part or incorrect tuning that would cause it to jump to timing that wasn't written that way.
 

S Phinney

Active member
Aug 15, 2008
4,011
18
28
Quncy, Fl
Look into ect and iat for a issue with temp readings because that would be the most likely cause of a modifier making a timing change.
 

PACougar

Active member
Jun 27, 2012
2,105
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40
El Dorado Hills, Ca
I have a very similar problem on my reg cab. In fact I would suspect the same problem. Let me know if the Maf rescalling makes the difference. I'm going to log mine later today and compare it to my ext cab, they both have similar setups and the same tuner. The ext cab rins so well it's ridiculous. I'll post up if I find any obvious differences.
 

quinton

Active member
Nov 28, 2011
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Granbury Tx.
This may sound crazy but just going from a 1058 to a 1053 cleaned up the smoke from mine a lot with the same tunes


Ya that's why I asked. Lol. When I had mike stock stall ml and 475 smokey pig. Sent it off to precision to get restalled and everything cleaned it up a lot. I had bad timing rattle to.
 

DMAXchris

It’s only temporary!
Apr 28, 2009
2,274
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43
Natrona Heights PA
Something is up with tuning or a major boost leak. My truck is smokeless once the charger is above 30 psi. Looks like a stock turbo max effort going down the strip.
 

gmduramax

Shits broke
Jun 12, 2008
4,045
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Nor cal
Your injectors must be bigger than 40's. I had an S475/83 1.10 AR with 100's and dual pumps and dynoed 785 and trapped 119mph with 2800 pulse.
 

Cknight199

New member
Aug 23, 2012
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Salt Lake City, Utah
You just did this build right? Piston selection will determined how you approach the timing as well. Those injectors and turbo combo should not have a problem with smoke levels if the tuning is right. Bad injectors could cause this issue but would most likely occur from contamination destroying them. There would have to be a part or incorrect tuning that would cause it to jump to timing that wasn't written that way.


If I had bad injectors would my balance rates tell me that they are bad? My balance rates are perfect...

Look into ect and iat for a issue with temp readings because that would be the most likely cause of a modifier making a timing change.


Can you view your tuning or are you locked out?


I am locked out :/

Something is up with tuning or a major boost leak. My truck is smokeless once the charger is above 30 psi. Looks like a stock turbo max effort going down the strip.


I will boost leak test it today

Your injectors must be bigger than 40's. I had an S475/83 1.10 AR with 100's and dual pumps and dynoed 785 and trapped 119mph with 2800 pulse.


Hmm this could be the case, but then I still should be making more power right?


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LbzDMax07

Member
Dec 16, 2013
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PA
Since your running the 83 turbine maybe its on the upper limits for power where your at. Maybe that's causing some smoke issues.
 

mike diesel

I'm alright.
Sep 6, 2012
4,005
0
36
SLC, Utah
Wonder if it got smashed when the motor was out? How bad is the leak? For the leak to make the truck do what it's doing, it would have to be leaking as soon as you apply air, not after you see 10+ psi.
 

Cknight199

New member
Aug 23, 2012
1,827
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Salt Lake City, Utah
Wonder if it got smashed when the motor was out? How bad is the leak? For the leak to make the truck do what it's doing, it would have to be leaking as soon as you apply air, not after you see 10+ psi.


Yep that's what I'm thinking. It's a major leak. I hear it as soon as I apply air


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DMAXchris

It’s only temporary!
Apr 28, 2009
2,274
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Natrona Heights PA
Yea,, time to upgrade


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:thumb:

I'm extremely interested to see what it runs since we have the same size injectors, but I don't have dual pumps yet. I've been wondering how deep in the 11s you can go on fuel only without a lot of fuel. My turbine is 87mm and it'll have a 1.0 soon, but they should be fairly close.