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View Full Version : How much smoke at full throttle?



Scrufdog
03-23-2006, 19:55
What should I expect to see when I'm flooring the throttle in my truck? Assuming its warmed up and such. Right now I'm see a decent amount of gray smoke.

1997 K2500 6.5 Turbo Diesel with 155k miles.

charliepeterson
03-23-2006, 20:50
These trucks don't have a throttle delay on the engine so when you drop the hammer off the line you'll see smoke untill the turbo catches up. We are using two differant turbos. The GM-4 is slightly smaller and should spool up quicker off the line but kind of runs out of air at about 60-65mph. That's not to say the truck won't keep going because it can just not as strong as at say 30-35mph.
The other turbo is the GM-8 which is just the opposite. Both are good just made for differant applications.

rob from bc canada
03-23-2006, 21:02
I had a 93 6.5 TD standard, and it would smoke BLACK with the pedal down, if I got my RPM much over 2500. If I eased off the pedal a bit, I could run it up to 2800 before the smoke got really thick.

I never got any gray smoke, that might indicate water getting in someplace where it shouldnt.

Hubert
03-24-2006, 06:18
Its hard to say because smoke color and quantity is hard to quantify. Its relative to what you are use to.

You will see a good bit of black smoke at first then maybe dark dark gray smoke at WOT if the truck is all original. When my truck was newly used at ~ 70,000 miles it was pretty clean not much smoke. I experimented with different fuel additives and some increased smoke some did not.

My smoke levels increased slowly until the new exhaust and then got lighter due to easier breathing.

The amount of black smoke is dependant on mainly (3) things: 1) The amount of air (boost), 2) injector performance, and 3) fuel quality.

1) Keep a clean air filter and exhaust mods are usually the first advised (then guages. Depending on who you ask. Maybe a toss up: boost and pyro will help with diagnostics). 2) Injectors start to noticiably deteriorate at 80-120 K miles. They will work much longer but with slowly increased smoke and emissions and performance falls off slowly. 3) Buy good diesel and find an additive you like either for every tank or periodically for maintenance to keep fuel system clean.