Is it just me?

Cummins Driver

Cummins Driver

THE Cummins Driver
Joined
May 16, 2007
Messages
2,405
I guess it must be the summer air. Its been fairly hot here this summer and also pretty humid. My truck just doesent seem to like it. It seems to be spooling slower and smokes more.

I guess its to be expected with the summer air. I have an exhaust leak under the hood(post turbo) and im wondering if it could have maybe clogged my filter some, but I dont really think thats the problem since EGT's seem to be in check, and spool is fine in the higher RPM(1800rpm+). I can still have 10psi by 1200rpm, but it just seems like it takes it a while to get past that. It seems like the mid range(1400-1700) takes longer to build boost than it should. It will build it, it just seems to take longer.

I hate to check it all out and it just be the fact that its hot and humid, but I also hate to have a problem and not know it. Does anyone else's truck seem to act this way in the summer?

Eric
 
Well I would have to agree about the heat and humidity!!

Of course I just put this thing together and the heavier pistons make it a bit laggy off idle but it's not too bad at all with the new adjustable LL setting from the SSR Smarty....

But I was thinking last night when driving, that the last time I drove my truck and it was spooling pretty dang fast, it was only 45-70 degrees back then...I blew it up in March I believe, so temps and humidity were definately lower..

So I may not have as much of a spool change as I thought with these pistons.....I'd have to wait till it cools down to the get a good comparison..
 
Darn common rails and their fancy tuning:hehe:

I have had my exhaust leak for a good while. Im not sure if that will clog a filter enough over time to make a difference or not. I might pull the filter soon and take it for a drive to see how it acts.

Eric
 
My 99' with He351cw definitely is down on power, slower to spool, and makes more smoke when it's 105*F here in Vegas vs a month ago when it was upper 70's.

If you really want to feel a doggy slow spooling motor, go drive around in Utah or Colorado at 5000' on a 100+ degree day!
 
High, hot, and humid are 3 things which will affect performance. The air isn't as dense, that's just the way it works. Electronic motors are nice because they can mask some of the potential drivability effects associated with the 3Hs, but they're still going to be affected by it too.
 
Yea in march at the dragstrip I was trapping between 90 and 91 mph in the 1/8th and last weekend the best I could manage was 89...that's a difference of like 20-30 hp...that may not seem like much but when you get used to how ur truck feels it kind of scares you because you think something is wrong with it
 
Yep... My truck does the same thing when the heat and humidity rise.

You can actually feel the difference between the middle of the day air and the cooler air in the evenings and nights.

It's a very noticable effect on my truck.
 
Ever notice how on a cool foggy morning your truck runs like a raped ape. Free water injection
 
Here you go, now you can figure out what "altitude" your truck is "seeing" on these hot days. Humidity is not factored in, but it should be noted.

http://www.asiresource.com/DensityAltitudeChart.PDF

Here's a local (for me) example:

Current temperature: 18C
Current altimeter setting: 30.10
Local airport elevation: 902'

We need to find pressure altitude first so you can do that by taking 29.92 - the current altimeter setting, then multiply by 1000 and add the local elevation.

29.92-30.10= -.18
-.18*1000= -180
902-180= 722'

Now that you know pressure altitude you can apply it to the chart, and looking at that it shows my local density altitude to be at roughly 1400' above sea level, which means that my car/truck/airplane/boat or whatever will perform like I'm at ~1400' above sea level even though I'm at only 900'.




lorendiesel5.9 said:
Ever notice how on a cool foggy morning your truck runs like a raped ape. Free water injection
Click to expand...

Yes, but I'm going to lean towards there being other factors involved with this besides a lot of moisture in the air. What's the air temperature, altimiter setting and elevation during these events?
 
my truck always smokes a lot more when its warm and humid and takes just a bit longer to spool...gotta love mother nature
 
Im glad im not the only one.

Not to mention that whatever you lose because of the air can be stacked with the loss from running the A/C compressor. Im not sure how much difference that makes, but im pretty sure it takes a few HP to run it.

Come on fall! :hehe:

I was pretty sure it was normal, but i just wanted to be sure everyone else felt as much difference as me. Its 93* here today and has been a pretty hot and humid summer in general.

Eric
 
I hate summer!!

Wearing a 30 lb. uniform and standing outside dealing with chit bags or working accidents for morons that can't drive!!

SUX!!!!!!!!



Like you Said, "Come On FALL"!!!!!!!!!
 
Yeah, i bet that is fun. Its 10:00pm here and I just got done washing my truck 30 minutes ago. The humidity was killer. I was soaked from sweat just from doing that. The sun only makes it worse.

Oh well, I start my new job tomorrow and I think ill be in the A/C a lot! :hehe:

Eric
 
Big Swole said:
I hate summer!!

Wearing a 30 lb. uniform and standing outside dealing with chit bags or working accidents for morons that can't drive!!

SUX!!!!!!!!



Like you Said, "Come On FALL"!!!!!!!!!
Click to expand...

I hear ya brother! Up the crapp I wear by 60lbs and go for 115+ temps.

Last summer it was one of those hot, muggy, haten life, Al days and my EGTs scared the chit out of me. I called Jeff G and he said you just got a lesson in air density. Can you say bigger intercooler.

Brian
 
Big Blue24 said:
My 99' with He351cw definitely is down on power, slower to spool, and makes more smoke when it's 105*F here in Vegas vs a month ago when it was upper 70's.

If you really want to feel a doggy slow spooling motor, go drive around in Utah or Colorado at 5000' on a 100+ degree day!
Click to expand...

you aint kiddin LOL at least its not humid LOL
 
I can attest to how much the A/C compressor puts a drag on an engine...my poor TDI loses its already nonexistent balls when I kick the air conditioner on.
It's so bad, VW designed the cars to disengage the compressor until 2nd gear. You know when it kicks back in...
 
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