Anybody dynoed in cold weather? How does it effect it?

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Feb 11, 2003 | 11:10 AM

EuG

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From: Vette

Anybody dynoed in cold weather? How does it effect it?

I’m interested in hearing from people who dynoed in cold weather (dyno room temp ~40-50F or lower)

What did you notice?
Was your SAE corrected power about the same? ? (assuming you dynoed before in different weather)
Was you’re A/F ratio effected by much? or at all?

Thanks. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

[ February 11, 2003, 11:12 AM: Message edited by: EuG ]

Feb 12, 2003 | 01:31 PM

John B

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From: Phoenix, AZ

Re: Anybody dynoed in cold weather? How does it effect it?

I recently re-dynoed when I was changing TB's and it was 47 degrees in the garage with the dyno and about 38 degrees outside. I was having KR limit my maximum timing so I was down about 12 RWHP (SAE) but the un-corrected numbers were 4 RWHP higher than before due to the colder weather. There was actually a pop-up window warning note on the dyno software that stated caution when making comparisions with this data due to "extreme" temperature variation.

Feb 12, 2003 | 02:34 PM

EuG

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From: Vette

Re: Anybody dynoed in cold weather? How does it effect it?

Thanks.
So you’re saying you saw some KR that you usually don’t see? Is that right?
Did you’re A/F change at all?

Thanks again! <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

Feb 12, 2003 | 08:45 PM

John B

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Re: Anybody dynoed in cold weather? How does it effect it?

<blockquote>quote:<hr /> So you’re saying you saw some KR that you usually don’t see? Is that right?<hr /></blockquote>Yes, normally I have zero KR. My only conclusion was that I am either sucking too much oil (I have bought an LS6 PCV set-up but haven't installed it yet) because when I changed the TB's I could see that the intake was oil soaked inside and when I dynoed last summer I just put the heads on so their was no oil in the heads. I can't remember which gas station I stopped prior to this dyno run so it's also possible that I also had some oxygenated gas in the car too.
<blockquote>quote:<hr />Did you’re A/F change at all?<hr /></blockquote>It was running just a hair leaner but what was strange is that I was about 20+ RWHP down and I decided to reflash the PCM with the exact same program that it was already running and I immediately picked up ~13 RWHP....go figure!

Feb 12, 2003 | 11:11 PM

EuG

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From: Vette

Re: Anybody dynoed in cold weather? How does it effect it?

Well, so after you re-flashed PCM you were basically only down ~7rwHP from normal? Is that right?
Perhaps computer learned something <img src="http://www.agrnet.com:8888/Pictures/Images/Smilies/Dunno.gif" alt=" - " />

Did you have any KR at that point (after reflash)?

If you were only within 7rwHP and possibly had some KR that you don’t normally have then I think we could assume that corrected numbers are pretty accurate regardless of the weather.

What do you think?

Feb 13, 2003 | 12:17 AM

John B

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From: Phoenix, AZ

Re: Anybody dynoed in cold weather? How does it effect it?

<blockquote>quote:<hr />Well, so after you re-flashed PCM you were basically only down ~7rwHP from normal?
<hr /></blockquote>Yes, it was closer to nominal but still down a bit because the timing still saw about 2.5° KR
<blockquote>quote:<hr />Perhaps computer learned something. Did you have any KR at that point (after reflash)?
<hr /></blockquote>I got a little less KR than before the reflash (was about 3.5° before and 2.5° after) but it also ran a bit leaner....about 13:1 A/F instead of 12:8 before the reflash which made no sense to me. I suspect that the leaner A/F got me more power back than the less KR but who knows at this point.
<blockquote>quote:<hr />I think we could assume that corrected numbers are pretty accurate regardless of the weather<hr /></blockquote>At this point I would say you're probably right although I personally believe that for us folks living north that Std Corrected numbers (rather than SAE) are a better number to use since the weather conditions better reflect reality (I believe it is ~68° temp plus a higher level of humidity).