Estimated HP increase in Cold Weather Driving - Page 3

Norm Peterson · 02-21-2019, 10:24 AM

Quote:

Originally Posted by danhr

Your track changes altitude?!?!?!

Look up something called "density altitude".

Norm

Deakins · 02-21-2019, 12:26 PM

Yeah this whole thread is pretty much proof positive that almost no one (at least in this thread) has ever done any serious performance work. Every real racer that I know travels with a portable weather device so they know for certain, at their location, the DA, temp, humidity ect. These numbers are critical to understand how the car (or aircraft) will perform.

danhr · 02-21-2019, 03:32 PM

Quote:

Originally Posted by Norm Peterson

Look up something called "density altitude".

Norm

Your sarcasm meter is broken bro

lt4camaro · 02-21-2019, 06:24 PM

Quote:

Originally Posted by MackSteelPrivateEye

There is definitely an HP increase in 20deg/cold weather driving over warmer temps of 60's and above. Feels like a good 10 to 15 or maybe 20 HP more. Anyone have a better idea of the cold weather increase Vs. Summer temps.

1 % for every 10 degrees

RyanR623 · 02-21-2019, 06:38 PM

Yes colder denser air provides more horsepower given there aren't compensation tables built into the ECU. I think the real question I'd like to know is what temperature Chevy tested the lt1 to get to 455hp. Based on dyno numbers I've seen it must have been at 115 degrees at high altitude ha ha!

BFella · 02-22-2019, 01:04 AM

Unless you're boosted you're not going to feel a difference between ambient temps.

whiteboyblues2001 · 02-22-2019, 07:38 AM

Quote:

Originally Posted by RyanR623

Yes colder denser air provides more horsepower given there aren't compensation tables built into the ECU. I think the real question I'd like to know is what temperature Chevy tested the lt1 to get to 455hp. Based on dyno numbers I've seen it must have been at 115 degrees at high altitude ha ha!

Folks keep talking about copensation tables, but isn't that just for boosted engines?

From what I understand, the MAF (Mass Airflow Sensor) measures the MASS of the air going by, so no compensation for altitude or pressure should be needed. If the sensor was just a volumetric flow meter, you would have to know and compensate for the changes in air pressure because that would change the amout of air even if you have the same amount of flow, but by measuring the mass, you already have the number you need, no compensation necessary, just add the correct amount of fuel based on the amount of air, and BOOM, proper combustion...

mdhopt36 · 02-22-2019, 08:08 AM

About the most sensible thing I've seen here.

About density altitude being sarcastic?

Pretty smart reply followed by an ignorant response, IMO.

danhr · 02-22-2019, 08:25 AM

Quote:

Originally Posted by RyanR623

Yes colder denser air provides more horsepower given there aren't compensation tables built into the ECU. I think the real question I'd like to know is what temperature Chevy tested the lt1 to get to 455hp. Based on dyno numbers I've seen it must have been at 115 degrees at high altitude ha ha!

Well the 455 rating is SAE certified, so it would be at SAE temperature

grampa_ss · 02-22-2019, 08:40 AM

Quote:

Originally Posted by BFella

Unless you're boosted you're not going to feel a difference between ambient temps.

When I was NA...I could definitely feel a difference. My local track is 4500'. if it's 40 degrees outside, I run 12.4. If it's 100, I run 13.1. So yes, you can feel that difference. The DA will vary from 4000-8000+ depending on the temperature.

Jim50thSS · 02-22-2019, 10:07 AM

There is more going on than just colder denser air, which changes the combustion and should have an effect on output of the engine. However the ability to keep the engine cooler changes how well the components and lubrication works as well. Just remember starting your cold engine when solid lifter were common and how rough they ran until the engine gain some temperature.

02-22-2019, 01:04 AM	#34
BFella Drives: 16' Supercharged 1SS Join Date: Apr 2014 Location: Scottsdale, AZ Posts: 650	Unless you're boosted you're not going to feel a difference between ambient temps. __________________ My Build Thread 760RWHP Magnuson 1SS

02-21-2019, 12:26 PM	#30
Deakins Drives: 2017 2ss, m6 Join Date: Jan 2017 Location: Iowa Posts: 231	Yeah this whole thread is pretty much proof positive that almost no one (at least in this thread) has ever done any serious performance work. Every real racer that I know travels with a portable weather device so they know for certain, at their location, the DA, temp, humidity ect. These numbers are critical to understand how the car (or aircraft) will perform.

02-21-2019, 06:38 PM	#33
RyanR623 Drives: SS A8, NPP, Red Hot Join Date: Jan 2019 Location: Toledo, OH Posts: 583	Yes colder denser air provides more horsepower given there aren't compensation tables built into the ECU. I think the real question I'd like to know is what temperature Chevy tested the lt1 to get to 455hp. Based on dyno numbers I've seen it must have been at 115 degrees at high altitude ha ha!

02-22-2019, 08:08 AM	#36
mdhopt36 Drives: '17- 1ag37 V6 traded, for 1SS 2018! Join Date: Mar 2018 Location: MA Posts: 469	About the most sensible thing I've seen here. About density altitude being sarcastic? Pretty smart reply followed by an ignorant response, IMO.

02-22-2019, 10:07 AM	#39
Jim50thSS Drives: 50th SS Convertible Join Date: Jul 2017 Location: Swanton, Ohio Posts: 103	There is more going on than just colder denser air, which changes the combustion and should have an effect on output of the engine. However the ability to keep the engine cooler changes how well the components and lubrication works as well. Just remember starting your cold engine when solid lifter were common and how rough they ran until the engine gain some temperature.

User Name		Remember Me?
Password