Pro Mouse

iTrader: (15)

My Car has an open loop tune and puts down seat of the pants power with a 200 degree coolant temp vs. 170-180.My OLFA is the same at these temps and my PE is the same as well.So what would make it have more power at Hotter temps?Thanks

fenix999

iTrader: (17)

For some reason ive seen these cars run much better at "operating" temp then in "colder" conditions. Remember these cars come factory to run at 210* and 220 as well in hotter conditions. Stock fans etc dont turn on till about 220-225* so yea thats hot. lol and yes its weird ive experienced them running better when they're warmed up, more than one actually

Modsquad

iTrader: (6)

I've had a couple guys tell me not to run the lower temp thermostat because they are aluminum block motors. I forget exactly the reason, but because I design & built metal tools for oil wells, I'm just taking a guess, maybe it has something to do with the rate of expansion of the different types of metal.

Pro Mouse

iTrader: (15)

Mine used to run Better in Colder weather.But Now I have an Iron Block 408 and my Tuner has it tuned in Open Loop only.But I dont get how it can run better with Hotter Coolant temps...I am Talking a noticeable difference....

Modsquad

iTrader: (6)

Colder weather & colder coolant temps are not the same though. Colder weather you will get cooler/denser air & make more power. Colder weather may affect engine temps a little, but probably not much. At least at the race track, now if you are cruising on the highway, yeah, all the cold air flowing thru the radiator will cool the motor more....but I guess it's all relative to if you are talking about at the track or dyno, or just more power cruising down the road.

Pro Mouse

iTrader: (15)

Just cruising down the road.I hit it at 40mph and maybe a little flat at 170-180 degree coolant temp,but when I hit it when coolant temp is 200 degrees man its like I hit my N20...this is in 70 degree Temp outside

2002_Z28_Six_Speed

iTrader: (19)

Don't tell the 160 stat people this or they will beat you up. I believe the STOCK motor was designed from the ground up for that op temp. This includes seals, rings, the spec'ed spacing, bearings, everything in the motor. Remember that AL has a larger change in size with change of heat than FE does. I could be wrong though. I am an electrical and not mechanical.

This means that the lower op temps affects an AL motor more than FE. Plus, most people running gen i engines probably have aftermarket crate engine optimized for a lower temp. Also, I do believe older cars were also designed for a lower temp.

To get the whole story, we need to also dive into thermodynamic cycles. Perhaps we could also find answers there. A larger difference in heat reservous usually makes more efficiency.

Ed Wright

iTrader: (1)

I've never seen an all aluminium, normally aspirated engine that didn't make more power above 180 degrees. Put a blower on one and it is usually a different story. Iron blocks and forced induction engines normally like warm oil and cool water. 160' stats in a normally aspirated aluminium block LSX engine is usually a mistake. Properly tuned they normally make the most power between 180 and 210 degrees F. I think many guys do things because they hear it's the thing to do, and don't bother to test.

dan@masportspeedshop

iTrader: (6)

The above quote is right on the money. The engine was built and machined for those operating temps. If you machine the engine to run at lower temps, you won't lose as much power, BUT...you lose "thermal efficiency".

"Indicated thermal efficiency" is one of the four fundamental efficiencies of an engine. It's the measure of how much of the thermal energy (from combustion) performs useful work on the top of the piston. When you burn the air/fuel mix, the goal is to use as much of the resulting heat as possible to drive the piston down in the cylinder. What do you think happens when your cooling system pulls some of this heat out? Result: less efficiency and less power output. The goal is to run the engine as hot as possible (without destoying it!) to keep from "stealing" the heat energy from doing valuable work and keeping the intake air as cool and dense as possible to get as much a/f into the engine as possible (for greatest VE, another fundamental engine efficiency).

cals400ex

iTrader: (27)

what is the factory thermastat? when do the factory fans kick on?

dan@masportspeedshop

iTrader: (6)

Usually 195 degree F (that's the rated opening temp). Usually you get full coolant flow 15-20 degrees above that.

Fan 1 turns on at 226, off at 219. Fan 2 turns on at 234 and off at 227.

Ed Wright

iTrader: (1)

[QUOTE=dan@masportspeedshop;9556914]The above quote is right on the money. The engine was built and machined for those operating temps. If you machine the engine to run at lower temps, you won't lose as much power, BUT...you lose "thermal efficiency".

[QUOTE]

Even "built" normally aspirated aluminium engines make more power above 180 degrees. I see it every day. Many guys seem to assume they like to run colder and never warm them up real well to find out. I re-tune them all the time that have never been tested at higher temps. Put a blower on one, or an iron block, and they will make more power cooler. My old World of Outlaws sprint car made more power around 200 degrees, but back then I thought that was the methanol, not the alumium block. When the LS1 came out I was suprised they were the same way. Then I found the iron block 6.0L trucks prefered cooler water temps. LS1 strokers built with iron 6.0L blocks like cooler water also. All aluminium water cooled motor cycle engines they run in Mini-Sprint cars around here also like to run around 180/190. I would never use colder than a 180 'stat in an NA all alumium LS1 myself.

Gh0st

iTrader: (3)

My car runs like straight *** when it's cold outside, so much that I hate driving it.

Ed Wright

iTrader: (1)

That would be a tuning problem. It should drive fine cold, just make a little more power when it is warm. It's not a lot of difference, just a few more rwhp.

Gh0st

iTrader: (3)

It's been that way since it was stock.

and I'mr eferring to the engine being cold. After about 10 minutes of driving it's a lot of fun

CalEditor

iTrader: (1)

I guaranty that I can make the same amount of power at 160° or 200°!
The engine will have a much shorter life span at 160°
I can tune it for 160°, but the parts are not setup for 160° and will not live.
Have you ever wondered why the car will not down shift at the same speed when it is really cold out (30° to 40°) vs warmer out?

2002_Z28_Six_Speed

iTrader: (19)

You are confusing IAT and ECT there. BIG difference.

Ed Wright

iTrader: (1)

If it is a NA all aluminium LS1, I'll garuantee you I can make more power above 180. If it is a very high compression engine (over 13-1), the difference will be smaller. We are talking coolant temps, not intake air, right? The air outside is a different subject.

Ed Wright

iTrader: (1)

You may have a coolant or intake air temp sensor with calibration issues. I have seen them stick, and not indicate lower temps. That is similar to the choke not working on an old carb. Might hook a scan tool to it before a cold start to verify the coolant and IAT temps shown are about the same as ambient.

CalEditor

iTrader: (1)

Don't get me wrong here. I feel that the car will make the most reliable power in the ZONE. Yes all the stuff I work with is 12 to 1 or more.
You can work a Cal program to target 160°, but the engine wasn't designed for it and will increase wear.
The Zone 190° to 220° and maybe up to 225°, but you need to cool the air charge a lot more.
I will load some datalogs
This is the type of fun I have.

http://www.youtube.com/watch?v=eC9w2alvIDI

http://youtube.com/watch?v=ztnK5e9BSF4