power loss in heat, power q's

[slow5poh]

i have a 92 gt. it has headers, full exhaust, pulleys, gears, shifter etc.

at night in cool air it runs good and has a relatively responsive throttle, but during the day especially hot summer days it seems as if it runs about 15-20hp slower, and is not very responsive. and i never use th a/c. i realize that colder air into the intake makes more power, and it gets afuly hot under the hood with a stock hood. any suggestions on what it may be? i don't think a cai will help much either. but who knows, maybe the intake is getting heat soaked?

 

[RickyB]

the hotter the air the more prone to detonation also....the feeling you get may be your timing getting pulled

 

[slow5poh]

ricky i have the timing set at 14 degrees and i never hear it ping, should i back the timing off?? what do you mean by timing getting pulled? the computer retarding it to avoid detonation? what could i do to fix the prob?

 

[HISSIN50]

What engine temps are you seeing during the day? I think Ricky is referring to the puter pulling timing if the car is running too hot. However, the threshold for that is pretty hot - I doubt you run it in the 220*+ range.

Simply stated, as you know, hot air is not as dense. My cars run a LOT better when it is cooler out. It was 107*F today.

 

[slow5poh]

well actually when i put the underdrive pulleys on it does run 220-240 range when it's hot all day. wonderif i should put my stock w/p pulley back on. it's weird how most people don't have that problem with pulleys. unless my temp guage is faulty it does run quite hot in the summer

 

[87MustangGT5.0]

Do you have a stock temperature guage? If so they are junk and you need an autometer one especially if you are concerned about this.

 

[The Shape]

Yeah 220-240 is pretty hot I would varify that with a different gauge or it is posible your sending unit is bad. And it is normall for the car to feel slugish on really hot days.

 

[slow5poh]

today at lunch i drove it and got it hot. the temp guage said 200 deg but i used one of those laser temp readers on the rad hose and it said 160 deg. but a mechanic bud of mine told me that is not an accurate test. so i don't know if my guage is whack or not. but the car usually runs fine until it gets hotter. i am confused. it's irritating driving home from work ans the car lags hella bad, but at night it drives fine.

 

[dstanggt50]

Maybe chk the basics. Codes, plugs , wires, full tune up (fuel filter, clean maf, ect..) I know that my car runs a lot better when its cooler, but it still has some in it when its hot.

Just my opinion.

 

[slow5poh]

yeah it has no codes and it's been tuned up lately and i have cleaned the maf too so i don't know what gives :damnit:

 

[The Shape]

What is it doing besides feeling sluggish? Not running as strong in the heat as you do when it is cool is normal. But if you are struggling to hit 70mph then you have a problem. Give us some more information about what is happening.

 

[slow5poh]

well like when it's hot and you gun it off the line and quick shift to second it like hesitates a little, maybe it's just normal. for example at night it will break the tires loose in first and second, if im shifting hard. but during the day it will burn them in first then lag badly when i put it in second. it just seems like to much of a difference, like something is wrong. maybe not.

 

[The Shape]

Your temp guage needs to be verified, but other than that what you describe sounds normal for a high heat/humidity situation.

 

[HISSIN50]

Your temp guage needs to be verified, but other than that what you describe sounds normal for a high heat/humidity situation.

Exactly!
FWIW, the puter starts to pull timing at ~226*F.

Even if you use a 10 dollar parts store mech gauge for a few days, that will help A LOT!

Good luck.

 

[mfewtrail]

today at lunch i drove it and got it hot. the temp guage said 200 deg but i used one of those laser temp readers on the rad hose and it said 160 deg. but a mechanic bud of mine told me that is not an accurate test. so i don't know if my guage is whack or not. but the car usually runs fine until it gets hotter. i am confused. it's irritating driving home from work ans the car lags hella bad, but at night it drives fine.

Next time you get to use a infrared pyrometer, point it right where the coolant sensor/sender for the gauge is located on the engine and then compare the reading to the stock gauge. This will give you a better idea of the difference between actual temperature and the stock gauge, but it won't be 100% accurate since the infrared laser pyrometer is going to measure the surface temperature there.

 

[slow5poh]

who knows

well i appriciate every one helping me out. i think the gauge is whack cause yesterday on the way home it wasn't that hot at all maybe low 80's. and breezy, and the gauge was reading like 240 so it's probably wrong. plus it fluctuates more quickly than i think a temp would.