On hot days, around 97 and over, I've noticed my Screw's acceleration stinks when taking off from a stop. I assume this is a problem with the air intake getting hot "thin" air.

I've got the 5.4L and it's all stock. No mods on the engine or the computer chip.

Anyone have any suggestions or comments? Is this just something I have to live with?

Thanks.

 

Mine too! I`ve got a 2001 Screw 4x4 Off road with the 5.4 and 3.55 regular axle.... it sux on hot days if I feel like "playing" with a dodge or chevy.

 

Mine has a slow start even when just leaving a red light or stop sign. Pushing the accelarator feels sort of like stepping on a rotten tomato.... hardly any affect. Once I'm up to 40-45, acceleration from there seems normal.

It's got to be the hot air going in the air intake. Just not sure what to do about it.

 

is your AC on when it feels sluggish?

My 2000 5.4L AWD expy feels really sluggish when it is hot and the AC is on. so i asked around and people were telling me that the ac compressor shuts off when under Wide Open Throttle WOT. well mine doesn't and before i installed my supercharger i had the shop dyno it. well i was right the compressor does not turn off under WOT and i lost 14 rear wheel hp with it on. which will equate to about 19 hp which is a hp number you will feel. now with the supercharger on and a hot day it feels real suggish until i hit about 2200 rpm when that extra 7 pound of boost kicks in and then it really moves. so this might me your problem.

if my truck is supposed to turn my ac compressor off when under WOT let me know how i can fix this issue

 

ScottyBones,

YES YES YES......... read the subject "hot days" like 97+!!!! I aint gonna turn of the AC just to get a faster start.

In south texas, I use the AC 11 months out of the year, and the other month I DONT use the heater!

 

Mine AC compressor does shut off during WOT. And I agree with Wes... too darn hot here in Texas to think about turning the AC off just to start off from a red light.

There has got to be something with the air intake going on here since it is much worse on hot days. Hopefully someone will have a suggestion.

 

A few things here that will change your power. 2 things that you want for your engin to have the best performance.

- Cooler air
- More oxegen concentration (lower altitude)

So the lower your altitue is the better (air is not as thin) and the cooler it is (this is why they sell intercoolers) the better.

Also this is why the gas is a diffrent "blend" durring the summer and winter. For more info on this (very intresting) go here http://www.chevron.com/prodserv/fuel...gas/ch1a.shtml

As far as the A/C goes, it saps some horse power (anyone know about how much?) But your right it's not worth turning off to jump off the line a bit faster.

Basically move to a cooler climate or get an inner cooler...

 

Dcovell,

Thanks for your insight. I like your idea... cooler climate! Hmm... maybe Montana? or even Canada or Alaska would be good.

My altitude here is about 3800 feet... not high, but not low either. As far as the cooler air, it seems that Ford could put the breather snorkel up front taking air from behind the grill rather than from the HOT side panel.

Oh well... it's not a big enough problem to make me move, turn off my AC , or trade me SCREW.

Thanks.

 

Same truck, same 1/4 track, same driver (no AC)

July(95 degrees) = 16.1
Oct(60 degrees) = 15.7

 

Noticed same thing, but I am with the rest of the Texans, too damn hot to turn off the AC.

 

Something else which will sap your power especially in stop and go driving is the fan clutch. The

Imagine if you will, sitting at the stop light. The only air going through the radiator is pulled by the fan. As you sit at the light the radiator is shelling out hotter and hotter air...as it does this, the clutch on the fan engages more and more to maintain a constant temp. Now you leave the light...the fan clutch is engaged quite a bit and causing the fan to pull a tremendous amount of air through the radiator. Because the fan is ran off the engine it is sapping horsepower which results in sluggish acceleration

Once the air coming off the radiator cools down a bit the clutch fan engages less and less and most of the air going through the radiator is forced through by vehicle speed--doesn't feel like pushing down on a tomato anymore

 

Next time you are at a light for a while on a hot day, turn off the radio and reduce the a/c fan and listen as you take off...you'll hear a mild 'roar' (for lack of a better word) coming from the engine compartment. This is your clutch fan pulling tons of air through the radiator.

 

Z....

Thanks for the insight. I never thought about the fan, but you're right. We'll all just have to wait out the summer for cooler weather!

 

Try having tsb 02-12-3(I think that's the #-it just came out) performed. Reprograms the pcm to not retard timing when intake air temp. goes above
140 degrees(ambient air temp over or around 100)
and installs 2 body plugs near the coolant jug to
reduce the temp.

 

thanks for the tip. I'll check with my service advisor about it.