The original poster modified his filter housing resulting in his sucking more air from the engine compartment instead of from under the fender. He also has an electric fan. Assuming the fan doesn't run all the time at a stop, his underhood temps are rising a lot higher than it was with the stock fan.

I'm guessing the air getting into his engine is now a lot hotter than it was prior to the electric fan. This increase in air temperature results in less oxygen getting into the combustion chamber which results in a decrease in power.

I would suggest he plug up the holes he cut into his air filter housing so that the intake air is back to coming from under the fender and see if that doesn't help his acceleration.

 

I'm told that you lose 3% for every 10,000 feet of elevation, and 3% for every 10 degrees in temperature.

If that's true, there's quite a bit of loss on very hot days.

 

I agree 100%. Sometimes it's a lot of trouble explaining to people why a smaller engine is performing as well if not better than the larger ones they opt to get from the factory!

Since my mods, my worst tank was still over 14 MPG and that includes almost half the miles towing 4500 or so pounds.

 

For the most part, I am starting to agree. It's hard for me to imagine that I can pick and choose components that will actually improve my truck without any detrimental tradeoffs. For example, my Airraid intake is great until the temps get above 90F, then it just sucks (or doesn't suck, I guess). Superchips are great except for the lifetime sentence of 15mpg+premium fuel. So far all of my best mods are just minor little things like fogs+highbeams, undercarriage lights, FM y-pipe, and new shocks.

If you are trying to change the function of your truck, then all bets are off... for example if you want a monster off-roader or a drag strip ripper then you have to spend big $$ and live with the tradeoffs. If you want to improve a daily driver without adding noise, expense, or sacrificing reliability & economy, good luck. Live and learn, right?

 

When you modify your truck your looking for trouble........

Thats it!! I am undoing all I have done!!!!!!!!

 

Here is a horsepower calculator that will let you see how much difference temperature makes on HP.

http://rshelq.home.sprynet.com/calc_hp_dp.htm


Some of you guys are WAY overstating the impact of temperature alone. Barometric pressure, altitude and humidity have a much larger impact than temperature.

Personally, I don't care how much power the engine makes when I'm stopped. How much difference in air temp do you really think there is from one side of the fender wall to the other when the truck is moving? Is the air pressure the same?

Maybe you guys should insulate your fender walls and paint your trucks white for the coolest possible under fender temps!

 

I'm not saying that mods are all bad, I'm just saying you have to be smart about it and sometimes the stock setup isn't all that bad after all. I wasn't smart about some of my mods and now I regret all the time/money that went into fixing/replacing them. Some of my mods were actually worse than the stock setup! There are a lot of people on this board who know a lot more than me about their truck and performance in general. Unfortunately, there are a lot more people who base their gains on manufacturer's claims and anecdotal evidence rather than actual results - for example, K&N filters and big exhaust tips don't really give 15-30hp by themselves, but ask most any highshcool kid with an acura and they will probably argue that point for hours.

For my truck, underhood temps make a big difference only when I am stopped and when I just start rolling. I swear I could push my truck faster for those first 20 feet, but after that, hang on! I bet it would be much better at 1000ft than 6000 ft too.

It just kills me because from a standing start the neighbor's kid on a big wheel will kill my truck, but in a roll-on type race (above say 10mph) I can shame a lot of vehicles around here.

 

FamilyRide, don't laugh, I've had a similar throughts. But, my thought was using an auxiliary evaporator coil from the AC unit to wrap the intake tube and create a heat exchanger of sorts.

 

Howzbout surrounding the air tube of the airaid or fipk witha big piece of oversized pvc tubing,sealing up the ends, then filling the pvc with dry ice and alcahol

Better still, an intercooler submerged in the same! Careful your throttle body does'nt freeze at WOT

 

Ok, so per the calculation that dirt bike dave gave, it's only 1% per 10 degrees -- and at 177 degree input air (seems a reasonable temp), my 5.4 would be losing 26 HP based on air temp alone (didn't try to account for the dew point change as air temp changed).

So at my 1,000 ft elevation, I'm at 86% of rated -- at best!

 

BINGO!!!!!!!!

Watch your Mods and chose wisely Luke!!!!

You can set yourself back quick......

The intake is the most sensitive.......

 

OK, here is what I did. I had some of that famous JCWhitney padded heat shield. I wrapped the bottom of the entire air intake tube from the filter housing to the throttle body. Now I was also concerned about the radiant heat coming off of the radiator overflow. So I made a tube out of the same heat shield stuff that is the same diameter as the metal clamp for the air filter. I slid that over the air filter housing and extended it right to the inner fender wall. WHAT A DIFFERENCE!!! Now it runs the same warm as it does at start up.

Anyone with this problem, I highly recommend you do this. If you have a completely stock setup, wrap the the intake tube. If you have an FIPK, wrap the tube with heat shield. World of difference IMO.

 

Wrapped my intake with some 3M reflective insulated tape. Works great.

 

HI!... I was very interested in seeing underhood heat temps on my truck. I bought a digital temp guage that has a small sensor on about 10 feet of wire. I mounted the guage on top of my steering column in front of the 4 ways switch. The sensor was routed through my firewall and out to my K&N filter. I installed the sensor in the filter right before the MAF. This way I can get a really accurate reading on the temp of the air getting sucked into my engine. While driving the truck at highway speeds or in the city I have noticed that the temp under the hood is about 15-20 degree's at most above the outside temp. If travelling on a highway for long periods of time I noticed that the under hood temp is almost identical as outside. Now where the heat is really noticable is when sitting still, say in a parking lot or in heavy traffic or stuck in a traffic jam for that matter. This is where the temp really climbs because of no airlow through the grill and rad. In 105+ degrre ouside temps and stuck in traffic, I have got readings as high as 160 degrre's under the hood. The calculation I have been using and have seen other racers use at the dragstrip is this : After 64 degree's you lose 1% of your flywheel H.P every 10 degree's you increase over that set temp. So at that day that I hit 160 on the temp guage, that would mean I lost about 28.8H.P with me running 340H.P at my flywheel. You know, it felt like it too!!!! It felt just like when I run without my SUPERCHIP in cold weather. I hope this helps some of you out.

 

I have been saying and will continue saying wrap it all!!!!!

If you look at my sig line it is all wrapped ...

I wrap the A/C lines and it makes the 134 like 12...

Insulate and isolate....