Under Hood Efficiency

[Mikes91]

Was wondering... what can I wrap (and with what) to improve engine efficiency, lower EGTs, make my A/C work better, etc.?

Heard some folks on another board rambling about wrapping exhaust to lower EGTs... sounds backwards to me. My thought is that lowering underhood temperatures by wrapping exhaust, etc. might be a good thing... if it is possible... and that wrapping certain A/C parts might result in better A/C system function...

Mikw

 

[Dualie]

I wrapped the AC lines in my 1994 idi with heat reflective tape. It made a 1 deg difference in the vent temp of the AC. you could try that. I have however heard bad things about wrapping exhaust. Something about moisture getting under the wrap and causing corrosion and rotting the pipe out.

 

[Mikes91]

That's one thing I was afraid of...

If there's only 1 degree of difference in wrapping the AC lines, that's probably not significant enough to worry about. Good window tint may be a better option in my case.

Thank you for your reply.

Mike

 

[Dualie]

I forgot to mention that the thing that made the biggest difference in mine was to repair the insulation that covers the AC plenum where its closest to the exhaust manifold. That made a 3-5 deg. drop in ac outlet temps @ highway speeds.

I kind of subscribe to an old Hebrew proverb I was once told by an elderly Jewish man. "you take the crumbs, put them together, you make a loaf."

All the small things that make a little difference here and a little difference there ADD up. plus it does make it nicer if the tasks are low cost and simple which insulating the AC lines and fixing the plenum insolation was.

 

[93turbo_animal]

one thing I did to make the cab cooler is put in a heater core bypass keep the heat out

 

[Mikes91]

Do tell... how does one do that?

Thank you,
Mike

 

[soulpatchfr]

some cars/trucks had one from the factory.
i think the goat is where i learned about them - or maybe the moose ???

my understanding is that it's a vac accuated valve that shuts off coolant flow to the heater core whenever a/c is on. maybe electric? i think the late 80's rangers had them, as well as various gm cars.
take a gander over at the photo section of TDS... i'm sure i've seen a pic of someone's over there - Mel's?
seems like a simple mod, but my a/c freezes me out as it is, so i never went looking for parts.

 

[93turbo_animal]

yeah theres a valve from rangers I believe to do this with hopefully some one chimes in but I just put a cross over hose between the in side and out side of the heater core with a couple valves one to shut off the hot flow to the core and open the bypass then when you want heat just reverse them

 

[argve]

Yep The Enterprise sported a Ranger bypass valve. I don't remember what year it was off of but if you just go into Autozone and tell you have a mid's 90's Ranger.

It's vacuum actuated - just use the WHITE vacuum hose that runs the HVAC door that is laying over on the passengers side fender. Just tee into it - then the coolant flow will be diverted around the heater core when the controls are in the MAX A/C and the OFF position. When in the NORMAL A/C is selected the heater core WILL have flow through it.

 

[arizhnt]

I installed a manual heater valve in line, that made a big difference in cab heat and since my systen is a blend air-no heater valve in line no hot water in the heater core makes the a/c evaporator work a whole lot better. I also installed a mist system in front of the a/c condenser, and pulling in 100+ degree ambient temp this weekend my vent temp was 30 deg, with r134a freon.

 

[160k87F250]

Rangers and Explorers have heater control valves that are vacuum operated. When vacuum is applied, it shuts off coolant flow to the heater core. Usually it is tied in to the recirculation door vacuum. When you put it on MAX AC, the recirc door opens to draw air from inside the cab instead of outside air. The vacuum diaphram that operates the recirc door is under the hood near the blower motor on our trucks, just "T" into the vacuum line and run vacuum to the heater control valve. I've been planning on doing this, just haven't gotton around to it, yet.
John

 

[The Warden]

I took a couple of pictures of the bypass valve I installed, as part of a write-up for the coolant filter install that I keep meaning to finish but haven't had the time (the write-up, that is; the coolant filter's been working beautifully ever since January). The first picture shows the vacuum line that you'll need to T off of. It's the line with the white stripe that terminates at the vacuum pot to the left. The second picture shows the valve that I put in. I went to Napa and asked for a valve for a '96 Ranger and got that guy...and I have had a few issues with the valve leaking somewhat, so either Napa's valve is a cheap-o, it doesn't like ELC, or I got a "bad" valve. It's not bad enough to replace, though...

The valve should have arrows on it showing the coolant flow, but it's pretty straightforward. I don't know how much of a difference the valve made, since the A/C wasn't functional until shortly before I put the valve in (and, in that time, the heater core wasn't hooked up). Hope this helps some...good luck!

I agree with Dualie that every little bit helps, and will have to look into insulating the A/C plenum...I dont' think there was ever any insulation on the A/C plenum on my '84. Also, I seem to remember someone on here saying that they once wrapped up a set of headers in exhaust wrap, and the wrap insulated so well that the exhaust temperature was so hot that it melted the metal and ruined the headers...

 

[Diezel_Cowboy]

Was wondering... what can I wrap (and with what) to improve engine efficiency, lower EGTs, make my A/C work better, etc.?

Heard some folks on another board rambling about wrapping exhaust to lower EGTs... sounds backwards to me. My thought is that lowering underhood temperatures by wrapping exhaust, etc. might be a good thing... if it is possible... and that wrapping certain A/C parts might result in better A/C system function...

Mikw

The only way wrapping an exhaust pipe will lower EGT's is if you wrap it excessively. Any insulated pipe CAN be insulated too much..........what happens is that by wrapping the pipe in lots of insulation you increase the surface area of the outside diameter enough that the insulation makes the pipe lose enegry instead of keeping it in. In other words if you welded fins (pieces of flat metal) to the out side of the exhaust pipe you would have even more of a chance of lowering exhaust temps since the fins increase the surface area of the pipe and hence the rate of cooling. If the insulation is not heavy enough then it would have a heating effect not a cooling effect.