Manifold Heat......

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5.7 hemi

5.7 hemi

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Most of you guys know that I have a 6.1 intake on my 5.7 and use my own custom cnc'd spacers/adapters to clear the truck timing cover (was too lazy to mill the timing cover at the time). The spacers are 1.5 inches tall and work just great. Here's the problem....after driving and I pop the hood, the intake manifold is FLIPPIN' HOT, not just kinda hot, but hot enough to burn you hand if you left it on there. I got some phenolic material and will make some spacers/adapters to go between the intake and my aluminum spacers/adapters. Does anyone else have this problem with their 6.1? I'm open to all advise/constructive criticisim. By the way, damn thing runs like a scalded cat on a hot tin roof.
 
:happy1:

Glad to hear it is running well, clearly a cool intake manifold would make more power. How much more, depends upon the temperature drop. Since no coolant passes through the manifold all the heat building up in the manifold would be from conduction from the heads or radiation from the hot exhaust manifolds.

If you're going to take the time to place an insulator between the head and the intake manifold why don't you measure the temps both before and after with a non-contact thermometer. If the heat build up is due to radiation from the hot exhaust manifolds it'd be worth knowing that way the rest of us don't waste the effort to insulate the intake from the heads.

I'm thinking you could use something like this:

http://www.harborfreight.com/non-contact-laser-thermometer-96451.html

http://www.sears.com/shc/s/p_10153_12605_03450466000P

Of course I'm really good at spending your money. ;)

Regards,

Joe Dokes
 
Thats something you and my wife have in common, lol. I'll do it, my buddy has an IR temp gun. It's funny the car manifold never got hot like the 6.1, but it's a plastic pieceand doesn't absorb heat.
 
I assume the stock setup uses an IAT sensor at the mass air flow sensor before it gets to the manifold? The only reason I ask is I was thinking that if you had the equipment you might be able to read what the temp sender was saying to see just how bad the air is actually getting. I've got an aluminum Indy Mod Man on my 5.7 and it's pretty dang hot to the touch, but the IAT sensor (screwed right into the #8 runner where a big vaccuum port might go) usually only reads around 20 degrees hotter than ambient while cruising (got a 6 pack hood scoop on it, but I haven't isolated the air cleaner yet). I got some phenolic gaskets with the intake (required as there are no O rings on the Mod Man), but you still wouldn't want to lean an arm on it while working after driving it. Sitting in traffic you can watch the IAT temps climb, but once you're moving again they go down pretty quick.
 
You can have it coated inside and out. That's what I did on my charger and it helped a ton. Next just make sure ur getting cool air with ur air intake. This will bring the temps down faster than anything.
 
How hot does a stock 6.1 get? I see no difference from yours and a stocker. If anything, your should be cooler with the air gap under the intake...
 
Map, there is no mas sesnsor, only aat sensor located in the air intake tube. I've watched the aat sensor reading with my trinity and it does go down quickly when I start moving after a stop.


The reason I posted this question is because after driving 75-80 on the freeway, I took my exit, got off the gas, and started braking and the damn thing died, threw in neutral, coasted to the stop sign, fired it back up and pulled into the nearest gas station. Popped the hood and the intake manifold was hotter than hell. I was low on gas, but braking should make the fuel run toward the front of the tank and not starve it for fuel. I put 5 gallons in and took off back home. Not a single problem on the trip home after getting gas. Any thoughts on the possible corralation between low gas, hot intake, and stalling?
 
I actually had a very similar issue, but I'm still not sure what caused it. Was a hotter day, maybe around 90 or so and I was driving home from work through town when all of the sudden the car just died. The highway drive is 55 mph country road and I was probably half way through town after getting off the highway when it happened. Was waiting in line for a stop light and it just sort of dragged down real low for a bit and died. Tried starting it and didn't have any luck. Checked the fuel pressure gauge and couldn't get any pressure (in tank pump), but I swear I could hear the pump priming. Had my parents pick me up and went back a few hours later and it started up like nothing was wrong and hasn't given me trouble since. Don't know if I just got some junk in the lines or what, but since the issue hasn't come back I guess it may have just been some weird fluke.
 
Damn thing did it again today, stalled when making a right turn. Talked to a friend over on FBBO, and he said the intake is getting heat soaked, transfering heat thru the tb, air intake tube, and into the iat (aat sensor) and the computer is trying to compensate by dumping more fuel to point it cant do it any more and the engine stalls. At least thats how I understood it.

So he recomended the 6.4 iat sensor (direct fit to factory plug) as it's all plastic and doesn't suffer the inheirent problem of the older style and to move the location down to about 3 inches from the air filter. He said this will take care of the stalling issue due to the heat, so I'm on it. Also gonna put on the car manifold after I get done smoothing it out, and the 6.1 is gonna go up for sale. Almost forgot, he said to run a 180 t-stat instaed of the factory 203 degree t-stat, gonna be a busy weekend.
 
Manifold is done being shaved of it tits and extra protusions on top of it, and is in final primer, waiting on the paint to be mixed. New 180 t-stat with a 195 temp switch for the fans is done and the car at idle with the a/c on sits at 185-187. The 6.1 manifold will come off this weekend so hopefully the underhood temps will come down, also still need to do the ait sensor relocation.
 
Took about 6 hours to shave the tits and protusions, but it looks way better.
 

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I like it too... I would love to see a pre/post manifold side by side to really see the change.
 
Here is what the factory manifold looks like before shaving.
 

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Great job--just a simple question,Did you put the foam piece under the intake when you installed it????? I have a dense piece of foam under my valley pan the was on from the factory and when I put the xv intake on I put it back in,i thought that helped keep the heat from radiating to the intake?????? Steve
 
Swifter, I have the 6.1 on there now and it doesnt have any foam thingy, but being aluminum it does soak up the heat really fast. The car manifold does have one, but mine is MIA so I also got some phenolic spacers and this should help out alot. I also made a valley pan from aluminum and used some 3/8 spacers to get it off the block, kinda like an air gap, also put in the 180 t-stat which has helped quite a bit. I'm on the right track and I'll have it all figured shortly.

If you guys wanna do what I did with the manifold, just break out the dremel and get with it.
 
5.7, thanks for the pics. I noticed some of the stuff you shaved before the "pre" pics but holy cow... that looks so different, great work. What paint did you use?

JOE
 
I was using Tycoat47 from Eastwood, but they discontinued it sometime ago. So I took a small painted oart down to the local auto paint supply shop and they did a really good job of matching it, and they put together 4 spray bombs for me.
The color is titanium and has a metallic flake in it that show real nice when you clear it, but I just stopped after the paint...sorta a matte finish which I like.

I started with the dremel to do the cutting/shaving then 120 to smooth and blend. Spot putty was then used to get some of my "****, went alittle too deep" chingadera's. Wax/grease remover then adhesion promoter, high build primer, wet sanded to 400, wax/grease remover, then painted. Total time was about 6 hours on and off.

I put pcv valve, hose and egr block off plug (made that at work) and now it's just waiting on me to pull the 6.1 off and put this one back on.
 
So I guess after all that work, you're not gonna cover it up with an engine cover...
 
Tin, your right! But I could still use it as I still have the fuel rail hold down studs that the cover attaches to. That crap on top of the manifold really doesn't do anything.
 
How about if you make a couple aluminum plates to screw on where the engine cover mounts go, then you put a couple HEMI emblems on them.
 
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