Air intake running close to headers

[Alex]

My air intake tube is pretty farkin close to the headers (it is what it is due to body fitment and equal length headers). About 1 finger width away.

I've wrapped it in 2 layers of thermotec adhessive heat barrier to try to minimize heat soak while idling.

I'm kind of limited as to what I can use to reflect heat because it's close to the headers (so can't be loose anywhere near there) and also can't be very thick (because it comes like 1/8'' away from the body), so usual theory of as many layers as possible is limited here.

I don't think there's much else I can do? The only other thing I can think of is running some flexible ducting from the side scoop and point it at that area, but I don't think that will accomplish anything (at speed it will be cool anyways, at idle it won't do any good)

 

[Will Campbell]

Re the heat, I assume you are coating and or wrapping the headers? That should keep a fair amount of heat inside.

Looks like there isn't room for a heat shield, so wrapping the inlet is probably the right thing. Have you considered gold foil? I see that wrapped around the intake tubes in the GrandAm DP cars.

Are you running an SD tune on that engine? I don't see a MAF, and that strip by the fusebox is too far from the TB to be used as a mount for one.

 

[Alex]

Re the heat, I assume you are coating and or wrapping the headers? That should keep a fair amount of heat inside.

Looks like there isn't room for a heat shield, so wrapping the inlet is probably the right thing. Have you considered gold foil? I see that wrapped around the intake tubes in the GrandAm DP cars.

Are you running an SD tune on that engine? I don't see a MAF, and that strip by the fusebox is too far from the TB to be used as a mount for one.

There's a MAF - it's located in the straight section of pipe (picture 1, about 5-6'' past where that piece of pipe (for pcv) is stickign out of the intake piping....it's hard to see because it's blending in with the reflective foil.

Headers are stainless steel and will be ceramic coated (going to do that after I get a tune ..... I've heard that too rich or too lean can damage the coating very quickly)

I've got just a hair less than a finger width clearance between them, so no room for heat shield.

I was initially going to use gold foil, but from my research apparently silver is better - apparently because of the atmospheric properties on earth the gold foil is slightly less effective than silver at radiant heat reflection (in space though it woul dbe better ... I dunno, that's just what my research pointed to anyways)

 

[Doc Kaler]

The gold foil is used for it's reflective properties near the infrared spectrum. I haven't checked this out but I suspect there's a ton of ir shed from a set of headers. I guess we need to go to the nearest McDonald's to use their ir heat lamps to test this.....

 

[Pete McCluskey.]

It may be easier to re-route your intake pipe to the rear to one side so it doesn't
Suck exhaust fumes.

 

[Ian Anderson]

Personally I do not think it will matter that much.
Consider you are idling in stationary traffic.
Your 5 litre motor is burbling at 900 rpm
So there is 4500 litres a minute going through that tube

Assuming 4 inch or 10 cm diameter pipe
Cross section area 5x5x3.142 ok go over and call it 100 sq cm
Pipe is 100 cm long so total volume is 10 000 cubic cm or 10 litres
So the volume of air in that tube will be changed 450 times a minute
Or over 7 times a second

How much heat transfer can you get in that sort of time frame?

I could be wrong but that is my call

Ian

 

[Alex]

I could be wrong but that is my call

Ian

I like your call (only because it benefits my needs at the moment, hahah!)

 

[Randy V]

Personally I do not think it will matter that much.
Consider you are idling in stationary traffic.
Your 5 litre motor is burbling at 900 rpm
So there is 4500 litres a minute going through that tube

Assuming 4 inch or 10 cm diameter pipe
Cross section area 5x5x3.142 ok go over and call it 100 sq cm
Pipe is 100 cm long so total volume is 10 000 cubic cm or 10 litres
So the volume of air in that tube will be changed 450 times a minute
Or over 7 times a second

How much heat transfer can you get in that sort of time frame?

I could be wrong but that is my call

Ian

Math check... (and I suck at math)

A 5.0 liter engine will move 2,250 liters of air per minute at 900 RPM. Remember that it takes two full revolutions to move 5 liters of air. :thumbsup:

All that said..

Wrap the header pipes after you have them coated. Unless you plan on running it through a lot of water, the wrap will not damage the coating and the coating will still protect the pipes.

I've run fuel line right past headers wrapped like this and no ill consequences..

P.S. my money is still on the gold foil.. I've even made my own hat out of it! (signals from space you know)...

 

[Alex]

Math check... (and I suck at math)

A 5.0 liter engine will move 2,250 liters of air per minute at 900 RPM. Remember that it takes two full revolutions to move 5 liters of air. :thumbsup:

All that said..

Wrap the header pipes after you have them coated. Unless you plan on running it through a lot of water, the wrap will not damage the coating and the coating will still protect the pipes.

I've run fuel line right past headers wrapped like this and no ill consequences..

P.S. my money is still on the gold foil.. I've even made my own hat out of it! (signals from space you know)...

I'm hoping coating will be enough - i've heard enough bad stories about wrapping, even properly done, to keep me away from them. Especially with how tricky/$$$ these headers were.

My (hopeful) theory is that since I can drive my cobra for, say, 30minutes, park, and touch the headers (briefly) w/o burning myself, this should hopefully have minimal heatsoak, and only during idle

 

[Larry L.]

- i've heard enough bad stories about wrapping, even properly done, to keep me away from them.

I agree.

Four months or so after I had wrapped the one-off custom headers on my BB (LS6) powered '62 Biscayne, I got the word on what wrapping does to headers (pitting, flaking, etc.) - so I removed the wrap from a couple primary tubes to see if said info was 'gospel'. Unfortunately...it was. :veryangry:

'Haven't wrapped a set of headers since - nor will I. Jet-Hot coating (or similar) is the only option IMO.

 

[Randy V]

Larry were your headers coated before you wrapped them? Mine were and after two years I switched exhaust systems, un-wrapped those headers and the only damage was mild imprinting from the mesh of the wrap into the ceramic. And these were cheesy Hooker headers that came from Factory Five.

Do what you want, but this has worked well for me...

 

[Larry L.]

Larry were your headers coated before you wrapped them?

No. Coatings were juuust coming into being at that time...which will give you some idea of how long ago this was! Besides, I saw no sense in doing both...especially on a street machine.

Mine were (coated) and after two years I switched exhaust systems, un-wrapped those headers and the only damage was mild imprinting from the mesh of the wrap into the ceramic.

...which, again, begs the question: why bother to do both? (Unless of course you were out to keep EVERY DEGREE of HEAT possible inside the 'tubes.) 'Not really much point/benefit in wrapping 'coated headers is there? :shrug:

(Incidently, there was not-so-mild imprinting on the hi temp paint I'd previously sprayed on my headers too! )

[/QUOTE]

 

[Ian Anderson]

Math check... (and I suck at math)

A 5.0 liter engine will move 2,250 liters of air per minute at 900 RPM. Remember that it takes two full revolutions to move 5 liters of air. :thumbsup:

All that said..

Wrap the header pipes after you have them coated. Unless you plan on running it through a lot of water, the wrap will not damage the coating and the coating will still protect the pipes.

I've run fuel line right past headers wrapped like this and no ill consequences..

P.S. my money is still on the gold foil.. I've even made my own hat out of it! (signals from space you know)...

Damn I looked at that calculation a few times thinking I forgot something and of course it is the four stroke cycle.

Still a lot af air moving relatively quickly

Ian

 

[Jac Mac]

Damn I looked at that calculation a few times thinking I forgot something and of course it is the four stroke cycle.

Ian

Some 'Bean Counters' I have known apply the same practice to other than the 4 stroke cycle...

 

[Mark]

Bloody Accountants!

Is there no way you could gather cold air intake from another route, perhaps at the back of the car or from the above the engine?

 

[Randy V]

Larry - I suppose you could just ask yourself - do I want to control the heat or contain the heat? I chose to contain the heat as best as possible to maximize velocity in the pipes as well as minimize the heat put right back into the engine compartment which then migrates into the cockpit. This car was a race car. I'd won two SCCA Central Division championships with it along with numerous Regional Championships. I think I must have done something right. I could pull the car right off the track and measure surface temps at the ports of 900 degrees (coated remember), while the surface temp of the wrap only an inch or so away would be a much more tolerable 250 degrees. The temp of the header down by the fuel line was under 200 degree as I recall. EGT ratings had been about 1,250 at the port during hard throttle operation.

Your mileage may vary on all of this. Esthetics is important but not so much as to increase risk.

 

[Larry L.]

This car was a race car.

There you go! 'Exactly my point. As I suspected/suggested before, in your case, YOU wanted to contain all the heat you possibly could within the headers of your race car for various performance reasons. Whereas in the case of my street machine, doing that was nowhere near as 'bigga' deal. IOW, whatever minuscule power gain may have been realized by doing the 'coating/wrap combo was just not worth the extra time, effort and $$$ to me.
:thumbsup: :chug:

 

[marc]

Alex on the SLC doesn't the car have a fresh air scoop on the roof? Is that for the engine or the passenger compartment? If it was the engine, the Pontiac WS-6 style intake with a K&N filter would seem work with some ducting on the cowling. My P4 is supposed to have the side ducts that share with the rear brake ductwork (if I built to original design) with the intakes.

 

[Damian]

Alex do you have the original race tail or the street tail? If it's the street tail why not just pull air straight from the back where the two vents are. A LOT of GTM guys do it that way. I know Schwartz did his and builds his motors this way Ultima Can-Am Twin-Turbo LS7 | Schwartz Performance. Didn't breathless add vents back there to do just that (before the street tail availability)?