Cross Fire Question

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Cross Fire Question

Postby NZKnight » Tue Feb 24, 2015 2:16 am

Hi all

My car has the crossfire option however previous owners of my car have disconnected or removed pieces of the crossfire system. I am told the crossfire air cleaner had a flap that directed warm air off the headers into the air intake. Can someone identify the part circled in the picture below. It is not connected at present but I guess it should have a vacuum line going in and the other line goes to the air cleaner to operate the air flap?
Perhaps someone could post photos of the system complete?

Thanks for you help.
Attachments
photo 3.JPG
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photo 1.JPG

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Re: Cross Fire Question

Postby ripperace » Wed Feb 25, 2015 8:05 am

That would be the vacuum device that supplies vacuum to the Thermac motor on the air cleaner snout.

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Re: Cross Fire Question

Postby NZKnight » Thu Feb 26, 2015 12:17 am

Thanks for this Ripper. What I really want to know is how the crossfire air ducting system works when all complete. Mine has been butchered and but I am wanting to restore it to original operating condition. So I understand that a vacuum pipe should run to the vacuum switch which connects to Thermac motor? Does this switch determine if the engine is hot or not? Is there a connection air cleaner snout to the header to draw in warm air?

Cheers

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Re: Cross Fire Question

Postby IndianaKnight » Thu Feb 26, 2015 7:06 am

Does this help?

Image

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Re: Cross Fire Question

Postby IndianaKnight » Thu Feb 26, 2015 7:11 am

And I believe the round spot on the exhaust manifold connects to the air cleaner with an expandable aluminum tube called a "heat stove pipe". A generic version should be available at any auto parts store. Many cars had these. I think the purpose was to direct warm air into the engine so it would heat up faster for emissions. Once warm, the flap in the air cleaner assembly would open to allow outside air in.

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Re: Cross Fire Question

Postby ripperace » Fri Feb 27, 2015 9:25 am

That is correct sir! Although most people chucked that ducting because it either A) fell off anyway, or B) Rotted to the point that you couldn't attach it at either end, or C) the flange on the exhaust manifold rotted away. :lol: Or the Thermac motor would not work after time. :roll: It was really kind of simplistic in the way it worked, just the parts didn't hold up real well. Most people that took the ducting off never noticed a real difference in how quick the car warmed up anyway because, let's face it, nobody took off down the road until the car was warm enough to run on it's own regardless. Now, or course, that's all regulated by the ECM and you won't see any funky hoses like that on new cars. I'm sometimes amazed at the amount of crap GM put on cars from the mid 70's until the 90's that made no difference.

Ripper

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Re: Cross Fire Question

Postby NZKnight » Sun Mar 01, 2015 10:55 pm

Thanks to all that responded. I now have enough info to put the crossfire back to stock even if it doesn't achieve much!
Does anyone have a view on the hood cowl solenoid vent, is this just another GM gimmick of the time?


Greg

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Re: Cross Fire Question

Postby ripperace » Wed Mar 04, 2015 3:22 am

That setup is actually vacuum over electric. There's a vacuum operated electric switch that is supposed to close when you step on the throttle, that in turn, switches 12volts to operate that hood flap solenoid. Why they didn't just opt for a vacuum solenoid over this vac/electric setup is beyond me. BUT, you can instead wire your Pursuit button up to operate the solenoid rather than having all the extra vacuum crap (ie: potential vacuum leaks).

Ripper


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