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Author Topic: Because of the Demon I gotta ask...  (Read 450 times)

Offline RCCDrew

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Because of the Demon I gotta ask...
« on: April 15, 2017 - 07:33:12 pm »
So, is routing the cool air from the AC to the air inlet a thing now?  Are we going to be installing AC compressors into our cars to go racing? Or is this more like , "Well, we have to have AC in here anyway, we might as well have it help out. " just makes me wonder if we should have been doing this the whole time. I know personally that my Cuda runs much better when it's cool. What do you think?




Offline cudabob496

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Re: Because of the Demon I gotta ask...
« Reply #1 on: April 15, 2017 - 08:10:37 pm »
brought this up in the past. I don't think the Demon is cooling inlet air directly, but something else.
But anyway, the work to cool the inlet air would exceed the power output benefit, per thermodynamics.
Also, you won't get 750 cfm out of an AC compressor.

A 10 degree drop in carb air inlet temp gives you about 1.5% power increase.
Assume my Cuda is 600 hp. Then dropping air inlet temp 50 degrees gives 45 hp increase.
« Last Edit: April 15, 2017 - 08:14:23 pm by cudabob496 »
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.
Up to 4000 RPM, Warp Speed, Up to 5000, Rediculous Speed, Up to 6000 RPM, Ludicrous Speed!

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

Offline Strawdawg

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Re: Because of the Demon I gotta ask...
« Reply #2 on: April 17, 2017 - 01:07:23 pm »
I believe the Demon uses the AC to cool the charge cooler (intercooler) which can make a substantial effect in a f/a car.  It does not apply to our n/a cars that have no intercooler :)


Offline burdar

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Re: Because of the Demon I gotta ask...
« Reply #3 on: April 17, 2017 - 01:57:24 pm »
Quote
I believe the Demon uses the AC to cool the charge cooler (intercooler) which can make a substantial effect in a f/a car.

Correct.  The A/C lines run through the charger cooler.  After the air is compressed(heated), it runs through the A/C cooled "charge cooler".  This is basically the same principal as one of those intercooler spray bar setups.  Those systems use a spray bar mounted to the intercooler.  Nitrous or another gas is purged onto the intercooler which drastically lowers the air temp.

https://www.summitracing.com/parts/nex-20000r-05?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-nitrous-express-nx&gclid=CP_e0v6GrNMCFQcdaQodEQoA7g


Quote
But anyway, the work to cool the inlet air would exceed the power output benefit, per thermodynamics.

This would only apply IF the A/C compressor were turned on during a run.  In the 80's when engines and horsepower got really small, A/C compressors were usually turned OFF while under heavy acceleration.  Then they were turned back on during cruising speeds.  I assume they are still doing this today.  The Demon cools the "charge cooler" with the A/C system while you're at the starting line.  When you launch, the A/C clutch uncouples for the length of the 1/4 mile.  That's my guess.

Offline Strawdawg

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Re: Because of the Demon I gotta ask...
« Reply #4 on: April 17, 2017 - 03:13:23 pm »
Correct.  The A/C lines run through the charger cooler.  After the air is compressed(heated), it runs through the A/C cooled "charge cooler".  .....

This would only apply IF the A/C compressor were turned on during a run.  In the 80's when engines and horsepower got really small, A/C compressors were usually turned OFF while under heavy acceleration.  Then they were turned back on during cruising speeds.  I assume they are still doing this today.  The Demon cools the "charge cooler" with the A/C system while you're at the starting line.  When you launch, the A/C clutch uncouples for the length of the 1/4 mile.  That's my guess.

My only question would be what they did to eliminate the water drip from the evaporator.  Most tracks used to watch to make sure the AC drain was not dripping water in the starting box for obvious safety reasons.

In the early Buick days, we started with water-cooled IC's that circulated a dry ice cooled fluid across from a small tank to the core.  This was a pain because one run warmed up the water and we had to drain the tank and start over.

Then we tried spraying CO2 on the core ala the ricers, but this is hard on a big expensive IC.

So it was an even bigger IC or methanol injection which acts as a fuel and chemical intercooler.  Now, a lot of guys are switching to E85 (and a lot of it) instead of normal gasoline.

The hp chase never ends :D

I give a lot of credit to the engineers on the Hellcat and Demon programs.  They have used a lot of science and engineering to make power that endures....


Offline cudabob496

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Re: Because of the Demon I gotta ask...
« Reply #5 on: April 17, 2017 - 03:45:31 pm »
Correct.  The A/C lines run through the charger cooler.  After the air is compressed(heated), it runs through the A/C cooled "charge cooler".  This is basically the same principal as one of those intercooler spray bar setups.  Those systems use a spray bar mounted to the intercooler.  Nitrous or another gas is purged onto the intercooler which drastically lowers the air temp.

https://www.summitracing.com/parts/nex-20000r-05?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-nitrous-express-nx&gclid=CP_e0v6GrNMCFQcdaQodEQoA7g


This would only apply IF the A/C compressor were turned on during a run.  In the 80's when engines and horsepower got really small, A/C compressors were usually turned OFF while under heavy acceleration.  Then they were turned back on during cruising speeds.  I assume they are still doing this today.  The Demon cools the "charge cooler" with the A/C system while you're at the starting line.  When you launch, the A/C clutch uncouples for the length of the 1/4 mile.  That's my guess.

ya, I can see using the AC to get some component cold, then turning off AC, and getting a short power boost.  Similar to charging a battery, then doing a quick
discharge to achieve a power increase. But what is this giving us? 10hp? Seems like misting alcohol into the carb inlet air stream may buy you more power/
« Last Edit: April 17, 2017 - 03:51:20 pm by cudabob496 »
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.
Up to 4000 RPM, Warp Speed, Up to 5000, Rediculous Speed, Up to 6000 RPM, Ludicrous Speed!

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

Offline cudabob496

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Re: Because of the Demon I gotta ask...
« Reply #6 on: April 17, 2017 - 03:47:53 pm »
similar scenario with an engine vacuum pump. With a vacuum in the crankcase, reduces air friction seen by piston,
and you can get around 35 hp at high rpm on a 500 or so hp engine.  Question is, how much power is the vacuum pump
consuming?
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.
Up to 4000 RPM, Warp Speed, Up to 5000, Rediculous Speed, Up to 6000 RPM, Ludicrous Speed!

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

Offline burdar

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Re: Because of the Demon I gotta ask...
« Reply #7 on: April 17, 2017 - 04:39:27 pm »
Quote
My only question would be what they did to eliminate the water drip from the evaporator.  Most tracks used to watch to make sure the AC drain was not dripping water in the starting box for obvious safety reasons.

I had the same question.  If a dumb person like me questioned that, I'm sure the engineers thought of it too and came up with something.

Offline cudabob496

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Re: Because of the Demon I gotta ask...
« Reply #8 on: April 17, 2017 - 04:43:35 pm »
I had the same question.  If a dumb person like me questioned that, I'm sure the engineers thought of it too and came up with something.

you seem like a very smart dumb person
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.
Up to 4000 RPM, Warp Speed, Up to 5000, Rediculous Speed, Up to 6000 RPM, Ludicrous Speed!

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

Offline blown motor

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Re: Because of the Demon I gotta ask...
« Reply #9 on: April 18, 2017 - 08:57:34 am »
 :iagree:
In search of the eternal buzz!

Offline CUDA8U

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Re: Because of the Demon I gotta ask...
« Reply #10 on: April 18, 2017 - 07:25:44 pm »
just add a Snow Meth injection kit
http://www.snowperformance.net/

Offline cudabob496

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Re: Because of the Demon I gotta ask...
« Reply #11 on: April 19, 2017 - 02:58:59 am »
Can I mist methanol into the two 4 inch cold air ducts
going to my carb, and get a benefit?
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.
Up to 4000 RPM, Warp Speed, Up to 5000, Rediculous Speed, Up to 6000 RPM, Ludicrous Speed!

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

Offline RCCDrew

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Re: Because of the Demon I gotta ask...
« Reply #12 on: April 19, 2017 - 09:12:38 am »
Can I mist methanol into the two 4 inch cold air ducts
going to my carb, and get a benefit?
I would think it has to be inside the air cleaner.

Offline cudabob496

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Re: Because of the Demon I gotta ask...
« Reply #13 on: April 20, 2017 - 12:30:10 am »
I assumed it would cool a slug of air going into the carb, due
to evaporation?  Could always convert a window washer spray to
a methanol squirter?
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.
Up to 4000 RPM, Warp Speed, Up to 5000, Rediculous Speed, Up to 6000 RPM, Ludicrous Speed!

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"