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Author
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Topic: Noob question, inspired by glenn
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166 Merlo
FELONY
MOTORSPORTS
Member # 1549
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posted
 
 
Yea well I was reading Glenn's thread and asked myself, why is low compression better then high compression with running a super charger? Does this also apply to any form of boost, like nitrous? I though nitrous liked higher compression? ![[patriot]](graemlins/patriot.gif)
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'89 - Boss Coupe
'70 - Drop Cutthang
'68 - Cougnut
'87 - 0166, Its real
Posts: 3954 | From: Thebay | Registered: Jul 2002
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91 5.0
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Member # 1527
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posted
Too much air in the combustion chamber, along with the elevated intake temperatures, due to the blower, can cause pre-ignition.
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02 GT - Zinc Yellow
91 5.0 LX - Red
Posts: 1316 | From: Fairfield | Registered: Jul 2002
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Primer GR40
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Member # 476
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posted
Superchargers get the air hot with lots of boost. Too much heat and compression will lead to pre-ignition. Nitrous cools, it doesnt heat anything up, besides a little more fuel you burn. This is just a guess.
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Superdupercharged Cobra
No Transmatic Notch
Posts: 2108 | Registered: Sep 2001
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93PONY
Mr. Valve Events
Member # 60
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posted
HEAT
That's why low compression with boost is desirable. You can only run so much total compression (compression ratio * (boost in AU + 1)) before pre-ignition with a given octane occurs (the higher the octane, the higher temp/slower it burns). This is because whenever you compresses a gas, you heat it up. Heat up the air/fuel mixture too much & it will ignite.
N2O works very well with high compression for a couple of reasons. One, is that it is sprayed out at -120F degrees. This cools the intake air charge quite well. Also, with nitrous you're not compressing the air before it reaches the pistons.
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www.advancedenginedevelopment.com
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Posts: 4265 | From: Fair Oaks, CA | Registered: Nov 2000
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166 Merlo
FELONY
MOTORSPORTS
Member # 1549
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posted
Shaun, you are a beatiful person ![[burnout]](graemlins/burnout.gif) .
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'89 - Boss Coupe
'70 - Drop Cutthang
'68 - Cougnut
'87 - 0166, Its real
Posts: 3954 | From: Thebay | Registered: Jul 2002
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mustanggt5091
All I need is.....
Member # 444
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posted
Couldnt have said it better myself shaun
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88 GT 357w (SOLD):(
06 Limited Edition R6 !!!!!
Posts: 2353 | From: Fairfield / Santa Rosa , Ca | Registered: Sep 2001
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91 5.0
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Member # 1527
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posted
So when nitrous is injected, it comes out at 120F? Explain that to me. I'd think it would be a lot cooler since it was going from very high pressure, ~1000psi, to atmospheric pressure. When a something goes from high pressure to low pressure, it gets colder. Same concept as your A/C system.
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02 GT - Zinc Yellow
91 5.0 LX - Red
Posts: 1316 | From: Fairfield | Registered: Jul 2002
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JohnB
Tech Moderator
Member # 969
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posted
Ahhh, 91...that's NEGATIVE 120 degrees.. ![[Smile]](smile.gif)
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1965 Shelby Cobra
1993 Cobra
2012 F150 Raptor
2020 GT500
Posts: 6523 | From: Orlando FL/Redding CA | Registered: Mar 2002
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91 5.0
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Member # 1527
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posted
quote:
Originally posted by JohnB:
Ahhh, 91...that's NEGATIVE 120 degrees..
Now that makes sense. I was wonderin about that. Shaun is a smart guy, so I was wondering what was goin on. I re-read it and saw the (-) sign this time. Thanks for pointing that out John.
[ September 25, 2003, 10:51 AM: Message edited by: 91 5.0 ]
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02 GT - Zinc Yellow
91 5.0 LX - Red
Posts: 1316 | From: Fairfield | Registered: Jul 2002
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