Headers and a SC...
^basically what my 8 paragraphs said 
The only reason you make less power in lower RPMs w/ a free flowing exhaust is because of a poorly designed exhaust collector. A well designe dexhaust collector would mean power gains in the mid and lower RPMS range, and no difference in the upper range because angry drivers dont give a crap.\
Id like to add that another factor to concider is the pulse generated by the valves opening and closing. These travel much faster than the gas exelled by the wave, and the collector and length of the primary exhaust tube is what determines efficiency.
The only reason you make less power in lower RPMs w/ a free flowing exhaust is because of a poorly designed exhaust collector. A well designe dexhaust collector would mean power gains in the mid and lower RPMS range, and no difference in the upper range because angry drivers dont give a crap.\
Id like to add that another factor to concider is the pulse generated by the valves opening and closing. These travel much faster than the gas exelled by the wave, and the collector and length of the primary exhaust tube is what determines efficiency.
Last edited by plumpzz; Jul 25, 2006 at 12:08 PM.
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From: charlotte, nc
Didn't mean to start a debate. I uderstand that headers make the engine more efficient and the boost readings decrease. You don't lose hp or tq----you gain, but the curve at which they come in is higher.
I just didn't understand Stillen saying that they were contraindicated with FI when roots/centrifigal V8s benefit from them.
I just didn't understand Stillen saying that they were contraindicated with FI when roots/centrifigal V8s benefit from them.
I have headers on my stillen and my bottom end power is awsume. When i added the random cats I lost 6 rwhp. Car makes 8.5lbs of boost with headers on a 9lb pulley. its a 5 AT. with 3.53 gears and there is no loss of power in first or 2nd gear. Goes like hell and very easy to hit the rev limiter when shifting in MM. Stillen says that i am losing 3/4 lb of boost and about 12 rwhp. will post dyno results with 9 lb pulley soon.
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From: columbia md.
Originally Posted by sentry65
a simplified explanation is a highway and rush hour.
there's only so many cars on the road (amount of air)
a 2 lane highway will clog up easier than a 8 lane highway (how restrictive the exhaust is)
when rush hour happens (throttle) , the cars bunch up and get pissed off (condensed air)
when those pissed off cars finally get out of rush hour, they speed up beyond normal because they're pissed off (air wants to decompress and moves faster due to the barometric pressure difference to get outside to where the air is normal density again)
if you had a 8 lane highway, the cars would just pass right thru at their normal speed
there's only so many cars on the road (amount of air)
a 2 lane highway will clog up easier than a 8 lane highway (how restrictive the exhaust is)
when rush hour happens (throttle) , the cars bunch up and get pissed off (condensed air)
when those pissed off cars finally get out of rush hour, they speed up beyond normal because they're pissed off (air wants to decompress and moves faster due to the barometric pressure difference to get outside to where the air is normal density again)
if you had a 8 lane highway, the cars would just pass right thru at their normal speed
Originally Posted by jpc350z
With due respect your analogy's are mind boggling...
velocity = airflow/area
Power = torque x rpm
Force = power/velocity
Power = original power x new pressure ratio x density ratio x volumetric efficencies ratio x drive power efficiency
airflow rate = (cid x rpm x .5 x E) / 1728
density ratio = original absolute temp / final absolute temp
pressure ratio = (14.7psi + boost) / 14.7 psi
bore area = (pi squared) / 4
bore diameter = square root of (4 x area)/pi
Last edited by sentry65; Jul 26, 2006 at 07:57 AM.
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Originally Posted by sentry65
well then here's some physics forumla stuff that hopefully are more up your alley that you were originally requesting
velocity = airflow/area
Power = torque x rpm
power = original power x new pressure ratio x density ratio x volumetric efficencies ratio x drive power efficiency
airflow rate = (cid x rpm x .5 x E) / 1728
density ratio = original absolute temp / final absolute temp
pressure ratio = (14.7psi + boost) / 14.7 psi
velocity = airflow/area
Power = torque x rpm
power = original power x new pressure ratio x density ratio x volumetric efficencies ratio x drive power efficiency
airflow rate = (cid x rpm x .5 x E) / 1728
density ratio = original absolute temp / final absolute temp
pressure ratio = (14.7psi + boost) / 14.7 psi
E is the volumetric efficency of the engine
thought those formulas would help you get started for plugging numbers into things, but they give you single numbers so you'll have to plug in different numbers for different rpms and engine loads
there's some technical articles online that give examples how to use them
otherwise I've done all I can at this point to try to help
thought those formulas would help you get started for plugging numbers into things, but they give you single numbers so you'll have to plug in different numbers for different rpms and engine loads
there's some technical articles online that give examples how to use them
otherwise I've done all I can at this point to try to help
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From: columbia md.
Originally Posted by sentry65
E is the volumetric efficency of the engine
thought those formulas would help you get started for plugging numbers into things, but they give you single numbers so you'll have to plug in different numbers for different rpms and engine loads
there's some technical articles online that give examples how to use them
otherwise I've done all I can at this point to try to help
thought those formulas would help you get started for plugging numbers into things, but they give you single numbers so you'll have to plug in different numbers for different rpms and engine loads
there's some technical articles online that give examples how to use them
otherwise I've done all I can at this point to try to help
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