4.6L (1996-2004 Modular) Mustang Technical discussions on 1996-2004 4.6 Liter Modular Motors (2V and 4V) within.

boost and blown engine?

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Old 08-03-2006, 12:45 AM
  #11  
sweet99
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Default RE: boost and blown engine?

ORIGINAL: avlon06could some one explain the AF ration i am a little confused about it..
A Natural aspirated motor will idle and run in a air/fuel range called stoich, whcih is 14.7:1. That's 14.7 parts of air to 1 part of fuel. A leaner AFRatio makes more power. It can also cause the motor to ping, knock, preignite, etc. Run too lean and you can burn a hole in a piston as the temperatures in the combustion chamber also go up, as high as 1650*F with a turbocharged car. That is considered the upper limit. If you have a tuner like the Predator there is a parameter that will allow a user to lean the AFR but it is to be done on a dyno where exhaust temps and timing/knock can be measured. A wideband o2 meter will read the actual afr as read by a wideband o2 sensor. The o2 sensors in our cars are not widebands as they are much more expensive and we have no need for a wideband as all the o2's we have is keep the AFR around a 14.7 plus or minus a couple of points. A 14.5 that is not experiencing knock will make more power than the same motor with an AFR of 14.9 as it is leaner and as said in the beginning a leaner mix makes more power through more heat for one. It seems most of the SC's sold to the Mustang crowd are also supplied with a reflashed chip or ECM. The manufacturer puts a safe AFR among other features into the chip so the SC will not grenade the motor.
Here is another way to look at it. The Talon turbo's came stock with a 9.5:1 preprogrammed in at WOT, a very rich and conservative AFR. Guys with all of the supporting mods will run race fuel and a 12.5:1 AFR making much more power. A Honda is a ricer. A DSM is not. www.dsmtimes.org those are 1/4 mile times and trap speeds though they give 1/8 mile times also. Some of the 1/8 mile times are quicker than my 1/4 mile time with my Mustang! Get your stang dyno tuned with the tuner that the shop uses or whatever tuner you have and they will extract more power from the motor by leaning it out at WOT but you must use a specific octane rating. I have 100 unleaded available year round here in central NY.
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Old 08-03-2006, 12:50 AM
  #12  
Rusmisel01GT
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Default RE: boost and blown engine?

Cop here in the city had an 02 GT with a 10 psi vortech and nitrous... ran it hard all the time and sprayed constantly and the motor lasted a year... that seems pretty good in my opinion...
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Old 08-03-2006, 12:58 AM
  #13  
code3GT
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Default RE: boost and blown engine?

2000 GT with a Vortech V2-SQ @ 10psi and "POOOOOF". We had to get a built motor and jumped the boost to 14psi.
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Old 08-03-2006, 01:00 AM
  #14  
jpmustanggt
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Default RE: boost and blown engine?

how long did it last before it blew and did you run it really hard or what?
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Old 08-03-2006, 01:04 AM
  #15  
code3GT
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ORIGINAL: jpmustanggt

how long did it last before it blew and did you run it really hard or what?
We bought the car used in 2002 with 13xxx miles on it and drove it like a baby with a few romps here and there. The motor lasted a little under 2 weeks. Now, I don't know if the motor was tired and that's the reason they guy was selling it, but there was NO tick, knock or anything when we bought it.
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Old 08-03-2006, 01:06 AM
  #16  
jpmustanggt
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Default RE: boost and blown engine?

Dang, what would you suggest? Blower or build bottom end?
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Old 08-03-2006, 01:09 AM
  #17  
code3GT
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Default RE: boost and blown engine?


ORIGINAL: jpmustanggt

Dang, what would you suggest? Blower or build bottom end?
Well, my thinking is....do the bottom end and you will have a ROCK SOLID foundation for any future mods. BELIEVE me, you will say, "Awww, 9psi is plenty for me". But, it's never enough. Once you get comfortable with the 9psi, your car will feel slow again and you will want more. Just my .02
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Old 08-03-2006, 04:44 AM
  #18  
sweet99
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Default RE: boost and blown engine?

ORIGINAL: code3GT
ORIGINAL: jpmustanggtDang, what would you suggest? Blower or build bottom end?
Well, my thinking is....do the bottom end and you will have a ROCK SOLID foundation for any future mods. BELIEVE me, you will say, "Awww, 9psi is plenty for me". But, it's never enough. Once you get comfortable with the 9psi, your car will feel slow again and you will want more. Just my .02
True, boost is an addictive thing, unlike any other mod. It's like power at the turn of a switch. If you have the discipline to keep it turned down then enjoy the 400whp. I am not that disciplined. Mark
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Old 08-03-2006, 09:46 PM
  #19  
JJ03MustangGT
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Default RE: boost and blown engine?

i definitely gotta go with the guys up top....build ur bottom end, then focus on future mods. IMO its the smartest thing to do. temptation is a bitch, and it can drag u down if u let it. but have fun either way. peace



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