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Old 02-04-2001, 07:37 AM   #1
Scooby Specialist
Member#: 3962
Join Date: Feb 2001
Chapter/Region: SWIC
Location: Phoenix, AZ
2001 F250 7.3L TD
2011 STi

Question Boost at 4K RPM on n/a EJ25??

Hello everybody,
I'm new to the I-Club so bear with me, I've been attempting to gain knowledge with the STi-MList for a few months now.
I've been experiencing some sort of boost at 4100 RPM when I apply 60-90% of throttle during acceleration. Is this normal or is there something wrong. It's almost as if I had a 6-10hp gain.
Any help would eb greatly appreciated. Oh yeah, I have a 2000 2.5RS Coupe with 4500 miles (7500Km) on it. No mods except for strut tower bar. (for now)

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Old 02-04-2001, 10:12 AM   #2
inpreza kid
Scooby Specialist
Member#: 3334
Join Date: Dec 2000
Location: Calgary, Alberta, Canada

my car does the same thing. i think its just because we have a flat spot around 3500 rpm or somithing like that
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Old 02-04-2001, 11:02 PM   #3
Sea to Sky - OWNED
Member#: 610
Join Date: Dec 1999
Chapter/Region: VIC
Location: Vancouver, BC, Canada
2003 Lexus IS300
Graphite Gray Pearl


That "boost" is even more apparent with intake/exhaust/fuel computer!

I have VTEC baby!
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Old 02-05-2001, 08:59 AM   #4
Scooby Specialist
Member#: 2185
Join Date: Aug 2000
Chapter/Region: SWIC
Location: AZ

2 things to consider:
Our peak torque is at 4k, so it will naturally feel more robust at that point.

My car had a noticable flat spot between 3 and 4k, then my check engine light came on and turns out to be a bad o2 sensor. When fixed, the dead spot was gone.

1 more thing, I noticed slight hesitation the other day, ie, dead spot, and my Check Engine light came on this morning. I'm taking it in tomorrow.
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Old 02-05-2001, 06:35 PM   #5
Kevin Thomas
Street Racing Instructor
Member#: 110
Join Date: Jul 1999
Location: 1997 OBS, 1996 SVX, 1988 RX
1989 1989 XT6


I've always noticed the 'boost' at around 4100rpms in my 2.2ltr. That boost will become more pronounced if you ever get a turbocharger installed. It's were the torque peak is at.
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Old 02-05-2001, 06:45 PM   #6
Scooby Guru
Member#: 329
Join Date: Sep 1999
Chapter/Region: Tri-State
Location: NJ
1995 325i
Arctic Gray


I noticed this on my MY00 last night, I guess it's normal.
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Old 02-06-2001, 12:20 AM   #7
Homicidal Maniac
Member#: 1612
Join Date: Jun 2000
Location: Austin, TX
2008 STI


My car on the stock cams jumped with the fury of a small v-tec at about 3600rpm. I have a MY00 also.
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