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Boost's Performance Attempt

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Old 05-03-2007, 11:07 PM
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got a bigger pulley to slap on? what if you take off the SC belt?
Old 05-03-2007, 11:16 PM
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I'm still thinking torque management on this one, Bill. If it'* TM, all the octane in the world won't kill the KR. If you move up a pulley size the KR may go down, as that would reduce power/torque. Maybe a pulley swap could point you in the right direction, as Andrew suggested? Do you have a modular system and a bigger pulley you could throw on there in a jiffy?

Foghorn, what you do you think about the "flash KR" theory? You're the one who helped me pinpoint the problem when I was having trouble.
Old 05-03-2007, 11:35 PM
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Originally Posted by big_news_1
Foghorn, what you do you think about the "flash KR" theory? You're the one who helped me pinpoint the problem when I was having trouble.
Need to see a scan to see what'* going on, anything else is guess work. A scan with at least the following parameters would be helpful;

A/F
FT Cell
Gear
KR
LTFT
MAF
MAP(kPa)
MPH
O2
RPM
Spark
STFT
TP %

Cheers,
Old 05-04-2007, 01:14 AM
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You're having the same issue as I am Bill.
KR at light throttle.
I am convinced it'* a fueling issue caused by the Gen V moving moving more air at low speeds.
Old 05-04-2007, 12:52 PM
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It may be tuning and fueling. Anything is possible. And while every motor is a little different...this issue didn't occur on the other two motors. Well at least the first. Second motor didn't run long enough.

I'll get a few scans with those parameters. Things have been busy and hectic at work, haven't had much time to do much besides sleep and take care of one or two things a night.

Ben.. I'd love to think that torque management is pulling timing on me at 2% throttle coasting down the highway. Just don't know how that'* possible. :?: If I had KR while spinning tires or even at 25% throttle to increase speed, maybe.

Literally if I'm on the throttle say 10% or more there is no sign of the KR. Most of the time there is none at low speed or cruising. It has only been seen coasting/constant speed or a little upon gently roll from a stop. It hits and decays quickly with no obvious sound or feeling in the car.

Any chance a dirty air filter could cause any of this? I'm going to clean it tonight. Get scans... and get this KR in the rearview. I want to make power, not deal with KR where it shouldn't be. Made it through a bunch of motor swaps....this should be something that can be solved as well.
Old 05-04-2007, 01:12 PM
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I'd pulley up, and see if it'* still there. If you turn down the boost and it'* still there, it'* the computer/false knock.

What pulley are you running on the Gen V?
Old 05-04-2007, 01:30 PM
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Originally Posted by BonneMeMN
I'd pulley up, and see if it'* still there. If you turn down the boost and it'* still there, it'* the computer/false knock.

What pulley are you running on the Gen V?
Why should I pulley up when the bypass is fully open and I've got -10lpsi of vacuum? Unfortunately I don't have a larger pulley to try.... and honestly can't see a need. Anyone that could explain why I should, please do. I'm looking for knowledge and ideas.
Old 05-04-2007, 01:36 PM
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Forgive the novice in me, but if Bill goes up a pulley size and it fixes the problem, is this a step where you're cutting back a smidge on performance to ease drivability? In an pre-80'* hot rod you can build a nasty, solid lifter, 11 to 1, V8 that will run 500+ horsepower but the car is cranky in the street, doesn't want to start or stay cool, the high compression is hard to live with, etc. Is this the equivalent of this?
Old 05-04-2007, 01:59 PM
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Not really Karl.

The theory is if the engine is being force fed too much air, maybe there'* not enough fueling mapped and being delivered to offset the air and that could cause predetonation through heat etc.

However at the point that this kr is occuring.. it'* acting like an NA motor and pulling the air in as it needs, there'* no forcing of the feed.

Talking with Intense and Ed Morad ...both are more than helpful on the issue. They want to help and have suggestions of things to look at and try as well. Between BC and them it'* going to be found and corrected. Unbelievable how much support a person can get around here. Make me proud to be able to give back occaisionally and also come up with new and interesting issues to help fellow clubbers learn.
Old 05-04-2007, 04:26 PM
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True it is part throttle situations. I'm still in WOT KR fixing mode with the pully up suggestions. Fix? WOT all the time...

I'm assuming all wiring is ok, since you've had a scantool on there and can see normal values. Part throttle fuel maps may be off, and from every automotive board i've been on most PCMs have the majority of fuel map tuning done for WOT, there'* obviously some adjustments done for part throttle fueling, but is it as honed in as the WOT fuel tables?

Maybe you're just sucking in too much air at the lower throttle percentages and you've fallen outside of the adjustment range? Anyone ever seen any part throttle KR conditions who've done a Gen V swap outside of this board that we know about?


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