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heat is murdering performance


lil_z_33

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Mods:

rotated mount gt35r

rotated manfold

perrin intercooler

custom intercooler piping

snow performance water meth kit

custom 3" intake

ID1000 injectors

stock internals

opensource tune

 

1/4 mile last two times I was out was in the evenings, never trapped under 110mph...temperature was like 15-25 degrees celcius

 

today was blazing hot at the track, 42 degrees with the humidity...

 

first pass was like 108mph, then 98, then 91...car was pulling timing and boost like crazy in every gear except first...seemed like my subaru was the most greatly affected by the heat...

 

any suggestions or ideas on how to start correcting this? I have noticed even during daily driving it is doing the same, but not as bad...i tried spraying more water meth, but it seemed to not help much or make things worse...my car was tuned at the end of october 2010, and it was pretty damn cold then...

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Need data logs. That's a pretty big loss of power, so I lean toward the boost leak theory. But without logs it's impossible to say. Did you run Learning View at all between races?

 

My car will still trap about 100 with a small boost leak, so I think there's more to it than just heat.

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My guess is some serious timing being pulled... how did you know timing was being pulled if you haven't logged it? I assume you have a boost gauge? Possibly you were "limp-moded" to wastegate pressure, totally clueless on how thats work with an external wastegate? Aren't IATs measured pre-turbo?
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Woah now, didn't say that heatsoak was responsible for his drastic loss in performance. Just pointing out the obvious, and also so that he realizes when he datalogs that looking at the IAT column won't be super useful. :)
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The 110's were all ran on two completely different nights where temperature was like 20 degrees celcius. The 91mph trap was yesterday afternoon on the hottest day of the year. As the car heats up, the rpms start to stutter at wot and i feel boost cut and in and out power. Boost gauge and meth gauge are up and down like crazy as meth is based off of injectors and boost.

 

I got a tactrix cable today. Will log on wednesday.

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I have zero knowledge of datalogging, will the tables show symptoms that will point to a boost leak?

 

If you have a boost leak, it will show lower-than-normal boost and a richer-than-normal AFR when you're at full throttle.

 

It's worth taking some time to learn how to log - it's the best tool we have for diagnosing problems like yours.

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to put it all in perspective. The shitty times were ran at approximately 107.6 degrees Fahrenheit. with over 80% humidity. I'm not sure how much of an affect it will have, but I find the hotter it is outside, and the longer the drive, WOT and high boost causes stuttering and the rpms do not rise smoothly.

 

is romraider the way to go to datalog? what parameters should I log?

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I'm in Texas, its always hot. Last night, it was "cool" at 90*(at night). You should not be dropping from 108 to 91. That is hypothetically/roughly 170chp loss. My vf39 with terrible top end and a small boost leak still trapped 101 in 100* weather with a 2.4 60'(no launch,very much babying it).

 

You could follow the general log that nsfw posted on romraider. http://www.romraider.com/forum/viewtopic.php?f=33&t=5384

 

I would however, start looking mechanically for stuff. To be frank, I'd be worried. A boost leak should not drop traps that much, neither should heatsoak. My stage 2 LGT was trapping 97ish with the same babying 2.xx 60' launch. back to back runs, my traps never varied by more than +/-1

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Mods:

rotated mount gt35r

rotated manfold

perrin intercooler

custom intercooler piping

snow performance water meth kit

custom 3" intake

ID1000 injectors

stock internals

opensource tune

 

 

no logs at all...I need to learn how to do that...

 

.

 

I have zero knowledge of datalogging, will the tables show symptoms that will point to a boost leak?

 

Surprised it hasn't been asked yet. How do you have a mod list like that tuned back in October and not know how to datalog nor have any since this vehicle was initially tuned? Don't take this the wrong way and let this be a lesson to others; datalogging is of utmost importance when modding these vehicles.

 

There's great info here on this site that you have been pointed to. Also, I would think that a well tuned LGT with a rotated GT35r and meth should trap not above 110 mph, but well above 110. Perhaps somewhere in the 120 range. Maybe I'm confused. :confused: Who tuned this vehicle?

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Never too late!!! Im just hoping that you have no mechanical issues brohan: I would rather see you have an easy cheap fix than an expensive hassle.

 

Read this:

http://legacygt.com/forums/showthread.php/using-autonostics-vag-com-cable-read-flash-ecus-110768.html

 

http://legacygt.com/forums/showthread.php/using-ebay-vag-com-cable-datalog-96737.html

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