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Discussion Starter #1
Howdy. Disclaimer: my new '12 DGM WRX Hatchback is is my first turbo car ever, and as I only have about 1,500 miles on it I'm still learning how to really drive it well. Make no mistake: I absolutely love this car. But I've noticed that the car seems to be... well... inconsistent. I haven't quite narrowed down the behavior all the way yet, but there are times where it feels like a 12 second car and times where it feels more like a 15 second car. And I *think* I'm driving it the same.

Example: a week or two ago, I rolled away from a stop sign and floored it after the clutch was engaged (after making sure absolutely no cars were even in viewing range, so don't flame me). When the turbo kicked in around 3k it continued to slam my head into the headrest all the way through until I shifted into 2nd, where it continued to do the same thing. But last night I did the same thing, at the same place, and it didn't feel as strong; it almost seemed to flatten out around 5,800 RPM.

The only thing I can figure is that it was 90 degrees outside yesterday when I did it, and a week or two ago it was undoubtedly cooler outside by probably 20 degrees. This isn't the only example of this, and the performance hasn't been on a decline, either; I might find it crazy fast today on the way home again, for example.

Does the weather really make this much of a difference? Or does my butt dyno need to be calibrated?
 

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I dunno how you'd calibrate a butt dyno, but I don't wanna think about that :confused1

:rotfl:


But yes, cooler temps will undoubtedly make a turbo (or any car) perform differently, and more likely, seem more powerful. Cooler temps = cooler intake charge, which equals denser intake charge. More dense air leads to more powerful combustion in the combustion chambers = more power = feels faster.
 
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I Drink & I Know Things
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I dunno how you'd calibrate a butt dyno, but I don't wanna think about that :confused1

:rotfl:


But yes, cooler temps will undoubtedly make a turbo (or any car) perform differently, and more likely, seem more powerful. Cooler temps = cooler intake charge, which equals denser intake charge. More dense air leads to more powerful combustion in the combustion chambers = more power = feels faster.
I second that. I live in Michigan and we have a HUGE temp range here. In the summer when it's 90 and humid my car can feel downright wheezy with more turbo lag. In the winter when it's 35-40...no turbo lag and it's a rocket off the line and will push you back. It's just something you get used to...turbos are more susceptible than a normally aspirated engine with temp variances.
 

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Discussion Starter #4
I dunno how you'd calibrate a butt dyno, but I don't wanna think about that
lol For the record, I hesitated on that line before I submitted the post, for that very reason... But it was one of those things you do anyway with the understanding that it could easily go awry...

I second that. I live in Michigan and we have a HUGE temp range here. In the summer when it's 90 and humid my car can feel downright wheezy with more turbo lag. In the winter when it's 35-40...no turbo lag and it's a rocket off the line and will push you back. It's just something you get used to...turbos are more susceptible than a normally aspirated engine with temp variances.
Ok. Then no worries on my end. This is exactly what I'm talking about, and your responses have basically just confirmed my suspicions.

Note to self: get the car tuned in the winter.

Thanx guys for the feedback!
 

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The Fruit
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Its kinda funny that by nature the turbo engine likes to play when tires are hard and surfaces are slippery..

Like the engine loves to play when we really shouldn't be playing... user beware.


But yeah like everyone else said, turbo engines are very weather susceptible and a 20* difference will make huge differences in feel and actual performance, its not just in your head. The ecu does pretty well for the most part in keeping things even but there are some factors that are just plain physics and cant really be worked around.
 

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Living in the mountains of Colorado I definitely notice the same effect. I have a 2002 wagon but here its not uncommon to see temps in the 70s during the day and have the night time temps be low 40s during the summer. My car feels more fun to drive at night haha.
 

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Discussion Starter #7
haha

Yeah I leave for work at 5am and it's always a nice drive in. :)
 

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Alls you needs do is get rid of TMIC heat-soak and the heat-soak at the air cleaner intake box and funnel, then the car will feel/run the same all the time, mine does... I did (get rid of heat-soak) and now it doesn't matter, -40*F or +90*F, I just love the response and the torque of the car... :)
 

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Discussion Starter #9
Alls you needs do is get rid of TMIC heat-soak and the heat-soak at the air cleaner intake box and funnel, then the car will feel/run the same all the time, mine does... I did (get rid of heat-soak) and now it doesn't matter, -40*F or +90*F, I just love the response and the torque of the car... :)
Are you saying wrapping them and heat shielding or are you suggesting FMIC and CAI?
 

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Discussion Starter #11

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The Fruit
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Alls you needs do is get rid of TMIC heat-soak and the heat-soak at the air cleaner intake box and funnel, then the car will feel/run the same all the time, mine does... I did (get rid of heat-soak) and now it doesn't matter, -40*F or +90*F, I just love the response and the torque of the car... :)
*face-palm*


intake air temp has nothing to do with heat soak.

fmic or tmic you can only cool down to ambient temp anyway. Sure you dont feel it with a fmic but believe me you ARE affected by the higher ambient temperatures.

giving bad advice is frowned upon around here and there are dozens of studies around to show that fmic on oem turbo's aren't worth the lag or amount of money you'll have to throw at it.
 

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Discussion Starter #13
*face-palm*


intake air temp has nothing to do with heat soak.

fmic or tmic you can only cool down to ambient temp anyway. Sure you dont feel it with a fmic but believe me you ARE affected by the higher ambient temperatures.

giving bad advice is frowned upon around here and there are dozens of studies around to show that fmic on oem turbo's aren't worth the lag or amount of money you'll have to throw at it.
Well, let's give him a break. He didn't know his advice was bad until you told him!

But anyway, does reducing heat soak sound like what I need? And if so, how would you recommend I do it most effectively without heavy modding of the car, voiding any service I will ever want done on it at the dealership? I'm sure there's a link to it around here somewhere.... :confused1
 

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My guess would be that if you are stopped for a while at a light in 40 degrees and stopped at 70 degrees under hood temps are likely similar, so heat soak would be the same it would just be alleviated faster in cooler temps.

Does that thinking make sense to you guys?
 

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IBTL!
 

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Well, let's give him a break. He didn't know his advice was bad until you told him!

But anyway, does reducing heat soak sound like what I need? And if so, how would you recommend I do it most effectively without heavy modding of the car, voiding any service I will ever want done on it at the dealership? I'm sure there's a link to it around here somewhere.... :confused1
Avoiding heat soak isn't a huge deal. You will have no more issue with it than any one else with a WRX or STI. If you're worried that much about it, look into Phenolic spacers.
 

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The Fruit
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Its not so much a function of the intercooler but of the intake charge before the turbo. If the air outside is already denser the turbo doesn't have to work as hard to compress it, as well doesn't generate as much heat during compression. So not only would the air charge alone make more power the intercooler and turbo are more efficient at lower temperatures thus the entire assembly making more power.

fmic introduce a much greater surface area to fill vs the tmic. This greater surface area means the turbo has to take more time to fill it and thus creates lag. Sure a fmic sitting in traffic will not heat soak as fast as a tmic trapped over the engine, however while moving both will only get you down to ambient temp and that's under perfect conditions. No intercooler is perfectly efficient so you'll only get close to ambient.

the cooler the ambient temp is, the cooler the cooler stays. Get it? :D .. its all proportionate. The internal volume difference is the only thing that robbs the fmic of being king. Even still a larger aftermarket turbo and the proper tuning will eventually need the ability of a fmic.

Factory snail.. the tmic is just fine.
 

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I'm only in this thread because I'm waiting for SHAWN SMASH!
 

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The Fruit
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hahaha.. the time has passed brother.. there will be no smashing today. ;) lol
 

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Discussion Starter #20
I'm only in this thread because I'm waiting for SHAWN SMASH!
lol That's the second post from you here that I have no idea what you're talking about... I'm glad Shawn got the reference, but I didn't. And why would this thread be locked? Am I asking stupid questions that qualify me for a new fire-retardant suit?
 
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