Hello folks,

I have 2002 WRX 4EAT with these parts:
UTEC Stage 1
Greddy Evo Cat Back
Highflow up-pipe with cat
GFB BOV
Unifilter rampod intake
STI hood scoop
EGT Gauge
Knock Sensor
A\F gauge
Boost Gauge
Grounding kit

Basically when I just start the car up it seems to drive faster. Or I would bet 100$ it is faster. Anyone experience anything like this, or know what causes it? I still try and stay out of boost until the car is warmed up. I'm thinking of getting a full turbo back exhaust soon and want to make sure everything is OK. Thanks for your help.

 

It probably is faster. My car feels slightly more powerful as it's warming up, too. I think it may have to do with the entire intake path being as cool as the ambient air temperature, as opposed to the intercooler and intake manifold warmed up a bit by heat soak.

Cold oil temps will develop really high oil pressure and will cause a lot of unfiltered oil to push the bypass open and allow unfiltered oil to your bearings and cylinder walls.

Your practice of staying out of boost until warmed up is a good one, IMO.

--
0==WW==0
"…axles of evil…" - george w. bush

 

i don't go above 2.5 or 3k when its cold

 

Besides the intake components being cooler your ECU is probably advancing timing. My Legacy turbo is the same way and it takes an effort not to hammer it when cold. It is completely normal. =)

 

I'm not sure how much of an effect this has, but the tolerances beteween the cylinders and walls are tighter before the engine heats up. Thermal expansion of metals and whatnot.

 

Your intercooler also has less heat soak when the engine is cooler, not to mention the charge is more prone to be cooler over all when the engine and hence the entire engine bay is cooler. Cooler air is more dense, so more oxygen per CFM. Makes sense to me. Also seems to make sense to the guys who ice their intercoolers and leave their hoods up between runs at the track.

jason

 

Not so much a cold engine, but cold weather makes a big diff. I try to keep off boost when the car's warming up tho

 

i can testify that colder weather makes a difference. i like it when it rains, its like a non-stop intercooler spray.

 

Your buttdyno might be off in the rain Damp air robs you of power. The best day for a drag race is a cool day w/ very low humidity.

That's why Sac Raceway has notoriously better times than say Sears Point/Infineon. Well that and supposedly Sears' strip is on a slope (Wow say that 5 times fast, "supposedly sears' strip is on a slope")

Cold air/cold engine produce the same thing: denser charge.... except a cold engine is harder on moving parts.

jason

 

Thanks all for your great responses! Good to see some nice posts and no bashings. Seems like a good topic too, I live in RI and it was COLD this morning at 5am. Of course the first thing I thought of was this post.

 

It's not that, it's the fact that everyone else is driving 5-10 mph slower in the rain while us Suby's can maintain speed and traction with our AWD (and RE92's ) as if the pavement weren't wet

 

or....
he notices that the car is slower, and jams on the gas a bit harder to get to that speed he's used to.


ive noticed the car is much faster when the engine is cold too. but when you start up your car in the morning notice that the rpm's are very high. if you drive right at that point the car will be faster because the car idles at higher rpms. but thats just my hypothesis.
mmboost, your opinion about this? ive been thinking about this, but was never too sure.