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Discussion Starter · #1 ·
Hi guys, I've got NA 95 manual all stock except the exaust with no cats. I've noticed that when It's a hot day or when the car gets hot after driving for a while, it's loosing power when accelerating....I've got stock air filter...Just don't know what's the reason :(
 

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!black
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Does your temp gague go past the half mark? Any time you introduce a higher ambient temperature, power will drop.... but how much depends on many factors.

What weight oil do you run?
 

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Discussion Starter · #3 ·
No, the temp. gauge is even less than half and I'm using Castrol Racing 10W-60 ... Will do the compression test and ecu test on 1st of June in the local Toyota centre, but Im not shure that they will find the reason. Maybe anyone else here had similar problems?
 

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There is more oxygen in cold air so you should expect some power loss on a hot day, even if there you car is running perfectly.
 

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Discussion Starter · #5 ·
Then most of NA owners should have such problem, but looks like im the only one...I also thought about oxygen and hot air, but I've got stock air filter box and heat shield...
 

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i need horsepower
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i have the same thing happen to me, on a cold night with the car recently warmed up vs. a hot day after driving the car for a while i notice a difference. Jus go out to have fun with the car at night. i recently switched to the injen intake and i sense even more difference (faster at night, slower during hot days)
 

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Exiled Supra Owner
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You can change your oil to 10W-30 as 10W-60 is a little thicker when it gets hot.
If the whether isn't over 100F you can use 5W-30 (which is the preferred oil for the 2JZ-GE per Toyota Service Manual - The stock oil cap should say the same too).

When temperatures are hot outside, expect the air density to be come less and your car will run slower.
 

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Discussion Starter · #8 ·
old man celica said:
i have the same thing happen to me, on a cold night with the car recently warmed up vs. a hot day after driving the car for a while i notice a difference. Jus go out to have fun with the car at night. i recently switched to the injen intake and i sense even more difference (faster at night, slower during hot days)
what oil r u running?
 

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this is normal. more cold air= more power. hot air= less power. even with a stock airbox youre going to be getting different temperatures of air esp on hot vs cold days.
 

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Same here...Even more noticeable since I have the Apexi Power Intake without heat shield. As the coolest air is close to the ground, go get it there if you're planning on a intake upgrade.
 

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Discussion Starter · #12 ·
hm...so it's not the oil...I wonder if anyone solved or not this problem with sport air filter with heat shield and piping to the filter?
 

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2JZ NA-T
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y 10w60? i thought it had to b 10w30 or 5w30...why would u do a compression and ecu test? c\'mon man....this is simple....it feels like its runing slower b/c it is, and it IS loosing power, y? why do ppl put intercoolers on turboed cars? to cool the air, b/c the cooler the air to more u can fit, hot air expands, there for leading to less of it being able to compact its self inside of ure engine,thats y it feels slow, dont sweat it man, ure good
 

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Discussion Starter · #14 ·
well, im doing the tests because I need to be sure that car is ok befoe doing a 3000mile trip and I also was told that there can be ecu errors connected with temp/O2/fuel....And I know that car runs better when it has more cool air, but im my case the difference is VERY big between driving the first 15 mins in a cool day or past 30 mins of driving in the same day...
 

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i need horsepower
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i need to add that i have a huge exhaust, so low end is effected in the first place. How big is the difference? Im going on a 3000 mile trip myself. I would jus take the car in for a tune-up and stuff...
 

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Discussion Starter · #17 ·
well, the difference is really noticable, when I drive from the parking lot when the car is still cold, my wheels slip easily when starting without reving high and takes off from the place fast, when It's hot, I can't start fast without reving high, the car is like tired :(
 

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Altitude also can make a difference if your car parking lot is at sea level and your trying to do fast pulls in the mountains at 5,000 feet above sealevel.

If you believe the car is really slowing down significantly, then have it dynoed on a hot and cold day. You probably only see a ~10 RWHP difference at most.
 

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Discussion Starter · #20 ·
Ok, got my car from the local Toyota dealer.They checked the ecu for errors and compression. Comp. is ok, and they say that the reason why the car drives like shit when it gets hot is because the speed signal from the odometer doesn't get to the engine...Need to change the odometer comp. which costs $1090!!! FUCK..... will make another ecu check in different store on monday.
 
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