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damnjapanfan
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Discussion Starter · #1 ·
before i did any mods to my camry i checked the whp( using the g-tech meter) and it said 151.8whp (w/stock wheels brakes and everything else) i put on the cai and it said 157.5whp did the exhaust and it said 161.7whp. but after i put the wheels and brakes on it i lost alot. my hp went down -15.02whp. i'm going to do more tweaking to try and get back up to speed. btw that was with 17in wheels that were lighter than my oe by about 1lb. i lost more hp when i put my 18in chrome wheels on it:eek: ~17.15whp was lost with those. does anybody have input in this?

thanks:thumbup:
 

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larger wheel size is a larger rotational mass. Meaning it is harder for your car to turn the wheels. Sometimes you can take the car to a dealer and they can reset the ECU. Resetting the ECU to a different default wheel size may help you regain the lost hp, but not all of it.
 

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Mad Scientist
94 scepter coupe
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believe it or not the g-tech thing is accurate within -/+ 3hp. i've tested it against my buddy's car that was dynoed and it read about the same results. it was a saturn the dyno said at the wheels he was doing 85.3whp (sohc full catback cai 17x7inch wheels w/205/40 tires on it) the g tech pro that he has read ~83.8whp mine said ~85.7whp. so it is accurate.
 
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2wickedtoyz said:
believe it or not the g-tech thing is accurate within -/+ 3hp. i've tested it against my buddy's car that was dynoed and it read about the same results. it was a saturn the dyno said at the wheels he was doing 85.3whp (sohc full catback cai 17x7inch wheels w/205/40 tires on it) the g tech pro that he has read ~83.8whp mine said ~85.7whp. so it is accurate.
I'd still rather trust a dyno instead of a gtech. I like the idea of measuring what the wheels are putting out versus using an electronic device with virtually no connection to the wheels or their output. The best way to check wheel horse power is to go straight to the wheels, right?
 

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NO. The wheel is larger in diameter. that means the car has to work harder to move the tires a longer distance. If the wheels were smaller, with little relation to the actual wieght of the wheel, it would work less as hard to spin the tire. It doesnt matter if the larger wheel was only 1 pound total, it would still be a hp loss. There is no way around this, its simple physics.

All manufacturers design thier cars with a specific wheel diameter. Any alteration of this without any ECU reprogram will also alter how your ECU reads things like your speed and your transmission. Something to think about
 

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Auto-Cross Addict
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DarkPrince114 said:
you will lose power when putting bigger wheels on, no way around it (besides putting more performance mods to counter the effect)


Ok, time to school your kids with some knowledge.


First, you don't lose any power with bigger wheels.

Second, your car doesn't have to work harder to turn the wheels. That would require it to increase the amount of torque it is putting out. Which it can't do.

No, what is actually happening is you are recieving less forward motion for how many turns of the axel are occuring. Your car still weighs the same, so it isn't having to work any harder to push the car. The wheel is just rotating less times then it would be with smaller wheels.



You can thank me later:)
 

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Zoom-Zoom
2008 Mazdaspeed 3/2012 Ford Escape
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its been dyno proven that you lose whp by switching to larger and or heavier wheels..

the rotational mass is increased, making the engine work harder with what it already has...

your engine wont lose power, itll just put down less power..
 

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That's not losing horse power then. It is doing what I said, and making less rotations for how much work it is doing.
 

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Razo-E said:
its been dyno proven that you lose whp by switching to larger and or heavier wheels..

the rotational mass is increased, making the engine work harder with what it already has...

your engine wont lose power, itll just put down less power..
YOu awesome guy, you just contradicted yourself. you loose power by switchin to larger wheels. then you say you wont lose power, youll just put less power down. Why dont you do some reading and actually proof read. YOu will loose power, its a fact. Your cool by the way.
 

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Newbie? I dont think so. Horsepower is horsepower is horsepower, if its at the wheel or engine. Hes talking about a hp loss either way. Besides anyone interested in hp knows its what the car puts down at the wheel rather than the flywheel that is most important.

Anyway, an ECU reprogram at a dealer might cost up to $150-300. Generally they are the best since the technology is proprietary to them and they are better suited to do so. Im not talking like totally reprogramming it, such as sending it off somewhere where they remove alot of factory defaults. Its just a reprogram compensating for a different wheel sixe or wieght of a wheel or most anything else that might affect your ECU from interpretting something the wrong way. We all know a computer doesnt know crap unless you tell it.

YOu might find an independant shop that could do a reprogram, provided they have done it before or have some of Toyotas old electronics, highly unlikely, but possible. I would definatly go dealer since you will get what you want, plus its easy money for a tech and all he has to do is hook up a machine.
 

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There is no substitute.
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WissNX-01 said:
Newbie? I dont think so. Horsepower is horsepower is horsepower, if its at the wheel or engine. Hes talking about a hp loss either way. Besides anyone interested in hp knows its what the car puts down at the wheel rather than the flywheel that is most important.
And you should've said it without the need to call him an ass? :hammer:
 
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