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Still have stock exhaust? Do the world a favor and dyno the TRD vs. Stock. You will officially become the first persone who ever did that.
 

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I'm kinda curious about that too. I know it sounds a lot better.

late
 

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Originally posted by Kwiksilver@Dec 7 2004, 10:43 AM
i don't think anyone knows the real answer to that. trd should give factual numbers.
I would not trust TRD on that. They claimed 165 crank hp on a corolla/matrix with SC, but in real life we were getting 159-160 wheel hp with the blowers. that's 20% error right there. Good error, but still an error.

If going for HP, not sound - the header will make way more difference. I saw dynos of 12whp gain with just a header, or up to 20 whp with an intake added to it - stock muffler and all.
 

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it's kind of like computer hard drives. the computer specs might say 180GB but it is really 168GB or something like that. they round up, by a whole lot.
 

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Originally posted by Kwiksilver@Dec 7 2004, 12:01 PM
it's kind of like computer hard drives. the computer specs might say 180GB but it is really 168GB or something like that. they round up, by a whole lot.
I know this is off-topic, but I had to address your comment about computer hard drives, Kwik.
What you're talking about is not at all on overestimation of space, but rather a discrepancy in how the space is measured. Contrary to popular belief, one kilobyte is not 1,000 bytes, but rather 1,024. A megabyte (MB) is actually 1,048,576 bytes, and a gigabyte is actually 1,073,741,824 bytes.

Sorry, couldn't resist.
 

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Adding to what bas said, they drives are measured in Gb... not GB. The difference is that this Gb is Gigabits, and GB is Gigabytes. A byte is 8 bits. That adds another amount that is "lost" right there. Most people incorrectly assume that the loss in size is from the allocation table saying where all files are located, how much space they take up, etc. But that actually doesn't take up a whole lot of space
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Also, I don't believe the exhaust increases the horsepower at all.

On another note... there is always going to be a loss of HP from the crank to the wheels. The crank HP is measured immediately at the engine, while the wheels HP is measured at (as you guessed it) the wheels. There is always going to be a percentage lost from the transmission and the actual force needed to turn the wheels. Friction can be a wonderful and yet horrible thing.
 

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My Supra was rated at 320 hp. It put 330 to the wheels. Typical of Toyco to do that.

There are a LOT more ways to measure hp than simple brake tests, and even those can be deceiving. All those 60's hot rods were rated with the accessory load losses (water pump, alternator, power steering, etc.) added back into the measured number.

In the 80's the Japanese used BMEP (brake mean effective pressure) to calculate horsepower on their motorcycles, that removes ALL accessories including frictional losses from crank and rod bearings, oil pump drive losses, even piston ring frictional losses. It made good marketing material, but you can never achieve those numbers in the real world.

As much as I dislike inertial dynos like the Dynojet (because I can change tires and wheels and "gain" hp), I give them a lot of credit for killing the BS from the manufacturers by providing an inexpensive, widely available, fairly standard test for somewhat fair comparisons.
 

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How would headers add hp while the stock exhaust is still in? Wouldn't the air be restricted once it enters the exhaust, regardless of how big the headers are? I'm not that well-read on how this stuff works, but I'd be interested in hearing more about it :)
 

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A different header will change the way the engine makes power. It might not make more peak power (although most try to do this), but it might make more torque over a wider range of useful rpm which would make the car feel faster. Typically headers do just the opposite though, they aim for a bigger peak number and sacrifice torque at lower rpm. This does make the car faster if you know how to use the gearbox to take advantage of the power, but it also makes the car less friendly to drive on the street, and more prone to burning up clutches.

There are also other issues which may come with headers like a constant Check Engine Light (CEL) because the ECM detects something not quite right either with the second O2 sensor (if the cats are removed), or a problem with reversion, or because the way the exhaust changes the tune of the car, it may decide the correction for the fuel maps is excessive (and therefore something must be wrong with the engine, even though it isn't it's just not working the way the factory intended it to work).

That's the quick and dirty explanation.
 

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Thanks. I appreciate a quick reply. I guess I'll just stick with a CAI for my first upgrade :) This might not be the right thread for that question, but should I change spark plugs and wires to get an hp gain, or would that mess up factory settings as well?
 

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why are you wondering how much HP exaust gives you? Stickers will pump it up much faster... like 10 HP per square inch or sticker. But really the exaust might give it 10 hp MAx... but dont quote me on that.
 

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Originally posted by Pharohz@Jan 17 2005, 08:05 PM
Thanks. I appreciate a quick reply. I guess I'll just stick with a CAI for my first upgrade :) This might not be the right thread for that question, but should I change spark plugs and wires to get an hp gain, or would that mess up factory settings as well?
I doubt you could get any gain by changing plugs. I've only seen power gains with plugs when the original selection was so poor that the engine misfired badly. Not enough to make you say, OMG, it runs like crap, but enough to kill your fuel mileage. The engine comes with Iridium plugs intended to last 120k miles. That's awfully hard to beat.

There are no wires to change. It has what is called coil-over-plug (COP) design, just like the TT Supras. It works great until engine heat kills the coils from lack of cooling (and sitting in the hottest part of the engine not directly involved with exhaust).
 

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As in more than 2-3%? Not likely.
 

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Originally posted by QuadinScionTC@Jan 17 2005, 09:21 PM
why are you wondering how much HP exaust gives you? Stickers will pump it up much faster... like 10 HP per square inch or sticker. But really the exaust might give it 10 hp MAx... but dont quote me on that.
I'd be SHOCKED if the trd exhaust gave more than 2hp.
 
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