3" exhaust = POWER!! - Page 3 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


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Old 12-21-2004, 12:48 AM   #21
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Default Re: 3" exhaust = POWER!!

Ahh, I read what Intense said about them but they're the ones selling it. I guess real world matches up fairly well then. In that case though....

Quote:
Originally Posted by Dans2002bonne
Thats 23 WHP
Quote:
Originally Posted by 2000SilverBullet
The 1.9 rockers will add 23 whp... alone.
Raises the two questions then:

3" exhaust = power ?
or
Rockers = advertised power ?
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Old 12-21-2004, 12:57 AM   #22
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Default Re: 3" exhaust = POWER!!

Quote:
Originally Posted by DrJay
Ahh, I read what Intense said about them but they're the ones selling it. I guess real world matches up fairly well then. In that case though....

Quote:
Originally Posted by Dans2002bonne
Thats 23 WHP
Quote:
Originally Posted by 2000SilverBullet
The 1.9 rockers will add 23 whp... alone.
Raises the two questions then:

3" exhaust = power ?
or
Rockers = advertised power ?
That is what I was thinking too!
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Old 12-21-2004, 01:07 AM   #23
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Rrounds is also running with a full 3" into dual 3" muffler exhaust and his times are the same as mine and he has less mods.
It doesn't seem to hurt him.
I tend to agree with opening it up as much as you can with our SC engines.
Running open headers would be a little too extreme.

If I ever change my exhaust, I will go with 3" to twin 2 1/2" out.
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Old 12-21-2004, 01:10 AM   #24
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Do you have dyno numbers to compare? There are a lot of track variables.

I'm kind of interested in this because I'm fast running out of practical things to mod, and the exhaust is next. Mine, although unidentifiable, isn't stock but I'm still curious if 3" or smaller is best...meh
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Old 12-21-2004, 01:23 AM   #25
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Quote:
Originally Posted by 2000SilverBullet
Running open headers would be a little too extreme.
I think open headers would be best for WOT acceleration, you only hit the torque peak once, after that you're in HP the rest of your run.

He matched HP gains, but torque is up more then Intense says. Keep in mind those might just be 1.9 rockers, but that'* on a previously modded, Forced induction engine. N/A will see different gains, and non-modded cars will as well.
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Old 12-21-2004, 04:35 AM   #26
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Quote:
Originally Posted by dbtk2
Yeah, but that 240/280 is at the engine. You have to take into account the drivetrain loss of approx. 20%. 20% loss of 240hp would be 192whp.
Just wanted to point something out real quick...

Driveline loss is never a percentage of engine power. It'* a fixed number. No matter how much power your engine makes at the crank, it always takes the same amount of that power to turn the wheels over. If a stock L67 makes 240 hp at the crank and approximately 190-200 hp at the wheels, its a 40 or 50 hp loss through the driveline components. If you up your engine power, it doesn't take any more power to turn the tranny than it did before. Thus a car making 400 hp at the crank would make roughly 355 hp at the wheels. If you used a percentage rule you'd only figure it to be 320 hp, which would be incorrect. Power lost to the driveline is a constant
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Old 12-21-2004, 04:42 AM   #27
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wow...that has to be the biggest no brainer I've never thought of hahaha. really though, for some reason I never thought about that.
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Old 12-21-2004, 04:55 AM   #28
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Lol, yeah I hear you Jay. I always thought in terms of percentage until my buddy Doug from the Thunderbird and Cougar Club of America gave me that revelation one day. I didn't even understand it at first, but it makes sense. Just because you hop up your motor doesn't mean you lose anything more through your driveline!
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Old 12-21-2004, 10:50 AM   #29
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Quote:
Originally Posted by big_news_1
Quote:
Originally Posted by dbtk2
Yeah, but that 240/280 is at the engine. You have to take into account the drivetrain loss of approx. 20%. 20% loss of 240hp would be 192whp.
Just wanted to point something out real quick...

Driveline loss is never a percentage of engine power. It'* a fixed number. No matter how much power your engine makes at the crank, it always takes the same amount of that power to turn the wheels over. If a stock L67 makes 240 hp at the crank and approximately 190-200 hp at the wheels, its a 40 or 50 hp loss through the driveline components. If you up your engine power, it doesn't take any more power to turn the tranny than it did before. Thus a car making 400 hp at the crank would make roughly 355 hp at the wheels. If you used a percentage rule you'd only figure it to be 320 hp, which would be incorrect. Power lost to the driveline is a constant
No, that is not the case. I have heard it explained many many times. The major thing with an automatic tranny is, your torque convertor is going to be slipping. With more power its gonna slip more. Not only that, but with more power, the clutches in the tranny are gonna slip more. It makes sense that it wouldn't take more power to turn the tranny at first, but when you really think about it it does. Intense uses a percentage for driveline loss and they build trannies. I'm sure if you do a google search on it it will explain it to you. But, its definately a perfecentage loss.

Shawn
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Old 12-21-2004, 11:05 PM   #30
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Yes, I would have to agree with that.
More power usually means more heat and frictional losses so the power loss increases as a percent.
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