Is This Possible?
Registered User
Joined: Dec 2003
Posts: 269
From: Wichita Falls, TX
V6toV8, I think you are misreading what I said...
And back pressure any back pressure does not make horsepower, it robs it plain and simple. Anything that impedes the scavanging of the cylinders will cause a loss of power ...
I think I said that ANY backpressure robs horsepower. So what is your arguement? It sounds to me like we agree on that. If I had used the word "exiting" instead of "scavenging" would that have made it more clear to you. A little back pressure is good thing in an everyday driven street car because it causes the engine to have more low end torque and that makes the car feel stonger when driving a low speeds even though it will cost a few horsepower on the top end. Ask anyone who ever put on a set of headers and a low restriction exhaust and they will tell you that although the car runs faster at the track, it feels like it lost power in normal driving. Since we spend more time in the bottom half of the engines rpm range when driving on the street it's a good tradeoff.
And back pressure any back pressure does not make horsepower, it robs it plain and simple. Anything that impedes the scavanging of the cylinders will cause a loss of power ...
I think I said that ANY backpressure robs horsepower. So what is your arguement? It sounds to me like we agree on that. If I had used the word "exiting" instead of "scavenging" would that have made it more clear to you. A little back pressure is good thing in an everyday driven street car because it causes the engine to have more low end torque and that makes the car feel stonger when driving a low speeds even though it will cost a few horsepower on the top end. Ask anyone who ever put on a set of headers and a low restriction exhaust and they will tell you that although the car runs faster at the track, it feels like it lost power in normal driving. Since we spend more time in the bottom half of the engines rpm range when driving on the street it's a good tradeoff.
Registered User
Joined: May 2001
Posts: 1,122
From: Memphis, TN, USA
Just my $0.02 .......
On those cold mornings, I still get an exhaust contrail out of each tip, with the cutout open.
I also went through the sniffer test with the cutout open and they ran the probe in the driver's side tip and still got a solid reading.
On those cold mornings, I still get an exhaust contrail out of each tip, with the cutout open.
I also went through the sniffer test with the cutout open and they ran the probe in the driver's side tip and still got a solid reading.
Registered User
Joined: Apr 2001
Posts: 674
From: Sac, CA
Originally posted by Gold Z
A little back pressure is good thing in an everyday driven street car because it causes the engine to have more low end torque and that makes the car feel stonger when driving a low speeds even though it will cost a few horsepower on the top end.
Ask anyone who ever put on a set of headers and a low restriction exhaust and they will tell you that although the car runs faster at the track, it feels like it lost power in normal driving.
A little back pressure is good thing in an everyday driven street car because it causes the engine to have more low end torque and that makes the car feel stonger when driving a low speeds even though it will cost a few horsepower on the top end.
Ask anyone who ever put on a set of headers and a low restriction exhaust and they will tell you that although the car runs faster at the track, it feels like it lost power in normal driving.
What you are talking about is the 'ol ***-o-meter ... which will lead you to believe there is a loss of torque.
What is happening is the low end increase is minimal to none - but no loss - relative to the high end gain. Your butt is used to a certain power curve. You change in favor of the end high, with no relative gain at the low end and your butt percieves it as less, when in fact it is the same.
By the same token ... backpressure does not "create" torque.
It's the reverse effect of the ***-o-meter. Rob the highend of some power - which is what the back pressure did - but leave the low end power essentially the same; and you will create the feeling of more low end power.
You hear the same arguement about how LT1s have more low end power than the LS1. But look at the dynos and the LS1 low end is essentially the same ... it's just that the high end on a LS1 is so much more, that it leaves an impression of less on the low end, when in fact it is the same ...