|05-31-2014 07:13 AM|
Will it benefit more in any significance when compared to a 2.5" setup? If everything else is OEM, most likely not. If the intake is aftermarket, probably a little. Add a tune, probably a little more. But no matter what is or isn't added (outside of the header), it will not hurt power at all anywhere.
|05-30-2014 10:52 PM|
I wasn't comparing a V8 to a 4 cylinder, other than to say most V8's cannot benefit from a 3" exhaust, I don't know how people think a 4 cylinder, N/A with no building, can.
My whole contention was exhaust velocity and torque across an RPM range. A 3" exhaust will reduce both while allowing more HP at top RPM, which is not useful on the street.
|05-28-2014 06:41 AM|
I love how these threads go from simple exhaust pictures to comparing a V8 to a 4 cylinder.
So 2 side exhaust and no videos??
|05-06-2014 09:58 PM|
Four cylinder engines have to rev higher to make their power (N/A) than larger engines, this is why the peak torque is at 4450 rpm. Big block V8's are known for their low end torque. This is why you have higher revs in your Focus at cruising speed compared to larger engines. Four cylinder engines only get good torque numbers down low when forced induction is used. The torque curve in our engines are pretty flat, which is good. Notice that peak torque comes in at a good rpm if accelerating onto a highway, when it is needed most, but otherwise our engines don't go there much, but there is still a very useable amount of torque.
Horsepower is a calculation, not a measurement. It peaks at 6500 again because it is a small displacement engine and relies more on revs to help make power than an engine of larger displacement. V8 engines usually peak around 5240 rpm, if I remember correctly because of the calculation method and displacement, give or take 50 rpm or so.
Engine design for the mass market, to please the widest range of their customers, is a balancing act. There needs to be sufficient power for most types of driving while also not sacrificing fuel mileage in a very competitive market. Emissions are also a factor as well as NVH.
As for the exhaust on my wife's 66 Mustang, it has no cross over pipe. I will be putting in an H-pipe, it is just low on the priority list of things that need to be done right now. I don't want the affect to the sound of the exhaust that an X-pipe gives. The other engine will not be built for a while yet.
You are right, the exhaust can only hinder the efforts of the headers. However, in most everything in the world, the "If some is good more must be better" mentality doesn't work, or at best only works up to a point.
|05-04-2014 03:55 PM|
|Juicedz||What size exhaust tips are on the ford Escape? I was looking at a pair yesterday wondering if it would look good tucked into the rear valence or if they would be too big. I do like the slash/rounded cut tips.|
|05-04-2014 12:46 PM|
|05-04-2014 12:16 PM|
|05-04-2014 12:15 PM|
|mustang0||You won't get an argument from me, Duane is right. Iv'e have had my car on the dyno two times and seen good improvements from fairly simple mods. I might do it a third time yet.|
|05-04-2014 11:56 AM|
Like he said...
|05-04-2014 11:22 AM|
There is a lot of misinformation and old-school thought processes dominating the automotive world these days. You can either live in the past or you can embrace technology and science and move forward with the rest of the world.
Backpressure is a myth in the way people think of it. It doesn't make horsepower in any way and only hurts an engines ability to breathe, at least in the way most people here are discussing it (cat-back). Primaries and secondaries (header design) size/length/design are what affect powerband. Cat-back is just a situation of diminishing-gains in the fact that one you've gotten it large enough to effectively remove spent gasses then you will not see enough of a gain to justify the added material cost or work to make it fit.
Exhaust design is a compromise. The most power may not sound the best. The best sounding won't give the best performance. Either of those may not be the best solution financially.
There is a wealth of information available on the internet. You have to do a little research and work to sift through what is true and what isn't so don't just take my word on it. But on top of not taking my word I would also not recommend taking the word of those that still think removing backpressure in the cat-back portion of the exhaust will hurt performance.
Backpressure is the enemy.
Fwiw, the best sounding Mk3's at FocusFest last year were mine and Injected's (depending on whom you talked to, obviously, but many agreed), so that's a 3" setup and a 2.5" dual exit setup. Ymmv.
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