Muffler or no Muffler
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From: SE of Bennett Colorado
Muffler or no Muffler
89 F250, 460, 7.5L, 4WD, auto C6 trans, reg cab, long bed
I've heard going with no muffler lowers (worsens) the torque.
I'll gain horsepower but how badly is torgue affected by having no muffler (less backpressure)?
I just ordered a Cat-back system to tack onto a Perf Cat.
I've heard going with no muffler lowers (worsens) the torque.
I'll gain horsepower but how badly is torgue affected by having no muffler (less backpressure)?
I just ordered a Cat-back system to tack onto a Perf Cat.
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From: Hawkeye Country
with a 460 you should have no worries when it comes to torque.
if i read your post right you say you've got a performance cat, high flow? and your gonna add a cat back system behind it?
on my buddys truck, 76 f250 460, we added long tube headers dual 3 inch exhaust and a pair of glasspacks dumping before the axle. his truck lost no power, but rather gained power through the whole rpm range.
anytime you help the engine breath it'll help with power.
if i read your post right you say you've got a performance cat, high flow? and your gonna add a cat back system behind it?
on my buddys truck, 76 f250 460, we added long tube headers dual 3 inch exhaust and a pair of glasspacks dumping before the axle. his truck lost no power, but rather gained power through the whole rpm range.
anytime you help the engine breath it'll help with power.
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From: SE of Bennett Colorado
Yes, adding a high flow Cat, with Cat-back perf Dual exhaust.
Still looking for the right headers for this beast. Ordered Headman headers but their going right back to the UPS dude when they get here. Yikes, I found nasty reviews on Headman headers.
Any header suggestions?
Still looking for the right headers for this beast. Ordered Headman headers but their going right back to the UPS dude when they get here. Yikes, I found nasty reviews on Headman headers.
Any header suggestions?
Post Fiend
Joined: Oct 2003
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From: New Jersey
If the muffler is sized correctly it won't hurt performance at all. Running anything without a muffler is kinda silly unless it's a racing vehicle or a farm truck, or used in the mud only. Why? Because the louder it is, the more likely police will hassle you.
Me, I don't need hassles.
Me, I don't need hassles.
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From: SE of Bennett Colorado
Yes, this is essentially a Farm truck. However, I take it to work (into town) when I get the urge to. Plus, I live in a rural area where smog tests aren't required. It's also just a 'hobby truck' that I want to make bad-***
If a muffler is not "needed", then why buy one right? Plus my cat-back system is muffler-less. I was even thinking of going CC-less, but why not burn up some of the beast's breath to do my [small] part to save the environment. I'll feel better next time I fill up both gas tanks.
As long as I'm not losing torque (I heard a rumor that I would), I'll go muffler-less.
If a muffler is not "needed", then why buy one right? Plus my cat-back system is muffler-less. I was even thinking of going CC-less, but why not burn up some of the beast's breath to do my [small] part to save the environment. I'll feel better next time I fill up both gas tanks.
As long as I'm not losing torque (I heard a rumor that I would), I'll go muffler-less.
Last edited by grizz3000; Nov 25, 2006 at 11:43 PM.
Post Fiend
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From: New Jersey
Removing the muffler will lower the impedance of the exhaust manifold. However, this will shorten the life of the exhaust valves. The flow of exhaust gasses past the valves will be too fast, causing the valves to cool unevenly, causing them to seat imperfectly, causing them to wear excessively. The exhaust impedance is part of the engine design. The exhaust valves need that impedance.
Some back pressure is necessary, even if it's not a lot.
I still say a pair of turbos make great mufflers.
Some back pressure is necessary, even if it's not a lot.
I still say a pair of turbos make great mufflers.
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FTE Legend
Joined: Jun 2006
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From: Ottawa, Ontario
Originally Posted by frederic
Removing the muffler will lower the impedance of the exhaust manifold. However, this will shorten the life of the exhaust valves. The flow of exhaust gasses past the valves will be too fast, causing the valves to cool unevenly, causing them to seat imperfectly, causing them to wear excessively. The exhaust impedance is part of the engine design. The exhaust valves need that impedance.
Some back pressure is necessary, even if it's not a lot.
Some back pressure is necessary, even if it's not a lot.
This is not an issue with EFI engines however, because it can and does adjust on the fly to reach a preset air/fuel ratio measured at the O2 sensor. You can modify a motor to flow substantially more air that it did from the factory(full exhaust) with no increased wear on valve train components as long as operating temperatures are kept within spec.
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From: Hawkeye Country
Originally Posted by grizz3000
Yes, this is essentially a Farm truck. However, I take it to work (into town) when I get the urge to. Plus, I live in a rural area where smog tests aren't required. It's also just a 'hobby truck' that I want to make bad-***
If a muffler is not "needed", then why buy one right? Plus my cat-back system is muffler-less. I was even thinking of going CC-less, but why not burn up some of the beast's breath to do my [small] part to save the environment. I'll feel better next time I fill up both gas tanks.
As long as I'm not losing torque (I heard a rumor that I would), I'll go muffler-less.
If a muffler is not "needed", then why buy one right? Plus my cat-back system is muffler-less. I was even thinking of going CC-less, but why not burn up some of the beast's breath to do my [small] part to save the environment. I'll feel better next time I fill up both gas tanks.
As long as I'm not losing torque (I heard a rumor that I would), I'll go muffler-less.
headman headers arnt that bad, my buddys got them on his 76, and had anouther set of them on a 78 f150. just dont buy the elcheapo 85 dollar set. get a pair of headers that have a nice thick flange and torque them down right, check every now and then to make sure the bolts are still tight, and dont use cheap gaskets, do it right the first time so you dont have to do it again.
and if you want louder then hell and a wicked sound nothing will beat long tube headers and burnt out glasspacks on a 460.
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From: SE of Bennett Colorado
Wow, $86 headers? I didn't go that cheap. This set was $350, still on the economy side, but mid-range I guess.
Right now I'm running it with just a Cat since the exhaust broke between the muffler and Cat. Would be a pain in the butt to repair that short of a distance and also it is the original exhaust. I wouldn't think it could get any louder than it is now with a new perf Cat and new Cat-back exhaust.
Are the gaskets that come with the Headmans good enough? Should I search for thicker gaskets?
Right now I'm running it with just a Cat since the exhaust broke between the muffler and Cat. Would be a pain in the butt to repair that short of a distance and also it is the original exhaust. I wouldn't think it could get any louder than it is now with a new perf Cat and new Cat-back exhaust.
Are the gaskets that come with the Headmans good enough? Should I search for thicker gaskets?
Last edited by grizz3000; Nov 26, 2006 at 12:05 PM.
Post Fiend
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From: New Jersey
Originally Posted by Conanski
Frederic... I think that statement is misleading and doesn't tell the whole story. In the old days of non adjustable carbs,
If you could precisely measure the air/fuel ratio in your exhaust pipe before a low-band o2 sensor, and maintain that A/F ratio exactly while doubling the flow of exhaust, you'll find that the low-band o2 sensor will give you a different reading.
