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Kilroy was here
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I had a Ford tech tell me that running no cat and no muffler was a bad idea, because having no back pressure could damage the valves. I've heard a lot of discussion about back pressure, but nobody ever mentioned possible valve damage. Any thoughts on this? Does the turbo create enough back pressure to prevent damage?
 

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That's ALL B.S. I ran my truck straight piped for 40k miles, installed at the original 500 miles. The noise got old so I threw a muffler on since I leave early 2-3 am. I you want to straight pipe it you'll be fine.
 

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Captain Negativity!
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Pressure it controlled at the turbo. It has plenty of "back" pressure.

Now if you want to talk about valve damage, ask him about why the stock rocker arm for the exhaust has the crazy reach on it and wears out valve guides. Then you could ask him why one of the exhaust valves gets screwed on getting ehxhaust out of the cylinder and how it always seems to be a little blacker than the other.

When he doesn't have answers for this, mention to him not to open the door on getting technical if he can't follow you through it.
 

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Damnkids Motorsports
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Pressure it controlled at the turbo. It has plenty of "back" pressure.

Now if you want to talk about valve damage, ask him about why the stock rocker arm for the exhaust has the crazy reach on it and wears out valve guides. Then you could ask him why one of the exhaust valves gets screwed on getting ehxhaust out of the cylinder and how it always seems to be a little blacker than the other.

When he doesn't have answers for this, mention to him not to open the door on getting technical if he can't follow you through it.
I wish I could find a tech who understood more than I do, and I've only picked up my knowledge cruising the forums and turning wrenches on this truck I have now. :doh:
 

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mine is a 3.5 inch straight pipe. it sounds like crap. how would i get alot of whistle out of it. would a 4 or 5 inch be better. dosent the mbrp exhaust give the best whistle
 

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I'd rather have a rumble than whistle. at low end anyhow. otherwise they sound like a vacuum cleaner just idling around. I was thinking of running 4 or 5 in. with a muffler and hoping to avoid some of the low rpm whistle, save it for WOT!!!! I dunno... if it still whistles @ idle, even with that setup, then I'll just have to get used to it.
 

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I have a 4" turbo back bullydog exhaust system and I have mine straight piped and absolutely love the sound!
 

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40 lug nuts
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Pressure it controlled at the turbo. It has plenty of "back" pressure.

Now if you want to talk about valve damage, ask him about why the stock rocker arm for the exhaust has the crazy reach on it and wears out valve guides. Then you could ask him why one of the exhaust valves gets screwed on getting ehxhaust out of the cylinder and how it always seems to be a little blacker than the other.

When he doesn't have answers for this, mention to him not to open the door on getting technical if he can't follow you through it.
LOL

You're gonna confuse the poor tech Doug.

As stated, a straight pipe will not cause problems. I've been running a 4" turbo back MBRP (no cat, no muffler) for 115k miles.
 

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Way Out West
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Enough backpressure can actually damage a turbo and engine components. Run the exhaust straight for that awesome jet engine scream and v8 growl with confidence, you are only allowing the entire system to breathe better.
 

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Damnkids Motorsports
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Straight pipe will have the vacuum cleaner whistle at idle though. If you dont want the whistle, leave the cat on, if you're using the stock exhaust.

Stacks with no cat or muffler dont really have the vacuum cleaner whistle, but they do whistle.
 

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mine is a 3.5 inch straight pipe. it sounds like crap. how would i get alot of whistle out of it. would a 4 or 5 inch be better. dosent the mbrp exhaust give the best whistle

its a diesel the minimum u shoulda run was 4" this was somethin u shoulda researched before u paid the money/did the work. most after market exhaust systems you by, (edlebrock, flowmaster, etc) for these trucks are 4". def worth goin back and running 4 inch bud
 

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I'd rather have a rumble than whistle. at low end anyhow. otherwise they sound like a vacuum cleaner just idling around. I was thinking of running 4 or 5 in. with a muffler and hoping to avoid some of the low rpm whistle, save it for WOT!!!! I dunno... if it still whistles @ idle, even with that setup, then I'll just have to get used to it.
think of the sound as a jet not a vacuum cleaner that might help lol
 

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I had a Ford tech tell me that running no cat and no muffler was a bad idea, because having no back pressure could damage the valves. I've heard a lot of discussion about back pressure, but nobody ever mentioned possible valve damage. Any thoughts on this? Does the turbo create enough back pressure to prevent damage?
now to the first post and issue at hand.... i have a friend that has run his truck straight piped for close to 100k miles. absolutely no problems once so ever. i just recently did so to my truck as well and love the performance sound throttle response and all the other benefits that come with it. sure there might be the one guy out of the 100 people that straight pipe their truck that burn up a valve but u have to think is this the straight piping or just a fluke with the truck or other performance add ons? like running a dirty tune or too high of a tune all the time and ramping the truck all the time? you decide but i say theres no better way to run ur truck or cheaper way
 

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Straight pipe will have the vacuum cleaner whistle at idle though. If you dont want the whistle, leave the cat on, if you're using the stock exhaust.

Stacks with no cat or muffler dont really have the vacuum cleaner whistle, but they do whistle.
What about NO cat, but still run a muffler on like a 4 or 5 in. setup? Less whistle w/ muffler? or the same whistle muffler or not? Maybe 5 in. would have a deeper tone and not such a high pitched whistle. I like the whistle, it just sounds goofy to me at an idle... know what I'm sayin? I dunno.... I'm an ex-cummins and 7.3 guy, so the whistle @ idle just doesn't sound "mean" to me... just my opinion though....
 

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mine is a 3.5 inch straight pipe. it sounds like crap. how would i get alot of whistle out of it. would a 4 or 5 inch be better. dosent the mbrp exhaust give the best whistle

just wondering but why would MBRP give the best whistle over any other company like bully dog or magnaflow? considering that every system is straight piped when comparing sound in a perfect world. also any aftermarket exhaust kit you buy comes with mandrel bent pipe for better flow and for these trucks is usually a 4" set up.

best bet for the set up is a 3.5" downpipe then you run your 4" exhaust back from there. straight piped of course. the less restriction you have the better off you will be
 

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its a diesel the minimum u shoulda run was 4" this was somethin u shoulda researched before u paid the money/did the work. most after market exhaust systems you by, (edlebrock, flowmaster, etc) for these trucks are 4". def worth goin back and running 4 inch bud
Stock is 3.5", I think that's why he has a 3.5" strait pipe. I too have a stock exhaust with a gutted cat and no muffler, I don't think it sounds bad at all...

If you guys want no whistle then you need to go to a fixed turbo, the VGT is the reason for the whistle.
 

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its a diesel the minimum u shoulda run was 4" this was somethin u shoulda researched before u paid the money/did the work. most after market exhaust systems you by, (edlebrock, flowmaster, etc) for these trucks are 4". def worth goin back and running 4 inch bud
i just cut the muffler and cat out and welded a piece of pipe in there. 3.5 inch is stock tubing. and i was talking about the mbrp muffler, i said i thought it made the best whistle
 
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