An X pipe and H pipe use the same theory, to equalize pressure between the two pipes and to enhance low end torque and efficiency...like single exhaust. The X pipe does a MUCH smoother and MUCH better job!
I had true 2 1/2" glass pack dual exhaust that was obtrusively loud and had an H pipe installed that made a major difference in sound(loud not obtrusive), power(a little sat-of-the-pants better), and efficiency(minimally better). I went to a custom set of canister(turbo) mufflers that made it quieter, but nothing else. I later went to a dual 2
1/2 into one 3" with one of the custom mufflers and was IMIDIATLY impressed with the awesome sound(mild and deep at idle and deep and throaty under power), power(awesome throttle response and no more kicking out of OD going up hills), and efficiency(2 mpg higher before tuning and 3-4avg after tuning). Before tuning, the single exhaust won decisively in all areas over the best tuning of the duals.
I don't know if an off-the-shelf muffler design would do worse or better than my custom designed, but I do know that I am sold on single exhaust over duals for the right application. I and many hot-footers I know luv the sound of my exhaust over any dual that they have heard.
btw...My engine isn't stock, its mild with aftermarket intake, headers, and ignition and valvetrain mods. I am at the lower end of what my exhaust can handle and am looking into more power(of course!).
I can see how a x-pipe could work slightly better than the h-pipe design, My h-pipe also mellowed out the tone and boosted bottom end torque. What gets my heart jumping is that distinctive RING the pipes make when the power comes on line....WHOA
Hey Shades, Great info, THANKS! Can you help answer a few extra questions?
What is an X vs an H pipe? I assume that some place in the exhaust path the two pipes connect either in an X or H shape? Does this happen before or after the catalitic converter? Why is this better than running two completely independent pipes? I thought that 2 pipes were better than one? I can see how connecting them would equalize the pressure in each side but so what? Why is that important?
Also, you said that mpg improved after "tuning", what tuning? What did you tune to get this gain?
I'm trying to understand why when you went from a dual 2.5" exhaust to a dual to single 3" exhaust you gained performance? With my limited knowledge that doesn't make since. Isn't that going to increase the back pressure? Won't the engine lose power trying to pump the exhaust out?
I'm in the process of putting an after market exhaust on my '04 8.1L Chevy and would prefer to do this just once. I want the sound you describe (nice throaty sound without being obtrusive) and the power gains. I was going down the daul exhaust road but am wondering if I should change directions and follow this path?
There are sound 'waves' traveling up and down the exhaust system. When they travel up they cause power loss. The popping cackle heard on a true dual system is attention getting and power robbing. Running 2 pipes into one produces a scavenging effect that actually helps draw in the air/fuel mixture to produce more power and at the same time it causes the sound waves to slam into each other and cancel each other out thereby helping to reduce the cackle and increase power. The same works for an H or X pipe, just not as defined. The failing of the single exhaust is at top end.
A tidbit about the three ranges of an engine, low end, mid range, and top end...Low end is idle to 2-3000rpm, mid range is from 2-3 to 5-6000, and top end is above that. How often are you driving your vehicle in the top end? These RPM ranges are very general and average! I wanted to put that in BEFORE anyone started going off about a particular engines RPM ranges.
Back to a single exhaust example...a diesel engine. Low end is its battlefield and it is KING! No matter how many big rigs you see on the road with dual stacks, they come from one pipe. There are more points to diesels that add to its torque, but even diesel light trucks have aftermarket exhausts that are a single design.
Look at the venerable tri-Y headers! 4 into 2 into 1...doesn't it make sense to go 8 into 4 into 2 into 1? They are a tried and true design that optimizes scavenging, flow, and power.
I am not saying that a properly matched dual exhaust wont make tons of power, but the best have an X pipe. If you are making Pro Stock horsepower, then all your concerned with is getting the exhaust out. Everything has to be matched and from experience and investigation, it takes allot to make an engine to where it needs duals. Running 2 pipes into one muffler and 2 pipes out, the same as an H or X pipe.
Do some talking with exhaust system manufacturers. You will still get some that say duals all the way, primarily because that's all they sell, but major ones will have single and dual setups and will have documentation of which does what and how good.
$3-500 isn't chump change but it is worth it to have your computer optimized truck self adjust to a test between a custom bent single exhaust and a custom bent dual exhaust. DO YOUR HOMEWORK! You have allot of engine and a 3inch single probably wouldn't be enough. You might need 3 1/2-4 inch. Flowmaster is an awesome source for recommendations about exhaust. Call their tech line. Measure twice cut once...call many times and pay once.
I was in a position to install 2 1/2inch duals and tune the carb and timing and such to what works best, then a single installed and tune the same for it.
I say it again, do your homework, get input from the pros, and go from there. My single is FAR better than my duals were, and I studied before I made the leap.
Jest my 2 cents...well by the looks of it more like a buck and change...man this got long!
Adding a Supercharger will give you a whole lot more Horsepower. They are nice. Driven a few Before and After Supercharger jobs and it's like night and day. The down side, you HAVE to use Premium fuel, and well with what gas prices are these days.... Plus more wear and tear on the engine, transmission, and rear end. Not normally to bad, because they don't normally boost the engine to much for kits you add on to Stock Engines. Plus it's so much fun smoking the tires until you have to replace them. But if you have around 5 grand to spend on a supercharger system, then some of the Negatives aren't really a issue for you.
The magnaflow sounds great. Nice sound, not too loud. On the highway the Superswampers I put on make more noise than the exhaust itself. I've been slammed by several in the group for putting in a K&N which some have claimed can damage the engine. On a scale of 1 -10, with one being the stock exhaust and 10 being Nascar I would say it's a 7 when you "stand on it" and a 3 when "crusing".
Yes it is a catback system. The kit basically bolted straight on, it took more time to cut off the stock muffler. Caribe Muffler in Miami did the install in less than and hour and with parts, labor, and tax ran just shy of $500. Excellent Service. The Polished Stainless Steel Muffler and Tip look great. Magnaflow does not make a dual for the 8.1L (Why? I don't know.)
I probably could have installed the system myself, but then again I believe in letting the pros do what the pros do best. That's why I had someone else install my Fabtech Lift.
Hey Tailgator, Thanks for the info. The "7" when you stand on it might be a little louder than I'm looking for. Your truck sounds nice. I also put an K&N air intake on my 01 and now am doing the same on my 04. Why do people think that K& N air intakes will hurt your engine? I have never had any problems. The filters are pretty good.
Rocketman, The oil used in the K&N filter WILL eventually coat your MAF (Mass Air Flow) sensor and cause it to fail. There is sufficent data that refutes K&N's claim that they "flow more air". The best filter for your truck is an AC paper filter.
There is a TSB my local service writer showed me when he saw my K&N intake that clearly stated if an oiled air filter was used, many warranties were were null and void. I tossed mine really quick after that and I just hope they didn't record that I had one in their system. Might be total BS and a way out for the dealer, but even so I'd hate to void a warranty on a new truck regardless.
Just do a Google seach for "K&N MAF". I've heard that GM has a TSB out for this. Maybe Ian or someone can confirm this. As far as the performance of paper vs. K&N, check out
KB, Thanks for the info. I had never heard of this. How big a deal is the MAF? How would I know if one failed? If one fails does it damage anything serious or does it just decrease performance or MPG? How much to replace or fix the MAF?
If I was to change the air intake and the air meter on my 04` 2500 HD
6.0,what would be good besides the K&N? Also if I went with dual exhaust with factory size pipe and Flow Masters how loud would it be?What size is factory exhaust on my `04? Will it be louder than my `97 5.7? Thanks, Bill
I got duals from magnaflow performance on mine, 2.5" if I remember correctly It's not loud when you arre standing near it, but I can definitely hear the low deep rumble when I am sitting in my house when the truck is running. I tromp on the throttle and it's the most beautiful deep exhaust sound I ever heard!
Soon as I scrape a bit of extra money together, a local muffler shop is throwing on dual Nascar boom tubes to deepen the sound even further
----------------------------------------------------- users trucks from this group listed below
Bill, What are your objectives in changing the air intake? Look at the post above by KB 3/19 9:16am (Kyle). He provides a link which discusses the air intakes. There is test reports listed and details about how good or bad each brand does. In a nut shell the K & N (and other high performance intakes) isn't very good at "filtering the air" but allows a LOT of air to flow in. The stock paper air filter from Chevy does a great job at filtering the air but is more restrictive in allowing air to flow. The report also points out that the K&N filter gets clogged faster than others so it requires cleaning more often. If you're looking for power/performance and don't mind the dirt in the engine go K&N or some other high performance filter. If you want no dirt and don't mind current performance stay with your Delco filter.
As for the exhaust, loud is relative. Flow Master and other manufactures offer several different levels of loud. Flow Master offers a nice cat back system for that truck which will give it some sound but not a lot and will still improve performance. I think it is the American Thunder muffler. They also offer other mufflers which will provide even more sound if that is your goal.
All stock Chevy exhausts are pretty quiet if you ask me. So if your 97
5.7 was stock then any after market performance exhaust will be louder.
I had an 01 5.3L with a Flow master exhaust and it sounded a little deeper than the stock Dodge Hemi exhaust but not much different. They can make it louder if that is what you want.
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