Never satisfied with the 300's sound, just the way it is hugh? This story has a performance twist at the end.

What is the stock pipe diameter for the efi's? I wanna say 2.25" but I really have no idea, I had my entire exhaust removed a week after purchase in 97.

My current set up is 3to1 headers, dual 2" to an X pipe, then dual 2" to tube turbo style mufflers, turns down right as the rear wheel well opening begins.

I was tossing thoughts around about a single, as after I hacked the tailpipes off and turned it down right before the rear wheel well, I get this obnoxious shrill that I cant even begin to explain, every time I accelerate "aggressively", its fine if I putter along but damn its annoying when it happens. So it occurs to me, I bet I can block off one exhaust pipe now (at the end of the muffler) and let the X pipe redirect everything to one 2" pipe. This would give me the opportunity to hear what a single would sound like, at least with this type muffler.

So I did just that. Sound wise, it has a borderline stock sound, even with no catalytic converters, it was extremely quiet. Performance wise, the truck felt like it always does, until at one point I was cruising along at 60 and decided to give it some more of the old go pedal...one thing is for sure, that old truck hadnt ran that well ever...no if and or butts about it. So now Im thinking single 2.25"~2.5". With one pipe blocked, the exhaust had to work against itself, inside the X to get both sides to flow through one pipe..so Id imagine it would run a hair better with a more smooth transition.

If someone has a v8 and would like a truck X pipe (or simply to use it to quieten a true dual setup on your 300, works very well for this) and has a Y pipe with dual 2" and 2.25" out and would like to trade or something, maybe we can make a deal. Otherwise, Ill probably just hack half the X and weld the new single in the center, Im a perfectionsist so the transition will be smooth or it wont be done at all, thats just one option.



I notice a few people use a single 3" and when I do a little formula for area, my dual 2" still comes up on the smaller end, if im doing the math correctly??? Makes me wonder if there is some performance loss with the 3" vs say a 2.25"~2.5". Dont misunderstand, my truck runs very good with dual 2" but Ill be damned if it didnt seem to run alot better with the single 2". Im gonna give it some more driving time before I commit to this idea but initial reaction was a complete suprise, I was expecting a dramatic negative difference.


If for no other reason than sound quality and what I prefer, Im going with a single pipe, performance is icing on the cake...if anyone has any thoughts towards whether I should go with a 2"/2.25"/3" pipe, Im all ears.

On a related note, I dug out cliffords old catalog on pipe recommendation, on a 300ci engine with headers, it recommends between 1 3/4" and 2" single pipe.


Just keep in mind when responding, Im going with the single for sound quality or what I consider to be more ideal and have my mind set its gonna be a single with a turbo style muffler, the discussion on pipe size is what Im after.

Thanks

 

I personally have never felt that having a large pipe after the muffler matters that much. If you wanted to be really **** about exhaust sizing, the pipe would gradually get smaller as it progressed from the port to the tailpipe because the gas condenses as it cools and less area is needed to generate a given gas flow. As a general rule, you need dual 2.25" or single 3" to support 300 hp. A single is more efficent because the ratio of perimeter to area is lower. I run a single 3" for no real reason other than my headers go into 2.25 pipes and I built it to have a constant area from front to rear. I have no regrets about the 3", but 2.5 would probably be more appropriate even though I doubt there would be any gain from it.

If I was building from scratch on stock manifolds I would build a Y-pipe out of 1.875" pipe and send it into a single 2.5". You might have problems finding 1.875, but 1.75 or 2 either one would be OK.

 

i know that a bigger pipe size is not always better. as the ehaust pulse exits the head it gets help from the other pulses exiting ahead of it. they help pull the exhaust pulse along the pipe. if you use a pipe thats too big, the exhaust pulse cools down and also slows down, there by blocking the next pulse. its called exhaust scavenging. thats about all i know on the subject. someone else here will know more. good luck.

 

SS

Lets say you were going to build a new exhaust wtih headers instead of manifolds (I have headers), would you use the same 2.5"? The pipe running off my headers is 2" now, its still in great shape so Ill run that to a Y.


BB

I think velocity/scavanging and all those other scientific terms came into play with this little experiement. Im telling ya, when I goosed the throttle while crusing, I thought I was in someone elses truck.


If you consider the same length pipe(s), this is what Ive come up with as far as area.

SINGLE 3" = 7.065"
DUAL 2" = 6.28" (3.14" + 3.14")
SINGLE 2.5" = 4.9"
SINGLE 2.25" = 3.97"
SINGLE 2" = 3.14"

 

Too much pipe and one loses the savenging that helps flow through the head. I think 2 1/2 on a single out from the header collector(s) would be OK.

For those that want a sound like crap they can always use 6" sewer pipe.

 

2" off of headers will be fine, I would send it into a 2.5" pipe.

Too large of a pipe will hurt scavenging, but that is primarily a concern with header tube size. The farther away from the port you get the less it matters. As long as everything between the ports and the Y-pipe is OK the rest won't matter much as long as it's in the ballpark.

 

What Silver Streak said too.

 

You will loose a lot of lower end with the 3". I had almost the exact same exhaust on my old F250, but it didn't sound all that bad. I had both pipe coming out to the side in front of the right rear tires, so it got blown away from the truck instead of reflecting off the pavement. I then went to a 3" single. lost a lot of low end, and it was horribly LOUD. Resonated in the cab really bad, and just made me wish I would have kept the old system.

 

I have seen no loss of low end with 3" pipe.

 

I think Im leaning towards 2.25", 2500rpm is ambitious thinking when I drive, I like slow and easy, usually.....but open to suggestions....and reasoning...why 2.5" would be better.

The whole system will probably exit out the side, in front of the rear tire. To give a better perspective. Half the length of the exh setup will be dual 2" pipe. So basically your looking at a muffler and maybe 2' tops of 2.25" pipe.

With that in mind, if someone can give me a reason to go with the 2.5", Im all ears. My logic, stock is 2.25" with two cats, a muffler and horrible bends all the way back to the rear of the truck. My set up would be a couple horrible bends, no CATS, a muffler and straight back, exit in front of rear tire, although I may very well just turn it down...so that should be extremely more free flowing...............but again............Im open to suggestions, thoughts, theory, anything.


Anyone know of a cheap 2.25" muffler that cheap new or used, maybe someone has something. I might go with a single "glasspack" long as I can get it. Now if someone were to say, dude, if you go with a glasspack, go with 2.5" cause the glasspacks flow like complete crap...well...that might convince me.

I could just go with a long *** smitty and weld it directly to the Y,forget the 2.25/2.5 pipe altogether....although I havent heard those...so....

 

I would do 2.5 because 2.25 is barely good enough for stock and with headers you will be making more than that.

 

Using a 2 1/2 is not an absolute nor necessarily better/worse than a 2 1/4 or 3. I used 2 1/2 single out as the Walker Y pipe is 2 1/2...just made it simple from there on out through the CAT, muffler and tail pipe.

And what Silver Streak just said...again.

http://www.maxracesoftware.com/pipemax36xp2.htm There is the program for developing an application specific exhaust system.

 

I did when I took off my muffler.


Messing with exhaust on a 300 can be tricky. For some reason, the 300 is very susceptible to scavenging / backpressure. For instance; the very first time I ever started messing with my exhaust. I took off my muffler, didn't touch stock cats, ran 2.25'' Y pipe into dual glass packs. I lost quite a bit of low end, but gained good top end.

So by doing this I moved my power band up. I didn't get rid of it, I just moved it.

Took off Y pipe. Put on Flowmaster. Didn't notice a difference in performance. I got my #1 cat gutted, #2 replaced with a "high flow" cat. I noticed better performance. I believe this is because my stock cats were most likely plugged up. They had over 200K miles on them.

After going through one or two more changes, I came to what I finally have now. High flow cat runs into 2.25'' (I think) Thrush Glass Pack, into replacement tailpipe. My low end is poor, but my mid (40 mph) and high (60 mph) is great. When I punch it, she moves (for a 300 powered pickup with 31'' tires).

I've heard from repeated accounts that you get better mileage by adding a free flowing exhaust system. -shrug- Last I checked, before I changed out my o2 sensor, I was getting under 17 MPG going 55 / 60 MPH. This is with 4.11 / 31x10.50 tires.

Obviously if you over do it, you will lose all power. But if you keep /some/ backpressure, and make sure your pipe is small enough to help with scavenging, you'll feel your power band move.

 

Well folks, just to make sure I wasnt chemically imbalanced making my hypothesis yesterday......I test drove the truck again this morning, except I did a back to back test.

First run, I plugged one pipe and ran it. Initial thought, the truck felt eager to move, thats the best I can describe it, from take off to fifth gear, the truck felt more solid, as noted yesterday, I initially put that info in my original post but removed it, thinking maybe it was a placebo effect , and it had more top end this time, as it did yesterday, which top end for my truck is 2000-2500 . Also should note, about a 1/4 of my "plug" blew to the side or out, leaving a solid restriction of Id say 3/4 pipe area (same thing happened yesterday).

I came back, ripped all the crap off, put my nice shiny tip back on and ran it again, initial thought, my truck luggs when I take off and is lackadazy when I shift gears...it definitely took longer to reach shifting rpm...no question about it...however...it felt normal in the sense that its felt that way since I put duals on it....Id suspected this for along time but never put much thought in it or cared....now Im convinced and seek change.

If I take the area of two 2" pipe...6.28

divide that by 2 = 3.14 and times that by .2 5 (non restricted area of second pipe), I get .78

.78 + 3.14 = 3.92, which puts me right back at the area of a 2.25" (3.97) pipe.

Dont hate me, I get real precise and over think things when it involve my parting with money. Im confident that if I go with a 2.25 pipe, Ill mimic the benefits Im seeing now....the big unknown is how the 2.5 would affect things. Area wise its still substantially smaller than dual 2", and just looking at a 2.25 circle vs 2.25, there really isnt much difference...but then there is the what if, what if its too much for my application.

Another benefit to 2.25 pipe is everything is a few dollars cheaper....still thinking about the 2.5 though

Im still thinking things over and crunching numbers. I havent found a cost effective way to merge the two 2" pipes and run a single mufflers. I would like to use band/strap clamps but they are not cheap.

Which brings up my next question, anyone know of a source that sells steel band/strap clamps? Stainless steel is common and run about $8-9 a pop. Just steel are half price but so far Ive found either too small or too big. I tried local, noone has them. Most online searches end up showing results for OE parts, which if they put a 2" band clamp on an OE, Id like to know which one...most Ive seen are smaller or way too big.

I could go with the U bolt clamps, would need two and a piece of oversize pipe to merge two simillar diameter pipes but it still comes out to $8-9. Doesnt sound like much, but when you need two, theres 18 bux for a simple connection. Id like to avoid welding, Ive always chose that option and it guarantees rust sooner than later.

Initial plan was to weld the single 2.5 pipe on half the existing X but I noticed the way they have it, welded, if I do that, the opening would be too wide, if I add material, I might as well just buy a premade Y pipe. Magnaflow has a 2" in, 2.5" out for $26....anyone know of a cheaper one?

Im still open to suggestions, ive done more exhaust pipe diameter forumlas and charts than I ever thought possible.

Who knew something so simple could become so complicated, happens when you try and nail down correct sizing on a shoe string budget.

Anyone comes up with any suggestions, throw them my way.

thanks

 

im running 2 1/4" off the headers into a Y and 2 1/2" out to a raptor turbo muffler and exiting before the rear tire with a big shiny tip and it isnt bad. that is with no cat so it is pretty free flowing. being a 4x4 with 33" mudders and a built auto it'll boogy and i can easily rack it off the speed limiter (but it gets scary to drive, lol).

im happy with the pipe sizing just trying to get the "perfect" sound. so far its about the best it has been. i thought about having 2" off the headers but deep down inside i said to myself...self...u know u are gunna do more than just the cam and headers so go for the slightly larger pipe. the mpg sucks but im regularly doin 70 when i can