MikeV Posted September 3, 2008 Share Posted September 3, 2008 I like it, (I welded a crapload of 3/16" plate into my frame over the weekend; which jeepers would think was a waste of metal also...) Link to comment Share on other sites More sharing options...
tucdatruck Posted September 9, 2008 Share Posted September 9, 2008 FYI dual 2.25" tubes are way bigger than a single 2.5" or 3" pipe cross sectional area of 2.25" pipe (inside) = 3.5466 sq. in cross sectional area of 2.5" pipe (inside) = 4.4301 sq. in cross sectional area of 3" pipe (inside) = 6.4918 sq. in do the math: 3.547 x 2 = 7.094 ie dual 2.25" pipes will flow more than a single 2.5" or 3" There is such thing as too much exhaust pipe. Too big of a pipe hurts scavenging, which counteracts the work you did in the first place. That much pipe, you should be running a HUGE supercharger or turbo for there to be a need. I remember SCC making an article on this before and if I remember correctly N/A engine displacement/exhaust size describes these engines to run best with 2.25 and possibly 2.5" pipe. That setup is overkill on even a V8 engine. Link to comment Share on other sites More sharing options...
MY1PATH Posted September 9, 2008 Share Posted September 9, 2008 I've tried many diamters and settled with 2"-2.25" myself. I thought the combination of 2.5" and headers was just too much and when I reduced it I felt a little improvement in my low rpm range and no differance in the other ranges. Link to comment Share on other sites More sharing options...
2geepfinder Posted November 21, 2008 Author Share Posted November 21, 2008 I have that in mine for years Let's see some pics.... I like to see how they piped your system in compairson to mine. Oh, swapped out the Magnaflow mufflers for some "turbo" whatever those are to quite it down a bit. Link to comment Share on other sites More sharing options...
2geepfinder Posted November 21, 2008 Author Share Posted November 21, 2008 I wanna see your dyno results, when you going!?Also, did you wind up putting the o2 sensor after the cat? Works had me tied up for the past couple months, I'm now back in Burlington, WA I look for a local dyno here and get back with some results. Yeah, the O2 sensor had to be installed after the cats cause there just wasn't any room to install the x-pipes pre-cats. Link to comment Share on other sites More sharing options...
yozsi Posted November 21, 2008 Share Posted November 21, 2008 I sure as hell hope you did not install your O2 sensor after the cat convertor..... that would cause the ecu to run the engine wayyyy too rich. Link to comment Share on other sites More sharing options...
2geepfinder Posted November 21, 2008 Author Share Posted November 21, 2008 (edited) I like it!! I have to question your driver's seat dyno though. I'm kinda with GG on this one, for $1300 I'm sure I could pull out more ponies than dual exhaust. Your math is impeccable... DUDE, it's a friggin 3.0 liter motor that tops out before 6k RPM!!! Unless you have done something significant to the intake (and cams?) more than 2.5" is probably just a waste of metal. You can hang 6" HVAC ducting and a fart can if it makes you happy, I just won't believe it runs better. B [/quote You have to tell the whole story if your going to tell it at all............. so lets start from the top shall we.... Our 3.0L motors have an intake area of 9.6211 sq. in. and an exhaust outlet area of 10.6028 sq. in. (6 outlets 1.5" dia. each with a area of 1.7271 sq.in.). The stock manifolds only have a 2" dia outlet at 3.1416 sq.in. per side which is: =>(1-(6.2832/10.6028))*100%)) = 40% restriction of flow just at the manifolds. Both then flow into 2" pipes then are collected into a single 2" pipe which is: =>((1-(3.1416/6.2832))*100%) 50% restriction. Overall our factory exhausts restricts flow by at least ((1-(3.1416/10.60280)*100%)= 70%. Pre cat and Muffler, so lets assume that they'll add another 10% when their new. So, right off the factory floor say ~ 80% restriction. Let's break it down into 3 options; 1) 2.5" Single Pipe system Assumptions; Pacesetter Headers 2†collectors into 2 -- 2" pipes into 1 -- 2.5" pipe All calculations pre cat & muffler Calculations; [(1-(4.9087 sq.in./10.6028 sq.in.))*100] = 53.7% 70% - 53.7% = 16.3% increase in flow……..Not bad! 2) 3" Single pipe system Assumptions; Pacesetter Headers 2†collectors into 2 -- 2" pipes into 1 -- 3" pipe All calculations pre cat & muffler Calculations: ((1-(7.0686/10.6028))*100%) = 33.33% 70% - 33.33% = 36.67% increase in flow……Better!…. 3) 2.25†Dual pipe system Assumptions: Pacesetter Headers 2.25†collectors into 2.25†pipes All calculations pre cats & mufflers Calculation: ((1-(3.976/10.6028))*100%) = 25% 70% - 25% = 45% increase in flow…….Damn good! A couple of things to note the 2.25" Dual system is 2.25" front to back no reduction anywhere. As tight as the 2.25" pipe is I'd imagine it would be difficult to install the 2.5" or 3" without some reductions or additional bends not required with the 2.25" Dual set-up. I'd like to see some photos of the 2.5" and 3" single systems, if anyone has some post them up. Edited November 21, 2008 by 2geepfinder 1 Link to comment Share on other sites More sharing options...
RedPath88 Posted November 21, 2008 Share Posted November 21, 2008 So can you post some pics here now, for those of us who do not have or might not want a MS account? Link to comment Share on other sites More sharing options...
MY1PATH Posted November 21, 2008 Share Posted November 21, 2008 your equations show your dedication but I think you missed something; when you open up diameters to "increase flow" the gasses travel thru the pipes at a lower velocity becuse there is more room for them if the velocity is too low it can create turbulance within the pipes and combined with the fact that being able to expand into that area makes the gasses cool faster making them create more tubulance. this turbulace, if present, will disrupt the scavenging process(which heplps draw more air/ fuel into the engine) untill you reach a hig enough rpm to create enough exhaust to rise the velocty to a point where it clears the turbulance. that being said I'm not going to disprove you results, just providing some for thought. honesly noting speaks better that actual numbers and charts. I had my vg30i on a dyno and I will post my sheet for comparison when you get yours up here. MY low tq band is very flat (desireable) and my hp also is low. I assume you will show MUCH HIGER HP and higher peak TQ @ a higer RPM but with a steeper TQ curve to go with it. In the end and everyone should agree; you do what makes you happy. And it seems this mod made you happy so enjoi it reguardless of what others say. Link to comment Share on other sites More sharing options...
unccpathfinder Posted November 21, 2008 Share Posted November 21, 2008 dammit i wish I would have understood my thermal fluids class a little bit more...but I guess depending on your assumptions you could determine if it was turbulant or laminar flow but I think the only accurate way to determine the results is either by doing it and testing (which seems to be in progress) or using software simulations like flowworks to study the flow path you do what makes you happy 100% agree b/c i've been semi-flamed on several boards for putting the 94-95 dash/emissions in my 87 and granted i've run into every problem there is but it'll be complete some day and she'll ride like the best of'em and I like to be unique...no matter how many folks don't like it or think its stupid or a waste of time and $ theres always a few that will enjoy it and follow in the footsteps which is kinda the reason we're all here b/c if we were all into ricing out civics we'd be on a different board... Link to comment Share on other sites More sharing options...
MY1PATH Posted November 21, 2008 Share Posted November 21, 2008 100% agree b/c i've been semi-flamed on several boards for putting the 94-95 dash/emissions in my 87 and granted i've run into every problem there is but it'll be complete some day and she'll ride like the best of'em and I like to be unique... thats the curvy dash right? kool. takes allot of determination to do someting like that. Link to comment Share on other sites More sharing options...
GrimGreg Posted November 21, 2008 Share Posted November 21, 2008 In the end and everyone should agree; you do what makes you happy. And it seems this mod made you happy so enjoi it reguardless of what others say. There is truth to that, but when you share, you open yourself up for anything that comes. Our 3.0L motors have an intake area of 9.6211 sq. in. So is that figure pre-filter, at the MAF, or at the heads? Unless the exhaust is smaller than the MAF opening, there is no "restriction" on the exhaust side. Link to comment Share on other sites More sharing options...
unccpathfinder Posted November 21, 2008 Share Posted November 21, 2008 (edited) thats the curvy dash right? kool. takes allot of determination to do someting like that. eh no determination at all...just engineering experience in the automotive world...granted i've run into every road block and problem there is but it will be complete sometime. I think this exhaust routing would take more determination... Edited November 21, 2008 by unccpathfinder Link to comment Share on other sites More sharing options...
bitemedoughboy.com Posted November 21, 2008 Share Posted November 21, 2008 eh no determination at all...just engineering experience in the automotive world...granted i've run into every road block and problem there is but it will be complete sometime. one thing to remember when doing all these calcs on area and whatnot.... at any given time only one cylinder is firing, and the exhaust is not a constant flow, it is a series of pulses so regular flow formula's do not apply. thats why an engine with smaller exhaust pipes and a tuned tri-y header will out perform and engine with a huge exhaust and plain headers..... and on another note, if you headers that have the right size primary tubes and are the correct length what you bolt up to them from their doesnt matter unless it is excessively restrictive. the scavenging effect should take place in the header and not in the exhaust pipe 1 Link to comment Share on other sites More sharing options...
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