kpr Posted June 2, 2009 Share Posted June 2, 2009 yeh same deal here, thats why i was running a 2" system to start with. but smaller exhaust for better torque, velocity scavaging etc, seems to be bs in my case at least. just been comparing the tune we used on the dyno with 2" exhaust, to the current tune. ive added 45% more fuel at 5000rpm! tapers down to not much at high rpm and low rpm, but have added fuel everywhere. have done other mods as well, but exhaust changes are responsible for most gains. huge midrange gain from changing to the bigger exhaust. pitty it scrapes like shit on everything as it is, otherwise i'd be tempted to try bigger. Quote Link to comment Share on other sites More sharing options...
Spencer Posted June 2, 2009 Share Posted June 2, 2009 ^ yea seems to be alot of myths that you need to keep the exhaust size down when going n/a, but most dynos plots ive seen have gains with massive exhausts. Go big and deffinately flag that megaphone, they have there place but without extensive dyno time/experience its hit and miss. Ill be going 2.5" - 3" on my beams hopefully out the front guard Quote Link to comment Share on other sites More sharing options...
ProZac Posted June 2, 2009 Share Posted June 2, 2009 The stuff i've read indicates that header length and diameter = critical, but after that, not so much. Quote Link to comment Share on other sites More sharing options...
Truenotch Posted June 2, 2009 Share Posted June 2, 2009 Ill be going 2.5" - 3" on my beams hopefully out the front guard Don't think thats legal for MSNZ mang, has to be at least at the back door in a 4 door I think. Quote Link to comment Share on other sites More sharing options...
Spencer Posted June 2, 2009 Share Posted June 2, 2009 ^ oh yea i know the rules dude 75% of the cars length, but for track days its another story Quote Link to comment Share on other sites More sharing options...
Snoozin Posted June 2, 2009 Share Posted June 2, 2009 You'll still need to be under 95dB for a track day too or the track officials will get all antsy. Quote Link to comment Share on other sites More sharing options...
bubblegoose Posted June 2, 2009 Share Posted June 2, 2009 You'll still need to be under 95dB for a track day too or the track officials will get all antsy. install flame kit to side exhaust to deal with track officials Quote Link to comment Share on other sites More sharing options...
Spencer Posted June 2, 2009 Share Posted June 2, 2009 it will have a muffler dweebs and never heard any complaints at taupo about noise accept after 6pm, drag cars with zoomies are 1 million db. Anyway we're spamming his thread Quote Link to comment Share on other sites More sharing options...
Unclejake Posted June 2, 2009 Share Posted June 2, 2009 [ basically the thing was more than a total waste of money as I spent a year an several thousand dollars trying to make the engine go properly due to my hgesitation in chopping off something that someone else charged be a bunch of cash to make. cut out the megaphone today. now it has a section of 2.25" (300-400mm) welded to collector. then steps up to 2.5" for the rest of the exhaust. afr has stayed the same. but it accelerates faster. no loss of power down low. thinking i might try 2.5" all the way . least im going in the right direction now anyway, slowly! Choice! Quote Link to comment Share on other sites More sharing options...
Stu Posted January 11, 2010 Share Posted January 11, 2010 Turbo it already... Quote Link to comment Share on other sites More sharing options...
kpr Posted January 11, 2010 Share Posted January 11, 2010 no no, slow and reliable is where its at. err think exhaust is falling off again.. Quote Link to comment Share on other sites More sharing options...
von Mako Posted January 11, 2010 Share Posted January 11, 2010 Slow on the uptake I know, but fuck those are some sexy headers. Quote Link to comment Share on other sites More sharing options...
bubblegoose Posted January 11, 2010 Share Posted January 11, 2010 reliable exhaust is falling off again.. whats the go with those ports bro, how the ass dyno rate the mismatched manifold? Quote Link to comment Share on other sites More sharing options...
kpr Posted January 12, 2010 Share Posted January 12, 2010 i class the exhaust falling off as general maintenance, not a reliability issue. im use to welding it back together every few weeks. mismatched manifold doesn't seem to have effected it at all, goes better if anything to be honest. anti revision i say. its not so bad just a step down to the port at the bottom. the afr said no change untill 6k onwards, added about 3% more fuel from there onwards if you wanna get all techo . Quote Link to comment Share on other sites More sharing options...
bubblegoose Posted January 12, 2010 Share Posted January 12, 2010 i class the exhaust falling off as general maintenance, not a reliability issue. im use to welding it back together every few weeks. mismatched manifold doesn't seem to have effected it at all, goes better if anything to be honest. anti revision i say. its not so bad just a step down to the port at the bottom. the afr said no change untill 6k onwards, added about 3% more fuel from there onwards if you wanna get all techo . if my shit decided to fall out itl be an 8mm step at the bottom and 2mm each side, thats also alot of jb weld (6 packs) for the valve to try and chew up Quote Link to comment Share on other sites More sharing options...
cheater_5 Posted March 28, 2010 Share Posted March 28, 2010 Impressed, it sounds amazing dude. Any idea how much power it's making? Fender mirrors? Quote Link to comment Share on other sites More sharing options...
Guest Posted March 28, 2010 Share Posted March 28, 2010 caravan towing extendo-mirrors or bust Quote Link to comment Share on other sites More sharing options...
kpr Posted March 29, 2010 Share Posted March 29, 2010 yeh nar. dunno what power. guess 120-130kw how it is now on 4psi. will put it on dyno sometime. might take it to the outlaw drags next weekend. fix the boost leak and should do a high 12. /get a punch in the face from some v8 guy Quote Link to comment Share on other sites More sharing options...
Truenotch Posted October 19, 2010 Share Posted October 19, 2010 Hmm, that's interesting! So the exhaust is now 2" through to the rear muffler, which you've modified to flow the same as a 3" pipe? Quote Link to comment Share on other sites More sharing options...
kpr Posted October 19, 2010 Share Posted October 19, 2010 its 2.5" from the extractors, all the way to just before the rear muffler. then jumps up to 3" and through muffler. has a straight through muffler in the middle somewhere also. i tried to overkill the muffler as much as i could as thinking of trying a 3" system. im not sure why it went leaner will the muffler on it. possibly the 2.5 -> 3" cone i used before it, who knows Quote Link to comment Share on other sites More sharing options...
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