B_mouz Neutral Newbie October 9, 2003 Share October 9, 2003 As above, is having low backpressure or high backpressure better for your car performance? At the same time, do headers of the exhaust system have a play in determining the amount of backpressure produced? I noticed that most production cars start off with very short headers (roughly a foot)before they join up, while most after market ones come in longer ones with different config like 4 to 1, 4 to 2 to 1, etc. Do these setup of headers offer any benefits in performance, fuel saving, etc? ↡ Advertisement Link to post Share on other sites More sharing options...
Vidz 6th Gear October 9, 2003 Share October 9, 2003 Hi, the so call back pressure is actually a "vacuum" pull when the exhaust exits. thus it assist the piston in pumping air into the cylinder, most effective if its a twin cam engine. the size and length of the extractor do have a certain role in determining that, including resonance (frequency) to produce best results. Most stock headers are called "log" cos the pipes from the engine joins into a big cylindrical.. well.. log, and then out to the main pipe.. 4-1 are for high rev configuration, 4-2-1 are mainly for low/mid rev. Just changed my to 4-2-1, performance 10% increase... not sure if 100% correct but my 2 cents worth.... However, heard say inspection extremely strict now, will not pass... very moody man Anyone just went inspection? do share! Link to post Share on other sites More sharing options...
B_mouz Neutral Newbie October 9, 2003 Author Share October 9, 2003 Thanks for the info, currently driving a cheapo 91 Nissan sunny 1.4 and they are like you said using the 'log' extractors. Find it damn hard to get pass the 4000 rpm mark.... , wonder if its got anything to do with the extractors. Would low end power in the 2000-3000rpm range be affected if 4-2-1 extractors are used? Or could it be the ECU that's rev limiting the car to prevent it from being redlined? Link to post Share on other sites More sharing options...
Ace_t Neutral Newbie October 9, 2003 Share October 9, 2003 hi, u changed your extractors ? where and how much was it .. thanx Link to post Share on other sites More sharing options...
Vidz 6th Gear October 9, 2003 Share October 9, 2003 Yups... power manz!! when start engine sounds like the intial_D game changed at Fong Kim, at eunos. extractor+muffler+heat wrap $400, friendship price Link to post Share on other sites More sharing options...
Ace_t Neutral Newbie October 9, 2003 Share October 9, 2003 can pass LTA inspection? what if it's not 'friendship' price ? Link to post Share on other sites More sharing options...
Vidz 6th Gear October 9, 2003 Share October 9, 2003 I'm driving a 92 sunny too.. lotsa factors affecting the performance, the original exhaust manifold is surely one of the restriction. like i mentioned 4-2-1 will not affect low end, in fact for my can feel higher torque and faster gear change if don rev. above 2500rpm, more sleeping horsie will wake up.. then the fun begins.. ECU will only cut at 180km/h or 6800rpm or was it 6500rpm, whichever comes first.. after changing extractor the ECU need time to adjust and settle as well... recommend increase air intake before exhaust "enhancements"... have to consider inspection woes as well... Link to post Share on other sites More sharing options...
Ace_t Neutral Newbie October 9, 2003 Share October 9, 2003 u coming for meetups ? gotta see your ride. sounds good. Link to post Share on other sites More sharing options...
Vidz 6th Gear October 9, 2003 Share October 9, 2003 I'm not sure.... was told can, (maybe salesman talk?) but not so sure after checking cos recently lotsa people who used to pass with aftermath exhaust failed. *sigh* maybe may morphed into those hardcores who need to make a trip to "pre-inpection procedure" before the actual one.. you know wat i mean.. Link to post Share on other sites More sharing options...
Ace_t Neutral Newbie October 9, 2003 Share October 9, 2003 do u have a pic to show ? I guess if the diameter remains like stock, should be able to pass. Link to post Share on other sites More sharing options...
Vidz 6th Gear October 9, 2003 Share October 9, 2003 from wat i gathered, muffler can pass lah, not loud... just a nice bassy growl *real cool* However 4-2-1 extractor maybe cannot pass... obvious from undercarriage... Frankly, once you tasted the "dark side" you don want to turn back.... Link to post Share on other sites More sharing options...
Ace_t Neutral Newbie October 9, 2003 Share October 9, 2003 been there before. what was the purpose to wrap the exhaust... dun they use a flexi hose to connect to the main tail pipe ? Link to post Share on other sites More sharing options...
Vidz 6th Gear October 9, 2003 Share October 9, 2003 actually its wrapped on the extractor, to keep the egine bay cooler... it works, in terms of advantages of a cooler engine bay, not too sure, cos i run CAI, DIY one.. maybe a cooler air manifold... from the undercarriage can see 2 pipes joining into one, then the single metal pipe will run to the muffler.. apparently our car don have cat... another plus point! envorinmentally notwithstanding... no flexi hose la.. chau-ta Link to post Share on other sites More sharing options...
Ace_t Neutral Newbie October 9, 2003 Share October 9, 2003 flexi hose got metal braid lah.. wanna see yours. Link to post Share on other sites More sharing options...
Vidz 6th Gear October 9, 2003 Share October 9, 2003 (edited) the rib will reduce the flow, increase the drag.. will try to get some pics... hopefully within this year.. the undercarriage down pipe is stock i think.. din see them change.. the tailpipe is stainless steel 2 and quater inch... gees.. think i;m gettin obsessed.. i wan more, MORE... Edited October 9, 2003 by Vidz Link to post Share on other sites More sharing options...
Ace_t Neutral Newbie October 9, 2003 Share October 9, 2003 dun forget.. our model got no more PARF.... so no more 'value' I suppose as long as the muffler dun look like guni-kong, then should be safe from LTA/ TP etc... Link to post Share on other sites More sharing options...
Vidz 6th Gear October 9, 2003 Share October 9, 2003 more power la... got a list full of things to do... *die* muffler not a problem, just the extractor during inspection... Link to post Share on other sites More sharing options...
Genie47 1st Gear October 9, 2003 Share October 9, 2003 Explains why the willingness to add these exotic stuff. Hmm... 4-2-1 extractor. ↡ Advertisement Link to post Share on other sites More sharing options...
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