nickers Posted November 12, 2011 Report Share Posted November 12, 2011 not to mention most cars need their computers to be tuned to allow for performance increases, doing upgrades without doing so can rob you of performance. back pressure is not need in a turbo system... back pressure causes resistance on the turbo affecting how it spools, therefore less backpressure greater spooling allowing it to properly increase your volumetric efficiency of your engine. now based on my knowledge i could point out that there is valve overlap in between the exhaust stroke and intake stroke, the exhaust valve is smaller in diameter which causes the exhaust gases to be pushed out at a higher velocity, this low pressure created by the exhaust gases leaving causes a vacuum effect on intake air sucking it in. with reduced back pressure a greater quantity of air to be drawn into the combustion chamber causing your car to run leaner, which in turn causes performance issues. youve been mechanic'd Quote chevrolet all day er day. '81 camaro z28 performance '03 silverado ext cab show and go Link to comment Share on other sites More sharing options...
armykyle1 Posted November 12, 2011 Report Share Posted November 12, 2011 not to mention most cars need their computers to be tuned to allow for performance increases, doing upgrades without doing so can rob you of performance. back pressure is not need in a turbo system... back pressure causes resistance on the turbo affecting how it spools, therefore less backpressure greater spooling allowing it to properly increase your volumetric efficiency of your engine. now based on my knowledge i could point out that there is valve overlap in between the exhaust stroke and intake stroke, the exhaust valve is smaller in diameter which causes the exhaust gases to be pushed out at a higher velocity, this low pressure created by the exhaust gases leaving causes a vacuum effect on intake air sucking it in. with reduced back pressure a greater quantity of air to be drawn into the combustion chamber causing your car to run leaner, which in turn causes performance issues. youve been mechanic'd .... I believe one of the common terms is "over spooling" basically the turbo continues to spin faster and longer than it should, with drop in RPMs less oil is pumped through the turbo(depending on the oiling system of course) yes it takes the turbo the extra little bit of time to slow down. Not a huge issue, but an issue none the less. I've seen this to be more of an issue with HD trucks though. Quote TEAM XS POWERTEAM HEAVY HERTZMy build- http://www.stevemeadedesigns.com/board/topic/194454-e46-bmw-build-pos/#entry2914134youtube- http://www.youtube.com/user/armykyle1big build starting Link to comment Share on other sites More sharing options...
95legwagon Posted December 3, 2011 Report Share Posted December 3, 2011 *this should be stickied* great write up. found out about the muffler the hard way. went from stock 2 1/2 pipe to 3 1/2 id inlet and 4" id out. it was too loud and lost bottom end because of no tune..... it sounded the same as running with no muffler. LOL needless to say i put a different muffler on it with a lil bit smaller diameters..... its like 2 3/4 id inlet and 3 " out. does way better than before and also quieter ha -jarrid Quote i think there real i was looking through that guys stuff he sells and it looks like he finds stuff at auctions and just sells it Yea, it looks like someone got the mids about a month ago....shit. If I had a whole Hertz front stage my ears would jizz all over my cheeks. / LOL My Low Budget Build: Green 1995 Subaru Legacy wagon 147k- $1K headunit- pioneer premier deh-p650-$25 4 Lead acid batts. 1 up front and 3 in back- vented outside.- $50 4 vvme L11 10"s <- $30 shipped a piece 6 cu. ft box (after displacment) tuned to 32ish hz with 10 inch sonotube. -about $50 all together maybe a lil more 2 aspm 1300 strapped Selenium 6"s in the front doors on headunit power- for now -$20 quantum tweets in door-for now -$10 boston acoustic 5 1/4 in rear doors- for now-Free big 3 1/0 and 4awg throughout. roof sound deadened (not peel n seal ftw)-free on 80 amp alt (bench tested to put out 100 amps faithfully) <--?-$10 for test about $430 for everything<----Not bad at all still gotta add 3 way crossover, amp for front and rear door speakers and maybe eq Link to comment Share on other sites More sharing options...
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