ok would it be best to keep the stock exhaust, and buy the needswings dp with the electric cut out? This away i keep my stock exhaust, and stay quite for my daily driver, and then when i want to race it, push the button and go open dp? Or do i go needswings dp, and go ahead and purchase 3in catback system? noise isn't that big of an issue right now. What gains will i see if any runninga 3in over running dp open?
These are good questions Jed. Me = Needswing V5 DP w/stock exhaust My wife = MPx 3" TBE (Turboback Exhaust) We tested the Needswing DP open on a couple/few SRT-4's here on a dyno day and with it open the cars gain 17whp more. With it closed its not all that quite like it would be with the stock DP. You'll get the loud pops and backfires... alittle more aggressive sound and its a bit loud at WOT. As for the my wife's car (S3 with almost every bolt-on)... she had the QTP 3" downpipe with cutout and stock exhaust. Seemed a bit restrictive with her setup. But when her cut-out was opened it flowed nicely. We got rid of the QTP DP with the stock exhaust and got a MPx 3" TBE... its LOUD but it flows a lot nicer then the QTP 3" downpipe to the stock exhaust on here setup. Definately can feel the difference. So I would say it all depends on your goals and what mods you plan on going with. I don't really know the gains with a full 3" but its probably around the same/close-to as the cut-out being opened if I were to guess.
well for now i want 300hp range. im in college so money is an issue. the needswings dp is very do able compared to a full 3in tbe exhaust. i mean i can easly bolt up a 3in cat back system later on. I like the idea of keeping my car quiter then then a 3in and then having it loud when i want it. It is my my daily diver and long drives with a 3in exhaust on the HWY at 80mph could get annoying. I thinki this is the best move, for now if anyone else has there input please let me know. So would a stage 1 reach its potential with the dp open? Turbo cars do better with less back pressure correct??
go with a real, full 3" exhaust. what you aren't thinking about is the ecu having to adjust to opening the cut out, which does take a while. we "tested" this at the track one day. a friend was there on the stock turbo with full bolt-ons. he had a cutout on the car. he ran with the cut out open and with it closed. he ran faster with it closed. when looking at what was going on there, it was discovered that by opening the dp it caused the ecu to pull insane timing, so the car was slower. he switched to a full 3" exhaust the following week. not to mention the tendency of these things to fail. they either then don't open, or won't close. plus they warp creating a leak in the exhaust. just not worth the agrivation really.
go with a real, full 3" exhaust. what you aren't thinking about is the ecu having to adjust to opening the cut out, which does take a while. we "tested" this at the track one day. a friend was there on the stock turbo with full bolt-ons. he had a cutout on the car. he ran with the cut out open and with it closed. he ran faster with it closed. when looking at what was going on there, it was discovered that by opening the dp it caused the ecu to pull insane timing, so the car was slower. he switched to a full 3" exhaust the following week. not to mention the tendency of these things to fail. they either then don't open, or won't close. plus they warp creating a leak in the exhaust. just not worth the agrivation really.
why would your ecu need to adjust. On a turbo car isn't the point to get the rid of exhaust with no back pressure, compared to a NA car wich needs back pressure. why would it pull timing? your not upping the boost or anything.
I find this to be some sort of joke... seriously... Timing gets pulled by reasons... Knock and running too much boost outside the PCM's parameters causing the PCM to yank timing. There's parameters and conditions that need to be considered as well as IAT readings and Ambient temp readings as well as EGT. The cut-out being opened can cause false knock readings in essence the pcm pulling timing. You tune your car with the cut-out open as it runs lean with the cut-out open. Its all in the tune and within conditions. The PCM doesn't take a while to adjust to open cut-out Open cut-out = faster spool and more power. Its been dyno proven. I'm not bias to either or... I run the Needswing DP while my wife runs the MXP 3" TBE... they both gain.
