hi,
Im from australia, and i have an G2 LS integra with a B18A1.
I currently have a standard exhaust system except the muffler has been replaced with a straight through Magnaflow muffler. I am thinking of replacing the rest of my exhaust system with new piping, removing the resonator and adding extractors (headers). My mechanic told me that it is not wise to add extractors to a straight through muffler system because there won’t be enough ‘back pressure’ thus resulting in power loss. So I need to know what is the ideal setup for my exhaust system… Do i keep the straight through exhaust? What size piping should I use? Should i leave the resonator in or take it out? Also, since the extractors are going to cost me AUS$450 so i need to know how much difference it will make to performance. Thanks a lot for your advice boys.
cheers
The back pressure loss will sometimes result in a slight torque or power loss down low in the rpm range, but will usually result in gains higher in the rpm range. If I were you I’d get the header and replace the piping with mandrel bent piping, but keep a resonator (not necessarily the stock one). The resonator helps keep the exhaust a bit quieter and less raspy than an exhaust without (leave it out if you’re looking for loud and raspy). The loss down low will probably be minimal or be more than made up for higher up in the rpm range. Also keep in mind that any other power modders you do after that will typically benefit more from the free-er flowing exhaust, so keeping the stock manifold and then putting something like cams and such in will typically result in lower gains from the cams than you would see if you had the header first.
Most people here run pretty straight through exhaust systems and don’t seem to complain about a loss of power. I have yet to notice a significant loss of power on my car with an aftermarket header and a very straight through exhaust, but using my stock catalytic converter (the cat may provide enough backpressure to help compensate for the free-er flowing exhaust system). For piping, most people recommend 2.25" for naturally aspirated, and larger like 2.5" and 3" for turbocharged.
I’m running a kinda crappy airmass 4-2-1 header with stock cat and 2.5" mandrel bent piping with a 25" thrush resonator and straight through dynomax muffler. I haven’t noticed any real power loss down low, but I haven’t been driving with the new exhaust too long. I went with 2.5" since I’m setting up to turbocharge in the near future.
Just my .02
thanks for the info man,
just one other thing… how much power gain did u get after adding extractors? i just wanna know if its worth it or not. (AUS$450) i do not plan to do any internal engine mods or forced induction. ill be keeping the resonator cos i want the system to sound nice and tuned, not rough.
another thing, wats ur views on aftermarket air filters? i dont want a pod, i want to keep the current air box, but put in a different air filter? is it worth spending a lot of money on this? how much difference will it make with a full exhaust system as well? thanks a lot guys