ATTAK Z Posted February 21, 2011 Share Posted February 21, 2011 i have some magic beans; i'll let you have them for 300 quid Photos required with 'for sale' threads Rich ... I'm sure you know that Quote Link to comment Share on other sites More sharing options...
spursmaddave Posted February 21, 2011 Share Posted February 21, 2011 I see a lot on the eBay adverts for exhausts that they guarantee anywhere from a 5-15bhp increase, how true is this or is it a typical salesman pitch? It is possible but only in conjunction with one of those electric turbochargers that you can get of fleabay also Quote Link to comment Share on other sites More sharing options...
Zugara Posted February 21, 2011 Share Posted February 21, 2011 Plus a. "dump valve". Quote Link to comment Share on other sites More sharing options...
ATTAK Z Posted February 21, 2011 Share Posted February 21, 2011 I see a lot on the eBay adverts for exhausts that they guarantee anywhere from a 5-15bhp increase, how true is this or is it a typical salesman pitch? to be serious for a moment, I think you can only get power gains if you decat the car and retune at a place like Abbey Motorsport, but then that's only what I've learnt from the experts here Quote Link to comment Share on other sites More sharing options...
James B Posted February 22, 2011 Share Posted February 22, 2011 I've got the Scorpion and it sounds . It's not intrusively loud when pottering about town so you won't look like a burke but has a great throaty noise when you push the loud pedal! Quote Link to comment Share on other sites More sharing options...
bigbramble Posted February 22, 2011 Share Posted February 22, 2011 I see a lot on the eBay adverts for exhausts that they guarantee anywhere from a 5-15bhp increase, how true is this or is it a typical salesman pitch? Here's my super simplified explanation of exhaust performance: It is genuinely difficult to gain that much power from an exhaust alone on an normally aspirated engine. On a turbocharged car gains can be massive from plain exhaust changes. Exhausts are basically made to silence the sound of combustion gas leaving the engine, channel the exhaust gas away from the cabin, reduce harmful emissions via a catalyst. They are normally designed to minimize the loss of power and torque because of the processes I listed. The basic rule of performance exhausts is to get the waste gas out to atmosphere as quickly as possible which allows the engine to 'breath' or flow better. Back pressure is ALWAYS the enemy - this is normally caused by exhaust pipe restriction causing pressure inside the exhaust. Ok so here's the problem. If you imagine your engine like an outside tap and the exhaust like a hose pipe. If you put a pipe with a much larger diameter on your outside tap, what would happen? It will generally take longer for the water to reach the end of the pipe. If you make the pipe diameter too small masses of pressure will build in the pipe greatly slowing progress. So essentially you go too big with your exhaust and you lose power and torque as the gas meanders its way out of the tail pipe, too small and the pressure also slows the gas and strangles engine power. It's really hard to get this right and established performance parts specialists spend a lot of time optimizing the exhaust to get it right - which they don't always do! 1.0 Saxo's with whacking great 4" exhausts for example will have lost enormous quantities of torque as the tiny engine just isn't a sufficient pump to get that gas out. Will an ASBO exhaust like a Japspeed K1 increase power and torque? Unlikely, more likely to reduce it. Will an exhaust you pay £600 for made their and then compare favourably to an exhaust made by a company that has spent months testing and optimizing their pipes, like Motordyne for example? Well it's unlikely to be as good really is it? The only way to tell for sure is dyno all of them. Listen to what people that run dyno's say as they will know the best as they have probably seen many of the combinations first hand. One thing is for certain on a 350Z, the stock 'Y' pipe is a total piece of @*!#. You can see how restrictive it is just looking at it, if there are gains to be had anywhere it's there. So in reality, bhp gains will be tiny if anything at all, so in the end it comes down to what you can afford and how much noise you want. Anthony. Quote Link to comment Share on other sites More sharing options...
un1eash Posted February 22, 2011 Share Posted February 22, 2011 I've had my K1 for a while now and there hasnt been any problems with it. One side does sit about 5mm lower then the other though, it sounds alot better then it did when i first fitted it. Best thing was i got it of ebay new for £180 delivered when the guy selling them use to auction them. Quote Link to comment Share on other sites More sharing options...
1973safc Posted February 22, 2011 Share Posted February 22, 2011 +1 for the japspeed, i have a k2. sounds good, fits as good as the oem. £180 Put the other £400 to one side for a set of sticky tyres Quote Link to comment Share on other sites More sharing options...
HaydnH Posted February 22, 2011 Share Posted February 22, 2011 Why do people seem to rate true duals so highly? I though X and Y pipes were created to improve performance over a true dual? Quote Link to comment Share on other sites More sharing options...
rtbiscuit Posted February 22, 2011 Share Posted February 22, 2011 Why do people seem to rate true duals so highly? I though X and Y pipes were created to improve performance over a true dual? keeps the gases seperate, best with something like an x pipe in it which allows scavenging and increases performance Quote Link to comment Share on other sites More sharing options...
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