Heyz pipl,

I have been searching this forum to find some info on the performance gains from sport headers (ones that keep the cat in place). I failed to find any

Can you tell me how much an OBX or a similar header adds? Are there any rattling, hissing, melting, cracking, etc issues attached tot hose headers?

Finally, are there any good quality intake manifold gaskets? I bought one for $20 and installed it myself on the car. Best value mod of all time, during the winter

Thanks.

 

I'm thinking that unless you go full boat and implement a different intake, forced induction, retuning of the ECU, and custom plumbing for the exhaust, the simple addition if an exhaust header will yield virtually no gains in either the Net Output or Fuel Economy category.

 

The tune is always the key to ketting the maximum gains out of everything. However, there must be something.

 

Why? Depending upon the interplay between thermal energy expelled by any given engine at any given throttle setting and how the ECU controls ignition and cam timing (if the engine is so equipped), it is possible for the addition of header to actually reduce efficiency and net output of the engine.

How can this be? Simple, valve overlap actually requires some back pressure to achieve maximum volumetric efficiency; reducing the back pressure without a corresponding change up stream may (and often will) yield results contrary to what was intended.

 

Quite correct. Those new self learning ECU's can do minor adjustments and remappings on their own to accomodate the new mods. However their range is limited and they do not deviate far from the factory specs. Therefore the gains are less than half of what they would have been with a proper tune.

The argument of backpressure is semi obsolete. Thanks to the new ECU's, the cars do not lose AS much low end torque as they used to in the old days. Also, the simple addition of the header would preserve a plenty of backpressure from the cat and the catback exhaust. Finally, I am looking for mid-upper end power. If I wanted more TQ, I would have probably gone with a lightweight pulley. Those things rule!

 

If you say so; it's your money.

 

I guess no one will bother to give me a plain answer. Oh well. Off to the next board!

 

I gave you a plain answer in my first response to you; you're will not gain much of anything. Apparently you know better though.