Quote:
Originally Posted by terminx
Unfortunately, the only part of this post that is correct is the part where you admit you have no experience with the M54 engine. Headers are worth 10-20 hp at the wheels--depending on the particular headers and other engine mods--but modifying the rest of the exhaust does virtually nothing for performance here without removing the massive airflow restriction that is the OEM exhaust manifold. The collectors are very restrictive. They're designed to be quiet and lower emissions, nothing more.
|
I am unclear as to your point. You mention 10-20 hp improvement but then you qualify that with depending on the headers and the tune. There was no tune or well engineered headers in the equation. Exhaust manifolds are not designed to reduce sound or control emissions and certainly are part of the performance goals. Where does that come from?
I didn't say I was unfamiliar with the N54 engine. I said I did not know how the sound would change with headers but it wouldn't matter if I were not familiar with the N54.
My input is based on the universal benefits of an engine (a big air pump) from exhaust modifications. Stock exhaust systems downstream of exhaust manifolds restrict exhaust flow. That being the case any airflow benefit of headers will be lost without relieving the back pressure. Headers attached to a stock exhaust won't result in more air in because it can't get out.
Open headers would allow more out and an increase in HP though unless they are well engineered that can easily be a loss of TQ resulting in a longer time to go from A-B.
The higher the engine RPMs the more air is drawn in and pumped out. Open headers will allow more air out but unless the red line is increased the benefit is still minimal.
Since OP wants sound and performance but I don't get the impression he wants to get radical or spend thousands of dollars, my suggestion is to add a tune that increases the redline and improves HP and TQ. Modify the exhaust with low restriction mufflers, remove the resonators and enjoy. Time and dollars saved and more HP/TQ and better sound than just headers. However, I get the impression performance is secondary to sound. If that is the case I would just do the exhaust work and see if that met the goal. Since exhaust modifications can get loud quick and create a drone, might want to do exhaust mods in stages.