big loss with bassani headers

[sraizman]

i am very disapointed today.After spending over $1200 on my new bassani equal length headers.That price is also with labor to install.I now find that i have lost almost 30 h.p. not to mention the exhaust leak i got from the collector on the driver side.

The car was making 460 h.p to the wheels with everything installed you see on my signature.

After about 10 reflashes and dyno pulls with the predator i could not get above 425.
The car definatley ran better with the stock manifolds.
The car ran way to lean under 5500 rpm.and above that all i did was dump fuel.
I belive i am pushing way to much air into the car with my current setup.:shrug:

steve

 

[Silver 03 Cobra]

Scrap the Predator and get a chip from JDM plus a 9 inch Powerstack filter system. There's no reason why you can't make over 470-480 rwhp with that exhaust.

 

[stangin]

Originally posted by sraizman
i am very disapointed today.After spending over $1200 on my new bassani equal length headers.That price is also with labor to install.I now find that i have lost almost 30 h.p. not to mention the exhaust leak i got from the collector on the driver side.

The car was making 460 h.p to the wheels with everything installed you see on my signature.

After about 10 reflashes and dyno pulls with the predator i could not get above 425.
The car definatley ran better with the stock manifolds.
The car ran way to lean under 5500 rpm.and above that all i did was dump fuel.
I belive i am pushing way to much air into the car with my current setup.:shrug:

steve

You are not the first to complain about HP and TQ loss with headers.. I think these engines need some backpressure, especially with mods less than the KB level.

 

[KWladyka]

Yes, it is unlikely that there is any benefit and commonly a power loss from adding headers to this car without a significantly increase of the volume/mass of the intake charge and airflow "quantity". You will want at least enough residual pressure in the exhaust system to prevent the air/fuel charge from being drawn from the cylinder to the exhaust during any value overlap. This is more of an issue with our cars since they have four valves and at 4.6 liters do not have a large cylinder volume. The intake and exhaust on this motor is a balancing equation and headers will affect the airflow "quality" which is critical in the conveyance of fuel to the combustion space. Simply put, headers will change the pressure and flow balance so the intake side of the equation must also addressed for headers to add any real benefit. Certainly replace the stock cats but these cars are capable of low 11's with the stock exhaust manifolds and a high-flow cat in place.