Quote
Jaay
This was not an attempt to make a better intake - though I did and succeeded. I put a 3.4 in the car and needed a custom intake. It is comprised of a 987 airbox, bmw Maf housing and silicone to an ipd plenum. There is a lot more done to the motor too. The car needed to be tuned and is. The only answer I was looking for was the target afr and I got it from a very respected tuner. As for as a quality intake - I've seen just putting on a k&n setup on 996 requires tuning. I don't understand airflow/laminar but I would bet that more owners should get your car on the dyno and get some data from your cars after making modifications and realize the blip in hp is just a result in an over all loss.
an early Boxster and the transplant was rather straightforward, although there were several issues to be dealt with. One involved the intake but IIRC the stock 996 intake worked it had to be turned 180 degrees. (Is that right? I wish I could find the copy of the article to confirm...)
Well, I confirmed this by not finding the article I referred to but by visiting Pelican's site and specifically its site on engine swaps. Here's what Pelican has to say on this: "When installing a Carrera 996 engine into the Boxster, you typically use the 996 intake manifold. However, you need to remove it from the engine and then reinstall it later on in the opposite direction. This is so the throttle body will face the rear of the car. I suggest that you take many photos as you remove the manifold, as the routing of the vacuum hoses can be tricky to decipher when you're reassembling the manifold back onto the engine."
Installing a K&N filter should not require any tuning. What often happens is the filter is accompanied by some kind of "cold air intake" feature which simply results in hot air from the engine bay getting into the intake and this upsets the fuel metering. (Also, I'm ignoring the too often encountered problem of an oiled filter fouling the MAF.)
The stock DME and its population of sensors are quite capable of properly fueling an engine even with some modifications. What can happen is the mod's place a higher demand on the MAF and this shortens the MAF's life. At some point many owners of highly modified engines go to a MAF-less system of fuel metering.
The laminar air flow I was referring is important to the MAF's correct function. The MAF consist of a heated film and a control circuit. Incoming air cools this heated film. The MAF's control circuit monitors this and increases the voltage to maintain the specified temperature of the film. The DME monitors the amount of voltage the MAF control circuit uses to keep the hot film at the specified temperature. The voltage signal the DME monitors at the MAF control circuit represents the amount of incoming air.
This system works very very well. But it does have some special requirements. One is the air flow past this film must flow in a laminar manner, without any turbulence. Turbulent air flow results in rapidly varying air flow with a resulting rapidly varying cooling affect and the MAF control circuit can't keep up and the DME can't make sense of the voltage signals and is thus unable to correctly determine the amount of air engine is using at any given time and thus fuel metering is incorrect.
I would go one better than you and recommend any owner contemplating modifications should establish a baseline of not only engine performance (torque/HP) and not only their peak numbers but their curves. Also, the AFR's during all this should be logged. Then after the modifications repeat the measurements to truly know what the gains are and where they are. Often times while there is some gain at peak the curve is changed and not always for the better. And proper AFR's throughout the RPM range are crucial for a long and trouble free engine service life.