Engine swap help

[Dllrd23]

Originally Posted by 78F350

This is in reply to the message...
Yes, you no longer need to run vacuum to the flapper valve, so just use a 3 way coming from the vacuum source (H into G) as you said.

For the fuel rail, the simplest way to resolve it is to get a return type rail from a 2000 or 2001 model since your car already has all the return plumbing. There's probably some on eBay or I can sell you one or trade mine for yours (you pay shipping).

I’ll trade. PM me an address and I will send you mine off of the 2.5 and pay the return shipping on yours. Do you know if the crossover hose can be removed?

[78F350]

This evening I'll get a look at the fuel rails and pick a good one to send. I'll message tonight some time.

[78F350]

Here's what I plan to send:


That should be enough to replace the fuel rail on the 2002 engine and connect to the hoses in a 1999.

Sending a PM with address info...

[78F350]

Regarding the cross-over tube with the flapper valve, if you are running the car on your stock DME from the 2.5L, you can either leave the valve closed or force it to stay open after removing the vacuum hose that controls it. I think that closed is the better option. Here's a post I did back in 2015 that discusses the function of that valve:

Originally Posted by 78F350

Try looking up 'resonance flapper valve' for more info.
I think that any air going in or out of that hole is negligible unless you have excessive wear.

Quoted from: http://press.porsche.com/archive/products/press_kits/press_kits_2001/PDF/Boxster_in_Depth.pdf

"The Boxster inherits its twin-resonance air induction system from the 911
Carrera. The system acts as a “resonance supercharger,” allowing the engine
to draw from higher velocity airflow at certain engine speeds. A crossover pipe
connects the individual air collector/resonance chambers for each cylinder bank.
A flap in the pipe remains closed from idle to about 3,100 rpm. When it opens,
each cylinder bank can draw from airflow “excited” by the resonance created by
alternating induction between all six cylinders. In essence, “dual resonance”
creates two induction paths for each cylinder. Below 3,000 rpm, the cylinders
draw air from a “short” path. From 3,000 rpm to about 5,100 rpm – when the
resonance flap opens – the cylinders draw from a long intake path, which
boosts torque. Above 5,100 rpm, the flap again closes to allow the cylinders
to draw intake air from a shorter intake path to boost horsepower at higher
engine speeds."