986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - IPD Plenum

fokker2003 · 04-09-2026, 03:44 AM

Although this thread is old, I'd like to contribute my two cents:

First of all (since it's my area of expertise), I did the electronics, tuning the DME. I had several problems until I finally found the correct timing adjustment because the car was backfiring terribly when it reached 5000 RPM. But in the end, after several tests, I managed to adjust it.
To be honest, I didn't notice much of a difference, but I wasn't expecting much more; used to modifying turbocharged engines, all naturally aspirated ones seem underpowered to me.

Next, I installed a BMC air filter, and this time I did notice a small change, which I imagine was a result of the combination of both modifications.

The next step was installing an IPD plenum along with a larger throttle body. Once again, a slight improvement, but nothing spectacular.

The next step was the exhaust manifold, in this case from FVD Brombacher, and at this point, the change was truly remarkable.

With all this, I did a new stage tuning and again noticed small changes.

I have to say that before I bought this car, the right cylinder head was replaced at a Porsche center, and they broke the lambda connector in the wiring harness. I didn't want to solder them because it's a highband probe and they pick up the reference signal from the cable, which would occasionally cause an error. So, I opted to disable both lambda sensors.

Also, it always passes emissions inspections very closed, which is why I've kept the original catalytic converters.

One curious thing I noticed was that during a service, the air filter was dirty. I didn't have time to clean, dry, oil, etc., so I opted to install a Bosch one.
There was a significant loss of performance and engine noise. A few weeks later, I reinstalled the BMC, and the car was like a rocket again.

In summary:

Just tuning the electronics doesn't give the expected results. Just tuning the intake doesn't either.

If you want to notice a difference, you have to modify everything; that's how I think you achieve the ideal balance.

On the dyno, my car originally produced 253 hp. At this point, it's producing 289 hp, but my goal has always been torque.

In fact, I'm currently waiting for the arrival of a lightweight flywheel from AASCO and a clutch from SACHS Performance; that's my next upgrade.

04-09-2026, 03:44 AM	#71
fokker2003 Registered User Join Date: Mar 2026 Location: Spain Posts: 8	Although this thread is old, I'd like to contribute my two cents: First of all (since it's my area of expertise), I did the electronics, tuning the DME. I had several problems until I finally found the correct timing adjustment because the car was backfiring terribly when it reached 5000 RPM. But in the end, after several tests, I managed to adjust it. To be honest, I didn't notice much of a difference, but I wasn't expecting much more; used to modifying turbocharged engines, all naturally aspirated ones seem underpowered to me. Next, I installed a BMC air filter, and this time I did notice a small change, which I imagine was a result of the combination of both modifications. The next step was installing an IPD plenum along with a larger throttle body. Once again, a slight improvement, but nothing spectacular. The next step was the exhaust manifold, in this case from FVD Brombacher, and at this point, the change was truly remarkable. With all this, I did a new stage tuning and again noticed small changes. I have to say that before I bought this car, the right cylinder head was replaced at a Porsche center, and they broke the lambda connector in the wiring harness. I didn't want to solder them because it's a highband probe and they pick up the reference signal from the cable, which would occasionally cause an error. So, I opted to disable both lambda sensors. Also, it always passes emissions inspections very closed, which is why I've kept the original catalytic converters. One curious thing I noticed was that during a service, the air filter was dirty. I didn't have time to clean, dry, oil, etc., so I opted to install a Bosch one. There was a significant loss of performance and engine noise. A few weeks later, I reinstalled the BMC, and the car was like a rocket again. In summary: Just tuning the electronics doesn't give the expected results. Just tuning the intake doesn't either. If you want to notice a difference, you have to modify everything; that's how I think you achieve the ideal balance. On the dyno, my car originally produced 253 hp. At this point, it's producing 289 hp, but my goal has always been torque. In fact, I'm currently waiting for the arrival of a lightweight flywheel from AASCO and a clutch from SACHS Performance; that's my next upgrade.