Lerxst

In my endeavour to make my GT3 decklid fit my C2, I'm at the point for test fitting to fix the damage to the decklid during shipping.

To make this work, I'm removing the snorkel from the intake box. As I'll be sucking in more hot air from the engine bay, will I lose much HP? If so, how much do you reckon?

Should I block off the opening in the airbox where the snorkel attaches to force the FVD intake to draw more air from the passenger side, where the decklid will be ducting fresh air in, or will this be more restrictive?

Thanks for the input.

1999Porsche911

You will definately be losing power especially around town. However, if you do my fan mod you will reduce the loss.

Engine Compartment Fan

Connect a wire to the ground of the relay located in the relay carrier behind the passenger seat, driver’s side. Relay #8. . Feed this wire to where your switch will be located. I simply fed the wire along the driver’s side of the car and under the door sill. Connect the wire to one side of the switch. Connect another wire from the other contact on the switch and connect the other end of this wire to a chassis ground point.

With key on, this switch will now immediately turn on the fan drawing air into the engine compartment. When you turn the key off, the fan will continue to run for about 5 seconds until the relay shuts down. Your fan operation remains normal when the switch is off. This mod helps keep the engine compartment much cooler when driving around town and is particularly beneficial to any engine that draws from within the engine compartment.

Jim

Robin 993DX

You can test this fairly easy with an OBD2 reader device that will display real time information, one of the OBD2 feature is the intake air temperature monitoring. I did a test awhile back with the 993 and found some difference. So basically it is 10 degrees = 1% horse power difference, so do your math and decide.

http://p-car.com/diy/intake/

Lerxst

Does anyone have a sample reading of outside/intake air temps on a MKII? I'm not going to have a chance to get a before reading, but probably can do a reading after it's been done, to get a rough idea.

1999Porsche911

Should be very close to ambient temperature. Your intake temperture can get as high as 80F ABOVE ambient if sucking air from the engine compartment.

JimB

This is a huge no brainer. You do not want to suck air from inside the engine bay. Imagine how hot the air is right next to the engine and 10 inches above the cats!

Lerxst

All my costs are sunk at this point... just trying to make the best of a bad situation. As long as it doesn't damage the engine, I'll go ahead, try it and measure the temps. Worst case scenario, I go back to the stock decklid, sell the GT3 lid, and carry on with life.

Robin 993DX

I have the scantgauge II tool connected to my OBD2 all the time to monitor the intake air temp, ignition timing, MPG, coolant temp (It can only read 4 sensors at any given time) the results are interesting.

Regardless outside temp, the intake air temp is always 6-15 degrees hotter than outside air temp. Worst when you are stuck in traffic, but as soon as the tail goes up after 74 mph the temp drops at least 10 degrees.

For example:

Outside air temp 85, stuck in traffic IAT at 105, moving again tail up, 95

Lerxst

That sounds about right... I would guess there'd be some heat soak from the engine bay.

1999Porsche911

I suck air directly from the engine compartment right above a header and with the fan mod, I keep my intake temps less than 15F above ambient temps. Without the fan running, I have seen more than 80F above ambient.

Lerxst

I neglected to post a pic of the engine bay... the filter will be right beside the GT3 duct, but I doubt it'll make much difference in traffic.

1999Porsche911

If you do the fan mod, you will not have a problem with heat.

Ray S

GT3 Cups run this way

http://www.flickr.com/photos/nicktil...ol-734507@N20/

htny

I know this is going to sound ridiculous, but since you're already running an aftermarket filter element, do you think you could eliminate the resonator, take the existing snorkel and route right into the filter? it doesn't have to be pretty, but I'm sure if that won't work you can have fun with some PVC and some heat shield, just route from the filter side up to the inlet on the GT3 decklid, and if necessary block off the resonator with an orange cap?

Or just sell the decklid, damage and all, but a cheap imitation and call it a day I guess.

htny

where, is the MAF on the cups ?