Rennline sells the GT3 ‘smile’ vent kit with an optional template. I used painters tape following the flow of the creases on the hood to help line up the template to the center of the bumper. The protruding tab in the middle of the template, I lined it up to the edge of the bumper opening where it mates to the hood.
On the underside of the hood is a plastic bracket that holds the headlight washer fluid line. I unclipped the fluid line from the bracket to avoid accidentally cutting it.
I ended up using a Dremel with cutting wheel to cut through the bumper and the black plastic bracket underneath. I had to trim quite a bit of bracket seen here to clear the GT3 vent; basically all of the bracket visible here in the opening was cut off. My poor Dremel is around 16-17 years old, plugs into the wall, and I think still uses a brushed motor. It had started smoking when I was cutting the radiator support bracket which makes me think the brushes are toast. It was really smoking after I cut the bumper. I think it’s time to retire this Dremel and go cordless.
The vent and grill are held to the bumper using two sets of brackets. There are black brackets with fingers underneath the shiny metal dog bone looking brackets you see here; the black ones clamp the vent to the bumper and the shiny ones clamp the grill to the vent. I clipped the washer fluid line back into the bracket in this picture and you can see how tight of a fit it is. I would not recommend moving the vent any lower down on the bumper for reasons I’ll show in a bit.
I installed the front bumper, had all connectors connected, fasteners installed, and then I noticed this big foam crash bar cover sitting on my garage floor. Off came the bumper.
I put the bumper back on after installing the big piece of foam and noticed the fitment was a bit snug. The foam was blocking my airflow vent path. Off came the bumper, again.
11 comments
What a cool mod!
That’s not punny. You’re going to get punished by being sent to the punintentary.
Cool and rad. Nice article. I think I’ve accepted the fact that I will never be cool enough to understand Porsche life.
Just modding for more cooling for better track reliability like my other cars. Just happens Porsche has more factory parts to use!
Nice! I’m surprised you didn’t just buy the replica or OEM GT4 front bumper! You get the top vent, larger lower vent openings, and a more aggressive front splitter for maybe more front downforce. Plus you wouldn’t have had to hack up the stock front bumper. AFAIK, a GT4 front bump is pretty much a plug and play solution. Can’t wait to see even more progress on this build!
Maybe it’s just me but I would not want to put an aftermarket fiberglass bumper on a Porsche daily driven street car. An OEM GT4 bumper is pretty spendy. This is a nice compromise.
The reason for not doing a GT4 front end is that it would get destroyed around where I live. Lots of steep driveway entries in shopping plazas, gas stations, parking lots, etc. As it is, I scrape the air strake in front of the front tire every time I leave my complex. A couple people have done the full GT4 frontend conversion.
The center vent really looks factory – great job!
Great job and beautifully documented!
Fantastic final result.
It’ll be interesting to compare temperatures with a stock car with common “control” ambients and driving, at a track day.
I 100% agree with the perfect compromise of repurposing the stock bumper, on the grounds of cost and ground clearance. I have a 981 GT4 and conscious of the limited approach angle.
I live in the UK where local town councils instal traffic speed calming with “sleeping policemen”, which I negotiated at an angle and crab over.
Hotels in Europe tend to have underground car parks and on road trips I check if they are ok for low sports cars!
The 997 GT3 vent looks pretty good on the 718. But, why not just use the actual GT4 radiator kit instead of the GTS?
To do the GT4 center radiator right, either have to do the full GT4 front end conversion or make a custom center section to go from the base bumper opening geometry to the GT4 radiator. Neither are easy or low cost options.