911R style diffuser for 996s and 997s?
12-27-2016, 08:34 PM
#1
911R style diffuser for 996s and 997s?
Does someone already make one? I’ve seen in the 991 forum a fair amount of interest in this for 991s. Here’s why someone should make one for 996s and 997s, and why many of us should buy one:
The 911R diffuser is very different from all the aftermarket diffusers for our cars I’ve seen – indeed from all the other diffusers I’ve seen for any car – with many advantages:
It looks like it should be much cheaper to make. (The existing working diffusers for our cars (as opposed to those that are just for show) seem to cost $3000!)
It should be quite light
It should be less likely to get banged up
And it really works. In combination with a quite small rear spoiler (smaller than a Carrera’s??), it creates downforce on the 911R
Why get a diffuser at all? Why not just get a big wing?
• But a wing will almost certainly create more drag, especially if you tilt it to not just reduce lift but generate downforce.
• It will be expensive. The good ones seem to start at close to $3k and go well up from there.
• It will be heavier. Yes, you can get a carbon fiber wing and engine lid, but you still save little if any weight versus a stock carrera, and you may raise your center of gravity. Whereas if you want to save weight, you can get a carbon ducktail for much less, and combined with a 911R style diffuser, you might get roughly the same downforce as with an aerokit wing less weight, hopefully less cost, and hopefully less drag too. (I think a duck tail doesn’t add any significant drag versus the stock, raisable spoiler, but I’m not 100% sure.)
Here’s a thread with good pictures of the 911R diffuser.
https://rennlist.com/forums/991-gt3-g...iffuser-2.html
It’s different from most diffusers because it doesn’t extend all the way back to the bumper. Because it is closer to the wheels, despite being lower, it is less likely to get banged up over speed bumps, steep driveways, when reversing, etc. (Though one still needs to be careful. In the above thread, some have had bad experiences.)
It should be inexpensive to make because it is just some plastic fins, attached to a sufficently wide underbody plate. The optional Porsche motorsports plate which protects the oil pan is light (~2kg) and cheap (under $100 or close). Though to be as effective as the R diffuser, one would need a wider, and perhaps longer plate. As for the fins, the R’s are reportedly made of plastic, probably because they need to be flexible. These should also be light, as they are small. Indeed, Suncoast was apparently offering the OEM R diffuser for 991s and according to someone in the thread mentioned below, even this part wasn’t very expensive. (Alas, the link leads nowhere, so I didn’t find the price.)
The only thing that concerns me is whether, if the plate needed to be much wider and longer, enough heat could escape. I guess most of the areas that would not already be covered by the optional Porsche motorsports plate would be covered by any of the existing aftermarket diffusers. So if they don’t cause heat problems … . Also, it seems to me that if the R diffuser works with a 4 liter engine reving to 8500, it should work with our engines too.
Finally, as for downforce, on the R, together with a small spoiler (smaller than the Carrera’s?), it generates 35kg of rear wheel downforce at 186 mph (300 kmph). It may not seen like much, but it’s similar to a 996GT3, and that big wing pays off not just in lap times but also in high speed stability. Many have noted in this forum how effective aero mods result in an increase in stability that you can really feel.
So please, someone make one of these!
The 911R diffuser is very different from all the aftermarket diffusers for our cars I’ve seen – indeed from all the other diffusers I’ve seen for any car – with many advantages:
It looks like it should be much cheaper to make. (The existing working diffusers for our cars (as opposed to those that are just for show) seem to cost $3000!)
It should be quite light
It should be less likely to get banged up
And it really works. In combination with a quite small rear spoiler (smaller than a Carrera’s??), it creates downforce on the 911R
Why get a diffuser at all? Why not just get a big wing?
• But a wing will almost certainly create more drag, especially if you tilt it to not just reduce lift but generate downforce.
• It will be expensive. The good ones seem to start at close to $3k and go well up from there.
• It will be heavier. Yes, you can get a carbon fiber wing and engine lid, but you still save little if any weight versus a stock carrera, and you may raise your center of gravity. Whereas if you want to save weight, you can get a carbon ducktail for much less, and combined with a 911R style diffuser, you might get roughly the same downforce as with an aerokit wing less weight, hopefully less cost, and hopefully less drag too. (I think a duck tail doesn’t add any significant drag versus the stock, raisable spoiler, but I’m not 100% sure.)
Here’s a thread with good pictures of the 911R diffuser.
https://rennlist.com/forums/991-gt3-g...iffuser-2.html
It’s different from most diffusers because it doesn’t extend all the way back to the bumper. Because it is closer to the wheels, despite being lower, it is less likely to get banged up over speed bumps, steep driveways, when reversing, etc. (Though one still needs to be careful. In the above thread, some have had bad experiences.)
It should be inexpensive to make because it is just some plastic fins, attached to a sufficently wide underbody plate. The optional Porsche motorsports plate which protects the oil pan is light (~2kg) and cheap (under $100 or close). Though to be as effective as the R diffuser, one would need a wider, and perhaps longer plate. As for the fins, the R’s are reportedly made of plastic, probably because they need to be flexible. These should also be light, as they are small. Indeed, Suncoast was apparently offering the OEM R diffuser for 991s and according to someone in the thread mentioned below, even this part wasn’t very expensive. (Alas, the link leads nowhere, so I didn’t find the price.)
The only thing that concerns me is whether, if the plate needed to be much wider and longer, enough heat could escape. I guess most of the areas that would not already be covered by the optional Porsche motorsports plate would be covered by any of the existing aftermarket diffusers. So if they don’t cause heat problems … . Also, it seems to me that if the R diffuser works with a 4 liter engine reving to 8500, it should work with our engines too.
Finally, as for downforce, on the R, together with a small spoiler (smaller than the Carrera’s?), it generates 35kg of rear wheel downforce at 186 mph (300 kmph). It may not seen like much, but it’s similar to a 996GT3, and that big wing pays off not just in lap times but also in high speed stability. Many have noted in this forum how effective aero mods result in an increase in stability that you can really feel.
So please, someone make one of these!
01-17-2017, 06:27 PM
#2
Seems I was right that it doesn't cost much to make the 991R diffuser. Suncoast is selling them for 991 GT3s for just $560. Here's a link with good pictures:
http://www.suncoastparts.com/product/SKUGT3DIFF.html
Surely there's a market for something like that for our cars!
http://www.suncoastparts.com/product/SKUGT3DIFF.html
Surely there's a market for something like that for our cars!
01-17-2017, 07:58 PM
#3
Rennlist Member
its only about $550, all plastic. I am waiting to see, I think one could easily buy one and since it is made out of plastic one could make custom holes to help it to fit up to a 997. There is already a factory metal protection plate that one can buy for the 997, so just use the similar mounting points and I would think it would be an easy install. As of a few months ago they are all on back order. There is a thread about it on the 911R GT3 area. I also have all the measurements and angles that I got from a 911R so I can DIY if it proves to be to hard to get from Porsche and I still really want one.
