911 Spec build questions

porsche735 · 03-05-2011, 07:47 AM

I have a couple of questions about whether the following things are legal in 911 spec. They follow the letter of the law, but I am not sure if anyone is doing this.

The first is the carbon fiber A pillar winglets. The rules say no shaved rain gutters, but nothing about adding material..

http://www.***************/carbon-fiber-a-pillar-winglets-911-930-coupes-for-porsche.html

The second is hood ducting. The rules state "holes in bodypanels to direct airflow for downforce such as vented hoods or fenders." are not allowed. However, if all that is being done is cooler venting with a straight up angle with no aero (air not pushing down on bodypanels), is that ok? Here are some pics of inside ducting and exterior.

Also, is there a forum that is more 911 Spec specific?

Thanks,
Chris

gestalt1 · 03-05-2011, 09:57 AM

i don't have answers but are those rs rear flares on the front fenders? looks great!

porsche735 · 03-05-2011, 05:16 PM

Thanks! No, not RS flares... My dad and I built them from scratch along with the rears. I really like the way they turned out. Here is the link:

http://forums.pelicanparts.com/paint-bodywork-discussion-forum/581368-homebuild-flares.html

Any 911 Spec folks out there that can answer my questions?

Thanks,
Chris

Walt Fricke · 03-05-2011, 06:34 PM

What race series spec rules are you quoting? You need to be more specific than 911 Spec. I don't see the provision you quoted in the PRC/NASA Spec 911 rules. POC?

Lots of players these days.

porsche735 · 03-05-2011, 08:19 PM

Nasa's Porsche Racing Challenge Series Spec 911 class:

https://docs.google.com/viewer?url=http://www.nasaproracing.com/rules/Porsche-Racing-Challenge.pdf

Page 11.

Thanks!
Chris

jerryw · jerryw's Garage

PRC Forums are at Welcome to the PRC! but the forums are down right now for a software update. They are the ones that wrote the rules and you should be able to get answers there (once the forums are back)

Walt Fricke · 03-05-2011, 09:01 PM

I think you will have a problem.

The base rule is that you can ONLY make the modifications which are specifically allowed. No mention of louvering the hood. Factory hoods did not come that way, so reproductions of factory hoods don't come that way either.

You are interpreting a helpful hint: "here are a couple of things you can't do that we see people frequently wanting to do" as allowing you to do one of those prohibited things as long as it does not (in your estimation) increase downforce.

But let us all know how the PRC rules guys respond.

Eagledriver · 03-06-2011, 08:19 AM

Chris,

Welcome to the PRC! Hope you can make it out to some of our events. I'm the drivers rep for the rules commitee of the PRC. The website is down right now, which is where these discussions normally can be found. Walt is right in that our rules don't allow changes that are not mentioned in the rules. That being said we are not that anal about minor cosmetic changes that some cars may have. Hood venting is not allowed but we have allowed people to vent the hot air out of the trunk area through the sides. You could cut vents into the battery box area to vent the air out. The idea is that the air must end up under the car instead of coming out the top. A pillar winglets would not be allowed. The idea of the Spec 911 class is to have equal race cars to the maximum extent. If you find an advantage, you can expect it to be ruled illegal or if legal it will be copied by everyone else. The idea is to prevent an arms race like you have in GT classes.

-Andy

porsche735 · 03-06-2011, 08:30 AM

Thanks Andy for your response. Not what I wanted to hear....;-) I guess I am in the market for a new hood....:-) Making a box should not be a big deal. But I don't understand why the a pillar winglets illegal? They are pretty cheap and keep the noise down in the car going down the highway. They also don't change the frontal area of the car.
We hope to be done by the end of April and hit the Thunderhill event. There is a lot of work ahead of us and this will set us back (slightly, in the grand scheme of things) toward that goal..:-(

Thanks,
Chris

Flieger · Flieger's Garage

I also do not see how the A-pillar covers would make the series so much more expensive or less competetive. I doubt they are the difference between first and second.

Mahler9th · 03-06-2011, 12:42 PM

Hello:

I think Andy covered things quite well. I encourage any folks in the NorCal area that are interested in this class to come on out to Sears Point for our first event coming up soon, or to Thunderhill for our second event which is in April. Meet some of the folks involved, check out the cars and watch the races.

The a-pilar feathers make no material difference in performance, but as Andy states... they are not expressly allowed. I had some of these for my car and never installed them because they don't make any difference. You can test the theory with duct tape.

Anyone/everyone interested in the PRC rules, including Spec911 should always ensure that they have the latest up-to-date rules document (in this case 2011), and when in doubt... seek us out.

Good luck with your build progress.

- Mike
(I write the PRC rules)

pgeorgeson · 03-06-2011, 05:31 PM

Have fun with the build. As noted above, Mike writes the rules and Andy enforces them (at least out here on the west coast), so you have tapped in to the go-to guys to answer your questions.

porsche735 · 03-07-2011, 07:55 AM

Any idea when the PRC forum will be back up? I checked there first for about a week before posting here and it is still down... I have some pent up questions...

Thanks for the feedback so far. Like I said, not what I wanted to hear, but I don't want to get out there and have you send me home....so it is ripping stuff off and buying a new hood for me...

Thanks,
Chris

Mahler9th · 03-07-2011, 08:52 AM

Not sure when the forums will be back up... I am sure they are working as best they can.

As for questions, you can refer them to Andy and I. I write the rules. Andy represents Spec911 on the PRC Rules Committee.

I will almost definitely be up at Sears Point for our season-opener on March 19th. That is a great opportunity for you to meet some of the folks involved and look at some of the cars.

As for your hood, perhaps you could just modify the one you already have.

Regards,

Mike

cstreit · cstreit's Garage

Hell, I just use a strip of duct-tape over the rain gutters. Same profile, much cheaper.

Walt Fricke · 03-07-2011, 01:04 PM

Chris

Sounds like you won't be ready for the PCA Club Race at Fontana in April either. We have a Thunderhill race scheduled later in the year also. PCA has a class for Spec 911s, using the rules Mike writes. So there is another opportunity if you have time, energy, and money left over after your PRC races.

Mahler9th · 03-07-2011, 06:40 PM

All:

I spoke with Chris at length today and I have connected him with both Andy and our chief compliance steward Ron, via e-mail.

Regarding the a-pilars and the hood... here is an excerpt from the 2011 Spec911 rules document:

"Some examples of modifications that are not allowed are: shaving of rain gutters, addition of
aerodynamic devices other than specified in the rules, holes in body panels to direct airflow for
downforce such as vented hoods or fenders."

Regards,

Mike

jerryw · jerryw's Garage

The forums are back if anyone missed it.