996RR Road Rallye Build

I am undertaking a 996 C2 build for a client to create a Road-biased Rallye car that takes build cues from the Safari cars. Though I tracked a 993, my experience with the 996 is limited. I am hoping to get some suggestions from members here on this build. This car will live mostly in SoCal where the canyons are pretty rough. We also have a few dirt trails that can be explored. We are developing the car 90% for broken pavement and 10% groomed dirt roads. Our donor car is a pretty rough example that we are tearing apart to rebuild. We started blogging our progress as well: Part 1: Intro Part2: Assessment Part 3: Temp Graphics Part 4: Wheel/Tire/Brakes Wheel and Tire selection is my biggest challenge at this time. We have ordered the Elephant Racing suspension so the car will get raised up approx 1". I'd like to run smaller rims (17") to buy some sidewall compliance. Tire size will be biased towards roads use so will be staggered due to the weight distribution. Determining the best sizes has been a challenge but I am considering the following: Front 17x8 ET40, 225/50R17 and Rear 17x10 ET35 285/40R17. My friend who races 911s and is a Ride & Handling engineer at Toyota, suggested Conti Extreme Contact Sport2s. I've ordered Girodisc rotors to find some upsprung weight savings. We scaled the car (see pic above) and learned this one weights 3219lbs. These are larger in diameter than stock so my hope of running 17" rims may be dashed. We will test fit and take measurements. I appreciate your feedback and suggestions.

This sounds fun. What spring rates have y�all decided on?

I've decided to start with the rates that Elephant recommend. We will tweak the damper valving and spring rates from their starting point - if required. They feel confident that it should work for our use case. I know some folks have suggested that Safari kits are not great on the street so we intend to make them work properly on the street...maybe not GT3 levels of grip but I think we can exceed the stock levels with a whole lotta additional compliance...which = comfort.

The Contis are awesome tires. I have them on mine. I wouldn't think they'd be great in dirt though...

Yeah, I'm a bit skeptical on the dirt but really dialling the car in for the road. Once we are happy with that, we'll test on the dirt. I may end going through a few sets of tires in the interest of R&D!

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I run Conti's "AT" on my lowered/tuned Explorer. It's an incredible tire too. It was also by far the lightest of the top 5 AT tires. Pretty good mix of road/all terrain ability.

ECS02 is a good tire, I run them on the 997 and they do a good job balancing road manners and limit handling. Very much on-road only though... For dirt I love Yokohama Geolandar G015's, but for 996 (probably can't go much taller than 27" total tire) you're very limited on sizing, just 215/65R16 front and 235/60R16 rear. Falken Wildpeak A/T offers 215/55R17 and 235/55R17 so you can keep the stock 996 brake diameter. Keep in mind the Girodisc 996 package with its 340mm rotor can stop fitting under 17's, whereas the stock 317mm brake package definitely fits under all 17's, and some 16's.

Thx for the feedback. I know some experimentation will be needed with the tires. The brake rotors are going to be interesting challenge as well. I really want the unsprung weight savings Giro offer so willing to take some additional time/effort to see if we can find a 17" wheel...I'm cautiously optimistic.

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Definitely pay attention to tire weight too, then.

No doubt - this is a hidden issue we often miss with 'inch down' rim choice. In our case, we are also increasing tire diameter for clearance and sidewall compliance - a double whammy! Hence my keen interest in scrutinizing forged wheel options and hopefully, forgoing cast ones. This is the fun part of development for me...along with the actual test driving!

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Girodisc unsprung weight advantage is unnoticeable (and the ring is larger so you're gaining back rotational inertia). If you're doing it it's because you need the thermal capacity, or you just have to admit you're being vain like me when I installed mine. You will absolutely feel more difference from picking the right tire.

I noticed unsprung weight difference in the Lotus that I normally drive and hope to 'feel' that difference here as well. But 3218lbs is alot more than 1950lbs....so you may be right. I certainly prefer the slots vs holes and the longevity that we've experienced with Giro make it a worthy test. Slicing and dicing these small things are what make some of us tick, right?

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200front and 275 rear. My understanding is that the stock are 146/203. This should be enough add rate yet soft enough for the compliance that we are shooting for. The larger swaybars in the kit will manage roll stiffness so the car stays fairly flat. I can't wait to get these onto the car - just waiting on the coilovers.

Nice, that�s a teensy bit stiffer than the M030 (Sport) spring rates . It should do very well over bumpy pavement. What size are the sway bars? I can�t wait to hear how it drives!

If your only goal is unsprung weight savings, send the rear Girodiscs back. They're about 1lb. heavier per corner than the stockers. The fronts are a little bit lighter. IMO the advantage of Girodiscs are swept area and better cooling (functional), and looks (not-so-functional but so what). https://rennlist.com/forums/996-foru...all-on-c2.html Good luck on the build!

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They are the Euro GT3 street: Front = 27mm Rear 21mm.

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Thx. They just arrived so we will weight them. Lighter fronts are certainly a plus - I can feel the difference on lighter cars when we save unsprung at the front through the steering wheel. The slots and improved cooling benefits always a plus. I'm not a big fan of drill rotors as they often crack with hard use.

The Giros arrived and we have weighed them. My stock rotors were pretty worn so the #s are not as comparable: Giro F/R = 17.95/15.25 Used Stock F/R = 18.7/12.55 An internet search suggests new stock rotors F/R = 23/14.6. Anyone know if this is the case? I'm reasonably confident that we can maintain or reduce the overall unsprung weight of the brake/wheel/tire package. The tire choice will be the true test...

Looks good. Nothing better to look at than bigger rotors with a floating hat system Some of the biggest weight savings will come from replacing the heavy seats with lighter racing buckets and rear seat removal. Aftermarket exhaust from a top provider will save you quite a bit of weight. Then its down to gutting the car of stuff. Carbon frunk lid, engine lid, roof, doors, etc. But you will need to put in safety equipment for street driving which adds weight. But unless you are made of money, its not worth it. Wheels and tire weight savings are minimal in relation to the light Turbo Twists and Carerra 2 wheels which are already light as hell and strong. If you go to bigger rubber, you will gain quite a bit of weight.

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I agree, the bigger rotors look great. That's why I don't mind the extra weight of the Girodisc rears on my car. Wheel/tire weight reduction might not be a lot compared to seats etc. but it's unsprung weight which makes an inordinately large difference in how the car handles. I'm in the process of going to 996 GT3 sizes on my car and, based on published weights, I should be able to come in at the same weight or slightly less than I have now with Carrera 2's and stock 18" tire sizes. But for offroad/rally work I would put strength ahead of ultimate light weight.

For sure. Bigger rotors with a floating hat system with better cooling is worth an extra pound in the rear. At this stage, its tough to tell if this build is for show or function. I wouldn't want a "safari" build to rip around the canyons and expect great handling. But it would be fun in the Chicago snow and going down a few dirt roads. One thing for the OP to be careful with is to not go to fixed back bucket seats if you expect to use the back seats for kids. Its not safe, nor practical. Imho, if you are going to market this build, you should consider two different builds. (1) A "for show" build without a half cage, folding seats and the ability to use the back seats with minimum weight savings. (2) a "functional" build with fixed buckets, half cage, no rear seats and maximum weight savings.

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I appreciate the feedback as it helps me understand the setimiment/knowledge base of the Posche community - which is quite similar to Lotus. This build is for go and show. We will tune it to work on the rough canyon roads that we have here in CA. Hence the Road Rallye moniker. This 996RR will synthesize my love for 911s, practical performance while employing lightweighting tactics. I don't know it all, so I ask for help, from folks like you, and partner with like-minded companies. So I truly appreciate the advice. I will be driving this car hard - as will the Ride & Handling Engineer that I will employ to help us truly dial it in. This car will not compete with a GT3 in outright canyon speed - but it will be faster than a standard C2. It will certainly be more comfortable that a GT3 on the rough roads we strafe. The cosmetics of this car are pretty rough and a full repaint is not planned. We have some ideas that will allow the car to look cool yet appropriate for it's use case - with some expected patina. Think subtle graphics, smaller tube bumper, mud flaps and smaller driving lights. the Brumos-inspired graphics are temporary but my small nod to cool liveries of old. The seats (Recaro or Sparco) will fold so we can access the rear. And they will be much lighter than stock! That's a plus. We have created a rear chassis brace instead of a half-cage. The unsprung weight savings from brakes and wheels may not be realized but we are working towards that. I am a driver - street and track (member at SMMR for over 15yrs) and countless trackdays with BMWCCA, PCA and Lotus Club since the eary 90s. Here is a Lotus Elise that we build for clients, similar to Ruf: 111RS As an mechanical engineer, with 40yrs in automotive, I am particular about how things work. As a designer, I am also very interested in how they look. My madness is shown in a sportscar I created: Drakan Spyde r. We create improved versions of the cars we love and work on. I've had a picture of a '73 RS on my wall since the mid90s along with owning a 993 that I tracked and enjoyed in the late 90s. We are hosting an event for anyone to attend to see this build. We will also have the IMS out of the car so folks can see this infamous part - and hopefully get more comfortable with this issue. I should have the Elephant Racing suspension in time so that will also be on display.

Go for it! Many of us enjoy the ideas and innovation!

I like what you�ve done with the Lotuses, as well as the Drakan. Have you given any consideration to seam-welding the chassis?

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Thx. Seam welding is way beyond our budget on this build and we are not stripping it down that far. If this was a race car, that would be a consideration.

Gotcha. Any chance you�ll expand your raceVIEW mirrors to the 996 line?

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Do you think 996 owners would like it?

Most probably wouldn�t, I would guess. But maybe I�m wrong� I assume as these cars become more inexpensive, people would be willing to mod them and worry less about �originality�.

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Agreed. It seems they have dropped to rock bottom and are trending up!

I�ve kinda sorta done what you are going for. Grab a look here https://rennlist.com/forums/996-foru...lly-996-a.html I�ve done engine and chassis development for all the big names over the years and have a couple decades of experience in building everything from fun stuff like this to programs in the 8 figures. happy to help. This was a fun month of weekends project for me and the kids and we learned a bunch and actually innovated in some interesting ways. next Wed I put the car on my 7 post chassis dyno and inevitably will learn a bunch. happy to try to save you some time in testing.

Sweet! Thx for posting. Wheels and tires are a current challenge. I will PM you so we can talk off-line

We've made some good progress on the car. The IMS bearing got changed out and it is getting new clutch/fly. The Elephant Racing kit is almost fully installed and mounted some Yoko Ultra High Perf tires onto the 18" factory rims. I have decided to stick with the factory tire diameter so we will get a bit more side wall and the corresponding compliance. We are still trying determine the optiimal wheel size and get a set. I posted up several updates on our Blog: HERE

We have made great progress on the car. It now has the Elephant suspension in, new Yoko Advans, Giro brakes, Numeric shifter/cables, IMS, OE clutch/fly, mudflaps and Recaro seats. We had the front fascia sprayed with bed liner and will get the rest of the paint sorted with a light spray. The tube bumpers are still a work in process. The front fascia was replaced with one that we had sprayed with bed liner. You can see it in the picture below. Ride height, measured per factory guidelines is close to stock. The car turns in really well. I prefer it to the 964 C2 that we just fit PSS10s to. I have not had a chance to really hoon it yet. Overall it is driving well. We will get our Ride & Handling Engineer into the car as soon as the Braid 17" wheels + tires show up. We plan to go with tires that are at the stock diameter and will take advantage of the added side wall for improved compliance. We got a set of Recaros and installed them. They are supremely comfortable and supportive. We also added a Numeric shifter kit with cables. This also make a huge difference. It is set at the middle position which is OK. I will try the stock throws as well. I don't like the shortest throw but need more seat time in each before I decide my favorite. I think we were a bit too aggressive with the mudflaps. The scrape on everything! We will cut them back and extend them with rubber sheet so that aren't so annoying! Next steps are mounting DOT legal lamps below the front tube bumper, get the fuel gauge operational, tear the dash out for repair/reupholstery and then have the exterior refinished (partial paint). We will add a cool livery when it is all done.

Looking slick! Head to the mountains and find some snow. I'm having more fun than my version of a Rally 996 than cars 10x the price. Rally handbrake for the win! Happy New year

Those pix are epic! Thx for posting.

We have made great progress here on the build. The exterior body work was completed. The new Braid wheels have arrived along with the Contis. Mud flaps are to be changed and supplemental lights need to be wired. I've done a few things that may not be appealing to the purists but I am a 'form follows function' guy. Personally I think the form is still pretty cool. Note the bed linered fascias and rockers. I also perforated the rear fascia around the exhaust system to help vent out heat. I added fabric tow straps to the front and rear. I posted more info on our Blog: HERE

That�s awesome! I�m loving all of your changes, especially your two-toned wheels. What tire sizes are you running? And how�s the handling in its current form?

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I went with the inch down wheels - 17" vs the stock 18". Tires are 225/45R17 and 275/40R17. I take it out for the first proper drive tomorrow. Braid offer a lightweighting option that machines the face of the wheel to give it that two tone look. Glad you like them - I am really happy with how they look on the car. Did you notice the different spoke count?

Haha, how could I not? The density of spokes in the rear played an optical illusion on my eyes: I really thought you put a 16� on the rear! You made an excellent choice of rear wheel design and tire choice for this RR car. It�ll surely be bombproof. I look forward to your next update!

We rendered some livery ideas for the car. I'm partial to the Mobil Pegasus...one of the films is a black film that has gold flake in it. It shifts color from black to gold depending on viewing angle. The other is a satin gold vinyl. We're still messing around with various ideas....as we decide on the interior updates.