991.x GT3 RS best mods for track
 

Hey guys, I rarely post here but wanted to ask what people thought about the changes they made to their GT3 that actually made the car better without introducing issues.

My car is a 2016 991.1 GT3 RS. I bought it used with the GMG back roll cage and I added a full Akrapovic and Michelin N2 spec Sport Cup 2 tires on BBS Fi-R wheels. I also put an Anti-Gravity Li-Ion battery which basically offset the weight of the roll cage and I had Joey over at EMotion Engineering do a stage 1 suspension kit. My car is about 100 lbs lighter than stock.

I have been toying with the idea of a set of Ohlins dampers or the Manthey Racing KW kit. I do like about the Manthey Racing setup that you can keep the front axle lift but HOLY MOLY its about 20k for this setup.

I have tracked my car and I feel like I have reached the limit of the tires. Looks like my other options are Pirelli Trofeo R or Michelin Cup 2 R if I want more grip == better lap times

I am interested in making the car better but I don't want to waste any money on changes that I can't feel or don't make a difference in lap times.

My chassis is setup to Porsche recommended spec, which I believe is -1.3 all around.

I spend A LOT of time on track on a motorcycle but not so much in the car. I am looking to gain some knowledge on the car. This past weekend at Streets of Willow Springs I was able to get to 1:23 flat many times but could not really go any faster. I am able to do 1:17 at the same track on a motorcycle but with the car I felt at times like I had to wait on the front to turn and when hard on the brakes I was well into the ABS but the data only showed about 1 G of decel at max braking.

I have much to learn for sure but 1:23 is pretty good for my first time on track with my own car, I think.

I was considering getting some Trofeos or 2Rs and possibly having the car setup by GMG to be more track-focused to start.....thoughts?

You'll get mixed reports on the Cup 2 R, but if you're looking for a big upgrade in grip out the box, they deliver for sure. For how long, are they worth it, etc. that's all debatable.

Can't recommend getting knowledgeable indy shop support & alignment setup enough. Get their baseline track setup, and/or give them that feedback from your first day and see what they recommend. If you're waiting on the front end, for example, sway bar adjustments and ride height/rake can make a substantial difference. Don't underestimate the range of adjustments on the stock components and the effects.

Your camber is very conservative. For reference I run -2.6 up front, -2.1 rear. definitely go see GMG. :thumbup:

I just started tracking a 991.2 GT3 RS so right there with you getting up to speed with these cars. I can tell you that a proper alignment made a world of difference. My first time out was on the stock settings with Hoosier R7s. The next time out went with a much more track oriented alignment and made a huge difference. Ran -3.2 with a bit of toe out at the front and -2.6 with a bit of toe in at the rear and it was like a whole different car. I was also on Pirelli slicks last time which definitely helped too. The car actually wanted to turn in now. We swapped the top mounts to get that camber and keep the caster happy but since have swapped in the full compliment of E-Motion arms as I prefer to get the desired alignment in that manner and have the option to knock the camber back down below -3 in the front on the street. Would recommend a better alignment to start for sure after seeing how well my car responded to the change. Depending on what wheels you are running there are some quicker tires out there as well. Not the biggest fan of Hoosiers but they will be quicker than the 2Rs or Trofeos. Good fitments out there in 19s for a good track setup. Forgeline makes a popular setup. I prefer Signature Wheel as they make an excellent track wheel (been beating the crap out of their wheels racing the last few years). Also swapped out the brakes - full AP Racing kits from Essex.

If you get into replacing the suspension there will be another option soon. Have a test kit on the way from Nitron - their elec-TRON version of their R3 kit on the way that we will test extensively until we have it dialed in exactly like we want it. They already have a traditional 3way kit available but the addition of the electronic component ought to step it up a notch but we will see how that goes once we have it. Very excited to get my hands on these and will do a lot of before/after comparisons with them. Also just added a Verus Engineering full aero kit and looking forward to running it out at COTA next week. When we have the suspension nothing else will change though until we finish getting it dialed in.

Really though a proper alignment was a big first step.

Simple recipe to drop lap times:

• Get 19"s with Goodyear Supercar 3Rs or Hoosier R7s
• Swap your top hats for more front camber and more aggressive alignment
• More aggressive brake pads (Ferodo DS1.11 or DS3.12)

I have the Manthey kit on my non-RS, simply amazing.

HPDE track events

@DiscoWagon what differences did you notice with the Manthey kit?

I would say the biggest difference is the car's stability on corner entry/exit and the ability to take bumps. I can utilize much more of the kerbs on my local tracks which would previously unsettle the car. Also, with the MR alignment specs and out of the box shock settings, the car's turn-in is night and day.

I'm quite certain that your car would have a similar transformation, but since I have a non-RS, my setup is 3-way all around. The kit for the RS has 3-ways in the front and 4-ways in the rear.

https://rennlist.com/forums/market/1357844

Might want to check with this guy if he still has them for sale.

Check out MCS 3 ways from Dundon Motorsports. Valved for the platform and the single best upgrade you can do for track performance on a GT3 in my opinion. Coupled with a good alignment and good brake pads and fluids the car will be excellent on the track.

I’ve driven my car with stock dampers, with stock dampers and a DSC controller, then with Tractive dampers and then with MCS three ways. MCS is way better than any of those setups, more planted and stable, better under braking and in corners, way more confidence in the car. I’ve also driven a 4RS stock and with the same dampers, and had a simulate experience.

Check out the Dundon parts here:

Dundon 991.1 GT3RS catalogue.

I did the AP brake kit so I could box up the PCCB to keep the pristine for possible resale of the car, and also the AP racing kit makes it easy for someone as mechanically challenged I am to do pad changes when needed. My localish shop did some track specific alignment stealing some cup car part for the front and replacing some of the rubber bushings with the metal/spherical ones.

Also did the GMG half cage, harness and boxed the stock exhaust to put in the sharkwerks centre bypass (apparently these can go south with lots of track use and are expensive to replace).

I just got 2 sets of 19" Apex wheel so I can have some more tire options and better prices and bring 2 sets on trips.

I've been debating more suspension upgrades like the Dundon or Manthey stuff but really struggle justifying that. Maybe you shave some lap time but what's the point? There is no prize. All of the other stuff I've been able to "rationalize", the alignment makes tire wear beater, cage/harness keep you well seated(safer is debatable).... but 16-20k on better coilovers.... I dunno! hahah
https://cimg5.ibsrv.net/gimg/rennlis...5fad219da4.jpg

I’ve done all of that stuff. And beside proper buckets, harnesses, and brake pads, the single best modification to the car was MCS. Makes the car so much better on the track. It isn’t about absolute lap times (it is faster) it is about expanding the performance envelope for us amateur drivers. It is more confident, easier to drive quicker, more planted, more predictable.

Shhhh! That's not what my bank account wanted to hear ;)

Oh, and Dundon’s new splitter and swan neck wing is ridiculously good too.

https://cimg6.ibsrv.net/gimg/rennlis...828a23da3.jpeg
https://cimg7.ibsrv.net/gimg/rennlis...227d34104.jpeg
https://cimg8.ibsrv.net/gimg/rennlis...959fbf688.jpeg

Your car and my car are about to be twins. The Dundon Aero Package parts are shipping for mine this week. So excited for that one.

Back to the best mod for the track. The best you can do to help with confidence driving on the track is the MCS/Dundon Suspension Package especially on the 991.1 GT3RS. When Porsche came out with the 991.1 they used way to soft spring rates for the car and track use. I had one I bought new in 2016 and that was always my complaint with the car. Around the time the 991.2 GT3RS was released I was in talks with MCS about doing a suspension package for the 991.1 as I was planning on keeping my 991.1 for a bit. Then I got a 991.2 GT3RS allocation. That paused our talks for a bit but then they resumed when the 991.2 came in because that car was as comfortable on the street as my 991.1. That is where Dundon and MCS come in. I had the first set of shocks installed on my car and what a difference they made both street and track. For me the lap time wasn't that much faster at Road Atlanta with the MCS installed but it really made the car more comfortable and predictable to drive on the track. To dig up an old thread take at look at my response on how the car changed. It is a little long but I wanted to share the feedback I gave MCS and Dundon on the first initial package developed.

https://rennlist.com/forums/991-gt3-...-with-fal.html

Stoked for you, Seth. You got some laps in the 4RS with that areo on, right? The aero is legit.

I had a pro level coach in my car at T-Hill. He’s been in it stock and he also has a 991.1 GT3. He kept commenting on how much grip my car had, it blew his mind. The combo of the MCS, areo, tires and brakes works so well together.