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Just picked up a new to me 991.2 Carrera T. It has RWS. Want to get it up a little better for lapping.
I have my Bilstein B16 Damptronics from my prior 991.1 S, that I ran with factory upper mounts that I am wanting to install on the new T. Before installing I think I would like to do at minimum upgraded upper mounts. The springs are progressive. I am also considering upgrading to linear springs. This would dictate which front uppers I use.
Also, I would like advice on the best style thrust bearing (the thing between the spring and spring seat). Bilstetin uses plastic ones which are pretty chewed up. Could convert to a metal Torrington bearing style or something?
1. Which upper mounts do people like? I see we could have 4 options. To be honest, if there is an OEM-style upgrade I would prefer that I think.
2. Do the aftermarket rears do anything? The stock ones are all metal already. There are no camber benefits. Can you feel the change from a bushing to a bearing rear? I see the GT3 uses the same rear mounts as the regular 991 but the GT3RS and Cup have a different rear mount.
3. If I do the spring conversion, which rates? Do I need helper springs?
a. Tarett Engineering - Looks nice, you pick between linear spring style and progressive spring style
b. Rennline, looks IDENTICAL to the Tarett except for anodizing color. IMO Tarett and Rennline are made in the same facility. Rennline is on sale right now.
c. Elephant Racing - Looks good, could have sworn at one point someone said they had them, and the bearings made noise
4. GT3 OE - I think these could be made to work with linear spring conversion, no camber benefit, only $120 each so much less than the aftermarket brands.
Rears
a. Tarret - Similar to stock but with a bearing instead of bushing
b. Elephant - Similar to stock but with a bearing instead of bushing
c. BBI - Only works with linear spring? Converts to a real bearing
I will post some pictures of my coilovers, springs and thrust bearings in a little bit.
—————-
Just took some measurements, my current springs are 9” length, 60mm lower diameter for both front and rear. Spring rates are 285lb front and 629lb rear
I am tempted to at least do front linear spring so I can take my upper mounts with me if I go to different coilovers in future like MCS
Last edited by AdamSanta85; 11-12-2023 at 12:54 PM.
I notice that although the 991 GT3 uses the same rear upper mount as other 991 cars, they use a more performance-oriented rear upper spring seat. The Carrera one has foam in it. Has anyone converted to the GT3 ones?
For a nice up grade, You’ll want 100nm front and 150 rear which is about 570 fr 850 rear.
E-Motion have some new stuff now. Lower rear shock mount and lower rear carrier bearings.
Anything you can’t get in E-Motion, go Tarett.
You don’t want the noisy Elephant in the room. 🤣
I just went back a few pages. My car has progressed considerably since then.
Everything Elephant has been removed and replaced with E-Motion shim adjustable bars. I did the OS Giken mechanical diff. The side radiators they sent were all wrong. Mine were actually fine, its the air con condensers on top that were smashed up, so replaced those.
I’m at 120/170 spring rate now. MR Spec. And i run -4.4 font and -3.5 rear neg camber.
Cup2-R most of the time. Currently 255N and 315K.
9.5 x 20 et 44
12 x 20 et 50 About an inch wider track front and rear.
Save your money is my theme, only spend it when there is significant and quantifiable R.O.I.. Do these following mini-mods and you'll be Golden starting out. After your first 6 track weekends, then consider doing major (Expensive) mods. Phase 1:
By a Catalyst Lab timer. This is the most important tool for analyzing your lap times. They are about $1,200..well worth it. Worst case, you can readily resell it at some point in time.
Get some track friendly tires, and change your street tires out. I have found that Yokohama ADVAN APEX V601 work real well for beginning track work and they are cheap. When you get good, look for the Continental tires, the CONTINENTA EXTREMECONTACT FORCE, with a UTQC 0f 200. $1,200 to $2,000 a set. If you go out with stock tires and alignment, you'll eat the outside edges of the front tires; they'll be ruined.
If you're in a warm/hot area, get and install the center radiator kit for your car, get it from Suncoast Porsche in FL, about $800.
Have your cars brake fluid exchanged to Motul 660, about $150 parts and labor.
Check your pads....talk to Clark at Apex Performance in. S. Carolina *@ (843) 299-0997. He can recommend replacement pads for you, from mild to macho!
Inspect your drilled rotors for any cracks, especially if the crack(s) connect to any 2 drilled holes. Replace if needed, always in pairs, front, and or Rear, or both. Check the diameter of the discs to be certain they are within Factory specs.
Watch as many in-car driving videos as you can on the track you are about to run.
Join a track orientated club and attend their events. They will have a program to assist you in matriculating up the driving ladder, from Rookie to unconsciously competent.
Phase 2
After about 6 months, and if you are #1 or #2 in your class, and you're getting 80% or greater times than the record in your class, your are ready for stage 2.
GT3 # lower control; arms, you can't get enough camber with stock lower control arms, The rears are adequate. Contact Tarrett Engineering. You'll need an alignment post installation.
Upgrade your front brake rotors to 2 piece GiroDisc, or some other brand of 2 piece rotors. Call Clark for this too. He just sold me a set of front GiroDisc rotors. When you have the budget, order the rear discs as well. The rear GiroDisc for the 991.2 are 20mm wider, from 330mm to 350mm
That's it....don't do anything else or risk turning your car into a track beast, that will be compromised on the street, rough riding and noisy.. When you start with a 991.2, Base at 370 HP, Carrera S at 420 HP and the GTS at 450 HP, that's more than most beginners will ever need. Until you are an accomplished driver and are committed to the sport, don't waste you money on a Tune, or suspension modifications. The mod with the greater return on investment are upgraded, track orientated, tires.
Lastly the PDK automatic transmission with Sport Chrono is awesome for every situation. Normal mode is fine for the street, Sport mode when you are feeling macho and want the pops and crackles on deceleration, and Sport + at the track, no pops and crackles, sorry to report but quicker up and down shifts, performance is optimized.
In closing, I have 25 years experience driving at the track with a minimum of 6 weekends a year. Included in that the is 10 years of wheel to wheel racing with the Porsche Owners Club from SoCal. I have prepared for the track, the following: A 80 SC Weissach Coupe, a 1997 Carrera, a 2004 GT3, a 2015 Cayman GTS, a 2020 Mustang GT, a Porsche 991.1 Carrera S and a Porsche 991.2 Carrera GTS. Generally, I ran #1 or #2 in my class. I am now retired from the track: 25 years is enough time and enough money spent.
So I have been spending a TON of time over the past few days learning about Porsche upper mounts, from aftermarket to the various Porsche ones from Carrera, GT3, GT3/2 RS, and Cup... pretty interesting actually.
Front
------------
Carrera - Metal/Plastic with larger size to accommodate progressive springs
GT3/GT4 - All metal, with metal bearing, very similar to the aftermarket Race style plates. Centered caster (same plate L&R), accepts an upper spring seat, 60mm linear spring
GT3RS / Cup - All metal, similar to GT3/4 but with offset caster
Carrera
GT3 / GT4
GT3RS, GT2RS, Cup
Rear
-----------
Carrera/GT3 - Metal with rubber center bushing, accepts progressive springs, spring located against mount
GT3RS/Cup - All metal, all metal spherical bearing, accepts 65mm linear spring
Carera (Same as GT3 but diff upper spring seat, Carrera upper spring seat has rubber)
GT3 (Same as Carrera but plastic upper spring seat, progressive spring)
GT3RS, GT2RS, Cup - Nice pillowball mount, 65mm linear spring
Then there are aftermarket options
I think I plan to try to get my hands on some good condition used Cup upper mounts and upper spring seats, and try to install those with linear 60/65mm springs. Not sure if I should run the rates that are popular upgrades for the GT3 (560f/672r).
My B16's have 60mm front lower springs, and 65mm rear low springs already. The strut shafts are all the same dims, and spring lengths are the same... ::shrugs::
Last edited by AdamSanta85; 11-13-2023 at 03:05 PM.
Called Bilstein to see who, if any, could rebuild the Damptronic shocks. I have no reason to believe I have any issues, but wouldn't mind having them validated before spending money on them and installing, etc.
https://www.performanceshock.com/ in Sonoma California can. I reached out to them, yes they can test and service the shocks as long as there are no electronic issues.
I think I plan to try to get my hands on some good condition used Cup upper mounts and upper spring seats, and try to install those with linear 60/65mm springs. Not sure if I should run the rates that are popular upgrades for the GT3 (560f/672r).
::
Your 560/672 appears to be stock rear at 120 my speak and they just up graded the front from 45 to 100.
So they got the front end correct, but the ratio is very close.
100/150 (570/850) in your speak.
110/160
120/170
These are the best proven setups, with the golden ratio formula for Porsche.
Your 560/672 appears to be stock rear at 120 my speak and they just up graded the front from 45 to 100.
So they got the front end correct, but the ratio is very close.
100/150 (570/850) in your speak.
110/160
120/170
These are the best proven setups, with the golden ratio formula for Porsche.
Those who know, know.
Tractive
I wonder if these Bilstein can handle those rear rates....
The Bilstein out of the box is 45/120 in Kangaroo speak
I wish I could give Tom at TPC a ring and tell him to just send me his finest, but I can't, so trying to work with what I have.
Last edited by AdamSanta85; 11-13-2023 at 04:06 PM.
Save your money is my theme, only spend it when there is significant and quantifiable R.O.I..
That's it....don't do anything else or risk turning your car into a track beast, that will be compromised on the street, rough riding and noisy...
Poor people pay twice. I’m of the, buy well, buy once theme.
I git similar advice that you gave Martin, and it cost me three times the money. Half assing it always costs more.
All of the money spend doing half measures up grading brakes was pure waste. To SAVE money, buy the biggest BBK you can afford, because it still won’t be enough down the track. That will save you money. Buy the good stuff up front, and you won’t be paying twice.
The cheap stuff is what makes noise and compromises your car. The expensive stuff like E-Motion is silent. Zero compromise. I daily drive my car on the street in its full track mode. Why, because eventually I bought all the no compromise good stuff that has the best of all worlds. You can have your cake and eat it, but not if you penny pinch. Penny pinching ends up costing you more in the long run. The stuff you buy either doesn’t deliver or is worn out in 5 mins. You want to save money? Buy the good stuff up front and not do little paid steps that are wasted and need to be repeated over and over again.
Poor people really do pay twice. (It doesn’t mean you are poor.). It means people that try to save too much by taking the cheap stuff first, always end up having to re-do it and that money they spent was wasted.
So yes, by all means save money, but do it by getting the right stuff that will last so you are not having to revisit the same things again and again.
Brakes - Maximum Budget
Coilovers - if you go cheap, you’ll have a great track car and a **** street one. You have to spend big if you don’t want to compromise street at the sake of track.
Control arms- if you go cheap, you will
be driven nuts with nosies. They will fail fast.
You will want more power quickly to catch someone. And when you do, these cars absolutely hammer. You’ll want better brakes, so see above. YMMV. Save up front will cost you down the road. Spend up front, and you won’t have to spend again down the road.
What part of Porsche Racing did you think would be cheap? The Porsche or the Racing? 🤣
I wonder if these Bilstein can handle those rear rates....
The Bilstein out of the box is 45/120 in Kangaroo speak
I wish I could give Tom at TPC a ring and tell him to just send me his finest, but I can't, so trying to work with what I have.
45/120 (Kangaroo speak 🤣 is stock rates for 991.2 GT3.
If your rear Bilstein was 120 and you want to up grade to 150, that would be fine. The Valving has quite a broad range. +30 🦘 is fine.
Poor people pay twice. I’m of the, buy well, buy once theme.
I git similar advice that you gave Martin, and it cost me three times the money. Half assing it always costs more.
All of the money spend doing half measures up grading brakes was pure waste. To SAVE money, buy the biggest BBK you can afford, because it still won’t be enough down the track. That will save you money. Buy the good stuff up front, and you won’t be paying twice.
The cheap stuff is what makes noise and compromises your car. The expensive stuff like E-Motion is silent. Zero compromise. I daily drive my car on the street in its full track mode. Why, because eventually I bought all the no compromise good stuff that has the best of all worlds. You can have your cake and eat it, but not if you penny pinch. Penny pinching ends up costing you more in the long run. The stuff you buy either doesn’t deliver or is worn out in 5 mins. You want to save money? Buy the good stuff up front and not do little paid steps that are wasted and need to be repeated over and over again.
Poor people really do pay twice. (It doesn’t mean you are poor.). It means people that try to save too much by taking the cheap stuff first, always end up having to re-do it and that money they spent was wasted.
So yes, by all means save money, but do it by getting the right stuff that will last so you are not having to revisit the same things again and again.
Brakes - Maximum Budget
Coilovers - if you go cheap, you’ll have a great track car and a **** street one. You have to spend big if you don’t want to compromise street at the sake of track.
Control arms- if you go cheap, you will
be driven nuts with nosies. They will fail fast.
You will want more power quickly to catch someone. And when you do, these cars absolutely hammer. You’ll want better brakes, so see above. YMMV. Save up front will cost you down the road. Spend up front, and you won’t have to spend again down the road.
What part of Porsche Racing did you think would be cheap? The Porsche or the Racing? 🤣
I'm going to expound on 4 point 0's post a little bit further, as he makes some fantastic points about brakes and the buy once, cry once principle. Having supplied thousands of enthusiasts with brakes over the years, we've seen this scenario play itself out countless times. If you aren't on an unlimited budget, you need to calculate your cost per mile for any type of consumable you plan to use on track. When tracking your car, you willinevitably devour tires, fuel, and brakes. If you can figure out a way to stem the bleeding in any of these areas, you’ll be saving yourself a bundle of money. When potential customers initially consider our AP Racing by Essex brake products, they’re sometimes discouraged by the premium prices and initial cost of entry. We see it across the web on automotive forums, Facebook, etc. What they typically aren’t considering however, is the long-term cost per mile during the course of ownership. They also tend to confuse price and value, which aren’t the same thing.As a conservative example, if you spend $1100 on a set of brake discs and get 5,000 track miles out of them, that’s $0.22 dollars per mile ($1100/5000). If you spend $1400 on our AP Racing discs and get 7,000 miles out of them (2,000 more than the competitor), that’s $0.20 dollars per mile. In that scenario, the more expensive discs are already the better value on the first set of iron rings alone. If you extend the cost per mile estimates in the above example out over the course of several years, you may have 15,000 total miles at $2800 for a lesser brake disc, which is a cost of $0.19 per mile. With the AP discs they may last you 21,000 total miles at a cost of $3100, which is $0.15 per mile…again, a better value. Basically, the more you track your car, the more you will save over the long haul by going with the more durable product. Can we guarantee that you’re going to get twice the life out of our discs vs. any competitor? Of course not. Based on a mountain of evidence we have from customer cars however, it’s a safe assumption that you’re not going to find discs that last any longer than our J Hooks, or that run any cooler, or in any way perform better.
If you choose discs that run cooler than other options, you're also going to save you money on pad wear. A disc that runs hotter may eat a set of pads in 4 track days, whereas the best discs available could allow you squeeze out 5 or 6 days under the same conditions. The fewer times you change the pads, the more you save. Cooler discs lead to cooler pads, which leads to cooler calipers and less boiled brake fluid. That means you won't have to bleed your brakes as often and waste money on brake fluid. Your brake system overall is going to see less wear and tear with superior discs, which is going to save you money over the long haul.
Residual value also comes into play. Something else we've seen, particularly with our complete brake kits, is that they hold their value extremely well long-term since they’ve been proven time and again and AP Racing is one of the one of the most highly regarded brake brands. It’s typical for our complete brake kits to change hands on the used market at 65-70% of their original retail price, whereas most other brands often trade at 50% or less. That residual value difference alone makes up for the initial purchase price difference between our products and competing brands. Also, complete brake kits tend to retain far more value than aftermarket 2-piece discs in the OEM sizes, because the aftermarket calipers in the brake kits tend to be the most valuable components.
My suggestion to anyone weighing brake upgrade options is to look a little further down the road, past the initial purchase price. Yes, the initial purchase price on the best products tends to be higher, but when you run the numbers over the full ownership period that few hundred bucks, or even a thousand dollars on initial purchase is a drop in the bucket compared to the upside long-term savings.
In summary, many people confuse price and value. A product can have a higher price while also offering greater value. Most of our customers tell us our brake products were one of the most valuable, if not the most valuable modification they’ve ever made to their track car. There's a similar thread to this one going on right now in the 991 GT3 forum in which numerous clients have called out our Essex Radi-CAL Brake Kits as one of their top track mods.
Also of note, all our AP Racing by Essex brake products are currently on sale for the month of November '03 so feel free to PM me if you are interested in a recommendation for the most durable, best value option for your car and situation.
__________________
'09 Carrera 2S, '08 Boxster LE (orange), '91 Acura NSX, Tesla Model 3 Performance, Fiesta ST
Jeff Ritter
Mgr. High Performance Division, Essex Parts Services Essex Designed AP Racing Radi-CAL Competition Brake Kits & 2-piece J Hook Discs Ferodo Racing Brake Pads Spiegler Stainless Steel Brake Lines
704-824-6030 jeff.ritter@essexparts.com
I hereby retract my "advice": If one knows they are committed to racing get the best up front. To short cut the process, and possibly get the mods at "wholesale" and buy a fully prepared rack car. The collateral expenses such as a trailer, a tow vehicle, that's part of the game. You can always sell these down the line.
Combo track and street cars always suffer from the effects of comprise. The "advice" t was offered know from my experience, personal and otherwise, that beginning drivers do not have the expertise to drive their car max'd out for the track, at 100%. As a result some of the expensive, manly mods, example monster brakes, full suspension mods, installing a full cage, obtaining the electronics to monitor the car's functions in "real time" on the track, cannot be taken full advantage of. So why waste the money? But if racing is y0ur passion, you can't be prepared enough.
In my experience, on the path to converting my 993 to a 90% track car (I wouldn't strip out the interior for the 100%), I confess to doing mods sequentially, spending far more than if had I gotten the best up front. On my 993 track car, I went through many, many mods, before arriving on custom suspension. Went through as least 5 phases, short gears, exterior aero, wings, exhaust, etc., many expensive changes. I was running in a class where you had to run stock brakes, saved a few buck there.
To short cut the process, and possibly get the mods at "wholesale" and buy a fully prepared rack car. The collateral expenses such as a trailer, a tow vehicle, that's part of the game. You can always sell these down the line.
Martin is absolutely correct. If you're sure this is the sport for you, buying a built car vs. gradually building your own is the best way to save the most money. Twenty years ago I had a friend who decided to build his own Honda Civic racecar. He was insistent that he wanted to build it 'the right way' and poured something like $50k into it. At the end of the day, no matter how nice it was, it was still just a Honda Civic that nobody would ever buy for anywhere close to $50k! He could have bought a previously built car for half of what he spent or less; a car that someone else had also insisted was built the right way!
You definitely need to be cautious and do your homework when buying a used track/racecar, but there are some tremendous deals to be had. The buyer pool for full-blown track/race cars is so much smaller than for street-legal cars, and as such the prices tend to be far more reasonable than one would imagine. Many times peoples circumstances change, and they just dump everything they have to get out of the sport quickly. Many times that is a complete turnkey package that you won't have to then aggregate. I bought my last track Corvette with spares for less than the total value of the parts I could have quickly stripped off it and sold. If it blew up, I was secure knowing that I'd recoup my money on the parts and still have a roller/shell to sell someone.
11-12-2023, 10:36 AM
is stock rates for 991.2 GT3. 
so feel free to PM me if you are interested in a recommendation for the most durable, best value option for your car and situation.
