Tom@TPC Racing

Here's more pics of the rear shock tower section. Nice welds and very sturdy. I've installed many DAS Sport roll bars for customers before but I just can't stop admiring it on my car.





If you look carefully you'll see how I trimmed the ECU mounting plates to prevent the outer section of the plate from being sandwiched between the roll bar footing and the body.

Tom@TPC Racing

These seats!

LateBraking

Tom, I'm impressed at how you can do a hundred things per minute for the shop and still have the energy to pop in a roll bar at the end of the day before sundown, haha. Didn't know there was a bar like that, it looks damn appealing (if only I didn't have a bar already).

Will have to sit inside your car when you're not looking when I'm down there in two weeks. See if I get better headroom with that Momo setup in (or if my wide mass even fits). Uwa ha ha ha.

Tom@TPC Racing

Thank you for your kind words. Its all in a day's work. Frankly, if I didn't have house chores to do nor get thirsty, hungry, and sleepy, I'd work 24-7 non-stop because I love it!

You're welcome to sit in my car!

LooseMarble

Tom - Nice talking with you today. I'll see you on Monday for DSC, 3 axis accelerometer, and a nice street (some track) alignment. Look forward to meeting you in person after reading all this!

Tom@TPC Racing

Likewise. Looking forward to work with you on the setup.

Tom@TPC Racing

I am installing MOMO Lesmo One seats. This is MOMO's top of the line seat, the same seat used in the MOMO 997/991 GT3 Cup and F458 Italia GT3 race cars. I got Standard size for the driver and XL for the passenger. The Standard size is roughly 5mm narrower than the factory GT3 Cup car seat for an ultra racy fit. The XL fits more relaxed like the OEM GT2 seat, except with higher thigh bolsters. I have been a fan of MOMO Racing sponsored pro racing efforts for many years, they truly race with that they sell. Back in the mid-90's I have sold and installed many MOMO seats, this was back when it was popular to convert 964's and 993's to race cars. When the 996 Cup cars hit the scene it seemed almost everyone went on a Recaro Cup seat craze. Which by all accounts it was a great seat. With all the recent advancements in FIA approved racing seats, I am going back to the MOMO root. I am super excited to install my very own MOMO seats!


Those strategically placed cushions feel really good.



For those who haven't installed universal fit racing seats before, it is a lot more time consuming than it appeals to be. No two seat and no two brackets fit the same for each car and each driver. Since racing seats typically aren't height adjustable, its somewhat of chore to get the driver set at a height that feels good for the driver while leaving sufficient clearance between helmet to roof. So don't give your shop a hard time when they bill out more hours than originally expected. In my case, I spent two evenings from 6pm to 1am installing, test fitting, disassembling, modifying, reassembling, and then test fitting again until I got the driver side to perfect for me. I bought extra sets of side brackets for modifying just in case.

You'all are aware of my OCD. Must measure to 1/100th of a millimeter...


Making custom bushing on a lathe to allow the lap belt brackets to "float"(articulate). This prevent blinding allowing the lap belts to perform to full effectiveness. The measurements, trial fitting, machining and re-machining, and just blank staring at what I have to work with just burns up the hours.








HOURS later... one seat in!






The passenger seat took far less time to put in because I already machined the floating hardware and got the blank staring over with. AND no slider for the passenger.

Tom@TPC Racing

Before I installed the seats I was scrambling to get a pair of 6-point harnesses. Oh, I didn't mention that the roll bar, seats, and harnesses installation took place 5 evenings prior to a track event I registered for. As Murphy's Law would have it the harnesses I had my eyes on where either out of stock or out of the country or mismatching colors... Then Rennlist member RedRSA turned me on to TeamTech Motorsports(Thanks, RedRSA!). For more than a decade we have been using TeamTech SFI-approved racing window nets for Cup cars but have never once occurred to me they make 6-point harnesses, better yet they custom make each set! I got to choose the color of the belt, color of the pull tabs, and even color of the stitching! TeamTech offers other options as well for a truly customizing experience. You can really have fun and come up with some crazy combinations! I chose red belt, yellow pull tabs, and white stitching. I was being "difficult" by requesting them to change the color of the TeamTech patches to create the look I had envisioned. Having the proper finishing touch to me just makes all the difference.


I know its borderline psycho to have them change the patch from black to white...


They got it done on time and I swap out the shoulder belts the night before the track event.




It makes me feel like I'm in a MOMO sponsored pro effort.




We want to let Erin, who's Mike Levitas's daughter battling cancer, to know that you are in our hearts and in our prayers. Stay strong.

Spoddle

Subscribed to see updates, great build so far.

Ginsu Tim

Amazing work Tom & thank you for sharing so much valuable intel in this thread.

I was going to PM you this question, but thought it might add some helpful discussion and more insight about suspension setup/equipment.

Currently the suspension on my 7.1 GT3 is bone stock and I've had it for 2 years. I'm getting more used to the car and fast enough in it on track that little undulations and inconsistencies in the road surface seem to disrupt the car at various points. Examples would be slight dips or crests at high speed apexes (130mph+), dips or ripples in road surface during mid-low speed brake zones where I need to have some wheel in the car, etc. You get it..

As was mentioned earlier in this thread, anti-roll bars will play a key role in the setup, and while I'm currently "full soft" in the front and middle in the rear, I think I'm ready to transition this to more stiff up front while softening the rear. Maybe this simple change will improve how my car feels through the above mentioned sections (curious to hear your thoughts on this).

One of my friends with a lot of experience in GT3s and who is very fast in his own right recommends getting rid of all OE suspension/connection pieces underneath on these cars and replacing with aftermarket parts because they will make the car substantially more predictable all around. There is also a safety & consistency issue he brought up because the eccentric bolts can slip out of place easily once lateral loads become consistently high (amplified by use of R comps).

So I have a couple of questions related to this:
- You spent a lot of time talking about bumpsteer earlier in the thread, do you feel that utilizing aftermarket parts to neutralize bumpsteer is a crucial adjustment to make in the setup of any 7.x GT3?
- If you had to start from scratch, and let's just say for the wild sake of argument that you didn't feel like dumping $7,000 into suspension pieces all at once, can you prioritize the below parts in the order that you would purchase/apply them to your own GT3?

Front Tie Rod w/Bump Steer (2)
Front Toe Link w/Bump Steer (2)
Front Drop Links
Front Tension/Compression Links (2)
Front Monoball End + Adjustable Thrust Arm Bushings
Rear Toe Control Arms
Rear Toe Link w/Bump Steer (2)
Rear Monoball End
Rear Monoball Thrust Arm Bushing (Adjustable)
Rear Upper & Lower Control Arm Links (4)
Rear Tension/Compression Links (2)

Much Thanks!

Tom@TPC Racing

Thanks.

Tom@TPC Racing

Thank you. Yep. Classic .1 car characteristic, they tend to move around more under load than .2 cars. My preference is to run a stiffer front bar to favor corner exit. Many people like a looser setup. I prefer tighter setup; sliding the front rather than the rear. A personal preference adapted from my mentors to take advantage of the rear engine placement. I also like the effects of less moving around(more stable) front end and the added touch of resistance at the steering wheel, which in my mind the resistance smooths out my steering input. If you have an aggressively setup rear differential then you have not choice but to run soft front bar setting to get the car to turn/rotate. No disrespect to your friend, but my opinion is, and only my opinion, is that before getting rid of all the OE rubber pieces for monoballs more shock damping and springs are needed. The rubbers actually have some spring rate, like 30-lbs here and 20-lbs there from flexing the rubber bushings. The added spring force, I personally think helps on a cars that are lightly sprung from the factory. With only ~220-lb front springs from the factory the supplemental 30-lbs here and 20-lbs there make a 20% difference. Metal bushings are of course more precise, and are awesome on cars with higher spring rates. On a car with say 1000-lb springs the rubber spring rate doesn't matter. Certain metal bushings are essential for performance such as rear toe links to keep precise toe setting. I still have and will continue to run some rubber bushings on my car(front control arms and rear dog bones) and factory rear eccentrics. My thoughts on rear eccentric delete kits are they are nice in the name of safety and they eliminate setup errors since they are fixed position. Definitely an upgrade but the car's tub and subframe better be 100% straight to get good setup numbers since some adjustments from before are now fixed. While I consider fixed bolts as an upgrade although I have not personally encountered eccentric slippage on 996's and 997's(GT3's, GT2's, Cups, R's ...on slicks). I have had eccentric slippage on early 993's. I suppose handling of eccentrics and cleanliness of the eccentrics/bases is an influential factor. Unless the rubber is actually broken, the choice between rubber and metal is less important than the setup itself- I speak from personal experience working on race winning cars. But if you got money to spend, then replace everything! ;-) YES! More so front than rear though. My approach of stiffer front bar and stiffer front suspension via dynamic damping eliminated front dancing around. Plus i run OEM front ride height so not low enough to have bump steer issues. I am afraid the some of the items on your list are of no performance value to me for my setup approach. This is in no way implying that my approach is the only approach, it is not. Here's my list in the order of importance to me-

1. Proper alignment for the driving purpose, ride height, eccentric positioning, sway bar setting.
2. Adjustable rear toe links to set toe and correct bump steer.(Requires alignment). I prefer TPC brand. ;-) TPC provides setup details and support on our brand of parts.
3. TPC adjustable sway bars to refine front-to-rear balance to liking, and stabilize the moving around characteristic.
4. DSC module to optimize damping on OEM PASM shocks, and add true dynamic damping function, and to further improve stability by reducing suspension movement and rate of movement when under load. (More aggressive alignment is optional- align as if you bought coilovers with 500/700-lb springs).
5. Solid rear thrust arm bushings or buy Cup or R rear control arms. (Requires alignment)
6. Replace .1 rear rubber bushing dog bones with .2 rubber bushing dog bones, or buy metal bushing dog bone but keep stock length.
7. Tractive DDA coilovers. (Requires alignment) 8. Replace front control arms with Cup or R when OEM street car arms are worn. (Requires alignment)

It is a given that along the way replace any worn items such as tie rods, thrust arms, wheel bearings, etc. Fit a differential build in there between items 1 to 8 as the OEM wears out or just proactively do it. Have differential setup for your driving purpose/preference and setup the rest of the car to the diff from there. Many items on my list and your list requires alignment/setup changes so doing these items in steps let's say in a course of 2 years there'll a lot of labor cost accrued. For any setup approach, I find it best to set a goal, consult with a race shop that you trust(preferably not a shop that says yes to everything just to profit) work with them to create a plan to group appropriate items per increment to achieve your goal without spending over and over on the same task. However, this doesn't apply to someone in my position and for race teams who actually does all the work by self and do it over and over for the purpose of development, obsession, and for fun. Another words do as I say but not as I do.

Ginsu Tim

totally makes sense. I guess I'll try swapping the tension on front/rear anti-roll bars and see how she does. what's the worst that could happen??

Understood. You would definitely know better than me, but I thought factory spring rates were closer to 450 up front and 650 in rear. Either way that's neither here nor there, I get what you're saying about bushings offering more damping in relation to spring rates.

Got it - thanks!

I should have mentioned that I have a Guards LSD set at 40/60 ramps, so at least that part is already done I will start playing around with these things soon and let you know what I find! It's hard to find a good shop (not sure there genuinely IS one in this region) that is an expert in both parts/performance AND suspension setting details, but I will hunt around.

Tom@TPC Racing

Glad you mention your diff spec. Worst that'll happen stiffening the front bar is massive understeer, you'll feel it on semi-aggressive street driving such as entering medium speed exit ramps. As said before, the diff setup is going to dictate the ideal sway bar settings since diff changes the balance of the car via torque transfer, whereas sway bars do it via chassis weight transfer. These two items have to balance each other out and the function of the act is the balance of the car. I know what the outcome will be but I think it is good to experience it for yourself. You might find it to be a fun experiment. The thing about an aggressive conventional diff setup, in my most humble opinion, is that it is meant for driving "flat out". Really great for driving flat out at the track especially with appropriately matching suspension setup, but I find it to add mild rear instability during on/off throttle during a turn for casual street driving as the torque lightly kicks in/out, particularly when the build is fresh. Can spin a car in the rain on exit ramp if not paying attention. Stiffer front bar setting will calm this down for street. But remember to reset the front bar for track use. Ideal front bar setting for track on top of having balancing out the diff setup is for the driving style of the driver. Since my car is not a track only car, I am deferring the diff build until I decide to go for a flat out or milder build.


On .1 GT3 is ~220/580. On .2 GT3 is ~260/620. There are other threads to reference this.

Tom@TPC Racing

It has been a long harsh Winter here in the Northeast, my car has been in slumber since November of last year. Over the course of the Winter I have been swamped with many shop projects and I still am swamped, but I have been jonesing to work on my own car so it is time to wake her from her slumber. One of the items I need to do is to improve to shifting. At the last track event of last year I noticed the shifting had been degrading, even for normal street commutes shifting during a turn has became more difficult. So the first items on my list for 2016 are transmission mount bushings and shift cables. Before parking my car for the Winter I know that the OEM rubber transmission mount bushings have been failing(not completely broken but there's a lot of movement), and the shift cables are the original OEM cables with over 50K miles on them. The shifter is pretty fresh, I replaced it with a new OEM one in 2014. Before I get flamed for using an OEM shifter I just want to say that I prefer the feel of the it. While many of my customer prefer shifters that have bolt rifle action, personally, I actually prefer the feel of the OEM that doesn't require ultra deliberate shift action. Its just a personal preference, that's all it is.

Okay, let's get down to business. For the transmission mount bushings, I decide to give the Cantrell Motorsport 85A durometer rating a try. I made dyno runs and logged the ignition timing with OEM rubber mounts before installing the stiffer 85A mounts to see if the stiffer mounts would cause vibration that the ECU might interpret as engine knock and pull ignition timing and reduce power. In the past I have seen first hand that on some cars stiffer trans/engine mounts caused ignition timing pull so want to be sure it doesn't happen on this application.

Here we are, getting prep for dyno for baseline. Had to remove the passenger seat now since I don't have retractable seats anymore.



Once passenger seat is removed this is a convenient location to get engine RPM reference for the DynoJet dyno.



Strapped down and ready to roll.



Logging ignition timing during the dyno runs.