steveP911

I have recently embarked upon a full engine rebuild for my 70K 2005 997.1 C2S due to evidence of evolving bore scoring and having the original IMSB. Details in the 997 forum (2005 3.8S Engine Rebuild - Rennlist - Porsche Discussion Forums). I am having it done by Slakker Racing (Hartech 3.6L->4.1L Capacity Conversion - Full Rebuild – slakker-racing-development (sr.dev)). Just forked over my 50% deposit, and I expect to ship the car there around October/November (time to clear their current backlog) and drive it home (1300 miles) about six weeks later. I elected to have the 3.8L to 4.1L displacement bump with the GT3 throttle body upgrade. I am estimating that will increase power by around 30 hp, and I assume a commensurate amount of torque increase. That was not my primary goal at all in doing this rebuild, but the cost effectiveness to execute these changes with the engine apart was too attractive for me to pass up. I have to admit I look forward to a bit more "go" on the track. To go along with that, I am having the Hartech deep sump installed along with a GT3 oil cooler (25% more area?). Engine is currently equipped with full AWE exhaust system (how I bought it seven years ago).

I am an intermediate (White) HPDE driver in the PCA Potomac chapter. Promoted this past March to White, previous March to Blue; spent one solid year in Green. I have done about 15 track days each of the last 3 (almost) years.

I have some modest suspension upgrades (997 Suspension Setup Advice - HPDE Driver - Rennlist - Porsche Discussion Forums). Tarett monoball plates in front. 3 deg neg camber in front and 2-1/2 in the rear. For this season, had Tarett rear upper control arms, rear toe control arms, rear thrust arm bushings, and rear toe link locking plates installed. This has made a significant improvement in stability of the rear during hard braking; I feel most of that is attributed to the locking kits which kept the toe settings from drifting. I have just worn out my Falken RT660 tires (255/35 front and 315/30 rear, 18's) and my Girodisc front rotors and Ferodo DS3.12 front pads. Standing by with Sebro rotors and Pagid yellow RSL19 for the front. I am using Motul RBF660 brake fluid.

I have a Titan rollbar, OMP WRC-R racing seats on BBi sliders, and Sabelt six-point harnesses. Cockpit Safety Upgrade - Black Friday trigger - Rennlist - Porsche Discussion Forums This was my first season with them and I am very happy with all of it. Continuing to use my Simpson Hybrid S HANS. Fire extinguisher attached to rollbar with quick-release.

Thanks if you read through this far - I had to post all that to be able to properly ask my question. Given the increase in power (modest), what advice do advanced drivers have for me to best prepare myself? I know it's not a huge increase in performance but I want to keep myself and others safe (so far so good), so I am very interested in tips for what to expect and how to better handle the car. Any thoughts on accompanying car updates? I was okay with the 200tw Falken RT6660's but I think they are slightly less capable than my previous 200tw Continental Extreme Contact Force tires. I have been thinking about 100tw Nitto NT01's and they do come in good sizes for me. Suggestions? Should I consider a better brake setup? I still use my PCCB yellow calipers which fit 350mm rotors. Any special training to read about or do?

I know some of you may think I am overthinking this and exaggerating the power increase, but I recognize that my top speeds are around 25+ mph more than when I did my first Green DE. I am already going faster everywhere and I just want to make sure I am managing this added performance as sensibly as possible. I really love doing this sport and want to keep it up as long as I can.

Many thanks.

LuigiVampa

Your braking and shifting points are going to change.

In addition, you want to be careful feeding in power coming out of a corner. If you do it too early you will delay going back to full power. If you have more power that slight bump on the pedal will delay you even more so make sure to wait until you can commit to a full peddle.

Others will have more technical stuff but I think this is the simple list.

nineball

i LOVE the NT01 but you better make sure you can get them in the size you want. the rears for my car are not available and a call to nitto a couple weeks back said they were only making the grabber series right now, nothing else, due to supply chain issues and need for those vs all other tires.

winders

30 horsepower? So you are going from nominally 350 HP to 380HP? That's not even 9%. You will not feel a big difference. Your shift and brake points may change but they may not. You are overthinking this. Just go out and drive the car. Start out on the first lap or two being conservative and get some heat in the tires. Then go drive feeling out the car...again as you should normally be doing. You'll figure it out. But it's not going to be a big change.....

Slakker

@LuigiVampa makes a good point. Do you have an LSD? It might nearly be a wash with the extra traction on corner exit if you added one.

I run Girodisk fronts on my 987 but I think the stock front rotors feel like the right balance on my 996. I run motul 660 and have never had any issues. But as for the best way to deal with more power on braking, trail brake the crap out of the car. They rotate like nothing else I've driven when you do.

For tires, I prefer RE-71Rs or I know several endurance racing teams that swear by the A052s. I've tried to love the NT-01s several times and just can't. The sidewalls are too soft for me.

You will love the 4.1. It adds a nice amount of punch without upsetting the balance of the car.

Frank 993 C4S

Sorry to say but you are overthinking this.

Olemiss540

Adore the lifespan of the NT01s and love how they like slip angle. If you prefer firm sidewall tires that like to be driven "neat" they are not for you. If you like to slide through corners they are a blast to toss around and last me a good long time (but the square tires help me with that).

Cheaper the rotors the better. I prefer centric or other generic blanks on rockauto or amazon.

LuigiVampa

I drive my 991.1 Cup a lot at Lime Rock and most days are muffled, which restricts my horsepower by about 15hp.

I absolutely notice a difference in my shifting and braking points when I drive unmuffled. On the Newman Straight (nee No Name Straight) I shift from 3rd to 4th about two car lengths later when unmuffled and the same on the front straight going from 5th to 6th.

Don't overthink it but also don't ignore it. The difference in HP will change some things and you need to be aware of it. It's not a stupid question.

winders

Two whole car lengths??

LuigiVampa

On No Name it is the difference between shifting when there is a hump in the track which upsets the car and on the front straight it is sometimes the difference between staying in 5th or going to 6th. These things can matter.

winders

It's not going to be a big change...it just isn't.

LuigiVampa

Does it have to be a big change in order to be an important change?

jdistefa

Yeah but are you adding aero?

steveP911

Thanks LV. The "delay" aspect you mention twice - is that because early throttle with more power post-apex could induce oversteer, and I will then have to lift? Or do you think I will initially find the "new" pedal too responsive for that condition? This was the area I thought might potentially be troublesome. Yes, simple advice is the best.

Thanks!

steveP911

Thanks. I checked at Discount Tire and the sizes I want (245/40 and 305/35) are on backorder, which could mean N/A indefinitely. I did find them shown as available at Summit Racing. But I would ping Paul at my regular tire shop - Radial Tire of Silver Spring MD - to be sure what is readily available and what is not. He is also very good at recommending track tires given the amount of feedback he gets from track drivers.