Monday, August 31, 2015

Lupa's Debut Event - Tuning Suspension

After months of installing parts and getting her ready, it was time for Lupa's first autocross in full STR trim. Although I had adapted a lot of Bumblestook's settings over to Lupa to try and mimic her balance, I knew it would take time to get her the way we wanted since we had no actual starting point to compare against. We were also on fresh RE71s that hadn't been fully scuffed in so their performance was going to be reduced. Still, it was time to focus on the important thing at hand which was to try and get the balance to a good starting point.

Lupa ready to run - NNJR SCCA - 8-30-2015
I took the first run as a general systems check to make sure there were no issues with the car. There was no rubbing and we were going over the undulations with ease. We were good to push hard now to find the limits. I immediately noticed a very large amount of understeer that needed to get dialed out ASAP. We softened the front shocks and Hez took it out for a run and it was a bit better but still pushy. We also started off running 33/29psi but started to decrease this delta to find the balance and gain traction. I brought my pyrometer but the battery ran out so we were adjusting pressures blindly here unfortunately.

We increased rear compression and added more rebound all around to try and find that perfect balance between being critically damped and keeping the weight where we needed it to be in the transitions and powering out of sweepers. The goal wasn't necessarily to get the fastest time as it was to push the car to explore the limits and make all the necessary adjustments to dial out any observed weaknesses. Every run Lupa was feeling more and more balanced and the setup was moving in the direction we wanted. On the final run, which Hez took, it was important to drive for time rather than for tuning so he drove it normally and set our baseline. We were only a few tenths off the fast STR cars at the end the the day. This is very promising. You can see the difference in how the car behaves in the video of our fastest runs. My time was set on my third run and Hez was on his last run. You can see how much less effort it takes to drive her fast in that last run. He looks like he's on an early morning Tofu delivery run despite clocking in a respectable time.

Our Fastest Runs - NNJR SCCA Autocross - 8/30/2015

I'm highly encouraged by Lupa's performance. She unfortunately still exhibits push under power coming out of the tighter turn arounds and could be faster in the transitions with quicker weight transfer. We also ended the event running as low as 27psi all around. That was just a bandaid to try and balance her out but I don't think this is ideal as I'm sacrificing some of that sharpness in steering. There's also too much rear toe preventing her from rotating under power the way I want. The RE71s also seems to not roll much under load so I think we can afford to reduce some of the rear camber and salvage some straight line speed.

Below are the changes I plan on making before her next event. I think she's going to be up there competing for the top spot very soon.

Sway Bars:
Front: 6/6 full stiff (current 5/6)
Rear: 3/7 stiffness (current 1/7)

Front: -3.1, a hair of toe out (current -3.1, 0 toe ....well actually unknown since it shifted due to tranny installation)
Rear: -2.2, 1/16" (0.06) total toe in (current -2.4, 0.18 toe in)

Probably try 29/27 but bringing a pyrometer to make proper adjustments.

Also, big thanks to Kamil at Clean Cut Vinyls for making my awesome car/class magnetic numbers and other decals.

NESTR - Decals by Clean Cut Vinyls - 8-30-2015
Magnetic numbers by Clean Cut Vinyls - 8-30-2015

Sunday, August 23, 2015

Countdown to Nats: Final Testing...All Systems Go

After the final once over and re-alignment at SJF Performance last week, it was important that we do one final test before making the long trek to Nationals. This was her first event this year on Ethanol so I wanted to make sure the tune was still good. We also had to scrub in the fresh Hoosier A7s.

NNJR SCCA - 8-23-2015
The first runs were expectedly horrible as we made our attempts to scrub in the fresh tires as quickly as possible. Balance was all over the place but they started to come alive after about 6 runs (3 runs each). We ended up settling on a 4psi difference front to rear and the balance was perfect. The tune was also still very good and we were able to effectively put power to the ground...well almost. The course today favored more softly sprung cars. There were just too many spots where we were trying to go flat out through some very bumpy areas of the lot and after going airborne once we had to dial it down quite a bit effectively killing our times. Hez was still able to put down 5th fastest raw time out of 139 drivers and 10th in PAX. I struggled with cones and ended up 8th in raw and 20th in PAX.

Putting the times in context of the course today I was still very happy. The new alignment is working out beautifully. Bumblestook is on point, changing directions at the mere thought of it and is perfectly balanced through sweepers. I think she's going to be perfect on the concrete flat surface of Lincoln. It's on like donkey kong. For now she's going to just hang tight until we do and we'll be taking out Lupa next week instead to have a bit of fun seat time before the big show.

NNJR SCCA Autocross - 8/23/2015

Sunday, August 16, 2015

Countdown to Nats 2015: Final Alignment, changing fuels, and more trailer prep.

I get an alignment before every big event but the last "big event" I went to was the NJ ProSolo in May and since then we had changed transmissions which required dropping the front subframe so this was long overdue. SJF Performance blocked off the entire Sunday for me in case we ran into any issues.

Final alignment before Nats - 8/16/2015
SJF Performance
I'm so glad we did check the alignment because apparently it was all over the place. Not enough front camber in the front left, lots of camber front right, toe out right rear, etc.

The pre-alignment numbers were insane - 8/16/2015
The wheelbase is a perfect 94.3" left and right
Looking back it's actually kind of nuts that Hez and I were able to put down the times we have with this kind of wonky alignment. The good news is that fixing this alignment means putting the setting back to "fast" and that's an exciting prospect. After re-adjust, the final alignment was:

-3.1 degrees camber
4.9 caster
0 total toe

 -2.5 degrees camber
0.06 degrees total toe in (1/16")

The next step was to switch back to running ethanol to maximize the power we make (just a 10hp/tq increase across the powerband). This involved draining all the fuel out of the tank which is thankfully is as easy as hooking up a 3/8" fuel hose to the return line on the flex fuel sensor and emptying it into a fuel container. In total we drained 7.5 gallons out of the car and put 10 gallons of ethanol in. #InsertCornToPlay

Tapping the fuel return line to drain the 93 octane fuel - 8/16/2015
Hez helping me drain the fuel - 8/16/2015
For even more speed, we mounted up a fresh set of 295/30/18 and 315/30/18 Hoosier A7s on the second set of CCW Classics.

Sticker set of Hoosier A7 - 8/16/2015
Lastly, since the tires on the trailer were looking a bit tired after 2 years and 10K miles, I swapped in a new set of wheels/tires all around.

Getting ready to mount new wheels/tires - 8/16/2015
New wheels and tires mounted on trailer - 8/16/2015
One last thing is that while the car was in the air,  SJF noticed some oil leaking around the oil pan. It turned out that the fitting coming from the oil catch can to my oil pan had vibrated loose. A quick re-tightening fixed that issue right away. We also changed diff fluids to make sure everything is nice and fresh for some serious throttle aggression on concrete.

I think we're all mechanically squared away for nationals. Weather permitting we'll be doing a final sanity check and scrubbing in the A7s next weekend and then onto the big show.

Saturday, August 15, 2015

Clutch, Tranmission and Differential

One of the major mechanical issues with Lupa is 2nd gear popout under deceleration. This is due to a known defect that affected a small range of S2000s between late 2004 and early 2005 and is covered by TSB 05-009. Unfortunately Lupa's VIN falls into this affected range of cars  but I didn't trust taking my car to any dealer even for warranty service so I had originally planned to just have the transmission rebuilt professionally by Billman. However, after we swapped in an AP1 tranny in Bumblestook, I already had a perfectly known working low mileage AP2 tranny just sitting around so I decided to just swap it in instead.

Transmission swap - 8/15/2015
This time I employed the help of Jonathan (Soul Coughing on S2ki Metro) to do the swap for me. Jonathan had already done several clutch, transmission and diff jobs before and as a fellow dual S2000 owner, I felt confident he could do the job right. While we were going to swap the transmission anyway, I decided that even though I only had 55K miles on her, it would make good sense to replace the clutch as well. We put in a brand new OEM AP2 cluch, flywheel, pressure plate and bolts.

Old clutch and flywheel out, still in great condition - 8/15/2015
New clutch and flywheel in - 8/15/2015

Lastly we also swapped in Bumblestook's spare diff pumpkin which has a new ATS Spec III clutch type diff put together by Brian at Karcepts. The OEM torsen is more than capable but I prefer the feel of a clutch type diff and by keeping Bumblestook and Lupa on the same setup, it would be easier for me to continue a similar tuning philosophy and have matching spare parts.

ATS Spec III diff ready to go in - 8/15/2015
When Rad found his diff mounts were torn during the NJ ProSolo earlier this year, he found a method to just fill the OEM mounts with polyurethane for a cheap DIY poly mount alternative. I had him make a set for me too and we installed those along with the diff to minimize any play as we try to get power down to the ground.

DIY Poly filled OEM Diff mounts - 8/15/2015
Although we ran into a few annoying issues (mostly because of my swaybars, stiff mounts and dual exhuast was in the way), everything went in smoothly and she's now driving perfectly. I'll have to get another alignment since you have to lower the front subframe to swap transmissions on the S2000 but I probably won't do that until after I come back from Nationals. The good news though is that she's ready for her first event which should happen in 2 weeks barring any further issues. I'll have to make time to drive her quite a bit until then to break in the clutch and diff but that's something that I can at least enjoy. It's been almost 3 months since I ordered the very first part for this STR build and I can finally say all the major mechanical work is done and it's onto having fun and seeing how she stacks up against the other STR cars that have had several years to be developed already.

Huge thanks to Jonathan for doing a great job with this part of the project, taking his time to do it right. It's good to see fellow S2K owners who appreciate the need to do things right and not take shortcuts.

Sunday, August 9, 2015

Countdown to Nats 2015: Trailer Prep

It's less than a month to go before the SCCA Solo National Championships in Lincoln, Nebraska. For me, this involves a 3000 mile round trip drive towing Bumblestook to and from this event. The last thing I need is a trailer break down somewhere in middle America so the first order of business is to get my trailer up to par. I bought my trailer new 2 years and over 10,000 miles ago so a good look at the brakes, bearings, suspension and tires is long overdue. I decided to take it to friend and NASA Honda Challenge racer, Spencer, to sort it all out for me since he has plenty of experience with this stuff.

Shackes going bad - 8/8/2015
Many of the bushings were worn pretty badly and the holes in the shackles were no longer circular, they had turned oval causing play in the suspension. The bearings were surprisingly still in good shape but with everything apart and the parts being cheap, it made sense to replace the bearings with new ones anyway and put fresh grease everywhere.

Bushings/Caps starting to crumble - 8/8/2015
In the end, all bearings, races, seals, bushings, shackles and hardware were replaced. The breaks were still in great shape so there was nothing to do there. The tires are also shot so I ordered new wheels and tires and will be putting that on before the trip. Big thanks to Spencer for the quick turnaround. This is one less thing I'll have to worry about on my trip.

Trailer maintenance done - 8/8/2015

First Alignment for Lupa

After test fitting the STR spec wheels and tires, it was clear that I'd need an alignment ASAP if I wanted to have Lupa drivable and not ruin my tires or fenders. With SJF Performance unavailable, I was lucky to get squeezed in for an appointment at Camber Toe Performance in Lynbrook this past Saturday. 

First alignment - Camber Toe - 8/8/2015
Photo by: Joe Miranda / Camber Toe
Since I haven't autocross Lupa yet, I wanted to just set an initial baseline alignment based on some numbers I had been toying around with on paper. I'm almost certain I'll be re-aligning again before this season was over so a good ballpark would be all that was needed. I ended up with the following alignment specs:

-3.1 Camber
0 Total Toe

-2.5 Camber
0.18 Total Toe In

I'm glad we did the alignment since I was running almost a full inch of toe in at the rear and definitely wasn't running enough camber up front so my fenders were in danger of some carnage if I got full compression load due to a bump or something. I also asked them to bend the fender tab in the front for a little bit more tire clearance. There's no need to do a full roll on +63 offset wheels with 255 sized tires.

We're almost there. I'm shooting to take her out to her first event later this month.

Wednesday, August 5, 2015

Wheels and Tires

After weeks of letting the springs settle and adjusting the ride height, I'm finally happy with where she sits so I decided to put on the wheels and tires I got for her to complete her STR trim. I didn't want anything expensive or too flashy for the wheels. I looked for something that came in the CR wheels silver color or something that would very closely match the Silverstone color of her body. I went ahead and picked up a set of Kosei K5R in 17x9 +63 offset in light gray.

Lupa in full STR trim - 8/5/2015
In pictures it looked like a good match but it was still a gamble since I hadn't seen these in person on a Silverstone S2000. I was pleasantly surprised to see that they were a perfect match and looked great without being overly flashy or attention grabbing. I was further happy to see that they came mounted with red anodized valve stems. It's a great complement to my black/red interior and soon to arrive red/black class letters/numbers.

Lupa in full STR trim - 8/5/2015
They're wrapped in super sticky 255/40/17 Bridgestone Potenza RE-71R all around. I could immediately feel the increased turn in response with the wider front tires. Next up is an alignment since the front isn't cambered enough and I'm going to have to bend the fender tab a little since it rubs a bit driver side but overall I'm very happy with the fitment.

Bridgestone Potenza RE-71R wrapped Kosei K5R - 8/5/2015
Not visible on the photos are the lug nuts. I went with EVS Tuning (Evasive Motorsports) "Super lap" open ended racing lug nuts made of forged SCM435 steel alloy since I don't trust aluminum lug nuts.

Sunday, August 2, 2015

Top PAX at NNJR SCCA Autox

Last event Bumblestook was able to set FTD with me behind the wheel and this past weekend, Bumblestook managed to nab top PAX out of 100 drivers with Hez at the wheel. It was a hot 90+ degree day so our tires hit optimal grip at the third and fourth runs. Hez was able to set his fast time on the 3rd run but I spun on my 3rd run tossing it away and finding no more improvement in subsequent runs.

Hez sets top PAX at NNJR SCCA Autox - 8/1/2015
In total we got 12 runs between the two of us and Bumblestook continues to show good pace and reliability. I think we'll do one more event before Nationals to scrub in fresh tires and switch to ethanol and we'll be all set.

Our Fastest Runs - 1st and 5th in PAX out of 100 drivers
NNJR SCCA Autocross - 8/1/2015