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350Z SCCA racecar

41108 Views 190 Replies 15 Participants Last post by  dkmura

This Z was built to compete in the SCCA Touring racing classes, and has the distinction of winning in three different Touring categories: T2 (2008-2012), T3 (2013-2015) and T1 (2015). Most of the mods are concentrated in the suspension, with Koni DA shocks, Eibach springs and fully adjustable swaybars. Enkei wheels and BFGoodrich R1-S tires provide the stick, while Cobalt Friction XR2 pads provide stopping power.

For 2015, we had success in winning the Rocky Mountain Division Championship in both Touring 1 and Touring 3. Traveling to Road Atlanta, the Z has won back-to-back Touring 3 titles the past two years in the American Road Race of Champions (ARRC).

There's still plenty of SERIOUS fun to be had with the Z33!
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Well, I'm back in Colorado and here's the latest from the SCCA Majors race at Pueblo Motorsports Park on Memorial Day weekend. I had two second place finishes in Touring 3, but have to say I was outgunned (out driven?) by two other T# Zs for most of those races. One was driven by a former pro driver and Runoffs champ, while the other is up-and-coming hotshoe. Since I'm also competing for a Rocky Mountain Divisional championship this season, I ran two additional races. This meant I had to go through the Majors impound (making sure I was over 3,450# on the scales each time), before being released to go back to my pit. There I refueled the Z, changed all four tires and got back to grid up in time to make another race each day! Happy to say I won both RMD races, but I was one tired puppy at the end of the weekend!

Here's a shot from the pits this past weekend- sorry I didn't have time to shoot any more, but I was kinda busy this time out!
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Now that June is here, new SCCA rules concerning the Z and touring classes will take effect. In T3, the rule makers are trying to slow the Z33 down so four cylinder cars (MX-5 cup, S2000, etc) will be more competitive. To continue racing in T3, I'll have to add the following parts to slow me down:

-Twin 40 mm flat plate restrictors for the twin intakes of the HR.
-245/40-18 tires vs. the 275/40-18 allowed previously.
-The only plus is the Z will be allowed to weigh 3,300 lbs, rather than 3,450.

I could also race one class up in Touring 2 (against Boss 302, Corvette Z06 and other V8s), but that seems to be a difficult transition as well.
The last of the mid-states Majors races is coming up in a few weeks. It appears most Z racers are opting for reclassing in T2, but that'll be a difficult conversion. At least for the near future, I'll try T3 and have a plan for the High Plains race. The 40 mm restrictors are being built and I plan to dyno them--before and after--when they arrive. I'd hoped to find some used 245-40-18 r-compound tires for use at this race, but no luck. I'll order a new set of BFGoodrich R1S tires for the July race. Finally, most of the ballast (both lead and steel) will have to removed from the Z and my standard race prep done in the coming weeks.
Spent the weekend making the conversion to the new specs in Touring 3 for my Z. I considered creating a new post about it, but didn't think people would want to read about (or see photos) how to make your Z SLOWER. The 40 mm inlet restrictors were sourced from a pro team and were beautifully made. Unfortunately, no dyno time was available, so factual data for the race is going to be difficult to come by. Still waiting for the 245-40-18 BFGoodrich R1S to arrive, but those should also reduce the grip available for another performance reduction. SCCA racing is kinda crazy, eh?
Such a beau!!!

Thanks for the props! Sometimes the most effective graphics are the simple ones.This is the eighth year I've campaigned this 350Z and pretty much stuck with the same color and graphic scheme. Fresh Redline paint for last season and had to source that NISMO stripe kit from Hong Kong, but otherwise, it's remained a consistent sight at race tracks here in the States.
The 2016 "Freedom Sprints" SCCA Majors race at High Plains Raceway was completed over the Fourth of July weekend. Saturday was a DISASTER as the Z would go into limp mode at various points around the 2.55-mile circuit. That meant checking the mirrors, pulling off-line and attempting to manually clear the codes. Of course, this screwed up my morning qualifying session and had me scrambling the rest of the day.

The key to understanding the issue was the two codes that continued to show up in my Cipher scans: P2101 and P1233. Both relate to malfunctions with the "electronic throttle control function" and are ones I've never seen before on the HR. But it was the bullet I'd feared: a malfunction from the installation of the 40mm restrictor plates. After checking and rechecking the installation, and multiple "test runs", it was obvious this was not a problem that would be easily solved.

The key to this mystery was checking with Bob Schader, my loyal opposition (and defending T3 National Champ) who also had to run the restrictor plates. The ones on his HR were much thicker- closer to 3/8" and had been fabricated by his chassis and engine builder. It wasn't until Bob recalled what Jesse Prather had told him that the light bulbs went off: the sweep of the butterfly plates had been interfering with the restrictor plates. Seeing this, the fabricator carefully built spacers to fit over the plates and allow the throttle bodies to fully open. BTW- no spare spacers were sent with the engine...

Bob Schader's T3 Championship winning Z

Slapping your forehead in the paddock is never pleasant. We went back to my Z and examined the throttle bodies (intake tube removed) with a screwdriver blade to confirm the hypotheses. Pushing the butterfly inward from the bottom, it only opened halfway before hitting the plate itself. Since all Z33's use a fly-by-wire throttle, the signal to WOT was being interrupted and the ECM would assume a problem had occurred and used limp mode as a safety measure. But with no spares available and no way to access a machine shop to built a proper spacer before the afternoon race, I was left with either withdrawing or trying to limp the car to a finish. I chose the latter.

We installed a padded throttle stop under the gas pedal and I'd have to limit how much input I gave to the pedal itself to prevent the butterfly from opening and striking the restrictor plate, but I chose to look at this as a driving challenge: could I drive the Z like a Spec Miata? Despite some hopeful signs, this race was a disaster: starting from the rear and completing the pace lap, I was sloooowly accelerating onto the back straight when limp mode hot at only 4500 RPM! With no one to avoid, I pulled off line and desperately tried to clear the codes with the manual on-off method. It took three full cycles before I got it restarted and was lapped in the process--but worse yet and despite my best efforts to be easy and progressive on the gas--the Z continued to go into limp mode at various points around the circuit.

Eventually, I pulled off onto an escape road and was told by the race stewards (via the ES crew) to retire the car, rather than risk a huge shunt with the car being stuck in the wrong place on this hilly track. It was the first DNF the Z had suffered in several years and meant an end to any Majors title aspirations I had. Schader took the Mid-States T3 title that day, and I was left to ponder what would have happened if I'd found some dyno time or spent the money for a short track test. This was the price for being ill-prepared.

Despite being tired and sweat soaked from a bitterly fought DNF, I had to think about the following Majors race the next day. Should I just give up and pack up? What were my options? Not being able to fabricate the necessary spacer to compete in T3, I decided to just remove it completely and change classes. While I'd be badly outgunned in a full T1 field, at least I'd stay in the same run group and find out if the throttle bodies were damaged in this restrictor plate debacle. The positive news is without the restrictor plates, everything went back to normal and the Z was happily screaming down straights again. Using older tires and finding a significant exhaust leak were not ideal, but I still finished fourth in T1 after one Vette retired with a blown engine. So, a bit of redemption from what I can only describe as a disasterous weekend racing the Z.
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Latest update is I've got 1/4" spacers in front of the air restrictors on the HR. Manually checking the butterfly chokes show no interference and so we've entered the next SCCA race at Pueblo Motorsports Park next weekend (7/23-24/16). Going to be a hot time down south at this time of the year!
Interesting reading!

I think the 245's will be ok (ish)
Interesting reading!

I think the 245's will be ok (ish)
That last sentence really bears some scrutiny. "OK-ish" should be divided into two categories: performance and durability. I think performance-wise, the Z will still be quick, even though the contact patch will become smaller. The bigger question is how long will those tires last? Some competitors will have 3-4 sets of tires PER RACE. Usually, I'll have one set of used tires for practice and a new set for qualifying. That new set will have to last for that race after a single heat cycle in qualifying.

It doesn't help that I've got several sets of good BFG 275-40-18 R1-S ready to use, since that was what the T3 rules allowed prior to June 2016.
Yes, that's exactly what I was getting at, should still be pretty quick but durability is absolutely in question and may force you to use a hard compound
(265 would have been safe)

I fully understand the heartburn around regulation changes making equipment and supplies obsolete - it's hurts

One of the categories I wanted to race my Z in has collapsed and no longer exists which is even more alarming (but I still have 3+ categories to choose from)
Getting ready for another race in the SCCA Rocky Mountain Division series this weekend. Heading down to Pueblo Motorsports Park to race on their 2.2-mile 13 turn high desert road course. Triple digit temps with dual layer Nomex suits, helmets and one HOT Z should make for a hot and sweaty good time. The cool suit is sure to get a workout this weekend!

I've also got those 1/4" spacers for use with the 40 mm restrictors this weekend. No interference with the butterfly mechanism when fitted, but we'll see how they do on the track!
The Z cabin is hot with the heat from the exhausts - I have not done anything about it (and don't have a cool suit)
That will be something I need to address next year
The Z cabin is hot with the heat from the exhausts - I have not done anything about it (and don't have a cool suit)
That will be something I need to address next year
If exhaust heat is really a concern, I've found ceramic coating the headers makes a difference. Outside that, you could try using some heat shield material on the underside of the chassis.

Speaking of heat, this past weekend was about six degrees short of ****. Pueblo was triple digit heat for Saturday's races and even the cool suit helped only so much. At least the spacers worked and kept the Z out of limp mode. But with the 40 mm restrictors in place, there was about a 20% reduction in power and torque. Combined with the 245-40-18 tires, it made the Z seem somewhat ponderous to drive. On Sunday, I switched over to T1 trim and pulled the restrictors. On old tires, the car was 2.5 sec faster in comparable conditions and lots more fun to drive. Left the track with max points in both T1 and T3, but I was a sweaty mess. >:D
Yes, I do have my headers ceramic coated

I know how you feel, when you get used to a certain performance it's a really negative feeling making and driving it slower
Wow- ceramic coated headers usually direct most of that heat out, but if the cabin is still that hot you've really got an issue. Does the cabin (and floor) get hot while driving, or only when the car sits?

After campaigning this Z for the past nine seasons, I've always "played by the rules". And as an SCCA tech official, I know the difference between stretching rules and downright cheating! So, I've added weight, taken it out and used different size tires depending on which class the Z was put in. But these air restrictors are attempting to make the Z into a "momentum" racecar and the nut behind the wheel is having a tough time with that...
It's hot as **** when stationary,
but on hot summer days I can't get the cabin temperature down
I'm going to need a fan and some ducting I think

Very frustrating trying to find a category to fit into and run at the cost and performance level you want to
Here's a shot from a summer race with the air restrictors and smaller tires in place. Had to run #1 for this race rather than my preferred #7 :

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This past weekend was the season finale race in the Rocky Mountain Division SCCA series at High Plains Raceway. My first race didn't start off so well- after qualifying third behind a GT3 Porsche 911 and T2 BMW E92, I suffered ABS failure at the high-speed T4 off the back straight. This was the result:

After putting up a big cloud of tire smoke before gathering up a HUGE lock up, it was surprising to find I'd held position and the Z remained drivable. Not that I recommend it- but I nursed that poor, flat-spotted tire over the rest of the race, but had a STU Lotus Exige on my six the entire time. Hard to believe, but I held him off after some good dicing on the last lap and finished in third overall.

Couldn't believe the damage when I got back to my pits, but that BFG R1-S was a tough SOB. It was very tricky modulating the brakes that race, and I made it my first priority to get ABS back on-line for the second race! The Saturday afternoon race went much better and I quickly put the Exige away with FOUR good tires and ABS in good working order
Sunday morning I started from the rear of the field as I hadn't arrived to do any qualifying and had a great time. The trick is to look for the right opening, get alongside the other car under braking, or use VQ power/torque where needed! After blasting through the ITC, ITS, FP and EP field, my goal was to catch that same Lotus Exige, which was now 15 seconds ahead in a 20 min race. The Z was in T1 trim with no ballast or air restrictors and was game to try! Lap-after-lap, I lopped away at the lead, until I could draft past on the back straight. Now that was a long cool drink of serious FUN!

The last race on Sunday saw our lap times fall off due to the 90 degree late summer heat. I ended up finishing second overall to the T2 BMW who was practically untouchable all weekend. As it was the last race of the season, it's worth recounting the results: six weekends, 16 races with 15 finishes- the only DNF due to a mid-season rules change and untested air restrictors. The Z once again showed incredible durability and took both the T1 and T3 titles in RMDiv racing. I still need to figure out the source of my C1109 ABS code, which continues to crop up at times. I don't want anymore of this (different angle):

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