03threefiftyz

iTrader: (25)

In an effort to cut down on the number of emails/PM's I get on the subject, I am going to chronicle the steps, parts, etc you need to be competitive in STU/BSP. Even though I have thoughts of running the Z in SSM in 2015, it will almost certainly be cannon fodder for the RX7's, Lotus's and S2k's.

Phase 1: Car Selection.

IMO, the 03-04 is the car to have. For STU, you will want a Base. Yes, it does not come with an LSD, but the VLSD should be discarded as soon as humanly possible. In BSP, the trim level is less important, all the differences can be discarded through update/backdate. Both Brian Peters and I have 03-04's. The power/gearing (higher rev limit) of the HR does not offset the weight penalty in my opinion, particularly in STR/U. In BSP you can use an HR motor in the 03-04 through update/backdate.

Phase 2: Diff.

As mentioned, discard the factory diff as soon as you can. Different diffs will require different set-up. It's best to set-up the diff first, then tune around the deficiencies with the suspension. You can, and likely will have to play around with the lock-up to achieve the best out of the diff. I believe BP is still using a quafie (torsen) and I use a Cusco RS (clutch type). IMO, you can get a torsen to work, but a clutch type is preferred. You must keep both rear tires planted at all times with a torsen. Unless you run very short shocks and/or soft front springs, you are most likely not going to get rear wheel lift in ST trim, but you WILL in big r-comp equipped BSP car. Obviously, it would best to keep both wheels on the ground in BSP as well, but the clutch type won't unlock the diff if one goes airborne. If you go around a corner and the rear wheel is cocked like a DS ITR, you have a major problem.
Final Drive: No update/backdate in ST means you are stuck with a 3.5fd in the manual cars and the 3.3 for the auto folks. In BSP, you chose either one. I use a 3.5 with a bumped rev-limit.

Phase 3: Wheels and Tires.

ST: Use what you can. The 350z is among the heaviest cars in both classes (STU and BSP). Now that the 350 has been re-classed in STU, you can run a max of 285mm tire and unlimited wheel width. You would be silly not to use as big a wheel as you can without having to exceeding the ST rules set for fender mods. In ST, you can roll the fenders, but the contour of the fender CANNOT change from factory trim. BP can chime in here, but I would bet the farm an 18x11 with a 285 will fit up front with a roll. Yes, it will rub. Yes, it will eat up the fender wells. Yes, you will need it to be competitive. A 10.5" would be the absolute minimum, but you really should try for an 11" wide wheel.
BSP Again, use what you can. SP cars are not restricted in the same way as ST cars for tire clearance. You can roll/flare to your hearts content. Unlike many cars, you are going to have major shock body contact before you will need to modify the inner wheel wells, which is good since it isn't legal in SP . There is a point of diminishing return, however. Since you can only go in so far with the wheel before it hits the shock, you will have to continue to push the wheel/tire out to get clearance. Making the car wider is bad. Yes, widening the track can be a good thing for ultimate grip and stability, but you don't want to make the car any wider than it has to be. This is why many mod, prepared classes now have track minimums (but I don't think there is a single class with a max). R-comps like some heat. Sizing can be a matter of heat management. If you run in a cold location, you are going to want an A6, but you may not be able to run a 315 and get enough heat in it to work. If you live in the southwest, you might not be able to keep a 315 from melting. It's a give and take. I like A6's in the 100-120 range...anything over 135 or so and they start to slime a bit. That said, they still work within a .1-.2 of max up well above that temp...they just don't feel as good doing it. In 2013, I ran a 315/30/18 A6 on all four with 18x11's up front and 18x12's out back. You have two choices on tires, the A6 and the R1S. The R1S was the upstart this year, but it simply didn't live up to the early hype. The R-comp classes were still dominated by Hoosier. That said, BFG has a better contingency for classes with lesser entries. It also can withstand higher temps than an A6. It is, however, almost un-driveable without that heat, whereas the A6 will work once luke warm. The V710 is also available, but completely obsolete at this point.
Both ST and SP: The tire construction will also lead to set-up change. The tire sidewall is a spring, and all construction is different. For example, the Dunlop Z2 has a much stiffer sidewall than the RS3.
Both ST and SP: Light wheels are good. Light wheels that break are bad. Go as light as you can, while have the peace of mind that they will stay together. Wheels wider than 11" command a premium most of the time. There are a few, Rota, etc that do have some 18x12 sizes.

03threefiftyz

iTrader: (25)

Phase 4: Suspension (Long)

Basics: Set-up and dial in will be in phase 7
Black Magic (Dampers):

1way=Low speed rebound. Most (certainly not all) off the shelf shocks (OTS) are single adjustable for the 350z. This includes all the JDM, Chinese, etc 20-7129827321way listed coil-overs. They consider a click of adjustment a "way." They have a single adjustment. That said, they have a ton of crosstalk. Crosstalk is when a change to rebound has corresponding change to compression (or vice versa). It is nearly impossible to avoid in a single. If a ton of time has been dedicated to dial it in, it won't be a huge negative. It can, and is, difficult to completely dial in a single suspension. There are times when you will want to dial back compression but go up in rebound, and vice versa. Generally on the singles, an adjustment up in rebound will also increase, in scale, compression. Examples of this type would be Koni Yellows, Ohlins DFV/Road & Track and all the cheap chinese coilovers (CCC's).
2way=Low speed rebound and compression adjustment. IMO, this is what you want for a competitive entry level shock. Ideally you want to limit crosstalk and hystesis as much as possible. Low speed adjustment is generally effective for shock travel up to 2" a second. It isn't that you can't change what happens after that, but this is generally the accepted low speed range. IMO, triple shocks, which have a separate adjustment to control high speed (2+" per second) are overkill for autox. Unless you run on very bumpy lots, have soft springs, etc, you are fine with doubles. Examples of 2ways are KW V3's, Moton Club Sports and Koni 2812's
3way=Low speed rebound/compresion and high speed rebound. Genearlly all the triples will be built to order and spec'd to your wishes. You are starting to talk big money at this point. Expect to pay $6000-$8500 for just the shocks. Examples: Moton Motorsports, JRZ and Penske 8760's.
4way=Low speed rebound/compression and high speed rebound/compression. Hugely expensive and difficult to dial in. Outside of some mod cars, I don't think I have ever seen a 4 way in grid on a fender equipped car. Expect to pay $8000-18000 for just shocks. Examples: Moton Motorsports, JRZ, Koni 2822's and Penske 8770's.
5way=Go to bed, you're drunk if you are considering putting 5 ways on an autocross car. Examples Ohlins TTX and Penske 8780's. You could put a down payment on a small family home for the price of these.

I will assume, for the purposes of this write-up, that you are familiar with what rebound and compression of the shock are. Later on, if this is still a question, I can and will add the material. In phase 7 I will go through and include what adjusting each does to the handling of the car. I do not plan to have a section on shock construction, how to valve, etc, but it can be added later on if need be. I would be more comfortable with a pro shock guy doing the write-up. Maybe BP can get Jeff Wong (Koni shock builder extraordinaire from Pro Parts) to chime in.

Springs:

Progressive-is exactly what it says. The rate of the spring will progressively (oh hey!) go up as the spring compresses. Some people use them...even successfully. I find them way to difficult to dial in. They also require some custom valving to work even remotely well in my experience. IMO, not worth the hassle.
Linear-Probably 98% of the grid (outside of stock classes) at Nationals will be on a linear spring. Linear meaning that spring is a constant rate (ex. 800lb) throughout its compression. The rate, ex. 800lbs, is how much force it takes to compress the spring 1".

You want to use springs (and to some extent, bars) to control the roll/attitude of the car, not compression in the shocks. It is equally important that the damper have sufficient rebound control to keep the spring from unloading too quickly. This will cause bounciness and "pogoing". Don't put a 1500lb spring on an OTS Koni yellow and expect it to be able to control the spring when it unloads.

Manufacturers-The big three in springs for race apps are Hyperco, Eibach and Swift. The Swift springs are the most expensive and lightest. Hyperco being second in that regard. You can get pretty much any diameter, free length and spring rate you want from these guys.

Spring Orientation-The rear needs to remain in the OEM location per the rules. So, unless your shock/coil-overs come with adjustable rear spring perches, you'll have to source them. You can buy these from Truechoice, megan, etc.

Sway Bars:

Sways are often a point of contention. Some use big bars on both ends, some use no bars, but most fall somewhere in the middle. As far as set-up with bars, I have never liked using a rear bar on the Z. I am pretty sure that Brian uses a small rear bar on STR, now STU!, car, but I think the rear traction at corner exit sans the bar is of more benefit. Of course if you decide to run no rear bar, you must compensate with spring, or the rear of the car will be disproportionately floppy. I find no rear bar, the front hotchkis in the middle (depends on surface) and moderate spring to be the fastest for me. The stiffness of the bar will come from where it attaches (leverage), length, overall and wall thickness. There is a point of diminishing return with wall thickness, and a substantial difference in weight with a solid bar. There is a niche group of racers who firmly believe in not using sways on race cars as well, but in all honesty, I've never run the Z without a front bar.
Options for bars include Hotchkis (what I use on front), Whiteline, Cusco, etc, etc.
End Links are open in both ST and SP, so you can use metal spherical bushings. Available brands include SPL, Whiteline, etc.
End Links should be considered a wear item and checked every few events that they are not seized or broken. It is just good practice to take a look whenever you change the wheel/tire combo.

Bushings:

Generally speaking, your aftermarket options are going to be some sort of poly or metal. Metal is not legal for ST/SP, so you can toss that from your mind. The third option, which is popular in autocross is Delrin. This is not an OTS option, and you will have to have them made. Downside to delrin is the they are HORRIBLE on the street, even worse than metal IMO. They also tend to wear, particularly if you do not use metal sleeves in the bushings. I would absolutely not recommend these on a dual purpose car (Street driving and racing). That said, if you plan to run seriously in SP, you should probably look into this option. Most poly (and rubber if stock) bushings will bind. Some worse than others. Believe it or not, aside from the upper front arms, lower control arms bushings and the rear camber arm, my bushings as of Nats this year were all stock, 110k mile rubber bushings. This was more a case of laziness than them being "better", though. I have begun swapping over much of the rear bushings (subframe, shock, traction arm, diff, etc) over to whiteline bushings. We'll see how they perform once March rolls around. Until then, I can't and won't recommend any bushing types.

IMPORTANT: The front lower control arm bushings should be check every 4-6 events. Particularly on SP cars, we absolutely kill these bushings. Both the DS G35 of PJ Corrales and my BSP car had the front lower control arm bushings collapse on us at Nationals in 2012. I know BP has also had some issues with these on his STR car. Do yourself a favor, like the sway end links, give them a once over when you change wheels/tires.

Control Arms:

In ST/SP, you are only allowed one adjustment for camber on each corner. That said, the most recent revision of the Kinetix front upper arms are LEGAL. Both BP and I agree on this. Same goes for their most recent revision of the rear arms as well. These will allow you all the camber you need. They are inexpensive. No idea of fragility, but I would keep an eye on them, particularly the SP gents. They are cheap enough that if they only last a season, they are more than worth it IMO. I used the rear arms for about 10 events last year, and had no issue whatsoever. The front kinetix is the only aftermarket front arm I have seen that is legal for ST/SP autocross. If you need clarity on why this is, ask below. If you choose not to use Kinetix, you are stuck with offset delrin bushings in your factory arms. They are a MAJOR pain in the *** to get installed, but do work. I was able to get about -2.7 up front using just them and a lower ride height. That said, they are not adjustable and do wear.
Since you can only do one adjustment, you are better off retaining the rest of the OEM suspension and just pressing in better bushings.

03threefiftyz

iTrader: (25)

Engine:

Intake tract:
ST: You can only change intake parts up to the TB, and it is not legal to modify, replace, etc the Maf housing or sensor. You should target mid-range and throttle response with an intake for ST IMO. In the long run, it will be of more benefit to gain 5-10whp in the mid range, then only to make 5-10whp from 5500 and up. The biggest increase in throttle response will be through tuning (car is throttle by wire), but you can further increase the response with an effective intake. I don't really have a suggestion, just get what is proven and works.
SP: Unlike ST, SP has MUCH more flexibility for intake mods. In fact, everything can be replaced up to the head (and you can actual port match an inch in the head as well). This creates a ton of options, such as ITB's, custom plenums, etc. Last year I campaigned with stock plenum (not ported or anything), a 5/16 spacer and a stock TB. This is definitely not the ideal set-up and it will hopefully be remedied by Nationals next year. My plan is to go to a worked, PnP stock plenum, with a port matched tb area and a larger TB. Replacing the TB can be hit or miss with the idle relearn, but IMO it will be worth it to compliment the increased flow of the plenum. I am also considering the Cosworth plenum....but I would want to test it head to head first. I also use a larger maf housing, Samco intake tube and a pop charger with a port matched velocity stack. In the works for 2014, is also a pseudo ram-air intake box for the pop charger. IMO, you can gain only a relative small amount through the intake, but you can really lose power if you don't test.

Exhaust (motor back):
ST: You can replace everything, but you must retain a 100+cell cat that is 6" or longer. Go with what is proven. Several good options, search here and find what works. Lighter is better.
SP: Basically the same, but a cat is not required.
Both: SCCA National events require that every car not be louder than 100db at 75'. This rule is strictly enforced! You will get warned twice, then DQ'd. You must make an attempt to quiet the car if you are warned. There is no real wording on what constitutes an "attempt", but it is in the rule book, so bring a turn down, steel wool, etc with you to grid if you know you are close. There are, however, a few sites where the 100db limit is dropped to 93db or less to keep local residents happy. You must plan accordingly and seek that information out! The two sites that come to mind are San Diego and Devens, MA. Last I heard, Devens may have to drop all the way down to 90db to keep locals happy, which is significant. With packed steel wool and a turn down, it is unlikely I can make 90db, so I won't be attending if that is the case. Again, I can't stress this enough, you must plan accordingly.
This year at Nationals, after blowing sub 95db on the West Course, I didn't bother bringing my turn down to the East Course. Huge mistake as I blew 100.6 and 100.5 on my first two runs. I was forced to pack the muffler with steel wool (big power loss) and a peice of fencing to keep it in to stay under on my third run. The result....99.7db on the third run. Do not do this to yourself, it is unneeded stress and totally blows your focus.

Fuel Mods:
ST: Only stock injectors, pump, etc. E85 has been banned from 2014 onwards in ST. Only some cars were able to take advantage of E85 with stock injectors, and it was seen as an unfair advantage.
SP: Fuel mods are largely open. You can replace the injectors, pump, etc. You can also put in fuel cell, but it must conform with the road racing GCR, which usually means roll over protection, etc. My car runs large injectors, pump and burns a prolific rate of E85. The E85 was worth about 12whp/10wtq over a mix of 93/100 on my BSP car. I currently use UPREV, which does not have flex fuel sensor integration. This can be a problem. You should always test the fuel prior to use and make sure it is within the range of reason. If your car is tuned on 65% ethanol (can still be labeled as E85) and you run on something in the 90+%....you will probably scatter the motor if it is tuned to the point of explosion on the 68%. E85 is also very corrosive to the fuel system, you will need to play close attention to the rubber bits and such.

Internals: Cut and Paste from the Rule Book:
ST: Same as Stock Class Rules...exert below:
"A. The engine air filter element may be removed or replaced provided
the air flow path remains as originally designed (i.e., no additional
openings). No other components of the air induction system may be
removed, replaced, or modified.
B. Engines may be rebored to the manufacturer’s 1st standard overbore,
not to exceed 0.020” (0.508mm). Sleeving is allowed to repair
to the standard bore. Only OE-type standard or 1st overbore pistons
of the same configuration and of the same or greater weights are
permitted. No interchange between cast and forged pistons is allowed.
C. Rotating and reciprocating parts may not be balanced.
D. Port matching is not allowed."
SP: "R. Cylinders may be rebored to no more than 0.0472” (1.12mm) over
standard bore and the appropriate standard oversize piston may be
substituted. This overbore dimension is an absolute limit; no additional
tolerance is permitted to accommodate wear. Cast or forged,
non-stock pistons of the same dimensions and configuration as original
equipment pistons may be used. Additionally the replacement
pistons must be of the same weight or greater as the original equipment
pistons. Replacement pistons must match OE piston configuration
exactly including quench area. The allowance for the use of
aftermarket forgings vs. OE castings does not permit alternate piston
dome designs. This allowance does not permit alternative ring configurations.
S. Rotating and reciprocating parts may be balanced but not lightened.
T. Intake and exhaust ports and manifold openings may be matched
provided no change is made more than one inch from the port/manifold
interface. Material may be removed to facilitate port matching,
but no material may be added.
V. The engine cylinder head(s) may be milled only to that amount specified
in the manufacturer’s workshop manual. If no amount is specified
then a maximum of 0.010” (0.254mm) may be milled."

I currently use a stock long block that is quite weak. I had considered an SP built motor, but the sig cost is not worth the few hp gained IMO.

Tuning:
ST: Only one you should consider is UPREV for ST class cars IMO. You will gain some power, throttle response and some other bits, but the most important is the bumping of the limiter. You will play with fire on the early cars once you get above 7200rpm. This meant a lot of limiter when the car run on shortish STR sized tires, but there are some taller options in STU trim, which should allow a few more precious MPH in 2nd.
SP: Pretty much open. I use UPREV and its been great. That said, I do wish it had flex fuel integration. There are other options that due this, like haltech, but they just don't work in as smooth a manor as UPREV IMO. Same as ST on the rev limit, even on taller tires you will be mugging the limiter in BSP trim with a 3.5fd and a safe rev limit. The last few years at Nats have had some serious speed on the East course. I bumped my limiter all the way up to 7450 this year, but it wasn't enough. I am considering building a 3.3FD just for Nationals. Huge expense and effort. Especially since both years the 3.3FD would likely hurt on the West Course.
BOTH: Find a quality tuner. I cannot stress this enough. The tune will only be as good as the guy(or gals!)punching the keys on the laptop.

Clutch/Trans:
ST: Stock. No clutch or flywheel upgrades allowed. OEM or nothing. Trans must be OEM as well. This means you cannot run a CD009 if you have an 03-04.
SP: Clutch and flywheel are open. This includes mini-clutches, etc. Trans can be done through update/backdate. There are some obscenely light weight mini clutches available, but they are a real ***** to drive. Having driven a few, I will take the weight penalty any day. They suck at pro's and are even worse trying to get on and off a trailer. I use the aluminum single OSG set-up. The whole clutch/flywheel assembly is almost 20lbs less than the factory flywheel alone. I am also still on the cars original CD001 trans.

03threefiftyz

iTrader: (25)

Phase 6: Weight Reduction, Interior and Aero(for SP)

03threefiftyz

iTrader: (25)

Phase 7: Making it all work

dmsec

What do you think of the Wavetrack diff's available for our cars now?

Here is a link explaining the set up, http://www.wavetrac.net/technical.htm, but basically it's a helical lsd that can still provide lock while a tire is fully unloaded. I have my own thoughts about this but would like to hear your opinion.

SmoothZ

iTrader: (13)

Interesting and good thread. I was always classed in BSP here. Didn't realize that it was so fine tuned for each class.

secwind

iTrader: (8)

Great info! Subed

03threefiftyz

iTrader: (25)

I got side tracked....will continue later today. I am not a fan of the wavetrac at all! Way too many failures.

PDX_Racer

iTrader: (2)

Or start with an '05 Track model, replace OEM tires with FAR better tires, replace shocks with good single- or double-adjustable shocks, replace solid front anti-roll bar with hollow bar set to full stiff.

It's worked for me. It's working for my fiancé.

03threefiftyz

iTrader: (25)

...I wasn't really including stock class.

GreyZ

iTrader: (2)

Subbed. Great Info

350z-Na

iTrader: (5)

sticky!! thanks for taking the time putting all that down.

03threefiftyz

iTrader: (25)

No update tonight. I'll try and add some more tomorrow. Sorry about that.

MisoHoni

It's as if you knew I'd be looking for this when you started to write it.

03threefiftyz

iTrader: (25)

I had a premonition....

Scabd

I had to post, strange thing is, I used to be in CS and when I did a couple of mods I got moved to CSP. How come some are being bumped to BSP? At the last race this year that was myself in CSP and another Z in BSP...I don't care if I am supposed to be in BSP, hell I beat the guy anyways

I was under the impression that C (class) always moved up within C (CSP, CP, etc) until the no longer apply and then move around from there (SSM, etc)

03threefiftyz

iTrader: (25)

No. 350z is not legal for CSP. You need to be in BSP. I keep neglecting to update this thread. Just been super busy. I'll work on an update here soon.

Scabd

The only thing I could find is that in 2012 all 350z's were moved from BSP to the new CSP. 370z's were left in BSP though. It was in one of the 2011 Fast track PDFs. I cannot find anything in the 2013 rulebook about how I'm supposed to know I should be in BSP instead of CSP.

SnoXRacer183

iTrader: (3)

Page 188-189 of the 2013 SCCA Solo Rulebook

370Z (all) ASP
350Z (all) BSP