jmckuhen

iTrader: (30)

Now before we get into the whole "increase driver skills" discussion, I am currently working on this. I am competing in all the auto-x's I can go to, ie every weekend, and attending schools (went to one last weekend). I realize that I have a few things to work on as a driver to go faster and I am. I want to know what are some good competative mods to make the car faster and handle better in BSP. Is anyone on here really competative in BSP that would like to give me some insite to building a competative BSP car?

I currently have:
Injen Intake
Topspeed Headers
Kenetix HFC
Nismo Exhaust
Crawford Plenum + Strut Bar
Koyo Radiator
PS oil cooler
Hotchkiss Sways (3/4 full stiff in front, full stiff in rear)
Koni Single Adjustable's(1.5 turns from full hard in front, 2 turns in rear)
Front Hawk HPS pads
Track edition wheels with 245/40 Front 255/40 Rear Falken Azenis RT-615's

Any help is much appreciated.

mpowers

iTrader: (7)

Camber kit for the front and kumho 710's. IMHO worth about 2-3 seconds on a 50 second course over your current set up. You'll need to retune the shocks and sways for this set up though.

jmckuhen

iTrader: (30)

I also think the tires are somewhat limiting for what I am looking for as well. What sizes would be good to run/can fit on the track wheels or should I be looking at getting a new set for just auto-x, if so what would be a good choice? What camber setting should I look to put the frontend at for more traction?

Thanks,
Vince

jmckuhen

iTrader: (30)

I like those wheels, but was really thinking about 17's since there is more selection of tires with 17's than 18's, they are slightly cheaper (tires as well), and tend to weigh less. I haven't really decided yet which is why I am open to suggestions. Thanks for the input.

mpowers

iTrader: (7)

I would look for a 17x9 wheel to run a 275 tire. This will also allow you to rotate the tires from front to back to keep the wear even and make for a less expensive size as well.
My personal prefernce on camber kits in the 350evo model. For autocross I would rec 3+ degress of camber on the front. But keep in mind you can't drive on the street with this much camber and expect to have a tire when you get home.

350Zteve

iTrader: (6)

Get some Hoosiers and some wide wheels and you will easily drop several seconds off your time. Some 285's all around will do wonders.

christoc

iTrader: (2)

What about changing your suspension setup a bit? Springs, Control arms, bushings, etc?

jun14scr

iTrader: (1)

What I noticed in your mod lists:
1. you need stiffer springs
2. race tires. race tires. race tires
3. the stock LSD is dirt, get rid of it.
4. you've done nothing to lighten the car up. although the 350 weighs
similarly to the the c4 in BSP trim (they are still lighter by a bit), they have oodles of more torque than us and we need to make that up as much as possible.

I love threads like these.. as I really want to build a BSP car and see what it could do at nationals with a top notch driver.. but I have no money. If I were to build a BSP car, this is where I would concentrate my money at firdst, in the order I would do so. There are also a lot of small details you can change in BSP, including more bushings than you know what to do with.

Here's the short version: To make YOUR car more competitive, you need r-comps, stiffer springs, more camber, less weight, and more power. a tad bit over 3000lbs and 300whp/300wtq.

To have a competitve national 350z.. this is what I THINK is necessary.

Wheels and Tires:
17x9 F, 17x10 R, custom, probably Fiske, CCW, etc.
Kumho v710's in 315 all around.
Fender modifications to allow for super wide tires.

Suspension:

Camber: 350evo a-arms in the front. Forgot the name of the parts that go in the rear, but traction arms, tie rods, whatever. The car needs more camber. ~-3.5 F -2 R, 0 toe all around.
Shocks: Pay a certain member on here to build a one off custon Ohlin DA shock absorber.
Springs: err, not too sure about what I'd do in here. Probably t2 springs from performance.
Sways: either, 350evo F and R bars with Nismo heim endlinks, or the complete nismo t2 package.

Safety:
-Lightweight bucket seats. recaro, sparco, whatever.
-Schroth ASM harnesses.
-Avalon harness bar.

Exhaust:
-JIC single exit Ti exhaust... or... again.. pay a certain member on here for his custom 11lbs TI cat-back exhaust system!!
-crawford headers
-whatever test pipes

Intake:
-some type of short ram intake, JWT popcharger?
-aftermarket intake manifold.. not just the plenum.. ie.. kinetix.

Engine:
-some type of reflash, custom ECU tuning, etc.

Drivetrain:
-kaaz 1.5 diff.
-aftermarket clutch
-lightweight flywheel

Brakes:
-350z track model brembo brake
-stainless lines
-whatever pads. hp+, carbotech panters??. cobalts v-spec.
-some type of aftermarket fluid.

Not sure if you can do a steering wheel since ours have airbags in them, but that'd be nice as well.

total cost... $20k.

jmckuhen

iTrader: (30)

Thanks for all of the replys so far. It looks like next I need to get some race rubber and have some way to dail in some negative camber. Is an aftermarket LSD legal in BSP? What about the 3.9 gears? What about a UTEC to tune? I forgot to mention I have the RSR Ti springs on the Z as well. As far a lightening the Z, it doesn't seem like there is much stuff to take off to reduce the weight enough to make any difference what so ever.

Next steps:
adjustable a-arms
rear camber adjustments (whatever they r called)
race rubber (275's all around?)
LSD?
3.9 gears?
UTEC?
Lighten the Z?

Am i missing anything, other suggestions?

Thanks,
Vince

FritzMan

Last year I was running a moderately modified BSP Zed quite similar to your setup. Hotchkis springs & sways (full stiff up front, med in the rear), Koni SA (one from full stiff up front and 3 sweeps from soft in the rear), headers, Y-pipe and Crawford cats, POP charger, plenum spacer, light weight battery, HPS pads with stainless lines and larger rotor with caliper bracket extender, harness bar with 4 point belts, 8.5" wide Rays Track rims all round with 255/40 RT615s all round). The setup was successful enough I'd frequently place top 3 raw time in a 35-45 car field and win a club championship a couple of years ago.

With the Nationals coming nearby, I stepped up to the plate and made the car more competitive, without adversely affecting the street ride. I've added Cusco RS LSD (60% lock-up), Cusco A-arms, engine damper, SPC cam bolts, Axxis Ultimate pads, 17x9 rims with 275/40/17 v710s.

The tires go without saying as an important mod you need. I'd say the A-arms and the LSD are next with an about equal time-wise improvement (about 3/4 second each). The LSD is a really nice improvement and lots of fun, but the transition from power on/off is definitely more noticeable. The Cusco A-arms are easy enough to adjust on-site and then reverse before hitting the street (remove 2 bolts and loosen 4 others, slide the arm, then reverse with the 2 removed bolts being threaded in a different hole). Ditch the HPS pads, they're garbage and lack initial bite (especially for the v710s). I have yet to run the 710s as I'm saving them for August but I'm hoping to see at least a 2 second improvement over the Azenis.

I wouldn't bother with the gears as the OEM 2nd gear is just about perfect for Solo2 courses and the 275/40/17 tire is slightly shorter anyways. UTEC is definitely a possibility, but the bang for the buck is starting to greatly diminish for Solo2 benefits IMO. I actually had a full set of Nismo hard rubber bushings I was going to install but when I realized the work and cost required for the marginal improvements I bailed. It's likely a worthwhile mod but the bang for the buck is quite low.

My setups is still clearly a compromise from full BSP preparation. I did run JIC FLT A-2 coilovers a couple of season ago but the street ride was too much for the pavement up here and the performance gains over my current setup was marginally better, if at all. With the Konis/Hotchkis, my car rides better than OEM on the street and performs better on the course.

ULLLOSE

Gear changes are not legal in SP unless it is an update/backdate, had to come on the 350Z at some point, if it is not a factory gear you are looking at SM2.
Also imho it would be a waste of money to go with the 275-40-17 in BSP,you would be on the same size tires as the fast BS 350Z, so you only would gain some wheel width. At the very least you should step up to the 285-30-18 or get into the 315 range if they fit.
The rest of the parts on your list are SP legal.

mpowers

iTrader: (7)

Actually thats not ture a 275 40 r17 has a wider section ( kumho v710 at least) width than the 285 30 r18 so it has more tread to plant to the pavement. You also need to remember that on a stock car the tire is crowned when you squeeze a 275 on a factory 17 inch rim. Yes it work but not as well as a tire on a properly wide wheel for the tire.
Now a 315 if they fit might be worth it, but doubt it. The slight gain in width would probably be negated in weight and effect on overall gearing. Not going to mention the cost difference.

mhoward1

If you are really serious, I would also look at changing the front seat to a full cometition FIA one. You'll be surprised how much more finess you will have when you aren't fighting to stay in place as much.

ULLLOSE

Section width and tread width are not the same thing. Look at the numbers: the 275 list the section width as 11.4" on a 10.5" wide wheel they then list the 285 with a 11.1" section width on a smaller 10" wide wheel. Put them on the same width wheel and the 285 will have the same section width and a bigger tread width. The 285 also turns in better due to the shorter sidewall. In back to back runs on a DSP BMW, 275 V710s on 17X9 vs 285 on 18X9 the car was a full second quicker on the 285. That time came from better turn in and the 285 has a gear advantage over the 275.

Using 245-45-17 as a baseline:

Tire Size Sidewall Diameter Circumference Rev/Mile Difference
245/45-17 4.3 in. 25.68 in. 80.68 in. 785 0.0%
275/40-17 4.3 in. 25.66 in. 80.62 in. 786 -0.1%
285/30-18 3.4 in. 24.73 in. 77.70 in. 815 -3.7%

I do agree that the 275 will be much better on a 9-10" wide wheel over what the BS guys have to do with it, but no way it will keep up with a 285-315 on a big wheel.

Also the 275 weighs 24.4 lbs and the 285 weighs 23.6 lbs. The 18" wheel might weigh a bit more but it would be about a wash.

So what were you saying about gearing and weight negative effect.

ULLLOSE

Section width has nothing to do with rubber to the ground....
Just to help you out:

The TireRack

Section Width

A tire's section width (also called "cross section width") is the measurement of the tire's width from its inner sidewall to its outer sidewall (excluding any protective ribs, decorations or raised letters) at the widest point. This measurement is made without any load placed upon the tire and after the tire has been properly mounted on its industry assigned measuring rim and has been inflated and reset to its test pressure after 24 hours.

Because a tire's section width is influenced by the width of the rim upon which the tire is mounted, the correct industry assigned measuring rim width for the tire size being measured must be used.

The width of a tire mounted on a narrow rim would be "narrower" than if the same tire was mounted on a wide rim. NOTE: because the overall diameter of a steel belted radial is determined by the steel belts, there is little, if any, change to the overall diameter of the tire due to differences in rim width.

The industry rule of thumb is that for every 1/2" change in rim width, the tire's section width will correspondingly change by approximately 2/10".

For example: a tire in the P205/60R15 size is measured on a 6.0" wide wheel and this size tire has an approved rim width range from 5.5" to 7.5" wide. The tire has a section width of 8.23" (209mm) when mounted on a 6.0" wide wheel. If that tire were mounted on all of the rims within its approved range, the tire's approximate section width would change as follows:

Difference from
Measuring Rim Rim
Width Approximate Tire
section width
0.5" narrower 5.5" 8.03"
Measuring Rim 6.0" 8.23"
0.5" wider 6.5" 8.43"
1.0" wider 7.0" 8.63"
1.5" wider 7.5" 8.93"

Because of the different wheel widths used in the above example, there is a 9/10" projected difference in tire section width when comparing a tire mounted on the narrowest rim to the widest rim within its range. This may affect fenderwell and frame clearances when selecting optional aftermarket wheel and tire packages

Tread Width

The tread width is the distance between the outer edge and the inner edge of the tread of a new tire. However today's radial tires often feature tread designs that incorporate rounded shoulders and there is no industry standard pertaining to "how much" of the rounded shoulders should be included in the tread width measurement. Because of this, it is difficult to accurately compare the tread width differences of one tire brand to another. Tread width measurements are best used when comparing the various tire sizes or lines manufactured by a single tire manufacturer. Several tire manufacturers have chosen not to publish tread width dimensions.

Luke@tirerack

Sorry Mike you're wrong (sort of) though not in the overall debate,

The Tire Rack site specs (which were based on projected widths) are incorrect.

Here are the facts:
275/40-17 = 11.4" on a 10.5" wheel
285/30-18 = 11.4" on a 10.0" wheel (The Tire Rack listed spec is 11.1")

so, on a 10.5" wheel the 285/30-18 would be 11.6"

but, I would run the 17" wheel and tire package on a 350 for a few reasons.

#1.) the 30 series 18" tire and it's inherent lack of sidewall deflection would reduce the contact patch at a faster rate under extreme cornering (sort of like a box tipping on to it's corner) where the 40 series 17" would keep the tread area on the ground more consistently (like a parallelogram)

#2.) most of the courses I run on would make the shorter 18" tire a detriment by causing another shift where the 17" tires would barely let me get to the rev limiter.

#3.) the ease of accellerating the shorter tire could cause more wheel spin exiting the slower corners (some times alot of extra torque can hurt your times)

Luke@tirerack

but, the 710 in question is VERY SQUARED off at the junction of the sidewall and tread belt package

Reyes_USN

iTrader: (5)

im gonna be tire shoppin soon, right now I got Yokohama es100's hows the kumhos ?

ULLLOSE

#1. Nice theory, but you use negative camber to make full use of the contact patch.

#2. The difference between the 275 and 285 would be about 2mph at redline in 2nd gear. Even if it means you spend more time on the limiter the added acceleration will make up more time than 2mph of top end, not to mention that the SP rules allow for ECU tuning that you can use to raise the limiter and get back the 2mph on the shorter tire.

#3. Tq is never a bad thing for autox. Part of driving the car is working the gas pedal.

Like I said back to back test same day on fresh V710s the 285 was a second faster than the 275 on a strut car just like the 350z is.