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heavy85

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Posts posted by heavy85

    Roll Cage

    in Fabrication / Welding

    Posted

    Yeah Jon there is rust hidden inside but it starts to show visible orange rust at the seams if you dont seam seal it.. I would paint first or primer or somehow coat the bare metal then seam seal then paint the seams again.

     

    Thanks Cary maybe Ill try the Hammerite to recoat the wheel wells

     

    Cameron

    Roll Cage

    in Fabrication / Welding

    Posted

    Yeah it seems good for interior and engine bay it just chips easily in the wheel wells. I also found out to make sure you seam seal everything first as rust grows quick between plates if they are painted only.

     

    Cameron

    Roll Cage

    in Fabrication / Welding

    Posted

    Re Zerorust. I used that and it seems to work great on the floorboards and engine bay BUT it chips really really bad when exposed to flying debris such as in the wheel wells. And yes I used the primer powder stuff they sell for it.

     

    Cameron

    spring rate changes

    in Brakes, Wheels, Suspension and Chassis

    Posted

    Search here for staggered. Yes it makes a difference and can be needed if you have enough power. Tuning is all about balance and theres a thousand ways to get there. If you have the wheels and super wide fenders big rears may be fastest but you have to setup the car o take advantage of it. I run softer rears but thats road racing not autox and i dont run a rear bar. No magic answer. If you have different offset wheels front to back even with the same tires (square tires but not wheel) simply switch them front to back and you can see the difference.

     

    PS - speaking of track does anyone know where one can get proper wheel spacers? Everything I can find are generic swiss cheese or super thick with the dual sets of studs. I just need quality basic 10ish mm spacers.

     

    Cameron

    spring rate changes

    in Brakes, Wheels, Suspension and Chassis

    Posted

    Like has been said first decide how far you want to take it. Making it not very comfy on the street vs cutting it up into a racecar is two totally different things.

     

    You say the back end has issues under braking? If so toe in is your friend. Helps drastically settle the rear under braking IME. 225/250 or vice versa can be very fast locally with a good driver. If you are still early in the learning how to drive curve < say 3 years of consistent racing then just tweak what you have and learn to drive it before going way stiff.

     

    Cameron

    Helical Limited Slip Function and Torque Bias Ratio

    in Drivetrain

    Posted

    I'm always confused when people say helical last forever as there are no wear parts. It seems to me the whole thing is a wear item due to the way it works?

     

    PS: I used to run the factory LSD out of an ~88 300ZX with unknown preload. Had a lot of problems putting the power down on corner exit without the rear end stepping out. This year I switched to an OBX helical. The damn thing looks like it was machined with a blow torch and was fully locked up when I got it due to manufacturing quality issues but after a nominal amount of work I got it in working order. I REALLY like it much better than the old clutch LSD. It allows me to plant my foot and hold it there much earlier in a turn without stepping the back end out. I think I can hear the gears working in the on slow tight turns but hasn't caused any known problems. Again I dont know the settings of the factory diff I was using but the helical for me performs comparatively mooch betta.

     

    Cameron

    Splitter idea

    in Windtunnel Test Results and Analysis

    Posted · Edited by heavy85

    FYI - I added a splitter. Made of 1/4" plywood as a test piece. Extends 2.5-3" in front of the airdam and back to the front swaybar. Dropped 1/2 second lap time with no ill effects. It was noticeable from the drivers seat in med+ speed sweepers and seemed to help braking as well. The cheapest 1/2 sec you'll ever find and it doubled well to mow the grass. Lets just say the splitter planted to front end so well that I could apply significantly more throttle in some turns. Pushing it too hard I power on oversteered ... cracked a rear stub axle flange. Now need to find a permanent material although it's got a nice natural green patina. :)

     

    Cameron

    Help broke 240z stub shaft - no spare and have race next weekend

    in Brakes, Wheels, Suspension and Chassis

    Posted

    You should look for a set of 280Z shafts. They are much stronger than the 240Z ones.

     

    Are they really stronger? I know they have more splines but more splines of the same diameter does not necessarily mean stronger. Mine broke where through the wheel / rotor mounting flange where it transitions to pilot the center of the rotor. The shaft and spline area are fine. I've been running these for ~30 days on a racetrack + street miles + several autox + however many miles they had stock when I got them ... behind an LS1. Reason I want to keep 240 is because I'm running 280ZX CV joints so have the companion flanges that match.

     

    PS - up until ~7 track days ago I also ran stock half shafts. Only issue is the mounting bolts would loosen VERY often. Never broke anything though.

     

    Cameron

    Help broke 240z stub shaft - no spare and have race next weekend

    in Brakes, Wheels, Suspension and Chassis

    Posted

    Like the overly long title says. Last weekend I did some agricultural driving at .. er off the racetrack. Just realized why one of the rear brakes are dragging. 0.1" runout will cause the rotor to rub on the caliper. Imagine that :). Well root cause is a cracked stub shaft. I have no spare stub shaft and last race of the year is next Saturday Oct 1. If anyone would be so kind to sell one or preferrably two 240z rear stub shafts I would much appreciate it. Need them early next week if at all possible so i can install and shim and prep for Saturday. Im in Decatur Illinois 62521.

     

    Thanks

    Cameron

    Where to focus to take it to the next performance level?

    in Brakes, Wheels, Suspension and Chassis

    Posted

    2011 Update:

     

    Hopefully my lessons learned can help get others up to speed faster so I thought I would post them up. I'm now running High Speed Autox with Midwest Council of Sports Car Clubs (mcscc.org). These are single timed laps from a standing start on racetracks. No cones just a full racetrack. Also running HPDE with NASA trying out new tracks. Road America, Mid-Ohio, Putnam Park, Grattan, Blackhawk Farms, Autobahn North and South, Milwaukee Mile. After about 30 track days I've come to the following set-up. Note that my philosophy is start with bare bones and add only what's absolutely necessary so each of these items has been carefully chosen based on experience and to lower laptimes and make it dead nuts reliable:

     

    - '72 240Z

    - ~2400 lb w/out me

    - 4-point rollbar

    - Full length subframe and misc bracing on the chassis

    - '02 LS1 from a Camaro - bone stock, zero problems except one thrown belt - these throw belts if you hold on the rev limited w/ stock tensioner, now use Katech tensioner

    - All systems from the parts Camaro - fuel system, throttle cable, wiring, computer, etc but DONT try to have the Camaro driveshaft shortened

    - Custom aluminum driveshaft (see above)

    - R200 rear - replaced bearings over the winter but have had zero issues other than wearing out the bearings

    - Former factory 3.7 LSD, now modified OBX - puts power down much better with the gear limited slip

    - Keep going up and now to 425F / 375R springs - puts power down really well finally

    - 3/4 or 15/16 front bar and NO rear bar - took the rear bar off last year and haven't looked back

    - ~1/8" front toe out, ~1/8" rear toe in - rear toe in settled it down under braking

    - Camber to match the tires - always at least 1 degree more in the front than the back

    - Caster ?? but moved the EMI camber plates back as much as I can and shimmed the stock T/C rod as much as possible without running out of threads

    - Hankook RS3 tire 255/45-17 tires - these are f-ing awesome tires

    - Champion three row radiator - ran the stock for ~2 years but could only run hard for a couple laps before it would get hot, now runs ~220 degF

    - Front end blocked up except fresh air and radiator opening

    - Mocal Engine oil cooler (came in a box marked FBI evidence ...)

    - APR rear wing with custom extra tall mounts w/ add 1/2" Gurney strip - steep angle of attack gets best lap times

    - 240sx rear brakes Hawk HT10 pads

    - Two-piece 12.19x1.25 Wilwood front rotors, Outlaw 1 3/8 four piston calipers, Hawk HT10 pads - Ultra lightweight rotors crack too easy

    - Front brake cooling ducts from airdamn

    - Super Blue fluid - never boiled fluid but didn't with Motul either

    - 280ZX CV half shafts - never had a single issue with the stock 240Z half shafts but the bolts would loosen after a track day

    - 3/4" 'bumpsteer' spacers, would probable run the 1" ones but had to cut these down to clear the 15" rims I run with slicks

    - Rod-end steering rods adjusted close to no bumpsteer, stock tie rods had a bunch of bumpsteer

    - Sectioned struts with Koni SA 1437Race inserts

    - EMI camber plates - these came with the car and if I had to buy would probably get something else

    - Front control arms ~ flat w/ ~1/2" rake with rear higher

    - Penzoil Platinum 10W30 changed every two track days

    - Custom PCV catch can - the LS1 sucks oil through the PCV system so keep an eye on oil level

    - LS1 also starve for oil especially on left hand sweepers so keep it 1+ quart over full mark w/ 2 quart accusump

    - Group buy Rota 17" wheels but switched the fronts to the rear and vise versa, if I had them I would run the rears all the way around

     

    So how successful is the set-up? I've won fast time of the day among ~70 cars and I was on street tires. Two track records for fastest car ever on street tires. Equal speed to Porsche GT3 RS on several occasions and they were on race tires. Faster than any stock C6 Z06 Corvette I've ever come across on equal tires, even with decent drivers. I'm now to the point the car is completely reliable, very well sorted, fast, and I'm comfortable running 10/10ths on courses I know well. Please dont let this come across as bragging because that's not the point. It's taken me three years of track events to get to this point so thought I would share the experience to help others get up to speed faster.

     

    Cameron

    Front wheel bearings

    in Brakes, Wheels, Suspension and Chassis

    Posted

    It's still being weird. If I backed off the nut enough so that it spins free there was a LOT of play, if there was no play it dragged pretty good. So I left it tight and took it around the block to bed the new rotors (live among the corn fields ...). When I got home there was a lot of play in the bearing so I tightened it back up and it seems to be normal now. Something was somehow hung up in there I guess. I disassembled and re greased and played with it a dozen times and it still did this. Hopefully everything is where it's suppose to be now and is ready to go. I guess the race next weekend will say for sure but I hate having crap like this in the back of your mind on track.

     

    Cameron

    Front wheel bearings

    in Brakes, Wheels, Suspension and Chassis

    Posted · Edited by heavy85

    It's been a long while since I've been on here but need some thoughts. I've replaced front wheel bearings multiple times over the years. But I just replaced them again (1.5-2 years racing / track days whether they need it or not) and the right front is normal but the left front is very tight if setting per the manual (22 ft-lb - 60 degrees). I even bought a second set of new bearings from a different manufacturer and they are still tighter than I'm used to. I know the races are completely seated and made sure the seal is all the way in. Anything I could be missing and anyone know more detailed specs other than the Haynes manual 22 ft-lb minus 60 degrees? How 'tight' is acceptable? Again I've done this numerous times and have never had this so am a bit stumped.

     

    Thanks

    Cameron

    280zx axle short vs long

    in Drivetrain

    Posted

    Swapping to 280zx cv axles. I notice the longer axle fits into the left side of the diff since it has the longer input shaft attached ... But the diff is offset to the left so the shorter axle needs to be on the left side. What am I missing or do I have wrong axles or something? Not sure if the longer axle will bottom out yet but measured and the right side definitely has longer span from the diff to the stub axles but the shorter axle has the proper input shaft to go into the right side of the diff????

     

    Thanks

    Cameron

    Pinion bearing preload?

    in Drivetrain

    Posted · Edited by heavy85

    Replacing bearings in the R200 and see there is no shoulder to press the pinion ball bearing up against. I dont have a FSM so does anyone know how you gauge how far to press the bearing in?

     

    PS - I'm installing an OBX at the same time and it's a real POS. Looks like it was machined with a blow torch but that's a different story.

    PPS - R200 bearings are just about unobtanium

     

    Thanks

    Cameron

    Tires to use for Hill Climbs

    in Brakes, Wheels, Suspension and Chassis

    Posted

    I say you need to pick your goals and budget. R compounds will be fast but wear fast and are not very robust to user error (i.e. lockem up and you flatspot them). 140 treadwear street tires are still relatively fast but last forever, give really good driver feedback, and are really quite durable to surviving user error. If this is your first attempt at racing I highly recommend starting on 140 street tires. I used to run slicks - not R comps but true slicks and they feel more numb and easy to flatspot and ruin and they wear fast. Last year I switched to a different class running street tires and am so glad I did. I'm running Bridgestone RE-01 (since been replaced with RE-11) and have ~11 track days, ~5000 street miles, and two parking lot autox on them and they still have something rediculous like 4/32" minimum tread left. I plan to run four more track days then switch to Hancook RS3 street tires for the first race this season. After reading much feedback is seems they are one of the faster street tires and as a bonus are by far the cheapest. Hancook RS3, Bridgestone RE-11, Dunlap Star Spec are all the top end street tires and I'm sure would work well for you.

     

    Also need to consider the rules and what class you'll be in. If you have some racing experience and want to be fast the hot ticket is the Hoosier R6 R-compound but expect to spend $$$$$.

     

    Cameron

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