thehelix112

Guys, I'm in the middle of doing the P30-0032 bilstein upgrade, and switching to coil-overs on my 280z. I just thought I'd document what I've done so far here. The parts: From A1 Racing: (http://shop.a1racing.com/) - Threaded Alu sleeves: 4 x COK12452-H @ USD18.80 ea - Lower spring perch/nut: 4 x COK12460-B8 @ USD12.87 ea - Coil-over top: 4 x COK12465 @ USD13.08 ea From MJMAutoHaus: (http://www.mjmautohaus.com/catalog/product_info.php?cPath=2_12_37_71_293_4710&products_id=1995) - Bilstein P30-0032 shocks: 2 x P30.0032.SET @ USD199.95 ea From SummitRacing: - Front QA1 10" 275lb/in springs: 2 x HAL-10-275 @ USD37.88 ea - Rear QA1 10" 250lb/in springs: 2 x HAL-10-250 @ USD38.88 ea From Motion Industries: (https://www.motionindustries.com/mot.../mi/motion.jsp) - 28mm OD, 15mm ID bearing: 2 x FNT 1528 BRG @ USD3.49 ea - 28mm OD, 15mm ID thrust washer: 2 x LS1528 @ USD7.62 ea From Reid Supply: (http://reidsupply.com/detail.aspx?R=DM-14028&ST=Drill%20Bushings) - 22mm OD, 14mm ID drill bushing: 2 x DM-14028 @ USDnotmuch The tools: This assumes a general toolkit with appropriate spanners, sockets, drives and ratchets. Additionally helpful is: - bench vice - angle grinder with cutting and grinding discs - large pipe cutter (I got one that does up to 2-1/8") - 1" drill bit (had to order online) - 13mm or 1/2" drill bit - M14x1.5 tap - half round file - hack saw - welder The procedure: Preparation: Step 1. Remove front strut. Make sure you loosen, but do not remove(!) the top damper nut while the assembly is in the car as its much easier to hold. Step 2. Remove the top damper nut. The stock 280z assembly is preloaded so it explodes as the nut comes loose. So don't be sitting there looking directly down at it. Step 3. Using multigrips (aka channel locs), undo the damper gland nut and remove the existing insert/original body. Step 4. Bolt the assembly into a vice of some sort to make it easier to work with. You can remove the brakes to make it lighter but I was too lazy. Strut-tube Modification: Step 5. Using a thin cutting disc on an angle grinder, cut the stock lower spring perch off. Do not cut into the strut body, I cut 6mm (1/4") above the weld to get enough distance. [/u] Step 6. Using a grinding disc, grind down the remaining spring perch and weld until it is flat and the threaded sleeve can easily slide past where the weld was. Step 7. Slide the threaded sleeve down until the top of it is 2-1/4" down from the top. Scribe a mark around the entire circumference of the strut tube using the top of the threaded sleeve as a guide. Remove the threaded sleeve. Note: Don't worry, you are not going to be shortening the struts 2-1/4". The female carrier that comes with the Bilstein dampers will be welded onto the strut tube, adding an extra 3/4". So we are taking 1-1/2" out. The reason this is done instead of sectioning the struts in the typical fashion is that Bilstein do not make a gland nut in the M52x1.5(?) thread to suit the 280z struts, so we use the female carrier that comes with them instead. Step 8. Using the cutting disc, cut anywhere between 1/2 and 1" off the end of the strut. This does not have to be particularly neat, a few mm difference is acceptable. You will be using this off-cut later to stop the threaded sleeve sliding down. Step 9. Cut the strut tube at the mark scribed in step 7 using the pipe cutter. Advice: on the first orbit of the tube, watch the cutting wheel very closely to ensure it follows the scribe precisely. If it does not meet up with itself it will tend to try and work its way down the tube cutting a very shallow thread. Do a few orbits in between tightening the pipe cutter. Step 10. Cut the cut-off from step 8 into three equal concave shaped sections (roughly every 120 degrees). Step 11. Put the cut-off from step 9 into the vice and individually beat each of the three concave shells until they fit nicely against the outside of the tube. Female Carrier Modification: Step 12. Using the cutting disc, cut off the smaller diameter section (on which the PN is stamped) of the female carrier. Do not overcut into the conical (tapered) section. Step 13. Using the grinding disc, carefully grind down the remaining small diameter section until the carrier ends at the end of the conical section. Step 14. Using the round file, file the inside of the carrier down until the damper body can fit through it easily. Advice: use the internal steps as a guide as to how far you have filed. Coil-over-top Modification: Note: Unfortunately, the coil over tops I ordered from A1 racing are clearly not meant to suit the P30 bilstein damper. They require very minor modification. Step 15a. Place the Torrington thrust washer on top of the coil over top and grind down the coil over top until they are both level. Step 15b. Cut the drill bushing into 4 10mm long sections. These spacers centre the coil over top on the Bilstein damper. By making them a little longer than the thickness of the coil over top section, means that when installed the section clamps down while leaving the coil over top free to rotate on the torrington bearings, and keep the steering nice and light. Strut-top Modification: Step 16. Put the strut-top in a vice, and using a stanley knife, trim the downwards-protruding rubber lip off 6mm (1/4"). Step 17. Using a 13mm (or 1/2") drill bit, drill out the D in the strut-top. Step 18. Using the M14x1.5 tap, tap the hole in the strut-top. This, while perhaps not absolutely necessary, prevents the threads on the damper from being damaged by pressing against the metal in the strut-top during side loading. This helps hold the damper piston stable whilst doing up the top nut later. Additionally, it simplifies preloading the spring, as the top can simply be wound on an inch, providing around 275lb without necessitating spring compressors. Welding: Step 19. Get some 1-1/4" OD Alu pipe from which to make the spacers. I initially tried 1 1/2" but it was just a fraction too big to fit through the carrier. On my struts the fronts needed a spacer 9/16" long. Don't forget to test the assembly to ensure the spacer length is good. The gland nut should go solid with between 1 and 2 threads showing. Additionally, this locates the strut housing neatly in the carrier, and should provide additional lateral support. Step 20. Tack-weld two opposing sides (12 o'clock and 6 o'clock) of the female carrier onto the strut. Slide the threaded sleeve down to check that the top of the female carrier is even with the top of the gland nut all the way around. Tap with a hammer and/or re-tack as necessary to get this correct. Slide the threaded sleeve off. Step 21. Weld the female carrier onto the strut body. Step 22. Grind the new weld down to the tube OD until the threaded sleeve can slide on again. Step 23. Position the threaded sleeve so it is flush with the top of the carrier. Tack the three concave shells from step 10 at even intervals around the tube at the bottom of the threaded sleeve. Put the side of the shell with the thread against the sleeve as this side was the former strut top, and is perfectly flat around. Step 24. Slide the threaded sleeve off and weld the shells onto the tube in the lower and vertical sides. Do not weld the top as this flat step is what we want. Step 25. Splash some paint on the cleaned up struts. Installation: Step 26. Rub some grease around the tube and slide the threaded sleeve on. The grease will not only help installation, but will provide some corrosion resistance, and thermally connect the strut tube with the lovely heat-dissipating threaded sleeve. Anal-retentive much? Screw on the lower spring perch and put it all the way to the bottom. Step 27. Install the alu tube spacer and damper, ensuring the spacer is sitting correctly vertical. I was a little worried about the strut being supported at the bottom, so I drilled a couple of holes in the solid alu spacer the same diameter/spacing as the holes in the bottom of the strut; and put some small dowels between the two. Hopefully this will make the strut less likely to wobble around during cornering. Step 28. Using either multigrips (channel-locks?) or the Bilstein part number: E4-MS-08/7 (USD4.93 from Bilstein aftermarket) tighten the gland nut down, checking that between 1 and 2 threads still show when fully tight. Step 29. Install the spring preload bearing onto the lower spring perch. Then cut the lower 4 rings off the dust boot and slide the spring over the damper, being careful not to needlessly bang against the damper piston. Step 30. Slide the 10mm spacer, coil-over top, thrust washer, large washer, needle bearing, and remaining washers onto the damper. Step 31. Install the strut-top (with the bearing) by screwing the strut top onto the damper thread, and do up the damper top nut. Important: Check that you can hold the strut top, and rotate the coil over top and spring freely. If you have made the 10mm spacer less than 10mm, then the coil over top could be clamping against the damper top and jamming. Guess how I know. Step 32. Install the whole assembly back into the car. Phew. Dave

ktm, I thiiiink the two are related. The larger the volume the slower the air flowing through it according to the venturi effect. The larger the volume the lower the pressure and heat according to the ideal gas law. When I got my GT358R there was no divided turbine housing available? Is there now? I have considered extending the dividing material at the flange out and into the turbine housing though. Obviously this wouldn't be a perfect seal, but better than as is. I would also be wary of putting non GT-generation turbine housings on a GT35R. The GT housings are far superior than older housings due to the increased nickel content, especially so the GT35R. If the option had been available I definitely would have gone for it! I'll try to dig up a pic of it. I didn't make it, I got it from an experienced TiG welder who made it for his 240z race car. Dave

A divided manifold will yield improvements regardless of the turbine, as what it achieves is keeping the pulses from the engine from interferring with each other as long as possible. Of course this is even better with a divided turbine housing as well. I run a divided manifold with the GT3582R with 0.82 A/R T3 turbine housing. A T4 housing has a larger inlet, so the airflow will be slower for a given volume, so the boost threshold will be higher. Dividing the pulses in both the manifold and turbine housing I would expect to bring the threshold down a small amount. I have no idea on the quantities of these increases/decreases, and hence now idea how a divided T4 would compare with a non-divided T3 housing. Dave

I agree, great pics! Dave

The air there will be high dynamic pressure, low static pressure. What that means is that the air has more total pressure because the energy driving the car forwards is forcing it to accelerate up and over the bonnet. However the only way you will get it from dynamic to static pressure is by providing a restriction. One way to accomplish that would be to box the filter and run the duct into it and make it air-tight. However if you do that make sure that the exit of the naca duct is the same size as the intake piping, or you'll be choking the intake at low speeds. I think. Dave

*has his fingers crossed for you*

That makes sense, I just wanted to be sure I understood what was happening. That also makes sense. Cheers. Dave

Jon, Correct me if I'm wrong, but Ortiz did say that you can alter the locking torque for decel and accel with CLSDs independently. So you could set it up for the track I think. On a short tight twisty (autox?) you would have high decel locking torque so the inside tyre dragging as you say creates a yaw moment into the corner, and hence improves turn-in. I think the accel locking torque is always going to be setup depending on how the weight transfer affects the torque required to get longitudinal slip in the tyres. I guess I'm confused why a HLSD in this situation would provide better turn-in? Maybe I'm misunderstanding something. Does the CLSD in decel locking try to turn the car out of the corner? Dave

Looking good dude. Can't be far behind Austin with a startup? Dave

Definitely unique, but should work well. How did you paint the bay? Do you have a spray gun etc lying around or? Dave

Thanks Justin, Jon, I appreciate it. I will order one tomorrow. Myron, Dave

Hell no. I don't wanna scratch them. Dave

Guys, I am in the process of installing the Bilstein P30 dampers, but they did not come with a gland nut spanner, so I can't get the existing dampers out, nor install the new ones. Does anyone have either a, an old bilstein gland nut tool lying around they're never going to use again, or b, know where I could purchase one? Many thanks, Dave

I think its relatively save to say that might increase the rigidity.

Nice work Tim. I read something recently in a car mag about Viton degrading with E85 over time, but haven't found anything else to back that up. I presume you did some research on this? FWIW, if i remember correctly (been a while) my setup (stock L28ET) makes 19psi by 4600rpm in 1st with the GT35R and a 3.54:1 diff. I'm also curious how/when the boost comes on with your setup Tim. Got a boost curve for lower gears? Dave

Myron, Personally, I highly doubt the roll pan is contributing in any significant way to the amount of drag on the car. By the time the air gets back there its all completely turbulent and crap anyway. IIRC, the lower edge of your fuel cell is at or below the level of the bottom of the roll pan, so cutting it out isn't going to gain you much where the fuel cell exists. What could provide some benefit I think, it creating two channels on either side of the diff/fuel cell that head forwards and down to the front pivot of the rear LCA. Combined with a flat undertray all the way from the front splitter this I think would have positive effects. BTW, I have two quite good books on aerodynamics I could lend you if you don't have them already. J. Katz's `Race Car Aerodynamics' and S. McBeath's `Competition Car Aerodynamics'. Lemme know and I'll bring them over sometime. Dave

Any footage with sound? Or is it just me that its not playing sound for? Dave

Another thought that just occurred to me, is that when there is resistance (like you're in a ~1G turn and having to apply a fair bit of torque to the steering wheel to hold it steady) that maybe that vertically mounted rod end will end up wobbling from side to side? Something to do might be to lock the wheel in one position, somehow, then try to turn the steering wheel and get someone to observe how much (if at all) it flexes. I'm not trying to be a downer, but safety first. It might prove necessary to get a weld-in rod end and fabricate a small box that goes between the frame rail and the strut tower. Dave

Fair enough. Dave

Is there enough room to do a right angle forwards from the cutoff and into the cowl area racing towards the driver's side and then have the T/B, MAP, air filter all one after the other? I have a pic but can't attach it to this thread for some reason? Dave

I agree. Anyone read the latest road & track (Nov 08)? They compare tuned GTR, NSX and 997 Turbo around Streets of Willow Springs. Highlights: The 997 was built by TechArt, had larger turbos, exhaust manifolds, intake manifolds, remapped ECU and produced 630hp. Lest you think this car was setup by a bunch of fools, it had just finished competing in a 4000 mile cross-country race, driven by Lewis Hamilton I think. Maybe the recent hard use would have a negative impact on its performance? It lapped in 1:29.06 versus the stock 997 turbo 1:30.69. The GTR, by comparison, had a custom Mines's ECU, and an exhaust: 550hp. No larger turbos, no custom headers (the turbine housing is integrated into the exhaust manifold I think). The author notes here that the tyres had a number of hot laps on them and were well worn. Pity they couldn't describe the 997's tyres for us. It lapped in 1:25.79. 3 and a bit seconds faster than a car with reputedly 80hp more and 250lb less. It also did 0-60 in 3.0 (!) and the 1/4 in 11.1 @ 127MPH. This I find completely freaking staggering considering: It only had an ECU and exhaust modification for christ's sake! Can't wait to see how the non-entry-level GTR, aka V-Spec, which some places are reporting (http://www.themotorreport.com.au/3869/nissan-r35-gt-r-v-spec-update/) will see 550hp stock, and in the order of 300lb less weight (its a 2-seater). Holy crap, I sound like a fan-boy. Dave

Nice. Dave

You're a freaking machine. Stop doing stuff, honestly, you're making the rest of us look bad, or in some of our cases, worse. On topic, I'm confused why you made it extend forwards so far. It looks like it clears the engine mount by miles now, but the angulation on the u-joint along side the mount (on top of the rail) looks quite high. Did you do that to clear the planned headers or? I'm sorry I have nothing useful to contribute. Dave