BenOtomoto Posted October 16, 2007 Share Posted October 16, 2007 Hi all, this is my first post, but I thought I might as well make it a big one. I've owned a five S30-shell Zs to date, including one that was featured in Zoom magazine here in Australia, with a Toyota 1JZ-GTE engine. You can see it here: I sold this car three years ago to a guy in the UK, you can see him driving it here: Anyway after a year or so I decided it was time to start a new 240Z project, but this time my inspiration was the super lightweight drag cars I have seen in Japan. They have the best-sounding L-series engines on earth, with really light cars recording low tens naturally-aspirated. I had planned to build a tough NA engine years ago, but couldn't afford it. Now that I can, I decided to get the best of the best. I gathered some key parts and sent them off to Stewart Wilkins, who is a bit of a legend with Zs in Australia, especially preparing and racing rally cars. The engine is based on an L28 block, with an LD28 crank, L24 rods and 89mm pistons. The head is a P90A, heavily ported with Stewart's favourite cam, Tomei valvesprings, metal head gasket, modified sump, custom harmonic balancer and so on. I have a six-throttle injection set up from Japan waiting to go when everything else is finished. It won't be quite as crazy as the Japanese drag engines, as I want it to run on 98-octane pump fuel, so compression is only 10.5:1 and the rev limit will be around 7000rpm. The next problem was finding a shell. I found this car which seemed fairly original and straight, but as is often the case there was plenty of hidden rust. The rear wheelarches and sills were pretty bad, so we welded in new panel sections and lower sills. Some holes in the top of the sills had to be fixed too. There was rust above the tail lights as usual, so this panel was replaced too, along with large parts of the front floor The shell unfortunately had an aftermarket sunroof fitted. To get rid of this, I had a friend make a mould of a good roof and then produced a carbon fibre roof skin. We cut out most of the original roof and bonded the carbon skin in place Inside we welded in some bracing to stop the chassis flexing around the C-pillar. The rear towers are braced too, with mounts added for four-point harnesses. The engine bay was not too bad, but we had to weld up a couple of holes and also added more welds to the rails to improve rigidity, with diagonal braces inside the wheel arches As for the other panels, the front fenders and rear hatch are fiberglass (Australia), the doors are fiberglass (Japan) the hood and bumpers are carbon fiber (US), the dash is fiberglass (Australia), and the side and rear windows will be Lexan acrylic. I also picked up a pair of Bride Holding Monster seats which fit well. I don't plan to fit a full cage just yet, but I will add some side intrusion bars. I intend to use the car mostly for tarmac rally type events and a bit of drag racing. The engine is in the car now, here it is still on the crane with the OS Giken twin-plate clutch fitted. The car already has a close-ratio 71B gearbox, which I will keep for now. The rear end will be swapped for an R200 LSD and CVs from a DR30 Skyline (FJ20ET engine version). I'll follow up with more photos when the car is painted and going back together. Cheers Ben Ellis Quote Link to comment Share on other sites More sharing options...
BenOtomoto Posted November 27, 2007 Author Share Posted November 27, 2007 I just got the shell back from the paint shop. Looks pretty good so far. The rear wheel arches came up a lot better thanks to the work done by the shop (I'm not a pro). I'll be fitting the carbon fiber hood and bumpers later this week. I also have to get the new windows made (glass is much too heavy for this car). Feels like I'm on the home stretch now. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 27, 2007 Share Posted November 27, 2007 How much weight did the CF roof save? Quote Link to comment Share on other sites More sharing options...
BenOtomoto Posted November 27, 2007 Author Share Posted November 27, 2007 Only a couple of pounds, I mainly did it to fill the sunroof hole. There's still six inches of the original metal skin around the edges of the roof. Quote Link to comment Share on other sites More sharing options...
BenOtomoto Posted January 21, 2008 Author Share Posted January 21, 2008 Some more progress on my 240Z project. I've attached most of the new panels. Unfortunately the doors won't fit properly with door rubbers in place, unless I modify the rubbers. Likewise the rear hatch. In the photos the new acrylic rear window isn't properly in, but I'm hoping I can fit it with the standard seal. More disappointing is the Hartman carbon fiber bonnet, which has a big curve on the right side making it sit up too high and also making it half an inch too short on that side. I will have to cut the frame underneath to reshape it. The carbon bumpers were very difficult to get in place, but they do fit properly at least. You may also notice the headlights, which are halogen units made by Raybrig in Japan. The blue tint to the reflectors looks pretty cool I reckon. The Bride seats went in quite easily in the end, using some generic rails which keep them nice and low in the car. I also bolted in a set of 3-inch four-point harnesses. The fiberglass dash was fairly easy to fit with some hand-made brackets and the original instruments fit too. I used a fiberglass vent panel ahead of the dash too, with the original plastic ducts riveted into place. I plan to hook these up to the side vent inlets, which are now blocked on the dash itself. At least I'll have some airflow to keep the windshield clear (the heater box and other vents are all gone). One more upgrade is the Watanabe wheels. I managed to find a set of 16x8 and 16x8.5 in a deeper offset, so I could get rid of the wheel spacers. The deeper centers look much better and they fill the fenders perfectly. A few finishing touches this week and I'll be driving DAT240 again for the first time in two years. Once the engine has been run in a bit I'll fit the new injection system. More on that later, along with a weighbridge result.assembledfront.jpgassembledrear.jpgbrides.jpgglassdash.jpgwatanabe.jpg Quote Link to comment Share on other sites More sharing options...
BenOtomoto Posted February 2, 2008 Author Share Posted February 2, 2008 As you can see by the attachments, my Zed is back on the road! I hope you'll agree it looks pretty damn cool too. The acrylic rear window went in with the standard rear seal. Now I just have to figure out how to make the hatch sit down a bit lower. At this stage the fiberglass doors have no rubbers, as I have yet to modify them to suit these doors. Otherwise it's all good to go. I drove it around the block a few times with just the Hitachi carbs on the big 3.1 engine. Unfortunately the little fuel pump isn't up to the job and the fuel bowls keep emptying out. I'll have to find a bigger one to keep it running properly until I am ready to fit the OER six-throttle injection. More on that later. I also need to sort out the suspension a bit better, but for now it's just a relief to have it driving again. Quote Link to comment Share on other sites More sharing options...
BenOtomoto Posted February 11, 2008 Author Share Posted February 11, 2008 Here is the OER six-throttle injection system I'm putting on the car. It's basically a triple-Weber 45DCOE manifold with a bunch of extra vacuum fittings. The Rail is away getting the injectors cleaned and flowed right now. I had the manifold match-ported to the head when the engine was built, so it should all work pretty well when it's finished. Also I've attached a pic of the radiator I just bought from PWR in Australia. Good value compared to other Z radiators I've seen.injection.jpgradiator.jpg Quote Link to comment Share on other sites More sharing options...
BenOtomoto Posted March 31, 2008 Author Share Posted March 31, 2008 After running it in on Hitachi SUs, I've fitted the L31 with the OER six-throttle injection kit. Will be wiring up and tuning an Australian Adaptronic computer next week. Also had the headers ceramic-coated black. Still a few things to tidy up but the car is mostly finished now. Quote Link to comment Share on other sites More sharing options...
BenOtomoto Posted May 7, 2008 Author Share Posted May 7, 2008 All tuned now. On a Dyno Dynamics dyno it makes 269.9hp at the wheels. The generally accepted correction factor for these dynos is 1.3, so that's 350hp at the engine. This is the upper end of what I hoped for from this set up, so I'm very happy. The cam comes to life at 4000rpm and from 5000rpm up the sound is like a motorbike. Peak power is at 6700rpm so I set the rev limiter at 7000rpm. I'm just in the process of fitting an R200 LSD diff from a DR30 Skyline (FJ20 turbo) with driveshafts from a Z31. I'll head out to a dragstrip soon so you'll know the hp figure is accurate. Here's a video of it on the dyno: Quote Link to comment Share on other sites More sharing options...
BenOtomoto Posted May 28, 2008 Author Share Posted May 28, 2008 Went to the drags today but it rained Maybe next week... Quote Link to comment Share on other sites More sharing options...
BenOtomoto Posted June 26, 2008 Author Share Posted June 26, 2008 Made it to the track this week. With a 4.875:1 Kameari final drive ratio fitted and Hoosier 225/50 16 drag radials I got a 1.68 60-foot time and recorded a 12.82 at 103.9mph. The terminal speed isn't what it should be, so the car will be tuned again next week. Here's the Youtube video: Quote Link to comment Share on other sites More sharing options...
BenOtomoto Posted March 9, 2009 Author Share Posted March 9, 2009 Haven't made an update for a while, but now I'm getting around to finishing some important parts. The Kameari gearset has been fitted, (replaces first three gears for closer ratios) and I've gone back to a 4.3:1 diff ratio instead of the 4.875:1 Kameari gears. The result is much more drivable and only takes 10% off the top speed. With the 4.875s I was hitting the limiter in fifth even on the short Oran Park GP circuit front straight. Next week the car is going in for a Kameari electronic ditributor swap, thermo fan with custom shroud and a front brake upgrade. Photos soon. Cheers Quote Link to comment Share on other sites More sharing options...
BenOtomoto Posted July 31, 2009 Author Share Posted July 31, 2009 Another minor development, I'm in the middle of a coilover conversion. So far I've done the front only. I have use HSD coilovers which have a base height adjustment rather than just an adjustable spring seat. After cutting the original strut tube down to two inches, a cup type lower bracket is welded in. The brake line attachment from the original tube has been welded onto the cup and the coilover unit screwed into place. A modified top locator sits against the original top mount. The front is obviously a bit lower now. The back will be done the same way soon. I've got some Rota RBR 16x8 +4 wheels on in this shot, which I have my race rubber on. Quote Link to comment Share on other sites More sharing options...
BenOtomoto Posted February 14, 2010 Author Share Posted February 14, 2010 The rear coilover conversion was done the same way. I'm using 6kg/mm (336lb) springs front and rear with the HSD TT type coilovers. Seems to be a very nice balance, may try a lighter front spring for better turn-in later. The third photo shows the new ride height with the Watanabes on again. You might also spot the carbon fibre tail light surround, which I got from Restored in Japan. rear.jpg rear2.jpg height.jpg Quote Link to comment Share on other sites More sharing options...
BenOtomoto Posted February 14, 2010 Author Share Posted February 14, 2010 Shortly after the coilover conversion was completed I finally got around to doing a brake upgrade. This was all bolt-on, with the Arizona Z Car Wilwood kit at the front, Motosport Auto rear brake kit and a 15/16" brake master cylinder. I haven't fitted any proportioning valve as the balance seems fine at this stage (need some more track time to confirm this). The pedal travel is still a bit long, but nothing worth worrying about. About the only hassle was getting the cable handbrake to work. Needed a new cable and some modifications to the lever in excess of what MSA suggest. Quote Link to comment Share on other sites More sharing options...
BenOtomoto Posted February 14, 2010 Author Share Posted February 14, 2010 Here are the fitted brake components. Arizona Z Car were able to supply the front kit to suit my early hubs, so this was a very easy upgrade. Quote Link to comment Share on other sites More sharing options...
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