Datsun Roadster Forum-311s.org

Slowly but surely it's coming together. This weekend I built a frame to hold the fuel cell, surge tank, two fuel pumps, associated lines, and fuel filter. I mounted it behind the right rear tire. I will probably mount the water/methanol injection tank to that frame somewhere. I also built a mount for the battery. I was able to find a plastic battery box for the group U81 lawnmower battery. I bought a bunch of various size brake lines at NAPA for fuel and brakes. I am going to have to fabricate the brake lines because the motor is now located where the lines used to run. I'm going to eliminate the junction box with the sensor. I will probably run the rear brake line down the drivers side. A splitter will be located near the MC for the front lines. I was going to use the splitter off a spare rear axle but it doesn't have the right kinds of fittings. I'll probably make an order with Earls. I need a 24" throttle cable with a 90 degree end and a 45 degree end. I'll probably have Dennis Kirk make me one for $9.

Still to come. Brake, clutch, and fuel lines, roll bar, electrical wiring, aluminum panels to cover the holes in the floorboard and package tray, dash and gauge install, rear shock rebuild, and a million little details.

I'm still making progress. I have finished all but one custom brake line. I also have to install the brake porportioning valve for the rear. It was tedious to rebuild the entire brake line system. I put the stock distribution block on the firewall under the master cylinder. The MC goes to the distrubution block. The front left line is short and simple. The front right line is still pending. It will go over the motor on the cowling similar to the stock arrangement but higher up. It has to snake between the firewall and the supercharger before it gets to the caliper. The rear line exits the distribution block and then to the porportioning valve. After that it goes along the drivers rocker to the rear. I used the stock RX7 lines on the rear axle but had to cut and shape them for the narrowed axle. The stock RX7 rear discs and calipers will be retained with Carbotech panther plus pads. I had to mix and match metric hoses and fittings to get everything to work right. I never dreamed it would be so easy to swap out. For all those who don't want to spend a bundle on a new roadster M/C you can easily use the cheaper metric ones by switching out to metric fittings on the ends of your existing lines. I have a 280z M/C which was too large for the stock calipers and caused a very heavy pedal. I have ordered some Outlaw 2000 calipers which have a staggered 4 piston arrangement with 2 pistons at 1.62" and 2 at 1.75". This is larger piston area than the stock 2 piston calipers but not as big as the 280Z M/C would like. I think a four piston caliper with 4 1.75" pistons would be ideal. Wilwood Dynalite and Outlaw 2800 series calipers come in this size. I can't use those because of my wheels but they could work on standard wheels pretty well. I have diwe 5 wheels and the center section has studs that the base sticks out towards the interior about 1/4". That 1/4" of stud hits on the stock caliper. I had to put a 3/8" wheel spacer to keep the stud from hitting. This causes my front track to be wider than I would like and causes the scrub radius to increase. This increases steering effort. The Outlaw 2000 calipers are narrow at just 1.6" from the centerline of the disc to the face of the caliper. That is about 3/4" narrower than the stock caliper. I will be able to remove the wheel spacers. The Dynalite and Outlaw 2800 are about the same width as the stock caliper. The new calipers are 3 pounds each and will save about 25 pounds of unsprung weight off the front of the car. I will use Carbotech panther plus pads on the front also. I have ordered a new upper a-arm bushing kit and that will take some of the slop out. I also have ordered some Volvo lower ball joints. I am going to manufacture some adaptor plates that will make it easy to bolt-on the Volvo lower ball joints. The ball joints are $35 each. I built all new fuel lines and routed them to the tank. I have two fuel pumps with a surge tank between. I'm having problems with fuel pressure drop. I think the stock fuel pump relay doesn't have the power to run both pumps. I'm going to hook a relay to the battery and then trigger it with the stock fuel pump relay. I hope this fixes the problem.

It is getting there. I should be able to take a spin around the block next weekend. Now I need to work on the roll bar and the million little details.

After two years Bucephalus moved under his own power today. We took a brief stroll around the block without drama or fanfare. I did punch it a couple of times and found out that the supercharged KA24DE can spin 30 inch wide rubber at will. The wine of the supercharger is still pretty scary. I may have to move the intake out of the passenger floorboard. It is actually up higher under the dash but still in the passenger compartment.

There are a couple of minor brake fluid leaks. I will fix them when I install the 4 piston calipers. The Outlaw 2000 caliper install looks to be much simpler than it seems. I just need to fabricate a mounting bracket. The hard brake line from the hose needs to be bent a little. That's it. It will be much simpler than a Toyota 4x4 or Volvo conversion.

I need to tidy up some wires, secure some hoses and wires, install the methanol/water injection system, fabricate an aluminum cover over the package tray area, build a new roll bar, and tie some other minor loose ends. The radiator started leaking a little so I'm going to have to deal with that.

Overall It is coming together nicely and hopefully will be ready to race (but not completely finished) by Nov 10-11 which is the last autocross of the season.

Later,

Today I tidied up wiring, installed a bracket to hold the MAF, w ired in a main relay instead of having all the power going through the ignition switch, installed the methanol/water injection tank, lines, and nozzle, installed the boost gauge, installed the tach, made grommets out of heater hose where the wires go through the firewall, and I hooked up a tail light that runs off the fuel pump relay.

I took it around the block a couple of times. It will light them up at will. In second gear the car goes sideways with wheelspin. I need to jack with the suspension settings to get more traction. I noticed that the boost gauge was only going to 5 psi. I was getting 13 psi on the dyno. That was with water and methanol spraying into the supercharger. I didn't have the spray on today so maybe that is the problem. It is also conceivable that there is a boost leak or that the boost gauge isn't reading correctly. I need to go over the hoses and stuff to make sure there isn't a leak in the system.

I'm getting prepared to close in the rear deck and install a roll bar. I think with those two items out of the way I can take it out to the races.

Later,

Here is a poor quality video. I had the image stabilization turned on and it made the video do wierd things.
http://rides.webshots.com/video/3049437 ... host=rides

The car made it through two days of autocrossing. There were a few mechanical problems but nothing that sent me home early. The exhaust hanger melted, there was a radiator leak, there was fuel starvation caused by a pinched line, the exhaust pipe came off the header.

It was having some computer tuning problems both days. I worked on it a little but it still popped and spit. The rear suspension needed a lot of tuning. It didn't want to hook up and it was picking a front tire up off the ground during acceleration. I tried to raise the rear ride height but it was close to the limit of adjustability. I moved the panhard bar as high as it would go in order to raise the rear roll center. Those minor fixes seemed to help a little. It has way too much body roll and is too stiff in the rear. I may try and increase the front spring rate and reduce the rear spring rate. I also need to get the brakes sorted. The fronts were doing almost all the work. I should have more videos and photos in the next few days when my photographer frien gets them uploaded.

I did make a few drag runs on the deserted back straight after the event. It pulled really hard around 4000 rpms in third and then into fourth. It is about an eighth mile and I got well into fourth. That is around 110-120 range. Not bad in the 1/8. I'll have chances to do some real tuning at the dragstrip that is 5 miles from my house.

Later,

Dude that is bitchin'!!!!!!!!!!!!!!!!!!!!!

I've got a 60 mb good video avaible that was made by my photographer friend who runs the autocrosspictures.net website. If any of you are interested in downloading it then send me a pm. It is much better than the one I posted on my webshots album because it is full size high quality. Just leave yourself about 10 minutes to download it on DSL. It's really large.

Thanks,

Here is the good video.

http://media.putfile.com/Andy---68-Dats ... 07--111107

I found a problem on Saturday. I had my fuel pressure regulator hooked to the small vacuum port on the throttle body. I guess this port is on the wrong side of the throttle body because at idle there was no vacuum at this location and as throttle was applied it gained vacuum. I could watch my fuel pressure gauge as I revved the motor and see the fuel pressure doing exactly the wrong thing. I hooked it to an open port on the manifold and immediatly saw improvements. There was no rich idle or hard start problem as before. It now doesn't spit and crackle when the throttle is opened suddenly. I couldn't really judge full throttle performance going around the block but I would imagine that it pulls like getting rear ended by a freight train. In the past it would "get it" but always felt like it was starving for fuel. I'm excited to test it out at the first autocross on February 24th. I still have a starvation issue with cornering that needs to be fixed before then.

I got one side Volvo lower ball joint completed. I ended up welding the original lower ball joint holes in the a-arm and then drilling new ones to match teh Volvo pattern. I did weld a steel plate to the top and bottom of the a-arm. I need to do the other side now.

I have acquired a sprint car 1-1/8" torsion bar that is 30" long. It is just the right length to fit in the stock swaybar location. It is advertised with a 1050 pound rate. I bought a kit to make arms that will connect to the a-arms. I'm contemplating making the front swaybar non-adjustable and connected directly to the lower a-arm with a heim joint. I will then install an adjustable swaybar in the rear. If it pushes too much I'll just stiffen the rear bar. I doubt I'll have a problem with push. I have a roadster rear swaybar that is about as thick as the stock front swaybar. I also have an RX7 rear swaybar and another rear swaybar that I'm not sure where it came from. They are different diameters and I think I can rig it up so that I can change out swaybars as well as end link position to make them adjustable.

Update.

I have installed the front swaybar. It seems to work well. It is above the frame rail and the arms reach back above the upper a-arm. A link goes down to the back side of the lower a-arm. I have three positions on the lower a-arm to attach. Currently it is on the outermost one which is stiffest. Next I plan on cutting the frame in front of the a-arms. It is only holding up the front sheet metal at this point which can be done with small diameter tubing just as well.

The motor still has way more power than I can use. My injection computer freaked out and would only run at full throttle. Anything less was burn your eyes rich. I force fed new firmware to the ecu using a manual uploader. Now it seems to be working correctly again. A bolt snapped off on the tensioner for the supercharger belt. I had to remove the manifold and supercharger to get to it. While I had it apart I tidied up the wires and put them in flex lume. It looks much better now. I moved the pressure switch for the methanol injection and the boost gauge tap inside the cockpit to clean up the engine compartment a little. I also moved the oil filter to a spot just below the headlight bucket. My radiator clogged so I replaced it with a two row honda del sol unit from ebay. It is all aluminum and hopefully it will last a little while. I know that the cheap plastic tank ones are not well liked. I am going to have to tilt the radiator to get it to fit. I'm going to install an oil cooler next to it in the grille opening. I switched to R25B Hoosier radials in Formula Atlantic sizes. They are stickier than the R35 bias tires that I was using. My first outing with them was not too successful. I blew up a shock and the motor was running poorly from the crapped out ECU. The next outing should be much better. I have replaced the shock and fixed the ECU. I have also changed rear spring rate to 110 pounds from the 280 pounds that was on it. It should want to hook up more now. It seems to get better each time I have it out. Hopefully it will be tip top for Solo II Nationals in September.

Later,

Pics of the tires/wheels?

The Wheels are Wide Five bolt pattern made by Real Racing Wheels. They are lightweight. I think the front 15x10 are around 10 pounds and the rear 15x14 are around 14 pounds.

Click on a photo to go to the website. On the website you can click on the full size button to see them bigger.


The front tires are 22.5x10x15 (10" wide) Hoosier R25b radial slicks. The rears are 23.5x13x15 (15" wide) Hoosier R25b radial slicks. Here I am almost getting a front wheel off the ground under acceleration.


Here is a photo of the wheel and a cordless drill for perspective. You may have to roll the lip of the fender a bit to get these baby's to fit.




The center section is similar to this. It is a 3/8" thick aluminum plate with the wide five bolt pattern around the perimeter and a 4x114.3 bolt pattern in the center. I had them special made with the center hole large enough to fit the roadster hub. I drilled the center bolt holes myself and swedged some steel bushings to keep the lug nuts from pulling through.


I plan on swapping out the front hubs for aluminum wide five hubs. They will save a bunch of weight over the stock iron hubs, aluminum wide five adaptors, and brake rotors.

Here are some photos of the motor, swaybar, radiator, and other stuff. I still can't seem to get the car to run right. I had to miss a race today because it is running so poorly. I may have a bad MAF. I'll check it tomorrow. They should read about 0.08 volts at rest and 5 volts at full capacity.

Swaybar left side


Swaybar right side


Swaybar link. See the three positions on the lower a-arm used for adjusting the stiffness of the swaybar.


A piece of box steel is bolted to the lower a-arm and the swaybar mounts to it.


Del Sol Radiator. I had to tilt it to get it to fit. I have the catch can and the engine breather catch can sitting where I think I will mount them. I have an oil cooler which may take the place of the red catch can and move it to the other side with the black one.




Here is the motor and supercharger. You can see the fuel pressure gauge. It really has been useful in diagnosing problems.

The motor started running poorly in April.
It took a while to figure out why. I think I got it fixed last Sunday.
Here are some helpful hints.

1. Don't mist water/methanol through a mass air sensor
2. Don't use fuel line that melts into goo which ruins the fuel injectors and
fuel pump
3. Don't get the spark plug wires installed in the wrong order
4. Don't wire the alternator wrong so that it won't charge and runs the battery
so low that the ECU freaks out
5. Don't re-use fuel injector o-rings which leads to the oil pan filling with
gas
6. Don't keep adding stop leak to a radiator until it weighs double what it
should

After more disappointment I think I finally got the motor problems figured out. In addition to the list of stuff above I had to replace the throttle position sensor, spark plugs. and plug wires. That solved a nasty miss and also a lean condition at 1/4 throttle or more. It still had an intermittant problem with loss of spark completely. I traced all the wires and found no problems. I purchased a new wiring harness just in case. I was about to replace the coil and ignition module when I decided to check the ECU main board. When I checked continuity from the main board to the ignition module I got nothing. It ended up being a bad main connector at the ECU. It had cracked and allowed the wires to pull out a little bit. They made good continuity where I checked them at the back of the connector but just weren't touching the pin on the ECU. I super-glued the connector back together and everything worked well. I will probably shorten the spare wiring harness and install it during the next motor pull.

Today at the autocross the car ran like a top fuel dragster. It had bunches of power and ran like a swiss watch. It was very planted in the rear and was reluctant to step the rear out. It also plowed like a Camary on street tires. I think with the increased traction from the R25B radial slicks that I'm getting higher cornering loads and more body roll. This is causing it to compress till it hits the bump stops. I'm not sure what to do at this point. I may rework the 1-1/8" front swaybar to make it stiffer. I could also replace the 860 pound front springs with some stiffer ones. The bumpstops are cut down to the point that it is close to binding up the suspension. I'll think of something. I'm just glad it made it more than 1 run. We got 8 total runs and could have had 12 but I didn't want to push my luck. I also beat my co-driver by .5 seconds which is nice. I've been so disgusted with the car since May. My distraction allowed co-driver Dennis to beat me twice in a row. Now that I can concentrate on driving instead of what is wrong with the motor things are right in the universe.

I tried to get an audio clip of the supercharger whine during a run but the sound is so loud that it distorted my microphone. I even tried wrapping it with electrical tape, stuffing it instide a leather glove, and sitting on it. I may need to try a different recorder.

Later,