Racer Z

Three years ago, in the summer of 09 my brother and I bought a 1973 Datsun 240Z to convert into a dedicated track car. Since then we've been able to race (time trial actually) it four times a year and slowly build it. We finally got tired of sharing the one car on the track and two weeks ago we bought a 1974 260Z to convert into a dedicated track car. Like most race cars, the "build" is never really finished and everything is subject to change. We jokingly put number 13 on the 73 and that stuck cause nobody else in the club (AROSC, Alfa Romeo Club of Southern California) is using it. We later decided to paint the 13 car white and orange like a billiard ball and use a real pool ball for the gear shift knob. The only other stripped "pool ball" number not being used is 15, white and maroon, so the 74 just might become the 15 car. Currently the 73 is black and the 74 is white. "Spy VS Spy", my sister in-law called it. We intend on setting to two cars up very similar and eventually racing with VARA (Vintage Auto Racing Association). Since both cars will be very similar in build and they are shared equally, I don't see any need to have separate build threads. My brother's HybridZ name is beermanpete and will be contributing to this thread (I hope). The 74 was driven home, but wouldn't start up later. It's in bad shape, but we didn't pay much for it. We have not done anything to it yet. The 73 has been a learning experience. It's our first Datsun and our first race car. It was stock and in very good shape when we bought it. It had been garaged and un-driven for ten years. We bought it without being able to test drive it. Fresh gas and a new battery cured that. I had looked at a lot of Z's and felt really good about this one and three years later I still think I picked a good car. It was stock, never modified, no crash damage and no rust. I had test driven Z's that were in worse shape and wanted more money. A few months later we took it out to the track in absolute stock form. This included the OEM style tires, dead shocks and OEM brake pads. We took turns driving and turned a 1:52 (each) at WSIR (Willow Springs International Raceway), "The Big Track". (There is more than one track at Willow Springs and the main track is referred to as the big track.) Since then we've improved our driving skills and our car. Two months ago I turned a 1:42 at the big track. Pete was in a slower run group and got held up by slower cars. I'm sure he could have matched my time if he had a clear track. To quickly go over what we've done to the 13 car, not in any order: Gutted the interior. Rebuilt the suspension with polyurethane bushings. Replaced the springs with Tokico Lowering Springs. Replaced the shocks with Tokico Blues. Added a rear anti-sway bar from a 74 260Z. Upgraded the diffy with a Subaru STi LSD clutch type. We got our adapters from John Coffey of Beta Motorsports. Rebuilt the 4-speed tranny. Upgraded to 15x7 wheels. Upgraded to Falken Azenis RT-615K 205/50x15 tires. This is not a true race tire, but a high performance street tire that does well on the track. Removed the bumpers and other non-essentials. Upgraded to Porterfield Racing pads & shoes (R4). Relocated the battery to the rear of the car above the rear axle. Had the car on scales to get the corner weights. Found that it has 51% on the front axle and was within 30 pounds on the diagonals. Did not change a thing. We have not re-scaled the car, but I calculated that we've lightened it by about 130 pounds since. Removed all the wires and switches. Installed new switches in relocated locations and built our own wire harness. Installed roll bar, racing seat, 5-point harness and other safety items. Added a Spook and a BRE style spoiler. I busted the Spook at the next event. Replaced the alternator with a tiny motorcycle alternator. Our Dad machined a custom pulley for us. Wasted time arguing over small stuff. Put gas in the car and went racing. If you want to see some of our in-car videos, my YouTube channel is 13RacerZ Pete (aka beermanpete) on left, Bob (aka Racer Z) center, my 70 Ford F250 and our number 13 car on the way to Laguna Seca, December 2011.

What did you do to your Z today? Did you drive it? Did you work on it? Did you look at and wonder why you've ignored it for so long? The other night I drove over to another HybdridZ's house and bought an engine / tranny set. Chatted with him for hours about Z-cars and related stuff. The engine will sit in my truck until the weekend when I can get it out. Last weekend I went to the junkyard to look for brake parts from other cars to do a rear brake conversion. Found an early 300ZX with 4-bolt rotors to nab. Found a Mercedes Bendz E-body with calipers I liked. Got out of there for $70 to later find the calipers go for $200 each at the parts store. If the conversion works well with the stock front brakes on my 240Z I'll be smokin happy.

I don't have the answer to the original question. I think it has been addressed already. To follow up on the alternative direction the thread has taken: If you want the closest possible gear ratios, you will need the 80 to 84 5-speed. This has the closer ratio spread (gears 1 to 4). You're locked into using the first four gears as a set, you can not just change second gear for reasons already noted. You then need the fifth gear set from the early 5-speed. Put the early (fifth gear) "set" in the later model 5-speed and you will have the closest gear ratios. This may not be ideal for street performance but it will a better track (road racing, autocross) gear ratio set. I have not actually done this myself. I now have all the pieces to do this and plan on doing it soon. I have rebuilt a 4-speed and have some hands-on-experience.

SCCA, VARA and most clubs will require all joints to be fully welded. Some cut the roof off, others cut the floor out, finish all the welds and then put the car back together. I haven't done a full cage yet, so I'm not sure what would be easier or better. I'm leaning towards cutting the roof off at the "A" and "C" pillars. I suppose there are other ways to do this.

Nice looking wheel. Who makes it and what model is it?

For a daily driver, it's got more to do with looks. I doubt the extra holes would ever be a problem on the street. The extra holes look lame. Why pay for lame looks? My 240z is a dedicated track car. I doubt if the extra holes would lighten the wheels enough to matter. It just seems to me that I would be better off without the unnecessary holes. I'm not in a position to do a scientific experiment on Wheel vs Wheel. I'll spend the extra money on what seems to be a better choice. The better wheel can fail too. Let's hope it's not as often.

1) Looks lame. 2) Strength issues. 3) Looks lame. 4) Could be a place for cracks to start. 5) Looks lame. 73 240Z track car. 70 Ford F250 84 HoHoHonda Accord 12 Fiat 500C

Whether I think a wheel is attractive, or not, I would NEVER use a wheel with extra bolt holes. PERIOD.

Having discussed this in great detail with my brother, Beer Man Pete, the deciding factor for us was the weight. In my research, I decided that most alternators have the same drag, unless they're advertised as being "low drag". The only low-drag units I could find put out gobs of power and were even larger and heavier than our stock unit. It would seem logical though, that part of the drag would be based on the amperage output at run-time. That is to say that there is more drag with the headlights on than off. So, once the battery is fully recharged after starting, most alternators would have the same amount of drag.

Cutting the coils spring does indeed change the spring rate. But, what's that got to do with pictures of wheels?

Lots of talk and few pictures. Here are my new VTO Retro-4 wheels. They're a copy of the old American Racing Libre wheels. Mine are 15x7 zero offset sporting a 225/50-15 tire.

It's been a while, but we finally mounted some tires on our new VTO Retro-4 rims and were able to mount the wheels on the our Datsun 240z. The rims are the VTO Retro-4 15x7 zero offset. The tires are the Falken 912 225/50-15. The lugs are not what came with the rims. We have racing studs that are longer than stock and had to use open lugs. We drove the car around town a bit without problems and then a full weekend at Willow Springs Raceway without any issues. There was some concern that this rim/tire combination might rub or otherwise not fit right. We had no issues of any kind. The car is a 1973 Datsun 240z that is mostly stock. (well, sort of...) The things we changed that might effect wheel rub or fitment are as such: Energy Suspension polyurethane bushings all around. Tokico Lowering Springs all around. This lowers the car one or two inches and stiffens the ride a bit. These are street class springs. 260z swaybars, front and rear. The front swaybars are identical, the 240z came without a rear bar. The Retro-4 wheels are kind of heavy for racing purposes. They weigh in at 18 pounds each. I was hoping for 14 or 15 pounds. They did perform well on the track though. We lowered our laps times by about 3 seconds since the last time at this same track. We used the same tire, brand, style and size as our last event for comparative purposes. No, these wheels did lower our track time. LOL We lightened the car by 130 pounds, added a LSD (limited slip differential) and added an adjustable proportional valve sense our last event. The wheels look good on the car and I'm happy with them. picture resolution: 1280x768 picture resolution: 1024x768

Signed up to see the continuing build on this. We will be doing the same job soon enough to our dedicated road racer (240z). Fuel cell and full cage. Your job and setup (template) looks good.

http://qwildurn.game...tOfWeights.html Hybrid Z does not allow editing of posts after they're a few weeks old. Because of this limitation, I'm using an external web page to host the List of Weights. This external page allows for better organization tools to create an easier to read table. Please continue to post your item weights here and I will add them to my HTML table. http://qwildurn.game...tOfWeights.html

Hood latch with cable; complete with nuts, bolts, screws and related hardware from 1973 240Z = 2.5 pounds. Single post "Racing Style" hood latch = 1 pound. This is a solid shaft stainless steel post. I mounted the single post in the center of the hood where the stock latch had been. This weight includes a bracket I made.

I'm not sure why there are two weights listed for the same unit. BeermanPete is my brother and we only have one stock Datsun unit and one WRX unit. I was there when we weighed the 240Z R180 @ 59.25 pounds. He said he didn't know why he got a higher reading earlier.

59.25 pounds R180 differential; 3.364 gears; dry (73 240z) from: http://forums.hybrid...ight-reduction/ Not sure why we didn't weigh the WRX LSD. I can say it didn't feel like weighed any different.

The only way to know for sure if it's a clutch type or a viscus type is to remove the inspection cover and look. I don't recall the torque specs. I'm thinking around 150 foot pounds. We torqued ours on the bench and had a hard time getting it fully torqued. The unit is close enough to the original Nissan part that you can use the torque specs from Datsun.

By "he", I assume you mean the OP. I do not know what "he" did, but I do know what I did. I bought a set of new output shafts from John Coffey. See this thread for all the details. http://forums.hybridz.org/index.php/topic/78123-subaru-wrx-sti-r180-side-axles/

If the adjustable looks similar to this, it will only aggravate our bolt clearance issue. I also suspect this adjustable bracket is heavier than the stock bracket.

The stock Kaw pulley was pretty tiny, but we don't know what size the drive pulley was in the Kaw motor. Yes, we have stripped the car of all non-essentials.... it is a dedicated track car.

Nice goal. We picked up an old beam type scale a few years back so we could weigh things accurately. I think I paid $50 for this. Good thing I have a truck so I could haul it home.

Awesome We (beermanpete and I) have some loose parts buried in the corners we will dig out in a few weeks to add. I know we have some front suspension parts that are loose.

The correct term would be, "our 240Z", little brother. Our Dad made us this new pulley to fit the alternator. Beerman drew up the plans and Dad turned it on his lathe. We have not yet fit it to the alternator. We don't yet even know at what RPM range the Ninja alternator wants to spin at. This is an experimental size, about 4 5/8 inches diameter. We can turn this one smaller or make a bigger pulley as needed. Once we get the size for RPM correct we can shave certain areas to lighten it and drill a few holes in it for air flow cooling.

Got it all updated. Thanks guys.