Building a race car.. looking for advice!

[jsausley]

Hi everyone! First time poster.

 

 

We are building our 1973 Datsun 240Z into a race car. I'm looking for drivetrain advice:

 

We're on a budget! I'd like to get out TOTAL under $10,000. The car cost $1,500.

 

That leaves us with $8,500 to play with. Here's what we have:

 

L24 Engine (needs a rebuild or replacement)

4-speed transmission

Stock rear end (3.36)

Stock wheels/tires

 

Here's what I was thinking that we would need:

 

Engine rebuild/balance/etc. (~$1500)

5-speed transmission from 280ZX (~$300)

R200 w/ LSD (~$750)

Strong wheels/tires (What would you suggest here? The wheels/tires I was looking at will be about $1500 for everything.)

Brake upgrade (not sure where to go here - I know 300ZX all-around disc brake conversion is possible - how much does this usually run? How difficult is the swap?)

Suspension upgrade ($500)

 

Total of: $5,050 plus brakes, so let's say $5,750 total. Plus the price of car, so: $7,250 in the drivetrain and suspension, not including miscellaneous upgrades like roll cage, seats, steering wheel, wiring harness, paint, etc.

 

If this was your project, what direction would you take? Any advice to give? Which upgrades are going to give us the most headache?

 

We have a year to do this, it needs to be ready by Summer 2012, so we can watch prices and try to come out as low as possible.

 

Thanks for the help!

[fhptom]

Look for someone trying to sell there car. If the car is already sorted you will be better off in the long run.

Look into IT Forums on the web. Always cars for sell there.

[mark]

Look for someone trying to sell there car. If the car is already sorted you will be better off in the long run.

Look into IT Forums on the web. Always cars for sell there.

 

 

With out a doubt, follow this advice.

[jsausley]

Thanks for the quick reply guys, but we already have this car and have put a considerable amount of work in getting it stripped out, so now comes the part of putting it back together.

[johnc]

not including miscellaneous upgrades like roll cage, seats, steering wheel, wiring harness, paint, etc.

 

Amazing... really amazing. The safety stuff that will keep you alive is "miscellaneous."

 

Your thinking is completely wrong. Here's the order of importance when building a race car, any race car:

 

1. Safety.

2. Reliability.

3. Repeatability.

4. Speed.

[jsausley]

Amazing... really amazing. The safety stuff that will keep you alive is "miscellaneous."

 

Your thinking is completely wrong. Here's the order of importance when building a race car, any race car:

 

1. Safety.

2. Reliability.

3. Repeatability.

4. Speed.

 

John, thanks for the reply but I think you just misunderstood it. Of course safety is of number one concern at all time. If we didnt have a safe car, we would not be out there. By miscellaneous I just mean is doesn't fit under the drivetrain category that we need some helpful tips with. The safety stuff is pretty easy to get/design for, but me and the guys helping are relatively new to the Z platform and are not sure of which direction to take under your rules 2-4.

[JMortensen]

+2 on buying someone else's car.

 

Put it back together and drive it on the street or sell it, use the rest of the budget to buy someone else's racecar. For $8500 you can buy a pretty nice old ITS car or someone's autox car. Building a racecar will nickle and dime you to death, $8500 is not a lot to work with. Just as an example, if you did the engine, you've factored in $1500. I had that in my head alone, but assuming that you could get it done for that price, you're just putting all the old crap back on it. Is that really what you want for your racecar? Are you going to reuse the old carbs with no rebuild? New balancer? Light flywheel? Clutch and pp? Exhaust?

 

For the LSD you say $750 and I don't doubt that you can find a good used LSD for that price, but what about the mustache bar? RT diff mount or new stock front mount? Poly bushings?

 

Suspension upgrade for $500? I have $500 in shocks, not to mention coilovers, camber plates, adjustable TC rods and front control arms, bushings, sway bars, etc.

 

To answer your question though as to what is the hardest part of building a racecar, I'd have to say the cage without a doubt. Paying a shop to build a good cage is expensive, and doing it right is difficult. It requires many man hours ($$$) and to do it yourself you need a welder and a tubing bender and saw, and tools to notch the tubes ($$$). There is no cheap way out of the cage part of the build.

 

If you want a warmed up street car, you can do that within your budget, but you would be WAAAY better off taking on someone else's running racecar and going from there. Take it from a guy who has been working on his racecar for 8 years. It's going to be REALLY cool when it's done, but I should have started with a caged race car and gone from there.

[jsausley]

Jon, I think we should be more specific. As of now, this is not going to be a SCCA type car. This car is for the Chump car circuit. So a "warmed up street car" may be a better description...There is not doubt in my mind that buying a track car would be EASIER...but is half the fun not building your car with your bud's on the weekends and knowing the in's and out's of it for the race?

[skib]

if your building a chump car just focus on being able to finish the race

[johnc]

John, thanks for the reply but I think you just misunderstood it. Of course safety is of number one concern at all time. If we didnt have a safe car, we would not be out there. By miscellaneous I just mean is doesn't fit under the drivetrain category that we need some helpful tips with. The safety stuff is pretty easy to get/design for, but me and the guys helping are relatively new to the Z platform and are not sure of which direction to take under your rules 2-4.

 

 

OK, my misunderstanding.

[JMortensen]

$8K Chump car?

[jsausley]

Chump Cars start with a $500 car but they never stay that way. Some of the people at the events have between $15-20k invested in their car. It's cheaper than most forms of racing but it's still not cheap.

 

JMortensen - I found your thread on the differentials ( http://forums.hybridz.org/index.php/topic/49194-differential-cv-lsd-hp-torque-r160-r180-r200-r230-diff-mount/ ). Exactly which cars came with a LSD-equipped R200? It was just the late 87-89 300ZX Turbo, isn't that right? Would you say that LSD is necessary for a 240Z track car and if so, what's the best way to go about getting it? It seems like a much bigger headache than we originally thought... Looking at the installation guide it sounds like the R180->R200 swap is easy, but it's much more complicated if your R200 is an LSD version.

[jhm]

Not sure what the chump circuit is, but if it includes stuff like auto-x and track days, here's what I would suggest...

 

If you're really intent on building up this car (and there can be a great deal of satisfaction in doing it yourself, vs buying something that's already finished), I would concentrate on the brakes, suspension, and wheel/tires. You're really wasting time and money if you build a hot engine before getting this stuff sorted out first. You won't believe how much time you'll pick up just by putting on some good race slicks.

 

And if you've never had formal training, spend a few bucks on a good performance driving school. You'll learn how to get the most out of whatever equipment you're running.

 

Good luck and happy motoring!

r/John

[JMortensen]

Do some searching on LSDs. There are a few different options and I don't want to take the time to write out again here what others have written elsewhere. Search R180 STi, OBX, OS Giken to start. Yes, 87-89 300ZX turbo is where to get the factory diff from. I would weld the diff on a Chump car.

[Leon]

I would definitely go R180 STi with Coffey's axles as far as LSD goes, but that will be over $1000. As Mortensen points out, $500 is nothing as far as suspension goes. It's more like ~$1000 for a basic setup (shocks, springs, bushings, ball joints, tie-rods, etc.) and up if you're going with coilovers (I would for a track car). If the engine has good compression, I'd leave it alone and focus on the rest of the car. Maybe freshen up the cooling system, make sure the carbs are good and do a general tune-up. I do think you can go cheaper on the wheel/tire combo depending on wheel size, maybe $1000 or so if you go for something like Rota or Sportmax.

[jhm]

...and start out w/ used race tires!!! I've been buying from this guy for a while now, and am extremely pleased.

 

http://stores.ebay.com/Race-Tires-USDRRT?_trksid=p4340.l2563

[Tony D]

Our $500 LeMons car had somewhere in the area of $5000+ in the safety stuff alone and that was cut-rate-secondhand almost everything but the seat harness. The rest concentrated on a stock engine and making the parts dead-set reliable. I don't know about brake upgrades and all that, seems to me if John Morton made it all those years... and LeMans retired from Differential Problems, I'm thinking brake upgrades need only be limited to pads, fluids, and operational necessities like changing pads when needed.

 

In the end, it was failures of things which never should have failed that put us out of the race. Damper on the front end, large plymouth with big bumpers tearing off the front half of the car, etc...

 

I'm with John C on Safety, Reliability, and Repeatability, especially in ANY sort of endurance competition. The race doesn't necessarily go to the fastest, but to the guys who stay out there making laps while the rabbits refuel, refit, and retire!

 

Being there at the end is what matters. Get that down first, and consistently...THEN start adding speed!

[Pharaohabq]

I'd 3rd that recommendation to start with something already built. You're going to save a lot of money and you're not going to cut up a good shell. Racing is very hard on these cars and their unibody type construction. not to mention the scrapes and dents from real racing. A built car shouldn't be too hard to find. you can sell your decent car for what you've got into it pretty easy if it's in good shape. You also need to decide what class you're going to be in before building anything. A lot of classes have limitations.

 

I know you said you're not doing SCCA, but following the rules is what keeps people unhurt. You'll save a lot of $ too building toward a known class. something already built should be nicely braced with a legal cage. The engine, brakes, tires (cheap steel rims) should all be viewed as consumables. yes, pay good $ for decent stuff, but don't be attached. Racing will eat your consumables. it's the price of playing. The Stock engine is good, but you'll want to upgrade the electronics, fuel system, etc. it is 35 year old technology. a good seat and a NEW harness are a must, even if they say it's new, you might want to replace it, it's your life.

 

Map all that out before you get started building and you'll save yourself tons of headaches, bloody knuckles, wallet pain etc etc etc.

[h4nsm0l3m4n]

For a Chump car $8000 is not unreasonable, my chumpcar team has at least 1500 into just the engine rebuild on our RX-7.

 

In Chumpcar you are not allowed to run slicks. Street tires only, with a wear rating over 200 (if I remember right). Most people run Falken RT-615s or Dunlop Star Specs. For wheels, getting fancy wont buy you anything, any 14s, 15s, or 16s will do ok. As far as upgrades, keep in mind Chumpcar has rules for how much upgrades will add to your car's "worth." Springs, shocks, LSD, other improvements will greatly increase the value of the car dramatically, so most of those are prohibitive if you want to stay within the rules.

 

Just for reference, our chumpcar RX-7 runs ebay springs with stock shocks and slotted top mounts to add more camber, no other suspension work. Engine is a rebuilt stock motor with a couple mods to improve cooling and oiling of the engine at high rpms. Driveline, exhaust, intake, etc are all basically stock. Our car, with the right driver (not me), was capable of hanging with some of the fastest cars on the track. A Z car is a fairly similar car and should not require much more work to get to perform well enough to keep up.

 

I would say do as little as possible. Endurance races are many hours long and the more you mess with the car the more risk going wrong at the track. I feel its better to do less initially, get the car running and thoroughly test it to find its weak points. Once youve found them you can start thinking about what you can do to improve them. Consistency and reliability are much more important. Issues to improve braking and cooling will pay off, not necessarily increasing power or improving handling. Do what needs to be done to keep your car on track. Driving 5 seconds a lap slower than the leader is still faster than sitting in the pits. Organize your team so you dont waste time - 5 minute vs 10 minute driver changes can add up to a lot over 24 hours. Other stuff such as driver communication, driver comfort, crew support, are also things that may be worth thinking about. Endurance racing at this level is as much about these kind of logistical issues as it is about actually being fastest on the track.

Edited August 24, 2011 by h4nsm0l3m4n

[RACERZ]

As a new member who just joined I agree with those above we have gone both routs. Built an IT car then bought an EP prebilt car built car was much fasted and sorted. You can do what you want and build a car if you have access to a lot of tools and have a lot of friend in the fabrication/machinging world, and do it for a relatively low budget. It will take a lot of time though, the first thing will as stated above plan on what you want that will fit in your budget, then start crusing the net, the are a lot of good used parts out there for at least 1/2 of what it would cost to buy new. Secondly look for a parts/basket case race cars lot of good stuff, also dont forget that a lot of 510 stuff will fit the Z. I have seen a lot of people selling old 510 race cars less motors fairly cheaply You may be able to get parts off of them.

As far as the diff if your are planning on running a near stock motor forget the R200 its very heavy and would be overkill, the R160s will work (we ran one for years in our 240 autocross car.) The are light and dependable, most importantly cheaper than R180s or 200s, also the Subaru R160s came with LSDS the old ones esp. are cheap I have seen then for as little as 100 used, so even if the broke you could afford to replace it cheaply, also this allows for a grater selection of gear ratios,if not that then just run a welded R180 again lot to be had cheap and for a beginner locked vs LSD wont be a big diff, for brakes either run the 280zx conversion or the Toyota fronts with zx or 240sx rears you can scrounge these from junk yards for little or no cost then get a good set of pad, if you can fab brackets and hardware and do you own welding you will be able to come close to your budget of 10K, that being said if you dont have access to inexpensive fabrications your cost will go out of sight quickly, even if you do find used parts cheaply. Also depending on what part of the county you are from will have an impact on your cost (west coast is a lot more expensive).

Look at the racing forums there are a lot of good used racing parts there (NASA, SCCA , IT ,PRODracing, ect.)esp thing like seats insterments belts ect. Another cost is lighter bodywork nothing helps a race car mors then less weight so you will want to pull everything off you can get, so fiberglass body pannels plus lighter wheels will be a must depending on what direction you are planning on going (for IT the car must remain mostly stock).

Also agree with those who stated building toward a set of rules you think you might like to race in the future, so you dont end up investing in say a set of trick shocks that you later find out are not legal for the class you want to run somtime in the future,that is where looking at the different orginazations and the rules for the cars will help you decide which direction to go.

Good luck though love to see the old Zs out racing still.