zguitar71

Welcome to the fun world of autocrossing. Here is my $.02 Before spending the money on the V-8 make sure you get some good autocross tires that fit into the class you will be racing and give it a go, the tires will do more for you than any engine modifications. Go to www.scca.com (under solo, and look for the pdf rule book) and look at the classes and see what types of mods can be done in each class. With a V-8 you will either be in Street mod or E Modified. I would stay away from the E mod class they are partal tube frame race cars that weigh 1700 LBS and have no interior ect.. Street Mod is for street legal cars with full interiors but heavily modified from stock (like a V-8, suspension, flares ect..) and run DOT approved tires like the Kumo V710 or Hoosier A3S05. The V-8 will not make the car faster around the track as compared to your driving ability the tires and suspension, they will be the determining factors and in that order. The first thing to do, really, is just take the car as it is and go out and have some fun. Z cars can be potent autocrossers in the hands of a good driver. It is good to see that you are into racing the car because there are less and less Z's out there competing, lots of people are running Corvettes and Minis and Suburu's and other newer cars. It is great to see the look on people's faces (especially Corvette drivers) when they are beat by a 35 year old Japanese car with Datsun written on the side. Of course doing it with an inline 6 really gets them.

What type of racing are you getting into?

For an investment the 240 is the way to go, and it needs to be a `70 with a low vin number (under 5000) but that will cost you a bit of cash. You should be able to find a `71-`73 240 in good shape for 6k or so. I have a friend that is going to sell a `70 for 4K soon, the car does not have any rust and the interior is original and rough, it does need new paint and new interior, it was stored in a garage for 20 years or so in California, it is a good car for restoration but not something you would buy and drive without some beautification, in the end you would spend around 8-10k to buy the car and paint it and make it look nice, not to bad for a good looking non restored rustless `70 with a vin in the 7000's. Finding any older car in good shape takes time wheather it is an old Mustang or a Zed. Be patient and you will find what you are looking for, do not settle for something else because you want it now. In the long run you will be happier getting what you wanted in the first place and the time you waited to get it will not seem that long in the end.

I heard the Ford GT is being price gouged up to twice the asking price. But even at 300K it is still much less than the Porche GT and has equal performance but not as much technical stuff.

I have seen those post too and commented on one of them. IMO rolling resistance could never be noticed on a street car, well a 205 vs a 305 could but the 205 vs 245 would hardly make a difference worth fretting about. The alignment on my car gives more rolling resistance than the tire size I use. I think Mazda uses the 205 size for a few reasons. A low powerd sub-2500LBS car with sticky 205's will handel great, the wheel and tires weigh much less which leads to smaller brakes and lighter suspension parts and most of all it leads to LOWER PRODUCTION COSTS! I doubt Mazda gave a lot of though to rolling resistance. The Pontiac uses 18" wheels as a selling point (BLING) one that attracts people who do not understand what wheel size and weight can do to a car's handeling. The Mazda made the Miata as a drivers car and continues that tradition, there is no bling in a 16" wheel but there is a match to the chasis and suspension and brakes and an overall balance for good handeling.

I prefer the rawness of the 240 (to each their own). I do wear ear plugs on the free way though, at 80 the noise gets kinda loud. Around town the raw feel of the car is great. I have a much stiffer suspension and an L28 block so I guess it is not a "real" 240 but it does have the 240 feel only a faster one. The SU's on my 240 are never touched. I got them from Ztherapy, put them on and tuned them and have not touched them since. I get nearly 30MPG at 75 (with an 83 ZX 5 speed and a 3.9 R 190) on the free way and about 20 in town. The intown milage can go down fast though if I "drive" the car. Even though the SU's are not as frugal as fuel injection the light weight of the car counter acts that in the world of fuel economy. I think the diference in the 4 speed and 5 speed transmissions in the 240 and 280 make more of a difference in milage than the type of fuel delivery. When I had the 4 speed in the car (3.54 diff, low gearing) the milage was terrible on the free way.

It is too heavy, I would buy a Mazda Miata (2006). I really do not see any similarities to a Z at all.

The light weight of the 240 is the selling point for me and because, I know I am not supposed to say it, it is the original. The feel of the lighter wieght is awesome. I have done some modifications to the car, but if I did the same suspension work and got the same power to weight ratio in a 280 as my 240 and used the same tires the 240 would win in an autox (autoxing is the reason I drive a Z) due to the weight difference. Lighter weight cars handel better and feel better.

The Hoosier tires seem to measure the tread width. I ran 205/50's but the carcas was nearly 9" wide and the tread was 8". The 225's are nearly 9.5" wide which is close to a 245 on a street tire.

For handeling purposes an 8" width is preferable with a 225 tire. I guess for top speed drag could be an issue but when does anyone ever get to do that. Of course the handeling difference between a 7" and 8" wheel is probably not that big of a deal either unless it is on the track.

http://www.takumiproject.com/ These guys get jdm wheels for our cars. I believe thay can order new wheels from Watanabe too.

My 83 5 speed weighd 80 LBS when it was shipped to me.

Congrats on the new Z, I am also from TN originally. I am from the other side of the state thoutg, I grew up in Memhpis. I moved to Montana when I turned 20. I love to go back and visit as much as I can now. I had a lot of friends that went to UT after high school.

Nissan 920 Gold, great color. I do not know if it was rare originally but many people have changed from that color to a more contmporary color over the years so it could be getting rarer these days to see one.

In Missoula MT regular is $2.47, medium $2.57, and premium is $2.67. Deisel is up to $2.75.

The round top SU's from the 240 are the way to go. You can get a rebuild kit from www.ztherapy.com or buy a rebuilt set from them but the shipping might be pricey. The flattop SU's from the 260 are not very good, they were made for better emmisions and not performance. I do not know the gas mileage difference between the two but I get around 25+ on the road and 20 in town, but if I drive it hard then the milage goes way down.

With the right amount of power, a LSD and a very stiff rear suspension they can be driven sideways. I think the 240 SX would be better though and cheaper to build. The Zcars are better for track racing and autocrossing.

A 160 thermostat that stays open continously (once the motor is fully warmed up) is much the same a not running a thermostat at all. While the flow is restricted by the opening size as you stated earlier it is still flowing constantly which I think will lead to a heat problem especially in 100+ tempratures.

Did you read the first sentence of my post? I am assuming the 160 thermostat is open all the time. I do not think you have a full understanding of the post. The thermostat staying open is a problem. In a hot climate with a constant open thermostat there is more chance of over heating than with a warmer thermostat that opens and closes especially in stop and go traffic. To understand why go back and read my post you quoted. "If the engine is assembled correctly, it should run as well hot or cold, with less wear if it is warm." That is a quote from the book "How to Hotrod and Race Your Datsun." The info from that book is compiled from the author's, Bob Waar, racing experience and information gathered from the BRE racing team mechanics and from the Electromotive Company. I trust what these people know about the L24-28 motor. I did not just make up the info I gave. The info came from literature I have read. Many New cars run hotter than 190-195. If the colling system is in proper order the 190 thermostat should be just fine in a hot climate.

The 160 thermostat can cause problems by staying open continously. The coolant in the radiator is passing through but not staying long enough to be cooled down. The coolant needs to sit a while in the radiator to cool down then when the thermostat opens a rush of cooler coolant comes into the motor and you can see the temp guage go down. If the coolant does not stop in the radiator but passes through eventually the coolant will build up heat and the motor will over heat (in stop and go traffic not constant cruising). I run a 190 Thermostat and have no problems; I do live in Montana, hardly a hot climate, but we just had a few days recently where our temps were up to 102 and the temp guage did not run any hotter than today at 65 degrees (the guage needle stay in the middle of the "M" on the guage). And according to the book "How to Hotrod and Race Your Datsun" the L24-28 motors run best and give the best performance with a thermostat of 190-195 degrees. I think you might have better luck with a 190 thermostat.

On another Z site there is a person that recently got a Rebello stroker built and I think the total was $8500. That included the NISMO header and the 45mm Mikuni's. His motor produces around 315 HP. My friends makes around the same power but is not that streetable with 12.5:1 compression. He has to retard the timming to run pump gas for the street and the power goes way down, but when he is running race fuel the car is very fast. I would never go beyond 10.5:1 for a street motor myself.

The first car I had was not actually mine. It was a `65 Mustang with a 289 and factory air. My mother bought it new when she got out of college and I got to drive it from 16-17 1/2 years old. I did not own it but I drove it every day and loved it like it was mine, 17 1/2 years later I still dream about that car every now and again. There are obvious differences between a `79 and `65 mustang one less obvious difference is more than your back can get screwed in the back seat of a `65 Mustang. It was a great car but the Z is far better.

In Modified the car can run non dot tires, aka racing slicks, the interior is gone and there are probably other things too. In street Mod the car must be street legal so you would have to run DOT tires (like Hoosiers ect..), the body structure must remain but can be modified to allow larger wheels and tires (flares). You can incorperated a roll cage. If you go to www.scca.com you can look at the solo II rules and find all the differences. In the end a Modified car and a Street Modified car are very different. A streetable stroker can make 300+HP with the right build up. I race a friend of mine who has one. He races in Modified but the compitition is mild around here in his class. He still has the car's interior and only has a roll bar. I have driven his car before and the low end torque is great. I put the car in 2nd gear and run the course. The car pulls from 2000 RPM all the way to 6500. The interesting thing though is I beat him in my F prepared Z 50% of the time (this race season so far). I Do not have a roll bar or cage and have the full interior and make around 100 HP less. My car has a better suspension and no rust so the body is stiffer (he has a bit of a rust problem) and we run the same wheels and tires. I have beat him on tight courses and long fast courses too. The suspension, alignment and body stiffness will do more for the car than high HP. He is no slouch behind the wheel either, he has many years racing Z's and come from a family that races oll over the country (His brother is Goerge Bowland the multi time A mod National champion). You might want to spend less money on the cars suspension and stuff and go faster than spending big dollars on a stroker motor. No matter what class you race in (other than stock) you will need to change the suspension and should stiffen the chasis. once that is done you would be suprised how fast a Z can be even with the stock suspension. Then go for the fast motor.

The motor you choose will dictate the class you race in too. A stroker will put you into either Street mod or E modified. In e mod the cars are hardly cars anymore, beyond the front and rear bulkhead they are usually converted to tube frames. A stroker is great but a Lotus Europa with 600 HP that weighs 1600 LBS will blow it away. In Street Mod the cars are still cars, full interiors ect. This would be the best class for a stroker. Strokers are great for their low end torque which work well on the autox course. Look into the classes for racing and decide what you want to do, getting into a clas where you can never compete is not fun. Out side of racing strokers are great street engins too, I would love to build one myself.

I like the classic urathane or fiberglass one like I have on my car (and so many others have on their's) but I like the BRE dam the most. I do not like the intigrated bumper/dam from MSA however. But if you like it you should go for it.