"Mechanix Menace": An LS7-motivated, chopped and heavily modified 1973 Datsun 240Z

[chevyz240]

October 26, 2014. Over the years I have contemplated different headings for the project. Especially during the last years, when I (for different reasons) haven't been doing much actual work on the car. (It is easier to get carried away, when you forget how much time it actually takes making all those crazy ideas a reality.) One day I have "decided" that the car will be an extreme track day tool with barely tolerable streetability, only to the next day "decide" that it should be comfortable with all modern amenities including climate control, noise insulation and a good stereo. The last months I have thrown around the idea of making it an AWD car for instance. As late as a few days ago I thought I had "decided" to make the car as light as possible by building the entire chassis out of aluminum sandwich panels and making the body out of fiber glass or carbon fiber, with basically a totally new design according to the renderings I have posted. The suspension would be a fully custom made A-arm suspension all around, with probably even my own spindles. The radiator would reside in the trunk to get as big a rear weight percentage as possible. No concessions to comfort would be made at all. A lot of all the work I have done to the car to this date would be scrapped. Fairly thorough calculations showed a possible dry weight of under 2100 lbs.

Yesterday I made a definite decision (I think) to be a little bit more realistic and make it possible that the car actually will be finished before the earth's crude oil reserves run out! After doing a lot of research on suitable donor cars I thought that a 5-series BMW E39 would be a good candidate. First I went to a junkyard to look at BMW E39s to see if it seemed that it would be feasible to use the suspension and other systems. Everything looked good, and after that I went to a car dealership to test drive a car they had, just to feel if the potential was there. I wasn't really thinking about buying the car at all. The thought was just to mull this idea over and later make a definite decision. But since the car seemed solid, I threw out a really low bid, which they accepted! So, as of yesterday, I am the proud owner of this BMW 523 from 2000.




Since I have actually bought a donor car I have more or less locked in the project future! Well, this isn't totally true, since I did buy a Chevy van to use as a donor car for the drivetrain to my Chevy pickup. I never used any parts at all, and I parted the van out in pieces. A lot of work for nothing! Well, I think this will not happen this time. The idea is to take the suspension, steering, ABS system and so on and use them on the Datsun. I think I will try to use as many systems from the Bimmer as possible, including the climate control system. I may even use some of the airbags. To do this I will research how critical it is that the crush properties remains the same.

I will probably try to use as much as possible of the rear floor structure of the BMW and mate it to the Datsun body. From the front end, I will probably use the main chassis beams and the front subframe, building new inner fenders. Due to the Datsun's low profile, I can't use the Bimmer's MacPherson struts, plus I really would rather have an A-arm suspension. The idea is to take the strut away, and build an upper A-arm instead. One of the beauties of the BMW front suspension is the divorced lower A-arm with twin spindle joints, creating a virtual pivot point. This gives, among other things, a shorter scrub radius, making the steering less nervous when braking on uneven surfaces and so on. That way you can use wheels with less offset, which I really like from a looks standpoint. I will use a suspension modeling program to see if I can get by building a traditional upper A-arm with one spindle joint or if I need to use two. For the cockpit of the car I will probably still use sandwich panels, but not on their own. They will be glued and riveted to a steel tube frame structure.



In order to save lots of time and money I have ditched the idea of making my own car body. I will use what I already have and just make some traditional fender flares. They will be pretty wide though, to accommodate a much wider track than stock! The stock modified steel doors will also be retained. So now you guys that haven't liked my renderings can relax! The car will now still be recognizable as a Z-car, which also is kind of nice! Compared to building the car as I described above, it will be a lot heavier. Now the focus will not be on ultimate track performance, but instead on a car that will be enjoyable on long road trips as well. I will use as much sound insulation as necessary to not having to use ear plugs when driving (I have pretty sensitive ears). I will not throw handling prowess away totally; the goal is still to be able to kick sports car ass on the track! Since the car is so small, it still will be reasonably light, compared to traditional pro touring cars. I can imagine a dry weight of under 2800 lbs being realistic.

In my day job I sometimes get to ride in, and sometimes even drive, pretty extreme super cars like Koenigsegg, Pagani and others. This, in combination with higher age, has made me a bit blasé. I'm not all that impressed by the performance. So if I really concentrated on making my car as racy as possible, I think I still would crave more. With the above outlined project description, the car will be more allround, making it enjoyable on more levels. We will see if I'll have to eat these words later on!

Now, I will modify the Blender model to show the new (old) look of the car. The side view should be close to the previously made Photoshop rendering below.

[chevyz240]

November 1, 2014. Before I started taking the BMW apart, I took some test drives on bad roads, and it seems that the tramlining sensitivity is pretty low, as I hoped. The suspension also swallows big potholes with great composure and it rolls really comfortably. This indicates that even with a considerably stiffened suspension, I will still have great streetability. I have made a first rough model showing the new look of the Z. Since I’ve decided not to widen the entire car body, the fender flares will be pretty wide. It feels pretty good to have decided on using existing suspension components and to retain the modifications I’ve done so far on the car, instead of throwing them away and starting all over again. I think I have saved maybe two years of work this way!

[84TransAm]

I really like your build, for the most part. Some of the stuff you did was cool, some lost the feel and spirit of the Z car. I'm glad you found it again with your last rendering. My friend and I have 6 Z cars. We are planning a build LSX monster build ourselves. Ours will not be as extreme as yours,but you did give me some cool ideas. I look forward to seeing your Z come together!


Here's a rendering of what we have in mind.

[chevyz240]

I really like your build, for the most part. Some of the stuff you did was cool, some lost the feel and spirit of the Z car. I'm glad you found it again with your last rendering. My friend and I have 6 Z cars. We are planning a build LSX monster build ourselves. Ours will not be as extreme as yours,but you did give me some cool ideas. I look forward to seeing your Z come together!


Here's a rendering of what we have in mind.

Hi!

I like your rendering! How much of it is real, and how much is computer rendered?

[84TransAm]

Hi!

I like your rendering! How much of it is real, and how much is computer rendered?

As far as the rendering, I couldn't answer that. My friend I'm building the car with, did it. I just try to make the metal match the rendering. The base car we are starting with is a 72. We have a 73 for the mint door, 74 for a mint interior, a 77 cause it came with the 74 and it's now a driver, a 78 2+2 cause it was complete and very cheap, and an 80 10th anniversary, cause I like it. I've had the 72 and 80 since 1992. I'll start a build thread for the 72 when it moves from the barn to the shop and we finally get started. We have 95% of the parts for the build, just not the time yet. Anyway I can't wait to see the next phase of you car.

[David LaBuda]

The rendering looks like it was done with Indigo Renderer and Google Sketchup. I actually have a file with that 240Z model.

[chevyz240]

As far as the rendering, I couldn't answer that. My friend I'm building the car with, did it. I just try to make the metal match the rendering. The base car we are starting with is a 72. We have a 73 for the mint door, 74 for a mint interior, a 77 cause it came with the 74 and it's now a driver, a 78 2+2 cause it was complete and very cheap, and an 80 10th anniversary, cause I like it. I've had the 72 and 80 since 1992. I'll start a build thread for the 72 when it moves from the barn to the shop and we finally get started. We have 95% of the parts for the build, just not the time yet. Anyway I can't wait to see the next phase of you car.

Hi again,

could you maybe ask your friend about the rendering? It sounds like you have lots of part on hand to create a great car! Best of luck! This weekend, I hope to pull the engine and tranny out of the Bimmer, and maybe even start cutting out the suspension. Pictures will be posted!

[chevyz240]

The rendering looks like it was done with Indigo Renderer and Google Sketchup. I actually have a file with that 240Z model.

Thanks David! Would it be possible for you to send me the file? What format does it have? Nice Chevelle build you've got goin'!

[David LaBuda]

If you PM me your email address I should be able to send it to you. I couldn't figure out Blender for the life of me but I learned these programs quickly. You shouldn't have a problem if you're that good with Blender haha.

Sketchup is a free program that can be downloaded here: http://www.sketchup.com/download
I don't know how much experience you have with 3D CAD software, but Sketchup is very easy to learn.

I use Indigo Renderer to render Sketchup models. It works as a plug-in and will render scene you are currently viewing in Sketchup. You will need to define the materials used in the model (paint, stainless steel, glass, etc.) in the plug-in on Sketchup. Everything else is straightforward after you set up your materials.
Indigo can be downloaded here: http://www.indigorenderer.com/download-indigo-renderer
You can still use the program after the trial period is expired. The renderings will be limited to the size of the ones I posted and they will have that watermark. It's a small price to pay for such useful software!

I hope this helps. Let me know if you have any other questions.

-David

[chevyz240]

If you PM me your email address I should be able to send it to you. I couldn't figure out Blender for the life of me but I learned these programs quickly. You shouldn't have a problem if you're that good with Blender haha.

Sketchup is a free program that can be downloaded here: http://www.sketchup.com/download
I don't know how much experience you have with 3D CAD software, but Sketchup is very easy to learn.

I use Indigo Renderer to render Sketchup models. It works as a plug-in and will render scene you are currently viewing in Sketchup. You will need to define the materials used in the model (paint, stainless steel, glass, etc.) in the plug-in on Sketchup. Everything else is straightforward after you set up your materials.
Indigo can be downloaded here: http://www.indigorenderer.com/download-indigo-renderer
You can still use the program after the trial period is expired. The renderings will be limited to the size of the ones I posted and they will have that watermark. It's a small price to pay for such useful software!

I hope this helps. Let me know if you have any other questions.

-David

Hi again David,

I work as a design engineer, so I work with 3D Cad every day! I am hoping to be able to import the file to Blender. I would like to compare it to my own model, and see if I maybe can use some features, so I can save some time. Otherwise I may check out Sketchup and Indigo Renderer as well! You have a PM.

[84TransAm]

Henrik,

I just talked to my friend, It was Sketchup that he used.

[chevyz240]

Henrik,

I just talked to my friend, It was Sketchup that he used.

Thanks!

[chevyz240]

November 15, 2014. The BMW is coming apart nicely, and today I mocked up the rear suspension roughly where it will sit. I will have to either get suspension geometry data from BMW or get it myself by measuring all the coordinates of the joints in order to specify the exact height, to get the roll center height, camber curve etc. where I would like it to be.

[andrewb70]

Nice!

Andrew

[84TransAm]

Very nice! The BMW stuff looks like a nice fit, I might have to borrow that trick when we get started.

[chevyz240]

Nice!

Andrew

Thanks Andrew!

[andrewb70]

How durable are those BMW rear ends?

Andrew

[chevyz240]

Very nice! The BMW stuff looks like a nice fit, I might have to borrow that trick when we get started.

Thanks! Yes, it does fit kinda nicely! It's also pretty lightweight, since everything is aluminum. The whole assembly as you see it here, with wheels, 3rd member etc. weighs 320 lbs. When I'm done, it will be a bit heavier, due to bigger brakes and wheels, but also due to the fact that the E34 M5 3rd member I will be using is pretty heavy at around 100 lbs.

[chevyz240]

How durable are those BMW rear ends?

Andrew

I'm not really sure about the halfshafts and differential that's on this rear end, Andrew. This is the medium case diff with 188 mm ring gear. The M5 diff I'll be using is the large case 210 mm version. This is really strong. There are guys using it in dragracing on cars that have over 1000 hp, at least! I think the medium diff is pretty strong too, though.

[chevyz240]

November 16, 2014. Today I removed the front suspension, the engine and the tranny from the BMW. I got them all out as an assembly, lifting the body off of it. Now I have the major parts I need removed from the car. Then, it's just a matter of removing the wiring harness and all the different small parts I may use.