A&Q about 350Z
Q:
Now you're asking the same question that I'M asking!
WHAT suspension CAN I use, for a FWD trans, converted to straight axles, as a Midengine application?
I have seen it done already, with a FWD TH425 ('70 Olds Toronado) trans, using straight axles, midengine, and I think it was using standard RWD suspension (shocks, springs, upper/lower control arms), which is how I got the idea in the first place!
I don't remember where I saw it, in a Hot Rod magazine, or on the internet, but I saw it, and it worked with the car that the guy built!
At the time, I wasn't even thinking about building my own vehicle like this, but now that I am, I need to research the chassis and suspension more.
If I can figure out, specifically, which suspension that I can use, then I can build the chassis, and the rest will come easy after that!
Maybe I shouldn't say that I want to build a "unique" vehicle. Maybe "unconventional" would be more appropriate.
A:
If you want to use a solid rear axle with a fwd tranny your going to have to hinge the entire motor and tranny so that it all moves, it would just be easier to use the cv axles like everyone keeps saying. If you cant understand this you shouldnt be doing this project.
A:
Define standard RWD suspension?
IRS has been in common use since the 60s, but the live axle continued common use untill..... well its still in common use (which IMO is says something sad about the manufactors who still use it).
A:
by unconventional do you mean "wrong because you don't know what you're doing"?
A:
Fwd trans + Midengine = either an independent suspension or De dion suspension.
Independent is either double A-arms type, multi link, Mcpherson strut (including conventional strut, or tri-link).
All these type require a double articulated half-shaft (driveshaft) on either side with "plunge"(length changing ability) incorporated into their design.
The older Corvettes, newer Corvairs and Jag XK-Es had an IRS where the upper A-arm was replaced by the half shaft, and a no plunge type shaft was required.
A weirder design with some really ugly limitations is the "de Dion" where a solid beam running under the transaxle or differential connects the right and left side wheel hubs. Fully articulated half shafts are used, with plunge.
Therefore you get a beam axle effect without adding the weight of the drivetrain to the unsprung weight.
I.E. the powerplant and transmission stay affixed to the car, and the wheels bob up and down together rather like the live axle on cousin Fred's '67 Camaro.
These can work pretty good, except if you start dumping serious power and tire width into the equation--then the whole rear axle system can go into a "tramp" (low frequency, high amplitude vibration) mode.
Jim Hall tried it in a later Chaparral Can-Am car--and it sucked, and Ferrari tried it (very briefly) in a 312T F-1 car--and it didn't pass muster.
A de Dion axle could be called a "straight axle". But it's better to call it a "de Dion", because if you mix mid-engine with "straight axle", it really messes peoples minds up.
Oink!
A:
Not all independant set ups need a length changing axle/driveshaft, its quite possible to enginer geometery into them that keeps everything equal length through the suspension travel.
Although its generaly easier to have plunging shaft.
A:
Also Jag XJSs.
One must also not forget the Mercedes Benz "low-pivot swing axle".
Well, OK maybe we should.
A:
By unconventional, I mean "I'd rather build a car, with the appearance and performance that I want, rather than just go buy a car that looks and runs like every other Japanese Plastic Eggmobile that you see on the road everyday, that I don't want!
I don't have to know what I'm doing.
I just have to know what someone else who's already done it, did, so I can do the same thing, and maybe add my own upgrades or improvements.
Anyway, I didn't come here for debates or definitions.
I'm capable of building the vehicle, as long as I get the correct answers from the qualified people that have them (hopefully someone who's already done this conversion, as I know there are a few)!
I know that the FWD TH425 ('70 Olds Toronado) has been successfully converted into a Rear Axle (no CV's! Straight left and right Axles, direct from gears to hub/wheel!)/RWD Suspension (Coil Springs, Shocks, Upper/Lower Control Arms), because I've seen it done!
I may just stick this FWD/Midengine Big Block concoction into the bed of an S10 pickup truck, add a tonneau cover, and call it done! Maybe that would be even easier yet! All the parts are available, anyway, either cheap or Free!
Depends who you know.
A:
Of course its possible, but if there is no moving linkage between the engine and the wheels, then either there was no Suspension travel, or the whole engine had to move when the wheels moved.
Neither is going to make the car useable on anything but a very large flat surface with no need to go around corners.
A:
A:
uh huh...
A:
I think you need to visit these chaps----
A:
Im one of the few who will sort of agree with you, but be aware it will help, and could save you lots of money.
A:
Thanks for your advice, Mop, but I'm one of the few that doesn't let money concern me, when I'm investing into my own cars. That's why most people refer to them as "toys", because they're just for Fun, nothing more.
I have a professional chassis shop that will build the frame for me, as I don't have the tube bending equipment to do it, myself, so it will be easier to have them do it, and it will also save me time that I can get the engine and transmission ready to install, as soon as we figure out the suspension.
I'm sorry if most of you have misunderstood my question, as I wasn't asking the Differences between the 2 types of suspensions, but rather how it's possible to Combine them, as I've already seen it done!
Thanks to all of you that have tried to participate, but I've found a partial answer to what I was looking for, Thanks to Black Lotus, through the guys that have already done it with the Fiero conversions!
I'll take it from here, now.
A:
Why do I get the feeling he didn't really understand the basic issue with straight axles?
Oh well....I guess he'll figure it out soon enough....