Alrighty... the durocco has me thinking. (And it's merely just that, thinking, at the moment.)
Other similar shaped cars... hatchbacks.
What's the hardest part? Co-ordinating the two transmissions?
What's the easiest, most straight-forward way to get the motor mounted in the back "correctly?"
For arguments sake, let's say the car in question would be an MX3.
Ive been investigating twin-engine cars for some years now. I want to do a twin engine Geo Storm for some reason, wish i could tell you why. I would say doing the shift linkage to work together is the tough part...
I would say the hardest part for an amateur fabricator is swapping a suspension into the other end of a car. That is the only precision part that needs to be done. An engine can be mounted at an angle, a couple inches to the left, etc... it doesn't matter. Get your suspension half an inch off-trouble.
My thought was to use a car with awd factory and just adapt the rear engine and trans to the factory hubs with custom axles or some homebrew junkyard variety of custom axles.
Why would the suspension need to be swapped? In the case of the MX3, the only major fab i could see would be to just get another set of front struts/hubs/knuckles into the rear. Simple (famous last words) matter of making an adapter plate for the top mounts.
In case you can't tell, i'm probably in way over my head, but that's why i made the thread. 
Thread makes me think of this:
http://www.autoblog.com/2011/02/28/video-twin-small-block-v8-priaprism-is-enviable-hedonism/
92CelicaHalfTrac wrote: Why would the suspension need to be swapped? In the case of the MX3, the only major fab i could see would be to just get another set of front struts/hubs/knuckles into the rear. Simple (famous last words) matter of making an adapter plate for the top mounts. In case you can't tell, i'm probably in way over my head, but that's why i made the thread.
If that will work that is awesome. Usually the design of the rear suspension places things like springs, shocks, etc... in the way of the axles. If you are mounting the front hubs/strut assembly in the rear, how are you going to keep it from turning without a steering rack?
MrJoshua wrote:92CelicaHalfTrac wrote: Why would the suspension need to be swapped? In the case of the MX3, the only major fab i could see would be to just get another set of front struts/hubs/knuckles into the rear. Simple (famous last words) matter of making an adapter plate for the top mounts. In case you can't tell, i'm probably in way over my head, but that's why i made the thread.If that will work that is awesome. Usually the design of the rear suspension places things like springs, shocks, etc... in the way of the axles. If you are mounting the front hubs/strut assembly in the rear, how are you going to keep it from turning without a steering rack?
Ah hah! And this is why i have you guys around. 
I didn't think about that.
But, i wonder if that's all even necessary. I wonder if i could just slap some front hubs on the rear springs/struts and roll like that. (Assuming of course that the arms will clear the rest.)
I think i need to know what Ansonivan did... It's a pretty simple setup in the back of an MX3.
As far as i can tell, as long as i can get the axles in there, and i can keep the car from steering in the ass end, that's essentially the battle, yes?
The way I see it, is just take the entire front subframe, and weld the pig to the ass end of the car. I'd imagine shock mounting areas would be roughly the same distance apart, so getting the tower tops right would probably be fairly easy. The other thing I would do is pull the entire steering rack, weld in a section of round bar, and weld a support mount between that and the unibody of the car for rigidity.
Are there any basic measurements that i should take in the rear of the car that would tell me if this would require mndsm's suggestion, or if there's an easier way?
What should be looking for to tell me if this would be one of the "easier" chassis' available for this project?
If i go MNDSM's route...i'd just as soon weld up the steering rack in the FRONT, and turn the interior around, drive the thing around backwards. 
mndsm wrote: The way I see it, is just take the entire front subframe, and weld the pig to the ass end of the car. I'd imagine shock mounting areas would be roughly the same distance apart, so getting the tower tops right would probably be fairly easy. The other thing I would do is pull the entire steering rack, weld in a section of round bar, and weld a support mount between that and the unibody of the car for rigidity.
Fiat did something similar with the X-1/9. Only they hard mounted the inboard tie-rods to the frame. Otherwise, it is mostly the front end from a Fiat 128 in the rear.
A FX16 might be interesting with a MR2 drivetrain in the back. The linkage would be pointed the right way....
The Durocco suffered from bad bumpsteer in the rear apparently. Something that is inherent in strut-based suspensions. So you need to be aware of the suspension pickup points and work to reduce the amount of bumpsteer in whatever solution you end up with. I would look at ways to lock the uprights from rotating at the outer control arm pickup. Not as big an issue with systems that use upper and lower control arms.
BTW, here's the rear suspension from an MX-3:
I'm going to come right out and say that i'm a little less concerned with handling than Ansonivan was with the Durocco, methinks.
My extent of handling wants is as follows:
1) Somewhat stable
2) Won't actively attempt to kill me at all times.
This car would be more about gross displays of power/hoonage. Let's just say that it would be relatively "easy" to see almost 400whp to each axle without breaking the bank.
92CelicaHalfTrac wrote: 2) Won't actively attempt to kill me at all times.
92CelicaHalfTrac wrote: Let's just say that it would be relatively "easy" to see almost 400whp to each axle without breaking the bank.
This is so contradictory it's hilarious.
unevolved wrote:92CelicaHalfTrac wrote: 2) Won't actively attempt to kill me at all times.92CelicaHalfTrac wrote: Let's just say that it would be relatively "easy" to see almost 400whp to each axle without breaking the bank.This is so contradictory it's hilarious.
I realized that after i typed it...
I guess my point is that if i'm going to die, i'd like it to be because of the power, not necessarily because the suspension is COMPLETELY inept at well... being a suspension.
A dedicated autox/corner carver, this car will not be. 
Basically, as long as it's capable of cruising in a straight line, and making it around on/offramps at speeds keeping up with local traffic, i'm cool.
I'm thinking:
2x Millenia KLG4s (2.5 v6, $150 at the local junkyards)
2x MX3 GS trans ($75 at the local yards)
2x large-ish turbos
2x Evo 8 intercoolers (got my last one for $40)
2x Megasquirt (Or go cheap and go FMU + millenia injectors)
Fuel cell to take care of that pesky gas tank, and shift linkage.
It would be loud, it would be scary, and cheap (barring time for fab work.) I know i'm making it sound way easier than it is, but that's the general gist of the brain-vomit i'm experiencing right now.
Uh, Ansonivan found it to be very unsettling to drive on pavement due to the bumpsteer. I'm not saying you need to completely re-engineer the suspension, just pay attention to where the pickups are and before locking things in place, pull a spring and run the suspension through full motion and see what happens. That way you won't be caught off-guard by the 800hp 4WD behemoth you're building decides to rotate the rear on corner entry, every freaking time.
BTW, the 323 GTR/GTX were AWD with TTL rear suspension:
http://www.mazdafun.com/product%20info%20chassis.htm
So were some Aussie Ford Lasers (Escorts in the US):
http://users.tpg.com.au/tgrandja/images/Articles/overview.htm
Might be a source for rear uprights that will work for your solution. Worth some research at least.
Wow.... more similarities between the two than i thought...
Thanks!
Speaking of the MR2, it seems easier to drop an entire FWD (built B18?) into the front of an MR2 than going the other way round. Or why not drop an MR2 Turbo powertrain into the rear of the MX3 and save some issues?
Another question: A 4WD system routes one input powershaft to two output driveshafts right? Can you simply flip it around and run the output of two motors into it and out to one drive axle?
pinchvalve wrote: Speaking of the MR2, it seems easier to drop an entire FWD (built B18?) into the front of an MR2 than going the other way round. Or why not drop an MR2 Turbo powertrain into the rear of the MX3 and save some issues? Another question: A 4WD system routes one input powershaft to two output driveshafts right? Can you simply flip it around and run the output of two motors into it and out to one drive axle?
Main reason is cost. 3sgtes aren't cheap. I know, because the Smellica is getting one. KLG4s ARE cheap and plentiful, and will still make GOBS of power under boost.
I also have an MX3, and don't have an MR2. I also wouldn't hack up an MR2, i like them too much.
some time ago, Volkswagen built a couple of twin-engined cars for runs at Pikes Peak. I didn't do a search but there has to be something out there on those cars. I believe one was a Rabbit/Golf while the other was a Scirocco
rl48mini wrote: some time ago, Volkswagen built a couple of twin-engined cars for runs at Pikes Peak. I didn't do a search but there has to be something out there on those cars. I believe one was a Rabbit/Golf while the other was a Scirocco
I believe, reading the Durocco site, those were actually his inspiration.
pinchvalve wrote: Another question: A 4WD system routes one input powershaft to two output driveshafts right? Can you simply flip it around and run the output of two motors into it and out to one drive axle?
So you are saying use the two drive shafts as input shafts for the tranny and the input shaft linked to a separate drive shaft. Mechanically there is little difference doing it that way except then the ratios in the tranny will be backwards so instead of multiplying torque you would instead be reducing torque and multiplying speed. So, it could be done if you can completely switch all the ratios, but then the gears may not fit into the case. I'm thinking the idea is suitably outside the box but now it is an engineering and fab nightmare.
Some research indicates that the MX3 suspension links are longer than the Escort/Protege pieces, but otherwise seem to be interchangeable. Using the MX3 parts on an Escort widens the track by 30mm apparently.
Using FC ball joints up front widens the track another 13mm, but finding axles for that setup hasn't been discussed yet.
http://feoa.net/modules.php?name=Forums&file=viewtopic&t=71352
So perhaps a combination of Laser AWD rear hubs with MX3 links should work. Not sure if MX3 front axles would work, or if you'd need to do something different there. Once you gather parts and set them in place you can do some measuring and test fitting.
This way you use the existing geometry of the TTL and the bumpsteer issue is pretty much not an issue since it is built-in and seems to work.
Oh and here's an interesting discussion:
http://www.feoa.net/modules.php?name=Forums&file=viewtopic&p=240638
Unfortunately, the 323 GTX is nearly impossible to find anymore.
http://323gtx.homestead.com/
Bumpsteer isn't the hard part...
The hardest part is after all the work, having the resulting car suck. Think about having one end of the car start to pull earlier than the other due to slight differences in turbo boost, cams, and/or exhaust. There's a reason why twin-engine cars are never shown in any sort of situation requiring corner prowess. To fix it requires combining the power of the two engines, then distributing said power to the four wheels. May as well then just use one engine.
turboswede wrote: Some research indicates that the MX3 suspension links are longer than the Escort/Protege pieces, but otherwise seem to be interchangeable. Using the MX3 parts on an Escort widens the track by 30mm apparently. Using FC ball joints up front widens the track another 13mm, but finding axles for that setup hasn't been discussed yet. http://feoa.net/modules.php?name=Forums&file=viewtopic&t=71352 So perhaps a combination of Laser AWD rear hubs with MX3 links should work. Not sure if MX3 front axles would work, or if you'd need to do something different there. Once you gather parts and set them in place you can do some measuring and test fitting. This way you use the existing geometry of the TTL and the bumpsteer issue is pretty much not an issue since it is built-in and seems to work. Oh and here's an interesting discussion: http://www.feoa.net/modules.php?name=Forums&file=viewtopic&p=240638 Unfortunately, the 323 GTX is nearly impossible to find anymore. http://323gtx.homestead.com/
Yep, i had to fight off everyone telling me to take the rear suspension off my MX3 and put them on my Escort. The wider track wouldn't have done a whole lot for me.
Using FC balljoints up front is really only something you do with a V6 swap on the Escort/Protege. That lets you use the G25 variant that attaches to said V6 and use MX3 axles without binding and/or ridiculous geometry problems. The MX3 axles are shorter.
There's at least one person on here who has done the AWD Escort/Protege swap, but i'm 100% certain that the rear hubs aren't going to work with the front axles i'd be using... Not to say they couldn't be adapted somehow, but i almost think it'd be easier to somehow incorporate the front hubs in the back.
Of course, i'm new at all this, so i'm sure i'm missing something huge. 
The actual "doing" of putting a second drivetrain in the back of a FWD car is a lot of work but straightforward. This is a classic case of good workmanship != good engineering. Just because it can be done doesn't mean it'll be good at anything. Then again, if it's all for show then it makes perfect sense...
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