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 Post subject: project "top heavy" awd
PostPosted: November 27, 2013, 3:22 am 
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Been doing a lot of reading and since I dont want to buy a new engine every 50,000 miles (more like every 5000 miles with my lead foot) bec is out, and that also means no mid engine. My only other idea is doing a subi. The simple rear wheel drive car is apealing, but since this is my second and possibly last locost I want to do it crazy and do it detail oriented. So its all wheel drive. I know the engine will hang out but I dont care im thinking of that morgan with the v twin showing out front. Put the radiator in the back and keep everything else as far back as possible for weight distrobution.
the lostus elan and europa frame design still look like great options since its small strong and light. Maybe do some inboard shocks going across the top of the engine just for flare. Hopefully santa will bring lots of fabing tools this year.
How extremely hard do you guys think it will be to get weight distrobution remotely near 50/50?


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PostPosted: November 27, 2013, 4:41 am 
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OK, I understand you want to do what you want to do, but how does mid engined mean the motor won't last but 5,000 miles?

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PostPosted: November 27, 2013, 8:34 am 
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I'm with Carguy. Midship is probably more difficult with a Bike engine. On the other hand most cars are front wheel drive and you can just put that behind the driver. If you get a transaxle from audi/VW/Porsche/Subaru then you can put lots of nice motors in front.

A subaru makes this simple, the four wheel drive part just gets in your way…


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PostPosted: November 27, 2013, 4:51 pm 
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Sorry should Have worded that better, I don't want mid engine with a car engine, I just feel like it doesn't balance as good. I figured a bike engine would be light enough to put in the back without the side effects. And since people don't get 300K miles out of becs. Boxer was my other favorite.

Does anyone have any thoughts on the awd boxer?


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PostPosted: November 27, 2013, 6:50 pm 
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johnnybusa wrote:
Sorry should Have worded that better, I don't want mid engine with a car engine, I just feel like it doesn't balance as good. I figured a bike engine would be light enough to put in the back without the side effects. And since people don't get 300K miles out of becs. Boxer was my other favorite.

Does anyone have any thoughts on the awd boxer?



I thought you just said you don't want mid engine with a car engine??? What do you think the Boxster is?

I think Subaru is a great way to go. They must have flipped the ring gear or something in that pic above if that is a Subie transaxle. Because Subie are plentiful and powerfull AND reliable, it's a great swap into just about everything from buggies (both rear and mid engined), Porsche 914, Boxsters and God have mercy on their souls, even the 911.

Tom

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PostPosted: November 27, 2013, 7:11 pm 
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Off Road SHO wrote:
johnnybusa wrote:
Sorry should Have worded that better, I don't want mid engine with a car engine, I just feel like it doesn't balance as good. I figured a bike engine would be light enough to put in the back without the side effects. And since people don't get 300K miles out of becs. Boxer was my other favorite.

Does anyone have any thoughts on the awd boxer?



I thought you just said you don't want mid engine with a car engine??? What do you think the Boxster is?

I think Subaru is a great way to go. They must have flipped the ring gear or something in that pic above if that is a Subie transaxle. Because Subie are plentiful and powerfull AND reliable, it's a great swap into just about everything from buggies (both rear and mid engined), Porsche 914, Boxsters and God have mercy on their souls, even the 911.

Tom


I said BOXER not boxter and yes I want it to be a subi boxer engine


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PostPosted: November 27, 2013, 8:32 pm 
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johnnybusa wrote:
Sorry should Have worded that better, I don't want mid engine with a car engine, I just feel like it doesn't balance as good. I figured a bike engine would be light enough to put in the back without the side effects. And since people don't get 300K miles out of becs. Boxer was my other favorite.

Does anyone have any thoughts on the awd boxer?

Err, perhaps someone should notify Porsche, Ferrari, Lamborghini, and Lotus that they're building sports cars all wrong in that case :shock:

Seriously though, I'm confused as to why you'd come to that conclusion? The Subaru would make a great middy drivetrain.

D


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PostPosted: November 27, 2013, 8:50 pm 
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I said I FEEL as in it's my opinion. I had a first gen and third gen mr2 and I liked my miata better I like my friends miata better. It's my opinion and I want my car to drive a certain way, got a problem with it? Anyway I'd like comments about how you think an awd locost would work. Try to avoid being a Dick from now on


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PostPosted: November 27, 2013, 9:42 pm 
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I'm out, way too much attitude going on here.

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PostPosted: November 27, 2013, 9:47 pm 
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johnnybusa wrote:
Does anyone have any thoughts on the awd boxer?


It's a bad idea, IMO.

Subies have 60f:40r weight distributions due in large part to how far forward the engine and transmission sit. And that's with ~2900 lbs of non engine/transmission stuff spread out around the car. In a Locost with maybe ~800-1000 lbs of other stuff, you're going to have a heck of a time trying to get anywhere near the 50:50 weight distribution you want. And even if you do manage to do better than 60:40, likely by putting as much heavy stuff as possible out behind the rear axle, you're going to end up with a seriously high polar moment of inertia. I don't know what your knowledge level is so I'll give a brief summary; polar moment of inertia is how much an object resists rotational acceleration (turn-in for example), and the pmoi of an object (a car for example) is the sum of each component's mass times that component's distance from the center of mass squared (m*d^2). By putting as much weight as far away from the cg as possible you would end up with very sluggish turn-in and steering response which, IMO, defeats the whole purpose of a lightweight car.

johnnybusa wrote:
I had a first gen and third gen mr2 and I liked my miata better I like my friends miata better. It's my opinion and I want my car to drive a certain way


Out of curiosity, have you driven a Subaru? There is a much bigger difference in feel between a Suby and a Miata than there is between a Miata and an MR2. The difference between an AWD Suby based Locost and a Miata based Locost would be even bigger still.


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PostPosted: November 27, 2013, 9:49 pm 
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I think everyone knows Porsche put the engine in the wrong place (rear engine) Lol but they are still amazing cars.

As for using the boxer engine I think it is an amazing choice. As you have said the engine I'd going to be very far forward and maybe the front wheels a little further back. The car will be a blast to drive and will launch so hard. It would make an excellent drag car. I would look for a crashed series 1 imprezza turbo as a donor. I cannot think of and 4wd threads of hand but I think there are some have a look around.

This time buy the right steel and make the frame strong. You built your first car quickly and I don't think it would do well in an accident.

I wrote this before the guy above posted. I agree you are never going to make it 50:50 but the engine I'd a flat 4 so a very low center of gravity. All front and 4wd cars have a tenancy to push unless they are very expensive or have a lot of suspension work done.

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PostPosted: November 27, 2013, 9:57 pm 
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I think what he's saying is a transverse mid mounted engine will be hard to get balanced at the edge. Look how many years Porsche took to get the 911 working. And the other cars you mentioned are longitudinally mounted not transverse.

I personally think he's right. Look at how much bad press the At-om gets on handling. It's simply not stable and they've been working on it for years. Everyone talks about how hard it is to be consistent, how twitchy it is and what a handful.

Sure there will eventually be a formula that makes it work, you can make anything work such as putting the engine back behind the rear axle, but it takes much more time money, and maybe lives, than any of us have to give.

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PostPosted: November 27, 2013, 9:58 pm 
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Try to avoid being a Dick from now on


Don't talk like this here. That's a completely inappropriate response. Just take a deep breath and figure out how to answer people without calling them names…

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PostPosted: November 27, 2013, 10:08 pm 
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johnnybusa wrote:
I said I FEEL as in it's my opinion. I had a first gen and third gen mr2 and I liked my miata better I like my friends miata better. It's my opinion and I want my car to drive a certain way, got a problem with it? Anyway I'd like comments about how you think an awd locost would work. Try to avoid being a Dick from now on

OK, and you too please.

Best of luck with whatever you build - I'll stay out of the conversation.

D


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PostPosted: November 27, 2013, 11:04 pm 
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johnnybusa wrote:
I had a first gen and third gen mr2 and I liked my miata better I like my friends miata better. ....... Anyway I'd like comments about how you think an awd locost would work.


If you like the way the miata handles, a traditional locost is similar, just amped up due to the reduced weight. Maybe consider a more traditional locost build but go a bit more exotic on construction methods or components to give it a unique flare that you appreciate.

An AWD locost has been mentioned many times around these parts. It's a bit of a logistical nightmare. I can't recall anyone actually doing it and posting up a log here but I may be wrong. I think the big issues center around packaging. As gregk mentioned, you are going to have a hard time balancing out that massive weight in front of the front tires. It is a bit of physics that is just undeniable but unlike the 911 where the weight helps rotate the car (dramatically, it isn't called the widowmaker for nothing) your front engined car wouldn't want to rotate at all.

Instead of a transaxle setup that puts the engine in front of the front axle, I think a transfer-case with drivehsaft traveling forward is a better option. Image This picture was linked from wikipedia. It is of BMW's X-drive. Many vehicles use this sort of a system, and packaging it would be easier.


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