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PostPosted: October 11, 2011, 6:49 pm 
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Something else on the Kelmark style,

Bob Anderson of Cidco the Mid engine Corvair Guru, after many long talks with him I learned the reverse cut gears also require the engine to be built to run reverse,
The plus is with the super diff ( no longer sold ) the Kelmark lay out because about as strong as any lopo Saginaw, so still no hole shots...the quill shaft just won't take it.

Avoid corvair posi trac rears they are weak.

Wment, what type car you running I have a Valkyrie with the Fiberfab version of the Crown set up,
At first I couldnt wait to got to the audi 5000 but for now I am going to run the crown set up while I plan something wild and silly stupid for the future.


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PostPosted: October 13, 2011, 2:27 am 
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horizenjob wrote:
Running the Porsche box upside down is standard for a race car because it makes the engine sit very low. The input to the transmission and the engine crankshaft sit below the half shafts. Does that work out for you on the street and do you have a dry sump? Just curious. I wasn't sure you could work that out, that what my formula ford does, but it only has 2" ground clearence...


Marcus, missed your question first time around. Yes, it works well on the street. I use the standard Ultima mounts for the G50/52 and a stock wet sump pan on the motor. 315/30x18 tires and some designed-in droop in the half-shafts help with the motor's ground clearance. I'm much more likely to have my splitter hit pavement than the pan, although the consequences are quite a bit different. :ack:

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PostPosted: October 14, 2011, 12:20 pm 
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Location: Annapolis, Md. USA
the13bats wrote:

Wment, what type car you running I have a Valkyrie with the Fiberfab version of the Crown set up,
At first I couldnt wait to got to the audi 5000 but for now I am going to run the crown set up while I plan something wild and silly stupid for the future.


I will be using the Kelmark type adapter on a Corvair Transaxle. I may eventually go to the Audi 012 or 016 in my Fiberfab Valkyrie. Even though the 012 is a weaker trans I feel it would be ok considering reasonable horse power and my driving habits. The 012's are much easier to find and I have developed a SBF (289,302,351) adapter for it. KEP makes the adapter for the 016.

wm


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PostPosted: November 7, 2011, 1:28 pm 
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I have mentioned a few times that one solution is to turn the V8 around, run a 4WD box forward and run a driveshaft back to a rear diff and forward to a front diff if you want 4WD, well here is one very successful lo(w)cost example ...

So watch these ..

http://www.youtube.com/watch?v=TjyrCGWoguU

http://www.youtube.com/watch?v=dY19DBoJJVw

http://www.youtube.com/watch?v=9CdQHpdZClg

..and read this...

http://www.cordiapower.com/featurecar04.php


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PostPosted: December 8, 2011, 4:36 pm 
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I'm kind of late to the party but wish to jump in.
I really like warpspeed's suggested drivetrain layout. Lamborghini also uses this layout see this National Geographic video at address below (sorry I can't figureout how to make a link)

http://www.dpccars.com/car-videos-09/10 ... etrain.htm


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PostPosted: December 12, 2011, 6:11 pm 
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My thoughts to immulate the Lamborghini/Bugatti mid-engine drivetrain with locost domestic driveline components:

Small block V8 Dodge/Chrysler installed backwards, behind cockpit, AX15 transmission/NP231 transfercase from a Wrangler/Cherokee (all bolt together w/o adapters) and occupy the space between the seats. Transfer case may be "clocked" if required for ground clearence and partially occupy passenger's leg space. Driveshaft from the front drive take off of transfer case to 8.8 Ford IRS differential (c/w reverse rotational gears or mounted up side down) located slightly off center in front of the engine's harmonic balancer to maintain low C of G.

All the components are cheep, durable and capable of high torque. The AX15 has a low first gear but 2-5 gear will make a good 4 speed. Shifter will be near the driver, shift pattern will be backwards, short shift linkage may be required. The NP231 could be partially gutted of unnecessary gears and locked in high range.

This concept my appear "way out there" but Lamborghini and Bugatti have proven it. The cost of the alterative high torque transaxle drivetrain is no longer locost and I don't believe they can take much abuse, read more money!

Any comments please!


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PostPosted: December 15, 2011, 8:25 pm 
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How much is it going to weigh? I have thought long and hard about building a v-8 midi. I had a hard time figuring out how I could make it significantly lighter than my front mid engined v-8 locost. Using the components you list adds the weight of a transfer case and one more level of parasitic loss (the gear and chain). My dream design requires lightweight wheels ,tires, brakes, spindles etc etc etc and would have to be significantly smaller than mine to be meaningfully lighter. How you going to make it small when 2 seats and a driveshaft and a transmission have to fit in the width of the car? Thats wider than a locost by a transmission!


I also have trouble understanding how the mass will be any more centralized. I have my front axle centerline 12" forward of the harmonic damper . What your describing seems like the engine will be closer to the rear axle centerline than 12". My locost has a rearward weight balance with 1/2 gas and me driving. How much is ideal to acheive mid engined handling?

?Anyone?

My understanding of why a midi handles better is that because the front is light it turns in better. And it brakes and accelerates better because due to weight transfer it puts more weight on the driven wheels under acceleration and transfers weight to the front on braking making the fronts and rears closer in weight.

I'm still dreaming of mine and would love to see what one of those setups weigh.

my 2 cents

Phil


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PostPosted: December 15, 2011, 11:36 pm 
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That would just fall over!

Sorry, I don't actually have anything useful to add right now :)


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PostPosted: December 16, 2011, 9:48 am 
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pmatolcsy wrote:

I also have trouble understanding how the mass will be any more centralized. I have my front axle centerline 12" forward of the harmonic damper . What your describing seems like the engine will be closer to the rear axle centerline than 12". My locost has a rearward weight balance with 1/2 gas and me driving. How much is ideal to acheive mid engined handling?

Phil


You've got a good setup, the bulk of the weight evenly distributed and well between the axle lines - it is more than fine for what you want to do, just ask Panos.
Making your current setup AWD would be generally no slower than making a mid engine AWD.


Tom17 wrote:
That would just fall over!



Nah the really wide tyres will stop that.


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PostPosted: December 16, 2011, 11:17 am 
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Quote:
That would just fall over!


Ya, Ive been trying to design it light. 1/2 a car is definately lighter than a whole one.

Drawing half of a bilaterally symetrical object actually saves alot of time. And its much easier to see "inside" to see the relation of parts. It's super easy to copy and paste the second half when your done. This is only one of dozens of prototypes I've been playing with in an attempt to bring down weight and size , and also to improve the aero. If I have to build and mount a nose and 2 front fenders anyhow, why not just build a whole flip front end and clean up the aero at the same time? If everybody is using curved side bars on their cages anyways in order to gain shoulder room and keep the main chassis narrow, why not wrap the skin over the outside and gain some aero,style and interior volume at the same time?

Sorry for the thread highjack. I only included my prototype to demonstrate that I've been "thinking" about this.

How wide will it end up with this tranny setup? 2x 1" chassis sides + 2x seat width + 2x .75" tunnel sides + driveshaft = 42" in the book. Alot of us end up with plus 442
at 46". Now add a transmission to that width (guess at 8-10" width) . Thats wide and wide equals heavy.

I often feel the old addage, choose any 2 : fast, cheap, reliable often applied to engines , should become the mantra of the locoster in a slightly modified form . Light , cheap , reliable . Choose all 3 through elegant design.

Phil


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PostPosted: December 16, 2011, 11:50 am 
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The only difficulty I see in designing in half's is that the frame twist on heavy throttle isn't equal due to engine torque loading.
but that's not such a big deal at this level imhop. On my Buick I just ran an airbag on one side. .. that was a straight line toy though.
I mean, just how much weight could you really save by being able to thin down 2 or 3 tubes and how much time would you have to spend on FEA analysis to figure it out?

As far as aero, JackMcCormack related some pretty interesting observations in both fuel economy and accel/deccel numbers when he put a full body on MAX so. ..

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PostPosted: December 16, 2011, 12:03 pm 
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Phil, what are you using for software to draw with? I am going to start a mid-engine variation on my frame ideas soon...

Quote:
Light , cheap , reliable . Choose all 3 through elegant design.


That's beautifully stated, I am a firm believer. You can have three things, just need to choose the right ones...

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PostPosted: December 16, 2011, 12:28 pm 
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Quote:
I had a hard time figuring out how I could make it significantly lighter than my front mid engined v-8 locost.


It depends on what "significant" is. Midi's also can have crucial advantages besides weight. Single seat formula cars for instance would really suffer ( or at least the driver ) with the driveshaft going thru their middle.

I can change all four gear ratios in just a half hour.

You save weight and space by combining the transmission and diff. No drive shaft, tunnel and protection hoops. No need to transfer loads from engine thru frame to diff, no need for strong frame in two places ( different but similar issues ). If you can save 50 lbs. or more that can start to be a big deal. It's also simpler...

So it's a good idea. Transaxle choice can be more difficult, or you can just grab a modern transverse FWD unit.

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PostPosted: December 16, 2011, 3:16 pm 
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I agree fully with Horizonjob. Thats why I'm interested in the weight of that 4x4 transfer case trans combo. I think it might be going in the wrong direction weight wise. Even with a v-8 trans-axle combo, the frame can be lighter on a midi for the reasons Horizonjob mentioned. I'm using sketchup . Take the online tutorials . An hour spent there will save you days down the road.

When I said significant , what I really meant was significant enough for me to build a whole second car for. I'm talking about a street driven car for occasional track days, not a single seater. And just like a couple of other Yahoo's on this sight(no disrespect intended, HE doublehockeystick's , I'm one of you), I'm partial to v-8's. The only completed v-8 midi on this sight (BB69s) weighs 2441 sans driver, without much bodywork and no windshield. It uses fairly lightweight aluminium corvette spindles and a-arms and a robust aluminium trans-axle able to handle a v-8s torque. I'm fairly certain that car is extremely robust and will live a long time, and I love it. But I want a lighter car than mine. His car is large. I think the frame material and overall dimensions are what make his car so heavy.And its not streetable

My car has proven to be robust(I am Canadian ,but I plead the fifth, suffice it to say I have beat the *#*! out of it and haven't broken it yet). The windshield washers reqularly relieve themselves on the windshield , and it makes me smile everytime . It weighs 2000lb with full bodywork and a windshield and is fully road worthy. The frame is mostly 1.5"x.063" tube with some 1" as diagonals. The roll cage is 1 5/8" x .125". The wheels and tires are HEAVY, the six-speed trans is huge and heavy ( with the available torque a 4 speed would have been fine). The brakes are probably overkill size wise. And the car is quite a bit larger than it needs to be. I figure if I redesigned the car as a midi I could ditch the t-56, driveshaft and hoops, 8.8 IRS and replace with a Audi diesel 2wd box which could maybe handle the torque but certainly not the abuse ,I could save maybe 100lbs, but I might give up some reliability and it would be expensive by the time I got a working adaptor plate clutch starter and LSD. Reducing the dimensions of the car to 96" WB, making the frame from 1" and the cage from 1.5 x .095 might save me another 100lbs. Reducing the size of the wheels , brakes , spindles from v-8 car size to miata size might save me 100lbs but I might give up traction, and robustness . So I might , If I was very careful,be able to get the weight down to 1700lbs as a small v-8 midlana type midi with a lot of expensive components and potentially reduced reliability. Somebody correct me if I'm wrong.

The Midlana (which I feel is a brilliant design and beautifully built) weighs 1461 without gas , a windshield and several other little bits. So it should end up around 1650 by the time he's done with fuel in it(don't get mad at me Kurt , It's just a guess) . It has a 67% rear weight bias because the engine sits almost directly over the rear wheels. Is that ideal? Will the transaxle live at those power levels ? Will the engine live at those power levels ? Is it locost ? It is compact. And he's definitely using light parts( except for wheels and tires ).

But all 3 of these cars are as aerodynamic as bricks. For me to build another car , It has to be better than the one I already did. And that includes weight ,aero and reliability. I still haven't put on my front fenders because 1) they look awful 2 ) they wreck the aero 3) they break 4) they increase unsprung mass.

Sorry again for the thread hijack


Phil


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PostPosted: December 16, 2011, 5:58 pm 
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Thank you for your responses, perhaps I should have exposed the bigger picture of my project upfront (914 Porsche) but, I wanted to focus discussion on the drivetrain nuts and bolts and in particular draw out Oldejack's comments (from other threads appears to be knowledgable of drivetrain nuts and bolt and the engineering behind them). However Oldejack chose to comment on the highjacked subjects. No disrespect intended to anyone.

Back to the subject...

Again, Lamborghini and Bugatti are respected constructors so, I believe this drivetrain concept is a good one that addresses all other design issues as well. What interests me most is the locost applicability. I may be able to build this drivetrain for $1K or use a hightorque transaxle for $5-10K and break it anyway. That's what I like about this forum, putting together locost solutions and in some cases exteme locost solutions as a community. Call me cheep but I thought that was the program here.

Now, specifically a NP231 weighs 75lb. I intend to remove some of the gears not required if practicable, reducing some mass, not sure how feasable that is. Also add a driveshaft and I don't think that adds too much to the car overall. Yes, the driveline may reduce some passanger comfort but that isn't really my problem.

This drivetrain obviously will also lend itself to AWD capablities. This too seams to be of interest to others on this site.

Questions:
1) Can the NP231 be partially gutted (don't need low range or front/back differential) easily?
2) The NP231 is reportedly very strong but, can it deliver 100% engine torque all the time through what was intended to be the front drive?
3) Can the differential simply be inverted to correct rotation for RWD?

thank you


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