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PostPosted: September 29, 2014, 11:38 pm 
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After using the "Tube Miter Program" the interface between the tubes has improved:
Attachment:
tube notches using Tube Miter Program.jpg
tube notches using Tube Miter Program.jpg [ 992.56 KiB | Viewed 2847 times ]


The rear stays (or rear triangulation members) are taking longer than expected to notch and maintain parallelism between the left and right members:
Attachment:
triangulation members.jpg
triangulation members.jpg [ 791.28 KiB | Viewed 2847 times ]

Attachment:
rear of chassis.jpg
rear of chassis.jpg [ 629.34 KiB | Viewed 2847 times ]


The splay of the rear stays are a bit wider than anticipated.
Attachment:
rear chassis view.jpg
rear chassis view.jpg [ 1.21 MiB | Viewed 2847 times ]


I was thinking of making a 20 degree cut on the left and right longitudinal members after picking up the engine/trans mount. However the intake manifold will not clear the rear stays if relocated further inboard.

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PostPosted: September 30, 2014, 7:59 am 
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That is really coming together nicely. Can't wait for a whole frame pic.

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PostPosted: September 30, 2014, 8:41 am 
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TooBusy wrote:
That is really coming together nicely. Can't wait for a whole frame pic.



Yeah, it'd be swell to see the whole frame in context.

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PostPosted: September 30, 2014, 1:21 pm 
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Looks nice ! :cheers:

How much room does a motor and trans like this need ? L , W, H ? Thanks

Randy

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PostPosted: October 1, 2014, 12:22 am 
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The dimensions of the engine and trans assembled together are as follows:

21" longitudinal
35" lateral
25" vertical

The engine cradle is 26" longitudinal tube CTC, and 41" lateral tube CTC. The width is 41" such that it blends into the Locost7 Book Chassis width.

Regarding progress today, the rear stays and rear engine cradle member have been notched and tacked into place. Since a portion of the inboard rear triangulation member is covered by the rear engine cradle member, I had to weld part of the triangulation tube before tacking the rear tube:
Attachment:
welding 4130.jpg
welding 4130.jpg [ 1.02 MiB | Viewed 2768 times ]

4130 doesn't seem to weld any differently than mild steel, but I took care neverthess the preheat and slow cool the weld.

In terms of the overview of what the car looks like thus far:
Attachment:
chassis overview.jpg
chassis overview.jpg [ 996.11 KiB | Viewed 2768 times ]

Think of this as a 6" longer standard Locost7 build, but with more legroom, and room in front for the radiator, battery, and fuel cell.

From front to rear I am planning on placing components as follows:

(Front)__Radiator__inboard springs/dampers__battery and fuel cell (in parallel)__pedal box__driver and passenger__(roll hoop)

The rear of the car looks a bit like Mario Kart meets Mad Max:
Attachment:
rear stays and rear engine cradle member tacked in place.jpg
rear stays and rear engine cradle member tacked in place.jpg [ 1.21 MiB | Viewed 2768 times ]


Structurally I think this will be fine, as the rear stays pickup at the center of the top bend in the main roll hoop. I spent hours measuring the placement of these tubes to make sure they are even with each other. I'm thinking the X-brace may need to be placed further up the rear stays, as the X-brace will interfere with the intake plenum.

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PostPosted: October 1, 2014, 12:28 am 
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I forgot to add, the exhaust will be placed to right of the car (longitudinally), the same way it's laid out on a normal caterham:
Attachment:
Caterham_Superlight_R500_-_Flickr_-_exfordy_(1).jpg
Caterham_Superlight_R500_-_Flickr_-_exfordy_(1).jpg [ 1.28 MiB | Viewed 2768 times ]

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PostPosted: October 1, 2014, 1:23 am 
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Thanks LS !

You have given me some ideas for the 102"

Randy :cheers:

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PostPosted: October 1, 2014, 8:52 am 
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Sweet Build! I don't know how i missed it!

That engine needs a turbo cough...cough
Attachment:
2014-06-08 15.38.45-2.jpg
2014-06-08 15.38.45-2.jpg [ 125.41 KiB | Viewed 2749 times ]


I found the motor mounts on the B series to be way to big and cumbersome and leave a lot to be desired in the feedback you get from the car. Good thing though is that if you dont like them... tons of companies make more track friendly version ones (kind of pricey though). Be warned... the track friendly ones will shake the crap out of you though depending on what durometer you get.

Also if you stick to the poly bushings on the control arms... they will squeek... so keep them lubed. This also is a must for premature wear.

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You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.


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PostPosted: October 1, 2014, 9:17 am 
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LateralScience wrote:
Miatav8,MstrASE,A&P,F, I follow you. Ideally I'd love to make the A-arms look like ones off of a BAC Mono, but there are a few issues in doing so, as in my fabrication skills, as well as lack of adjustability in control arm length to tune caster, camber, toe, anti-squat, anti-dive, etc...


I went all out designing this stuff in to my suspension then i prioritized them once i realized i could send years playing with the numbers...

my 2cents - Rank for adjustability:
1. Camber & toe
2. Caster (mine is barely adjustable but i consider it non adjustable)
3. All the black magic stuff....Anti-squat, Anti-dive, etc... design them in but i wouldn't get too carried away about making them adjustable.

You will spend more time swapping out springs, playing with camber and toe, etc than worrying about these other things once the car is built... unless you plan on slaying the track every weekend or racing. You may end up with some anti whatever if you shift your suspension points slightly during welding... Dont ask me how i know.

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PostPosted: October 1, 2014, 9:22 pm 
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mjalaly, I've gone through your build log of your car, and the construction of your car is FAR better than my contraption of a car. From your bell cranks to the uprights, the attention to detail on your car is absolutely superb. A very inspiring build!

If I had the time, budget, and tooling as you did, I could maybe approach the build quality of your car. That being said, I've got a VERY limited budget for this build.

As per the turbocharger, with 12.5:1 compression ratio, and lumpy Skunk2 Pro3 Cams, boosting would be dangerous. A piston and cam change would be required, but my Darton sleeves could take the boost. In terms of my 2.0L engine:
Attachment:
JE 12.5CR.jpg
JE 12.5CR.jpg [ 795.25 KiB | Viewed 2699 times ]

Attachment:
JE Forged Pistons Darton Sleeves 85mm bore.jpg
JE Forged Pistons Darton Sleeves 85mm bore.jpg [ 823.38 KiB | Viewed 2699 times ]

Attachment:
balancing pistons.jpg
balancing pistons.jpg [ 773.23 KiB | Viewed 2699 times ]

Attachment:
Darton Sleeves.jpg
Darton Sleeves.jpg [ 815.93 KiB | Viewed 2699 times ]

I had Kotzur Racing Heads do the port work:
Attachment:
Ported Head.jpg
Ported Head.jpg [ 1.09 MiB | Viewed 2699 times ]

Attachment:
intake ports.jpg
intake ports.jpg [ 803.96 KiB | Viewed 2699 times ]

Attachment:
4340 Manley Rods.jpg
4340 Manley Rods.jpg [ 779.9 KiB | Viewed 2699 times ]


(Very close piston to valve clearance. 0.008" exhaust valve to piston clearance before increasing relief)
Attachment:
0.008 inch piston to valve clearance before relief cut.jpg
0.008 inch piston to valve clearance before relief cut.jpg [ 1.15 MiB | Viewed 2699 times ]

63 degrees of valve overlap on the vtec cam. 13mm of peak lift on intake.
Attachment:
76mm Throttle Body.jpg
76mm Throttle Body.jpg [ 1.11 MiB | Viewed 2699 times ]


I will concede more power can easily be had with a turbo. I suppose my approach is somewhat like running a sailboat...certainly more speed can be had with an outboard Mercury engine, but there is something rewarding about doing something the hard way.

I love crisp throttle response and linear power feel, despite this engine is very peaky and high strung. Plus I love the naked elegance of a simple engine, without all of the turbocharger auxiliaries of wastegates, blow off valves, WG dump tubes, intricate exhaust manifold, oil supply/return plumbing, intercooling, charge piping, etc...

I have a set of the Energy Suspension Polyurethane inserts, and I've found the transmissibility to be horrible, causing blurred vision at idle. To think I was playing with the idea of using the engine as a semi-stressed member was insanity. Perhaps I'm just getting old and boring, but I'd like reduced transmissibilty, and very soft suspension.

I'd like to be able to flog this car with some regularity at the local SCCA autocrosses. Essentially, I would like to tune the angle of my control arms such that lateral loads induce ZERO body roll, and springs compress only in bump and not during cornering. IMHO, lateral loads should be supported by the control arms, and vertical loads should be supported by the springs/dampers. My goal is to use the SOFTEST springs possible, without adverse affects on roll. A low CG, and carefully situated control arms would allow me to get away with very soft springs. I have no intentions on using anti-roll bars, as coupling the left and right wheels often reduces the normal load on the inside wheel, and increases the wheel rate of the outside wheel.

I would like to design the car to have the option of tuning the suspension in nearly every aspect, and it wouldn't be too hard to design for multiple mounting locations of inboard pickup points. As I'm not sure how this animal will act whilst turning a wheel in anger, I'll finalize the pickup points after the car has been driven for a while. At the moment I'm designing for zero Anti's in the car, and aiming for neutral handling. I'll start with soft springs in the rear, and start with safe understeer, and go from there.

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PostPosted: October 1, 2014, 10:37 pm 
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Quote:
Essentially, I would like to tune the angle of my control arms such that lateral loads induce ZERO body roll, and springs compress only in bump and not during cornering. IMHO, lateral loads should be supported by the control arms, and vertical loads should be supported by the springs/dampers.


Do a google search on something like "suspension jacking roll center" and you should be able to find some good explanations for why people don't do this. You can use the Vsusp web page to help you visualize the force angles from the contact patch and the virtual swing arms created by the upper and lower control arms. You run the risk of the wheels folding under your car during cornering and someone can probably find you pictures of this.

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PostPosted: October 1, 2014, 10:41 pm 
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Here's an example. The early Triumph spitfire had a high rear roll center and you can see the car trying to climb over the wheel. Ralph Nadar became famous writing the book "Unsafe at any Speed" about the early Corvair which would also do this. Later Corvairs were wonderful handling cars...

I have seen even more dramatic photos..


Attachments:
Spitfire+jacking+11090328641.jpg
Spitfire+jacking+11090328641.jpg [ 12.61 KiB | Viewed 2689 times ]

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PostPosted: October 1, 2014, 11:14 pm 
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Perhaps I mispoke earlier, as I meant "nearly zero roll" as I don't intend on inducing jacking loads causing the wheel to camber positively. Very scary indeed. I was planning on placing the roll center just above the ground. Making variable length lower outboard LCA pickup points may make it easy to tune the roll center, similar to extended ball joints or "roll center adjusters."

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PostPosted: October 1, 2014, 11:36 pm 
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Below is an approximation of what I had in mind horizonjob. The placement of the inboard pickup points are somewhat constrained by the engine. I'm most certainly open to suggestions on the design as there are alot of talented folks here. Also, with a 4" ground clearance, this puts the RC 3/4" below ground, but close to the surface.
Attachment:
Locost7 approx susp.png
Locost7 approx susp.png [ 268.68 KiB | Viewed 2683 times ]

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PostPosted: October 1, 2014, 11:50 pm 
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horizenjob wrote:
Here's an example. The early Triumph spitfire had a high rear roll center and you can see the car trying to climb over the wheel. Ralph Nadar became famous writing the book "Unsafe at any Speed" about the early Corvair which would also do this. Later Corvairs were wonderful handling cars...

I have seen even more dramatic photos..



Isn't this more from it being a swing axle ?

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