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PostPosted: January 22, 2016, 2:23 am 
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So I've been dreaming with Solidworks again, and I find myself drawn to the boat-tail styling of many pre-war roadsters. My great grandpa used to race in these types of cars back in the day and I really want to try and capture some of that essence in this car. Without much more intro, here are some pictures (and description after):

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It is quite small. Total width at rear tires is ~58" and wheelbase is only 86". I think all the body work will be doable. The rear boat-tail will be challenging and I think the top radius will take some trying. I'm thinking all body work in 18g mild steel. It should be more forgiving than aluminum when reworked repeatedly.

-Yes that steering wheel is huge, and yes it will be 16" in diameter. I want to pair it with a rack that will be ~1turn lock to lock. Between the fast rack and the big wheel, it should be precise without being too twitchy, all the while feeling very old-school.
-Tires are the most common size in the world: 225-45-17. I may change this. I was thinking about Blockleys until I saw what they cost. WOW.
-The engine modeled is an LT1, though I'd like to find an LS for the weight. Ultimately, it will be what is affordable when I start up the build. I'd like fuel injection of some sort, but nice velocity stacks out the top of the hood seem pretty awesome if I can swing it. I've modelled the exhuast as 1.625" primaries into a 3" to the back.
-The Transmission modeled is a T5, but I want to go for a Super T-10 Plus. I've read they are exceptionally smooth, I like the "S" ratio gearing paired with a 3.73 rear. I also learned to drive in an old C10 with a 4 speed and there is something nostalgic about 4 speeds for me.
-Due to the very narrow nature of the car, there is no room for a clutch pedal, so I was thinking: Why not use a lever on the shifter? Think like a motorcycle. Once you got used to it, it could be more ergonomic. One foot for each pedal, one hand on steering wheel and one actuating clutch while shifting.
-I want to use a 5.5" clutch and flywheel to get the engine low and reduce the intrusion into the passenger compartment. The hand clutch may actually help with this as hands are more sensitive than feet, so 1" of travel isn't a problem. Thoughts?
-I'm thinking about using a 2" driveshaft due to the fact it will be less than 12" long. Is that too weak?
-The rear is a Ford 9", though I think I would like to switch to a 7.5" diff. I've modeled a Hub-to-Hub of 56". Any suggestions on this front?
-I'm thinking about a 3-link with a Watt's link for rear suspension. I'll use poly bushings on one end of all arms and a ball on the other to help with on-road compliance. Should I use a bushing or bearing in the Watts bellcrank?
-All brackets are drawn in at 3/16" plate. All tubing is 1"x16g. If triangulation is missing, it is likely because I intend to have sheet metal there.
-The dashboard will be structural and tie the top rails together across the passenger compartment.
-Fuel cell is 12 gallons. I think this will provide more range than is comfortable to drive without a stop.
-Front suspension is not done yet. I think I will use mustang2 drop spindles. The lower control arms will have bushings, the uppers will be fully adjustable heim and balls.

This is a for-fun road car, prioritizing the emotion it inspires more than the numbers it can create. Thus no cage, a SAS, a big steering wheel, and narrow pre-war esque styling. The more exciting and involving it can be at slow speeds, the better!


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PostPosted: January 22, 2016, 5:48 pm 
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Neat design. I like the cowl truss work, sort of like a Porsche Spyder.
I’d use a bush in the bell crank.
That does not look like an LT1, which is longer and lower, with a front mounted dizzy and beltless wp.
I understand the starter reversal with the tiny flywheel.
I’d go with a lighter diff. The bronco 2 usually came with a 3.73 traction loc 7.5 and rear swaybar and is narrow. I can measure tire to tire on mine if you’d like.
58 inches to the outside of the rear tires? Your 225-45 tires are likely 9 inches wide, bulge to bulge, with passengers shoulders about 18 inches wide. 58-9-9-18-18=54. I think you may be about 4 inches too narrow.
Given the length, a 2 inch with enough wall would be okay. You’d need to turn the weld yokes down since they often use 2.5” tube.
I think a 4 speed would be wider with the external linkage and the lack of overdrive would be rough with a 12 gallon tank.
Looks like it would be tough to get in and out off without a removable wheel.
For a hand clutch, I think you’d need serious effort reduction at the hand and at the same time an increase in movement at the fork. Not sure how you would do that.

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PostPosted: January 22, 2016, 6:06 pm 
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If you like the 'boat tail' look, you could still build a "7"!


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PostPosted: January 22, 2016, 9:39 pm 
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Miatav8,MstrASE,A&P,F wrote:
Neat design. I like the cowl truss work, sort of like a Porsche Spyder.
I’d use a bush in the bell crank.
That does not look like an LT1, which is longer and lower, with a front mounted dizzy and beltless wp.
I understand the starter reversal with the tiny flywheel.
I’d go with a lighter diff. The bronco 2 usually came with a 3.73 traction loc 7.5 and rear swaybar and is narrow. I can measure tire to tire on mine if you’d like.
58 inches to the outside of the rear tires? Your 225-45 tires are likely 9 inches wide, bulge to bulge, with passengers shoulders about 18 inches wide. 58-9-9-18-18=54. I think you may be about 4 inches too narrow.
Given the length, a 2 inch with enough wall would be okay. You’d need to turn the weld yokes down since they often use 2.5” tube.
I think a 4 speed would be wider with the external linkage and the lack of overdrive would be rough with a 12 gallon tank.
Looks like it would be tough to get in and out off without a removable wheel.
For a hand clutch, I think you’d need serious effort reduction at the hand and at the same time an increase in movement at the fork. Not sure how you would do that.

Thanks!

I think the dimensions on the engine I have here are pretty similar to a plane jane 350. It's a model I pulled off grabcad and the creator called it an LT1. I won't start building without the entire drivetrain on hand to pull real honest measurements from.

Bronco2 diff sounds like it might be just the ticket. If it is easy to measure, I'd appreciate it; but my feelings won't be hurt if you don't want to bother. A spot of googling will likely get me to it too. :D

For width, the frame is 38" outside to outside edge. I mocked up some cardboard and found that I can sit comfortably next to myself in the car (well, shoulder to shoulder). My model says 58" but honestly, the wheel offset and the tires and all that are a guess based upon published info. The true width may be a bit more or less. I'd like to get the car as narrow as is reasonable. Due to how far forward I pushed the rear axle, those tires will be right by your elbows which seems a touch dangerous. But I do like how it looks with the tires way forward like that.

I figured a custom driveshaft was in the works no matter what. I'm not running anything to suggest the driveshaft will see massive abuse. <300lb.ft. and only 225 tires propelling <2000lbs shouldn't be much stress on so short a shaft.

The T-10, as a diagram I found on the internet suggests, is considerably less bulky than a T5 and about 1 inch narrower. Add back in the external shifter, and it hopefully comes out about the same on width. The C10 I have such fond memories of was a Saginaw. I chose the T-10 for it's reputation for shifting smoothly and to feed my nostalgia for that old truck.

I'm not too concerned about range. This isn't shaping up to be a great long distance cruiser, so the 100 miles or so I might get on a tank should be fine. From my calculations, 4th gear will turn 3800rpm at 75mph. Not exactly comfortable cruising, but not thrashing on it either. I could see dropping down to a 3.55 or something similar. I anticipate that too much torque will be a problem, and higher gearing helps. 1st gear with 3.73 will take you to 50mph at 6krpm. Thats a pretty long gear already!

Removable steering wheel is definitely happening. I'm pretty skinny, but it does look tight. We'll see, but a cardboard mock up told me that would be a comfortable placement of the wheel once seated.

For the hand clutch: I really don't have a good sense for this. I'm told those triple disk 5.5" clutches have very very short strokes from engaged to disengaged and that on a street car the clutch becomes an on/off switch. My hope is that this behavior works to my favor on a hand clutch because a couple inch stroke is all that could be managed. I'm thinking I need to call around and see what the manufacturers say. Maybe a motorcycle clutch like below would move enough fluid to actuate the clutch, because that could be a pretty workable solution.
Image
I've also been thinking about seat belts. I'm not sure a 4pt harness adds much safety over a lap belt. What do you guys think?

ngpmike wrote:
If you like the 'boat tail' look, you could still build a "7"!


I considered that, but I really prefer the taller, narrower look of Indy cars. I kind of split the difference with my design.


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PostPosted: January 23, 2016, 4:30 am 
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Let me start off by saying I really like what you're trying to accomplish, and think you have the beginnings of a great design on your hands!! I also very much applaud your effort to give the car a certain nostalgic feel and character. However, as with any early development model, there are a number of areas of concern as well.

esp42089 wrote:
Total width at rear tires is ~58"
Measure again. Based on the posted images of your model, even the front wheels are in the 60" ballpark across the outsides of the tires. The rears are closer to 68. Not that this is a problem, especially if you like your elbows, but just a point of accuracy. To get a 58 inch width, with a 38 inch frame, and nearly 9 inch wide tires, would leave you with ~1" of elbow room between the inside of the tire and the frame.

esp42089 wrote:
Between the fast rack and the big wheel, it should be precise without being too twitchy, all the while feeling very old-school.
If by "old-school" you mean "extremely heavy", they you're probably right.

esp42089 wrote:
Tires are the most common size in the world: 225-45-17.
Good choice, and good on you for making this an early decision.

esp42089 wrote:
Why not use a lever on the shifter?...
...The hand clutch may actually help with this as hands are more sensitive than feet, so 1" of travel isn't a problem....
...I'm told those triple disk 5.5" clutches have very very short strokes from engaged to disengaged and that on a street car the clutch becomes an on/off switch. My hope is that this behavior works to my favor on a hand clutch because a couple inch stroke is all that could be managed. I'm thinking I need to call around and see what the manufacturers say. Maybe a motorcycle clutch like below would move enough fluid to actuate the clutch, because that could be a pretty workable solution.
Yes this style of setup can work great with a bike clutch in a bike engined car, no it will not work worth a damn with a racing clutch in a car engined car. Pulling a few random numbers from the internet...Lets assume a 9:1 ratio at the very tip of the clutch lever, a .312 in^2 master cylinder, a 1.215 in^2 release bearing, and a clutch that requires 650 lbs to release. This will actually get you down to a 18.5 lb pull at the tip of the lever...However even with a 3" pull, it will only move the release bearing .085 inches. The setup instructions require .170-.230 of air gap between a new clutch and the release bearing, to allow sufficient space for the spring fingers to rise as the discs wear, and that's in addition to the flex in the spring that needs to be overcome before fully releasing the clutch. So while it surprised me by getting the force into an acceptable range, it does so at the expense of travel. And reducing the travel enough to be viable would result in it being too much force to operate motorcycle style with you hand. While hands are more sensitive than feet, they are also much weaker. If you went with a dog-box transmission, you might be able to get away with a parking brake style lever actuation just for getting started...However, nothing about any of this is street friendly. These clutches aren't just an on/off switch from a modulation standpoint, but from a functional standpoint as well. The quickest way to kill one of these clutches is to slip it.

esp42089 wrote:
I'm thinking about a 3-link with a Watt's link for rear suspension
You'll probably want/need a significantly beefier mount/support structure for your center link. It's going to see as much load as:
(engine torque x gear ratio x final drive ratio) /(lever arm length from center line of axles measured in feet)
However, this is also limited to a maximum of the amount of torque that the tires can react against the pavement.

esp42089 wrote:
I've modeled a Hub-to-Hub of 56"
Considering this, in combination with my initial comment on the width of the vehicle, it appears that you modeled the wheels with the wrong offset. By my rough calculations you've modeled maybe a 38 or 40 mm offset in the negative (mounting surface inboard of wheel center line) direction, effectively widening the car. Where as the vast majority of wheels with that size of offset are in the positive (mounting surface outboard of wheel center line) direction...Most often also by a similar amount. So with more typical wheel offsets, expect to lose another ~3 inches of (frightening that you even have to measure it) elbow-to-tire clearance per side. Also, to get a 58 overall width from a 56 hub distance with 225 tires, would require something on the order of an 89mm offset, again in the positive direction.

esp42089 wrote:
Front suspension is not done yet.
Between that and the radiator, I have no idea how you plan to get the engine in and out...Although I suppose the chassis could literally be built (permanently) around the engine.

esp42089 wrote:
For width, the frame is 38" outside to outside edge. I mocked up some cardboard and found that I can sit comfortably next to myself in the car
What about your ability to perform large/quick steering inputs, like trying to catch a bit of power induced oversteer on a short wheelbase car? Seems to me like your passenger would be likely to inhibit this to at least some degree.

esp42089 wrote:
I'm not sure a 4pt harness adds much safety over a lap belt.
Absolutely out of the question if you plan to actually drive this anywhere on the street. Even a minor collision would likely result in moderate to severe injuries. I'm going to go out on a limb and assume that you don't actually think a 2 point lap belt would provide anywhere near the same level of safety as a 4 point harness, and that you are actually intending to refer to 3 point belts. In a production car where you sit further from the steering wheel, a 4 point harness may not add much over an OEM 3 point belt...But when sitting that close to the steering wheel a harness (preferably 5-6 point) is almost a necessity. In fact, as close as that's modeled to the driver, you'd probably still be well served to add a steering wheel pad in addition to being fully harnessed.

esp42089 wrote:
I really prefer the taller, narrower look of Indy cars.
Personally, I think you may be trying too hard to keep the overall package too small...Especially if this is meant to be genuinely enjoyable for you to actually drive, and not just look at while it's parked. Proportions could be kept similar, but merely made more realistically functional. Remember, while computer models may allow you to put 10 lbs of poo in a 5 lb bag, doesn't mean it'll actually work when you try it.

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Last edited by Driven5 on January 23, 2016, 6:28 pm, edited 5 times in total.

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PostPosted: January 23, 2016, 7:06 am 
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I measure 47.5” between the bulges at the ground, so probably slightly more than 48” at the top. This is with 2001 ranger 15x7 wheels and 225-60-15 tires on a 1988 bronco 2 width axle at 58”. You have several options around this width:

http://www.therangerstation.com/tech_li ... axle.shtml

The driveshaft needs to be custom only to the extent of cutting it in half to the appropriate length, machining off the tube from the weld yoke, then pressing the weld yoke back in, truing, welding, then spin balancing.

The tires pick up stones between the treads that can be flung toward your arm. Open wheel quickly makes a mess of the car and you if driving through any puddles. You may want to be able to tuck in behind the dash if it is cold on your way home or at least carry a good leather jacket. Not trying to talk you out of anything. I understand the appeal.

I had a 1969 442 convertible with a 22 gallon fuel tank, 455 cid v8, t400 trans, and a 3.73 limited slip 12 bolt axle. It was rated at 515 ft lbs of torque and 360 hp. It could spin the tires at highway speed simply by pressing the accelerator. However, also at highway speeds, I could actually watch the fuel gauge slowly drop as I drove.

Torque multiplies. For a super t10, the torque will be 300 ft/b x 3.73 x 2.88 for 3,222 ft lbs in first gear. You'll probably be short shifting anyway, most of the time.

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PostPosted: January 23, 2016, 11:42 am 
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My Dad's old "Automatic Stick Shift" '68 VW had a three speed manual transmission with a fluid coupling, a conventional clutch, and an electrically switched vacuum servo. The switch was built into the shift knob; when you moved the shifter, the clutch disengaged to allow the shift. Stopping and starting didn't involve any clutch work, the fluid coupling let it idle while in gear. Acceleration was noticeably more leisurely than normal 4-speed VWs though...

The midi I'm building for my wife will have a manual transmission. She has trouble with a clutch pedal now, after knee surgery. (so do I, but while painful, it's only an issue in city traffic at the moment) I remembered the old VW and searched "power clutch" and found that they're very common on some Japanese-market small trucks and utility vehicles; some of the bits are even eBayable. After noting that they seem to be nothing more than the old MG-style remote brake boosters, also available new from some of the street rod shops, I decided to try building my own from a lightweight vacuum booster and a Girling master cylinder.

Anyway, by selecting your booster you could have a clutch effort largely independent of the strength of the pressure plate.

I think I'd look at something like the "paddle shifter" arrangements some of the BECs use instead of a lever, though. Then you could keep your fingers on or near the wheel while shifting.


You might also consider a transaxle; at least one of those had the clutch in the back instead of on the engine, but I don't remember who did it that way at the moment. Or even an automatic transaxle, which would eliminate the need for a clutch entirely.


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PostPosted: January 23, 2016, 11:48 am 
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ngpmike wrote:
If you like the 'boat tail' look, you could still build a "7"!


Eh? Wot? Do you have an owner/builder/car name I could search on for some more pictures?


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PostPosted: January 23, 2016, 12:11 pm 
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esp42089 wrote:
The rear boat-tail will be challenging and I think the top radius will take some trying.

Back in the day some were formed from strips or wood, or even canvas over framing.

Quote:
-Yes that steering wheel is huge, and yes it will be 16" in diameter.

Lotus used 16" steering wheels in the Series 1 and early Series 2 cars, at least according to their printed specifications.

Quote:
I want to pair it with a rack that will be ~1turn lock to lock. Between the fast rack and the big wheel, it should be precise without being too twitchy


I've never understood the fad for kart steering, but I seem to be in a small minority there.

Quote:
-Tires are the most common size in the world: 225-45-17. I may change this. I was thinking about Blockleys until I saw what they cost. WOW.


Check out your favorite tire vendor. The bling crowd are running 26" and 28" rims now; I could drop one of my 15" tires through the center hole of one of those. Even with the thin sidewalls they're very tall. Not much choice on rims, though.

Quote:
The engine modeled is an LT1, though I'd like to find an LS for the weight. Ultimately, it will be what is affordable when I start up the build.

The cruelty of cashflow puts greasy prints on my rose-colored glasses, too...

Quote:
-I'm thinking about a 3-link with a Watt's link for rear suspension. I'll use poly bushings on one end of all arms and a ball on the other to help with on-road compliance. Should I use a bushing or bearing in the Watts bellcrank?


That's similar to my current layout; four link with rubber bushings on the axle, early Beetle tierod ends for the chassis end. I'm planning to use sealed ball bearings on the Watts and rubber on the chassis ends of the links. No particular engineering reason; the ball bearings are cheaper, lighter, smaller, and easier to use with the bellcrank.

Quote:
-Fuel cell is 12 gallons.

RCI and Jaz differ from each other, and offer multiple shapes as well. There are also some vendors on eBay selling welded aluminum tanks in various sizes.

Quote:
-Front suspension is not done yet. I think I will use mustang2 drop spindles.

My first build used Fox Mustang knuckles with balljoint adapters. The lower control arms wound up attaching to the chassis about halfway up and I had to build the top brackets over the top of the frame. This was mostly because the lower ball joint was so high, plus tall 15" tires. The drop spindles would probably save you a lot of hassle laying out your front suspension geometry.

Quote:
The lower control arms will have bushings, the uppers will be fully adjustable heim and balls.

You avoid the Heim joints if you make the brackets adjustable instead. Note that you can use tierod ends or ball joints for inboard suspension pivots as well as on the spindle.

Many tierod ends are more than beefy enough for A-arm use, and they're usually available in either right or left hand, so you can have the same adjustability as Heim joints in a sealed package. If you have to make or buy a taper reamer, you might as well get maximum use out of it...


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PostPosted: January 23, 2016, 4:28 pm 
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Eh? Wot? Do you have an owner/builder/car name I could search on for some more pictures?


TRX, the car in the pic is an early Lotus 7. Apparently the boat-tail was a factory option "Back-in-the-day"! Just 'Google' "Lotus 7 boattail".

Oh, and that LT-1 modeled in the drawing is probably the classic small block from the '70 z-28. A 350 with a solid lifter cam and Holley carb ala pre-1970 z-28 302 CID engine.

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PostPosted: January 23, 2016, 8:13 pm 
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ngpmike wrote:
Just 'Google' "Lotus 7 boattail".


Harrumph! Far too simple!


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PostPosted: January 23, 2016, 8:29 pm 
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Trx i like that power clutch idea. Some old Ferrari race cars had the clutch all the way at the end of the transaxle. I forget which models.


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PostPosted: January 24, 2016, 12:34 am 
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After some web searching:

C5 Corvette: clutch on engine
Porsche 944: clutch on engine
Porsche 928: clutch on engine
Porsche 924: clutch on engine
Pontiac Tempest: clutch on engine

*Somewhere* I've seen a layout that looks like a conventional transaxle, except with a cast cover and the clutch in back. At least I thought I did; maybe I was mst... mtksd... mistk... whatever.


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PostPosted: January 24, 2016, 1:53 am 
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I've modeled this car 6inches wider to accommodate a clutch pedal, and I really didn't like the proportions. I'd have to make the car around 8 inches taller to compensate, and then it's getting pretty big visually with the wheels.

I think I will likely end up making the car longer. I currently have about 2inches of forward movement on the engine to get it out. My idea was to unbolt the transmission in the passenger compartment and pull in back 2 inches, then pull the engine forward 2 inches and straight up and out. This is all theory. Ultimately it looks like I need more room for the front suspension, so I'll move everything forward a few inches and that'll give more room for the engine. I also am thinking that the cross members under the engine will bolt in which will give more room that way too. It's tight, and I think there will be some changes made when I've got it all in front of me to measure and see in real life. Solidworks really doesn't give you a good perspective.

I thought about going to a powerglide with a great torque converter. With the engine's low down torque and curb weight, I think this car could almost be driven entirely in a single gear. Ultimately though, I'm not nearly as attracted to this idea, even if it does simplify things. There is something about a 4 speed that calls to me. It feels right for reasons I can't explain.


I think the 5.5" clutch is risky. I, in general, tend to drive very lean. I start off with as little gas as possible, getting the clutch out fast without bogging the engine too much or letting things slip. Once everything is locked up, I then lay into the throttle and let the engine wind. I think this driving style would suit a 5.5, but I have no experience with one. I don't drive in much traffic and I don't use the clutch to creep forward. I feel like I have a reasonable chance of making a 5.5 work IF I can get the hydraulics worked out and can operate a hand clutch with the proficiency I operate a standard foot clutch with.

Quote:
You'll probably want/need a significantly beefier mount/support structure for your center link.

The 3rd link is still in need of some designing. It's 1" tube currently that mounts to a chunk of 1"sq crossing a 3inch gap between the tunnel rails. How would you guys mount it to the tunnel structure?

Quote:
What about your ability to perform large/quick steering inputs, like trying to catch a bit of power induced oversteer on a short wheelbase car? Seems to me like your passenger would be likely to inhibit this to at least some degree.

I'm hoping that the fast ratio means quick corrections are within the first 90 degrees of travel in either direction, leading to largely up and down movement of your arms and less elbow out as you turn the wheel over.

Quote:
Absolutely out of the question if you plan to actually drive this anywhere on the street. Even a minor collision would likely result in moderate to severe injuries.

I'm worried about neck injuries, but I can't find a head-support method that looks ok with this design. I don't know which way I want to sacrifice. My head tells me to add a roll bar and a nice pad to catch my head. My heart says to keep the look true to its roots.

Quote:
I think I'd look at something like the "paddle shifter" arrangements some of the BECs use instead of a lever, though. Then you could keep your fingers on or near the wheel while shifting.


I thought about a paddle, but it ultimately seemed like it would make it difficult to steer and clutch at the same time (bad practice but happens on the street out of necessity on occasion). I've been trying to look into some sort of cable actuated hydraulic master. I think this could work nicely for the hand clutch. Mount a lever (like I have modeled) on the shifter, that pulls a cable, that operates a master that can then apply much larger amounts of force to the clutch. I could probably MacGyver up a cable operated lever that pushes a traditional plunger style master, but that seems like a complicated solution.

Quote:
I've never understood the fad for kart steering, but I seem to be in a small minority there.

I personally hate shuffling the wheel. I'd like to keep my hands planted in one spot on the wheel and be able to do all the steering without moving them. I don't like the idea of a small kart wheel and a fast rack; I don't want it to be twitchy. It seemed like a large steering wheel with a fast rack would make each degree of turn a larger movement, reducing how darty the car feels. The large wheel also helps with steering effort. From a guesstimation, I think you could get near 1.25 turns lock to lock and never have to let go of the wheel.

I'm also thinking bicycle style fenders will need to be on it to get it registered here, plus they will help with pesky things like rocks and puddles.

Question for you guys: What is a reasonable amount of travel for the pumpkin? I figured it shouldn't really ever move much more than 2 inches up or down during driving. Does that sound reasonable? My design has a lot more room down, but only 2" of upward travel at the pumpkin. Out at the frame rails there is clearance for the car to bottom out before the axle tube hits the frame so it should be fine for bumps.


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PostPosted: January 24, 2016, 2:42 am 
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Joined: May 17, 2008, 10:55 pm
Posts: 313
Location: canada
You get finer resolution with a slow steering set up. The big- really big- example is on the street when it's snow and ice weather. You can constantly adjust as the slip angle goes up. A fast ratio, and you are off in the ditch- you simply don't have the ability to do fine adjustment.

I've sold probably close to 25,000 tires in my capacity as a parts manager for various car dealer. Never sold a 225/45r17. Try 215/55r17, maybe?


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