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Learning how to build Lotus Seven replicas...together!
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 Post subject: Re: The GWTFFM
PostPosted: November 19, 2017, 8:17 am 
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BBlue wrote:
Thanks for the CNC video, it confirmed all my worst fears. CNC is a special hell invented for the dyslexic.

Bill



Bill, Maybe you should join Mothers Against Dyslexia, DAM.

Tom

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https://www.youtube.com/watch?v=sG16m2e4O6I


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 Post subject: Re: The GWTFFM
PostPosted: November 20, 2017, 1:59 pm 
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BBlue wrote:
Thanks for the CNC video, it confirmed all my worst fears. CNC is a special hell invented for the dyslexic.

Bill


I do need a cheat-sheet for more than I usually care to admit. :oops: Doesn't help it's a new-to-me control and machine.

The CAM software takes out 90% of the "human goof" potential from programming, leaving mostly fixture/tool offsets and fat-fingered entry points/clearance planes as the source of unexpected problems.

As with everything, with practice it gets easier to know what you did wrong, and how to fix it/prevent it in the future.
Such as learning the hard way to double-check everything twice. :mrgreen:


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 Post subject: Re: The GWTFFM
PostPosted: November 20, 2017, 5:46 pm 
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Location: CNY
Just snagged a RHD RX-8 steering rack (F151-32960) from Ebay for £40.00 with £38.00 shipping.

The exchange rate meant it turned into $52.81 for the rack and $50.17 for shipping, with a grand total of $102.98 for the whole shebang.

Oddly enough, that ended up being about half the cost of a LHD one in the US, even witht he added overseas shipping.

Now I just need a power steering control module, and I'm all set. Luckily, the module is the same part number LHD/RHD, and the only change was the rack.


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 Post subject: Re: The GWTFFM
PostPosted: January 31, 2018, 12:38 am 
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I've got a 2000 Nissan Pathfinder front axle coming in, to snag the shorty center shaft from.

The plan is to stuff it into the Maxima axle, to get a shorter axle and therefore a narrower track width.

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Walt
04 RX-8 Touring RIP
90 Ram 50 4x4 V6
91 3000GT VR4
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.


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 Post subject: Re: The GWTFFM
PostPosted: March 6, 2018, 3:34 pm 
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CV shaft stuff is waiting on some more research before I can dump it all together here.

In the meantime:

Image

Nissan to the left of me, Mazda to the right, and here I am, stuck with an idea to use.

RHD Mazda RX-8 steering rack, and the Nissan Skyline RWS rack from Japan.
Now I just need to get some control modules.


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 Post subject: Re: The GWTFFM
PostPosted: March 7, 2018, 3:23 pm 
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Location: central Arkansas
Is the Skyline in-phase or out of phase on the RWS?

A friend and I argued the merits of RWS extensively, and he finally wound up buying a new Galant VR4. Neither one of us could tell that the RWS did anything noticeable. The only thing I remember now was that, whichever way the Mitsu steered, the Honda RWS was the opposite way.

Oddly, I was just looking through "The Automotive Chassis" by PM Heldt last night. It's circa 1952. In a section mostly about trucks, it mentioned that rear wheel steering can shorten the turning radius. Which would probably be important, making right turns into narrow alleys for deliveries, etc. But that's all he had to say about it.

The off-road guys are going into 4ws now. The hill climb cars use a joystick on the console to steer the rear axle, which ought to be an adventure, the way they bounce around...


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 Post subject: Re: The GWTFFM
PostPosted: March 7, 2018, 3:29 pm 
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The later versions of the Nissan system did both in-phase and out of phase, depending on the speed.

I think they were out for low speed, in for high speed.

The Mitsubishi hydraulic version was always in-phase, and would kick in based on the feedback force against the front rack.

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Walt
04 RX-8 Touring RIP
90 Ram 50 4x4 V6
91 3000GT VR4
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.


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 Post subject: Re: The GWTFFM
PostPosted: March 7, 2018, 3:47 pm 
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You might wind up going for more cowbell; I bet the control authority of the OEM system is fairly limited.

[blowing the cobwebs off the memory banks] I seem to remember the Nissan factory rally drivers had vastly different ideas about how they wanted the RWS system to work.


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 Post subject: Re: The GWTFFM
PostPosted: March 7, 2018, 4:39 pm 
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I do plan to design in a bit more rear steering angle than factory, if the actuator can handle the extra strain from the reduced leverage.

I'll probably keep the response curves close to stock, till I get track time. I don't want to do donuts on I-90 because of an over agressive anti-phase movement.

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Walt
04 RX-8 Touring RIP
90 Ram 50 4x4 V6
91 3000GT VR4
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.


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 Post subject: Re: The GWTFFM
PostPosted: March 13, 2018, 1:57 pm 
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Scooped up an RX-8 power steering control module on ebay Friday while they had their 20% site-wide coupon going.

Then found out on Saturday that the local pull-a-part was doing their monthly bucket sale, and had an RX-8 in the yard.
Anything that will fit inside the bucket, not tip over, and not reach over the counter, for $30 a bucket.

Got another steering module, most of an RX-8 front body harness+under hood fuse block, the electric smog pump, and a handful of nuts/bolts.

Also got a set of Fiero popup headlight assemblies, and an 03 Montero Sport cruise control module and actuator. Cruise control baby!

In all, 2 buckets because the headlights were a bucket each.

Still have to snag the hood for the popup covers and the fiberglass that surrounds them, that may be Saturday.
I'm also going to grab the hood stay and possibly the latches, because why not, right?


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 Post subject: Re: The GWTFFM
PostPosted: March 15, 2018, 9:29 am 
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The eBay special RX-8 power steering module came in Tuesday. Now I have to bench wire it at some point and get some CAN messages bounced at it.

I ended up getting an ABS pump and accumulator for a 2012 Prius, and am in the process of getting a Buick Grand National master cylinder that I can pair with it for full electrohydraulic boosted brakes in a miniscule space package.

The Prius pump/accumulator goes for under $60 used, so it's the ideal replacement for the $500 or more, 30+ year old, and discontinued Buick pump module.


Similar electric boost setups retail for ~$1200 on Speedway Motors, so if I can do the same for $200 I'll be happy.


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 Post subject: Re: The GWTFFM
PostPosted: March 15, 2018, 10:59 am 
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Most of my track experience is with autocross, where weight transfer is high enough that the inside tires have little effect, and HPDEs at a track (Memphis Motorsport Park) that have a lot of sections so slow they're just higher-speed autocross.

I was perusing Smith's "Tune To Win" last night. He had a lengthy section on front and rear slip angles and the car's turn center while cornering, and some stuff on how Ackermann affects things.

Essentially, the rear end wants to go straight, so the front wheels have to not only pull the car out of line into the turn, they're fighting the rear wheels to some degree as well.
Not really relevant for the courses I've run on, but on the huge fantasyland racing freeways I see in track videos... if the rear wheels steered, you could take some of the load off the front, and reduce slip angle some at both ends, which would reduce rolling resistance as well. For long turns where you don't have to worry about transients, I think rear steer would be an advantage.

If I was building an IRS, I'd be scheming an RWS system about now...


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 Post subject: Re: The GWTFFM
PostPosted: March 26, 2018, 2:01 pm 
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The master cylinder came in the mail last Monday.

Now to clean it up, tear it down, and clean the guts out.

I ordered an o-ring kit (came in last week), but the cup seals are apparently unobtainium.


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 Post subject: Re: The GWTFFM
PostPosted: March 26, 2018, 2:02 pm 
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I think I'll start referring to this as the G25E. Sounds like an exotic car model.

I tried to separate the outer CV joint from the Maxima driveshaft, and things did not go as planned.
The Milwaukee impact performed flawlessly, cranking up to it's rated 700 ft-lb torque.
The removal tool bent, and the damn axle has a permanent wire circlip, just like the Pathfinder one did. One time install, no user serviceable parts.

I called up Interparts on Friday, and the lovely woman in Automotive listened as I prattled on, and told me that while I can't order from them directly, there is a place fhat will be able to do exactly what I need, and was highly recommended.

I was referred to Constant Velocity of Ocala, and I will be giving them a call to see what it would entail to order an outer joint for this thing. And possibly a set of custom short intermediate shafts to reduce the track width I have on paper.

No photos of the axle stuff, because CV grease is horrible.


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