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Discussion Starter · #1 ·
It's taken me a while to get my little project this far, but I have finally arrived at the fun parts. It started out as a 74 Ghia with a rusted pan and no engine for $700. I hauled it back to a single car garage on an AF Base in Ohio and started in on things. Mostly wanted to avoid my first wife and relive some fond memories of my step dad in California fixing up his cars. He owned a VW shop, so I grew up with these cars. Ghia's look a bit more sporty, but that's about all. I wanted to make the car corner and brake as much as I wanted it to go fast. Making it light for road racing was always the goal. I couldn't rely on VW parts for this, so I ordered a 1914cc DRD Racing Heads Stage 2 motor, RLR tube chassis, and Lester Chatley transaxle. I then went to a salvage yard to grab Mazda Miata suspension (double wishbone) and bought many racing bits to round it out. The RLR chassis wouldn't work as it was designed, so I bought a mandrel bender and more tube to customized structural points for my suspension and general layout. I then built a steel square-tube welding table and built the car on that to keep things true. The body was always meant to be removable, so I built a hoist system to pull the body with a push of a button. The front end is removable and tilts on a complex hinge with an electric actuator. I'm now working on the body for paint and trying to add plastic covers to the chassis around the suspension to block rocks and debris. It won't be weather tight, but that's ok for the track and fair weather cruising on the street. I'm adding an O2 sensor now to start tuning the motor and playing with coil springs to get the suspension tuned better. Should have it out next year to play with in autocross and drive it around more. It's getting to be more exciting as it becomes more reliable. I hope you guys enjoy the few pics below. I'll add more info on the engine and chassis tuning as I learn more how to do those things. Might even ask for help!

I did all the work myself as a learning exercise, so be gentle with comments. I'm not a professional car builder. Just wanted something to do.

Body hovering over chassis. Very handy for chassis tuning and maintenance.
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Rear view showing custom tail light bulb holders. Couldn't source factory units. Had to clearance the body a lot to fit over tube chassis.
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Here is the body with track trim. Homemade large splitter and rear adjustable spoiler. Will make smaller street splitter and remove spoiler for the road.
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Will drill more holes in spoiler mounts to adjust angle. Need to experiment on this more.
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Chassis is self contained. Just need to add temporary lighting for the road and license plate mount if I want to drive it like this. The body only keeps the bugs off and carries lights. Quick disconnect wire harnesses make things easy to remove the body and front end.
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Made some ABS plastic frame covers and installed recently. Working on the rear suspension covers now. The sway bars are from Currie Enterprises and meant for 4x4's. Worked with their Engineers on torsion bar spring rates for my light chassis and low roll center. Still need to lean it into some high speed corners to make adjustments.
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Discussion Starter · #3 ·
I see the baja bug in your profile picture. Reminds me of when my step dad put one together and we took it up into the hills around Santa Cruz, CA back in the mid-80s. Learned the value of wearing a seatbelt on that trip. We both put one on after feeling the roof with our heads for the first time. That was my only off-road experience. He got rid of it shortly after. He was always putting VW based toys together and getting rid of them. Never understood that. Looks like you enjoy yours from the picture. I hope to have my toy out to play with soon. I'm just installing an O2 sensor now to improve the tune on the motor. I hope the sensor and the procedure I got online helps me to learn this part of car building.
 

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Discussion Starter · #5 ·
Got my O2 sensor installed. Waiting on a gauge pod to be delivered today to install the gauge properly. Got it setup in the video on the chair to be able to see it as I'm running the engine. The LED display is goofy when captured on my phone. Refresh rate must be out of synch with phone or something. Got the body off to do some mods. Below is a link to my YouTube Channel so I can post so I can share some videos.

Sensor_cold start
 

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Discussion Starter · #6 ·
I coiled up and installed a 3/8" aluminum tube vent loop to the fuel cell vent port. I need to get some fuel hose and an inline fuel filter to keep the bugs out. I drilled and tapped a hole in the floor for the brass hose fitting to vent vapor out the bottom of the car. Vapor has been accumulating under the front end for a while, but he frame was open all this time to keep things safe. Now that I'm enclosing the frame more, it was time to make things proper. The fuel pump wiring needs to be collected still and wrapped to clean it up. It's on the list.

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Pardon the mess. Need to drag the vacuum over. You can see the factory Miata lower control arm left of the brass fitting for the vent line. I had to flip the control arms driver to passenger to keep the offset bushing out of the footbox. the shape of these control arms is interesting on the factory Miata, but doesn't work well on a Ghia without some modifications. Got it all figured out though. The factory upper control arms have been replaced with tubular ones and adjustable ball joints for camber adjustments. Everything is setup for alignments with shims.
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Discussion Starter · #7 ·
I got some more work done this weekend. Finished the fuel vent line and added maintenance lights to the chassis. Just need to mount the switch and add a light to the engine compartment once the body goes back on. I also put stiffer springs on the rear and swapped rear springs to the front. I'm trying to add more coil spring rate to be in range of the 5 sway bar adjustments that are available front and rear. The coil springs were too soft where the sway bar was out of range. I need to drive more aggressively to make any more adjustments. I'll begin engine tuning this week since we'll be in the mid-70s and clear skies. I'm also beginning to template for my new dash. I'll just fold some aluminum sheet metal and blank it off until I figure out what I want to mount. This is the problem with a body that is designed to be removed. I need certain things to stay with the chassis to monitor the car, which doesn't leave much to install onto the dash. I use a Trail Tech digital dash for my speed, tach, shift lights, warning lights, and odometer. I suppose I don't need that when doing maintenance runs. Perhaps I can mount that centered in the dash. The steering wheel opening is too small to mount anything behind the wheel, and I sit too low to mount it above the wheel.

Fuel vent loop is installed and secured.
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The vent loop connects to a filter to keep bugs out and dumps out the bottom of the car now. The hinges in the foreground are for the complex hinge for the fiberglass front end. This allows for the nose of the front end to move up and pivot at the same time when the actuator is connected. This keeps the nose from hitting the ground if it were a single pivot point hinge. Fully adjustable for aligning the front clip.
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Got the O2 sensor gauge installed in a convenient place for monitoring the AFR. I put it under the dash and in the shade so it is easier to see.
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There are lights in several locations. The top of the frame looks back and front for cabin lights.
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The wheel wells have lights for suspension adjustments and hardware checks. I still have to enclose this area with ABS plastic to keep rocks out.
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I put a light up front looking back, but I may add one looking forward at the front end subframe and headlight wiring. These lights are inexpensive and easy to add. You can see the electric actuator in this picture. Very nice unit. 400lb force and slow speed.
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Discussion Starter · #8 ·
I got my dash cut up and starting to add reinforcement to fold the aluminum sheet metal over. May have pictures tomorrow.

Also checked my carburetor floats as recommended by the Air cooled O2 sensor article. Should be 10mm, but I measured 19mm on both sides. I pinched them down to spec and reassembled. Will go through carb adjustment sequence and re-synch tomorrow before following fine tuning guide. Not sure how much of a difference the float adjustment will make. All part of learning.
 

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Discussion Starter · #9 ·
Boy, after making those float adjustments, the car runs very well. Mixture screws work now. Idle is strong, and acceleration is smooth. Got a few more things to tune on, but very close.

After swapping rear coil springs to 350lb/in and fronts to 250lb/in spring rates and no preload, the body roll is nearly gone. Should be in range of the sway bar adjustments now. Still a comfortable ride without any bounce. Need to breakout of the neighborhood and put some heat into the tires, brakes, motor, tranny, etc. Fun to drive without the body. Might post some videos soon.
 

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Discussion Starter · #10 ·
I drove the chassis for about a half hour today, just 25-30mph in the hood. Got 205F on oil temp, header tubes were around 340F, intake manifold was around 130F. AFR was reading funny. Need to check a few things to understand the gauge better. Keeps wanting to start heating. Not sure what that means. First time running this long. Got vapor coming out of breather too. All seems like I'm heading in the right direction. Brake bias is to the rear. Rotor temps are higher on the rear. Need to turn bias bar to move to front system. Trans is smooth. Third is straight cut and whines a bit. Rigid mounting the power train makes it sing thru the tube chassis.
I was swaying aggressively and grip was good with little body roll. No parts fell off, so that's good.

More to come as I get more aggressive on my drives.
 

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Discussion Starter · #11 ·
Can anyone provide a suggested fuel pressure for my application? Dual 44mm IDF's on a 1914cc motor. I have a fuel test gauge installed right now at the Tee fitting just before the carbs and put a Holley regulator at the centrifugal pump. I have it regulated to just above 3psig at the moment, but can go up or down. Floats were recently adjusted to 10mm off the gasket. I just don't know how sensitive things are to fuel pressure.
 

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Discussion Starter · #13 ·
Thanks for the quick response.

What could a guy expect to come of the pressure being high/low from optimal? I'll drive with the test gauge in my lap to make sure the pressure is stable at RPM, but don't know what symptoms to look and listen for if I'm high or low. Again, I'm just getting into tuning and don't have much experience to dial this thing in. My AFR gauge may also have a weak ground that I have to fix before it is reliable. Keeps cutting out. I'll tie the ground wire back to the battery and try again. Still need to follow fine tuning guide using AFR, but need to get fuel pressure set.
 

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Discussion Starter · #14 ·
Just found this (below) on another forum. I'll drive it around today or tomorrow at 3psig with the gauge in my lap and monitor. If it drops at cruising RPM, I'll just add more pressure to get back to 3 and see how it goes. The 4psig you were thinking of is probably a good number to start with. I know it doesn't like anything near 2psig.

Here is from the weber manual, if you want to know.


Quote:
scale range, for fuel supply feed pressure measurements; may also be of the wide scale range type measuring, also depression (mano-vacuum-meter).
It must be ducted in proximity of carburetor connection by means of a plastic tube so that the instrument may be kept in driver's compartment and give pressure readings during vehicle operation at high road speeds when pressure drops are more likely.

For the majority of Weber carburetors, normal fuel feed pressure values are the following:

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Maximum pressure: 0.3 kg/sq.cm
(4.2 psi)

measurable when engine operates in the transition (progression) or idle speed stages


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Minimum pressure: 0.2 kg/sq.cm
(2.8 psi)

measurable on the road around top rated vehicle speed.
 

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Discussion Starter · #15 ·
I drove around more aggressively today with my fuel pressure gauge and set pressure regulator to just under 3.5psig. Saw pressure go down as low as 3psig at WOT, but stable otherwise. I'll run this way for now until next tuning step. Car felt good, but stumbles when stabbing throttle at take off or rev matching on downshift.
 

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Discussion Starter · #16 ·
Just returned AEM gauge and sensor for a replacement thru Amazon. No fuss to exchange with Amazon. All the tests for the gauge and sensor indicates a faulty device. Too simple to wire to be anything I did. Should have the new one installed soon to fine tune the engine. Still have plenty to do while waiting.
 

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Discussion Starter · #17 ·
Here is a quick video of a warmup. I've been driving around the neighborhood for longer rides and getting on the gas and brakes, along with aggressive swerving to get a general feel for things. The suspension still needs tuning, as does the engine, but I feel I could take it out of the neighborhood to drive on the street. Just need to put the body back on since it carries the lighting and plate, and it looks more like a complete car. The chassis by itself may get too much attention. I started it several times in a row after warmed up and it fired right up each time. I'm very nervous about getting too far from home.

 

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Discussion Starter · #18 ·
I was organizing some pics finally and came across some old ones of the first time I built this thing, somewhere around 2007. Been on and off ever since until this year. I ended up learning a lot and later cut most of it apart to reorganize the suspension so it would work. Packaging Miata based suspension was a little challenge for a novice car builder. There is no particular order to these, just early build pics.

First start of the engine after rolling out of the garage. Very minimal equipment.
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Still connecting basic power, fuel, brake lines (front system only), and clutch I think. I think I drove it the next day and realized I didn't put oil in the trans. Only went about 25 yards or so.
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Again, bare bones to just get it running. I've come a long way since this first start.
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Mazda Miata suspension. Had to flip lower control arms to make it work, and remade some attachments to remove factory shock and sway mounts.
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I was in a single car garage on an Air Force Base. Everything came off a light bulb on the ceiling to power the "shop." We are not even supposed to change our oil in base housing. Here is the car being winched off the welding table I made. Built the whole chassis with all major components on the table, then cut it free and rolled it out.
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Body is on, but not really secured yet. Front end is just there mocked up.
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No shocks installed. Just square tube to hold it up.
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First time body was installed and to make final clearance cuts on the underside. Looks like I got patch panels tacked in already. Only just welded them solid a couple weeks ago.
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Mazda Miata rear suspension and transaxle mounted. Had custom axles made for Porsche 930 inner joints and Miata hubs. Did you know the centerline of the trans is 3/4" off to one side??? I didn't when I ordered the axles. Had to make a spacer for the CV joint, which became my speed sensor ring. All worked out in the end.
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Discussion Starter · #19 ·
Just replaced the O2 sensor with the new one and all works great. Cold start on rough idle shows 19-20. Not sure if that means anything yet, but a start none the less. Fired right up with a couple pumps of gas. Will work to dial in the tune over next few days. Got a nasty sinus infection. Don't want to drip all over the car. Also got AMSOIL 75W-90 GL4 trans fluid to replace whatever is in there now. I think I just have Mobile 1 75W-90 in there. Not many miles and almost no load in the trans since it's been running. Shifts good, but thought I'd put the right stuff in there now that I'll be driving it more.
 

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Discussion Starter · #20 ·
Not sure how many people are aware of the neutral switch on the nose of the trans, but it seems to be a bit of a mystery for me to replace. I use it for a neutral indicator lamp to keep the car from rolling over me when I start the engine from the engine compartment. Out of convenience, I have a start button on my firewall to keep from having to crawl into the chassis every time I want to start. Welllll, I broke the spade connector some time ago and can't find a replacement switch. From what I understand, it was used on a limited basis as part of a seatbelt system that prevented a person from starting a car without the seatbelt clicked in, and it had to be in neutral as part of the logic. Most of what I read were stories of people finding a way around this feature because they didn't want the Government telling them they had to wear a seatbelt. Funny how times change. I defeated the seat switch on my riding mower so I could pick up sticks as I mow. A bit conflicted on safety it seems.

Anyways, since I can't find a replacement, I decided to make one. I would prefer to source a new one, or a used one if anyone has one to spare. It's pretty handy to have for starting things outside the car. I can manage without it, but better to be safe.

Here is the original trans with the switch installed by Lester Chattley.
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Here is an exploded view of the one I'm building, compared to the original. Notice the male spade terminal is missing! Just drilled and tapped a plug to make things fit.
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Here is the nearly finished part. I have to fill in the exposed threads of the screw behind the acorn nut to have a smooth surface for it to slide in and out of the brass plug. It catches a little and is not smooth as it should be. The small travel is just enough to make contact in the switch. I can wire the switch to be continuous when depressed or continuous when extended. It simply connects to chassis ground, so I just have it wired in the ground wire of the lamp.
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If anyone has a switch to offer, I'd appreciate a shot at making arrangements to buy it. My new switch may be ok for a while, but I'd prefer the correct part to be in there.
 
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