DuPuis Family Cobra Build

[Ted]

The Cobra IS a race car!

So I have race CARS to get ready.

 

[Half Fast]

The Cobra IS a race car!

Not unless he's willing to do a little fender rubbin' with it!

 

[Ted]

Not unless he's willing to do a little fender rubbin' with it!

And that there’s the rub (pun intended). The RX7 has been lovingly certified pre-raced, and has the battle scars to show it. The Cobra, I’m not sure I want to risk the body damage on. I also don’t want it to be a show car, but I haven’t built it as a real racecar either with some of the comfort features I’ve put in.

Really, it’s a racecar, but not an ideal one for racing.

 

[Half Fast]

One of my racing buddies told me, "The first thing to do when you get a new race car is to walk up to it and kick a dent in the door. Then you won't worry about banging into the other guy once in a while."

 

[Half Fast]

...but I haven’t built it as a real racecar either with some of the comfort features I’ve put in.

BTW - the RX7 still has the heater core but that wasn't done for comfort. Rotaries run hot, and once in a while I had to turn on the heater as auxillary engine cooling. If I'd taken it out I would have needed ballast, since I was already down to weight, so I figured it was best to leave it in and functional.

That cockpit gets quite warm, as you will learn. With the twin exhaust pipes snugged up against the driveshaft tunnel and glowing cherry red, it'll be toasty.

 

[Ted]

One of my racing buddies told me, "The first thing to do when you get a new race car is to walk up to it and kick a dent in the door. Then you won't worry about banging into the other guy once in a while."

My intent is to drive it on the street some before I do the body work; and that might help me decide how good of body work I care to do. If I think I’ll do more tracking it, I won’t worry as much about it looking perfect.

 

[Fiveslide]

Hey, @Ted , your shifter isn't going to be that far back is it? Or the seat so far forward? That looks almost undrivable to me, the shifter back at your hip joint.




This example from Back draft racing looks so much better.

 

[Ted]

Hey, @Ted , your shifter isn't going to be that far back is it? Or the seat so far forward? That looks almost undrivable to me, the shifter back at your hip joint.

I'm not sure which picture/video you were looking at for that. I made the TKO a "mid-shift" kit, which puts the shifter location in a more traditional location. The normal Mustang boxes have a rear shift kit, which then Factory Five handles with a forward leaning shifter. I installed this shifter backwards initially (leaning back) which yes, was basically unusuable as it was.

I don't think I've posted any videos or updates, but since then I've added another hole in the shift mount so that it's now essentially straight up and down. I also shortened it a bit. I don't have the seats bolted down, but I believe I have the location pretty well set now. When I start driving it I'll see if I need to adjust further.

 

[Fiveslide]

I'm not sure which picture/video you were looking at for that. I made the TKO a "mid-shift" kit, which puts the shifter location in a more traditional location. The normal Mustang boxes have a rear shift kit, which then Factory Five handles with a forward leaning shifter. I installed this shifter backwards initially (leaning back) which yes, was basically unusuable as it was.

I don't think I've posted any videos or updates, but since then I've added another hole in the shift mount so that it's now essentially straight up and down. I also shortened it a bit. I don't have the seats bolted down, but I believe I have the location pretty well set now. When I start driving it I'll see if I need to adjust further.

Oh, that's not your cobra. That's one off of BaT auction is saw. I mimicked using a shifter that far back while driving my truck and it was so uncomfortable. Glad to hear you went with the mid shift. And the second photo is a typical back draft, pro build that I've looked at.

 

[Half Fast]

My intent is to drive it on the street some before I do the body work; and that might help me decide how good of body work I care to do. If I think I’ll do more tracking it, I won’t worry as much about it looking perfect.

Y’know, that Cobra might be a hoot to take to an autocross or two.

 

[Ted]

Y’know, that Cobra might be a hoot to take to an autocross or two.

It might be. I've never been a huge fan of Auto-X. Too short of drive time for me.

 

[Half Fast]

It might be. I've never been a huge fan of Auto-X. Too short of drive time for me.

Agreed but it can be a good way to sort out handling. I auto-x’d for several years before I went road racing. Took a 2nd place in the Florida state championship one year.

 

[Ted]

I knew I hadn't touched the Cobra in a while, and this thread now reminds me that it's been close to a year since the last meaningful progress. Well, RX-7 took time, RV projects took time, and I got distracted with some motorcycle projects as well. All fun stuff. Summer I didn't get much done between work, kids off school, couple RV trips, and doing the solar project on the RV plus random other household responsibilities.

So yesterday I spent some time to just look at the Cobra, remind myself where I was with everything and what I needed to do, come up with a plan. While the RX-7 still has some tweaks to do, safety equipment to install, etc., it's driveable as-is. And I may end up just driving it some more before I attempt to race it to make sure I'm happy with how it's running. RV has tweaks to do (as always) but really, it's Cobra time.

Most of what I've got with the car at this point involves working on electrical, and even then most of it's done. I need to finish up some wiring for the dash (specifically the headlights and the turn signals/horn), finish some AC wiring, and then really just get everything connected and together. Then I can attach the dashboard to the car, attach the steering wheel (properly). Rivet in a panel or two. Make sure the suspension has its initial adjustment in and I can take the first proper "go kart" drive. However I'll probably try to get the air conditioning fully hooked up as well and some additional work relating to that. Once everything seems to be doing its job just fine, I can work on buttoning up the couple interior panels I want to leave off until I do complete the first drive, and then it's getting ready for the body. Some other details, but as I've said before, it's really not much.

With the kids going back to school tomorrow and life getting more in the "back to work" phase from summer, hopefully that'll mean I can more easily get some time here and there to work on it. But that'll be the goal. I have some more work to do still on the other vehicles, but hopefully that will be more of the "fill-in" work while I focus on trying to get a driving Cobra, finally, close to 4 years after first taking delivery.

 

[Sac Arrow]

We are all itching to see it drive.

 

[Ted]

We are all itching to see it drive.

Not half as much as I am...

 

[Half Fast]

Be sure to put a trailer hitch on the back so you can use it to tow the RX7 to the track!

 

[Ted]

Be sure to put a trailer hitch on the back so you can use it to tow the RX7 to the track!

It's got the horsepower.

I've actually thought about if I should put 4.11s in, but it has 3.73s. So I'll leave it alone for now. I could always weld a tow hitch.

 

[Half Fast]

It would be worth just staging a photograph!

 

[Ted]

Especially with the big 25' equipment trailer which is my only trailer I can tow the thing with.

 

[Matthew]

It's a beautiful day for a drive today.

I saw someone driving his Cobra earlier today. Metallic copper (that's about the best way I can describe the color), with gray hood stripes. I noticed he had two electric cooling fans, side by side, in front of his radiator. Unfortunately we were going opposite directions so I only caught a quick look as we passed.

 

[Ted]

Yesterday I managed to get a shop day and, after tending to a few items on the RV and the racecar, finally actually got back in to working on the Cobra for the first time in... way too long. Close to a year according to my post a few posts up.

Progress is slower when you're that far removed from a project time wise, and things that made sense when you left them a certain way make less sense after that time gap. But I'd figured out how I was going to handle the interfering ducting for the one HVAC vent, and removed the appropriate material from the bird box side to make that work. I also mounted one of the floor-facing ducts (the one on the passenger side), so that's progress on those fronts.

I also went through and finished up some of the wiring details. The lights all needed to be wired. I'd gotten some relays in place for those, but I hadn't wired up the headlights, tail/marker lights, brake lights, etc., I'd just run power to those. Those are now all wired. Of course the lights themselves aren't there yet - those will come with the body - but the wiring is now complete to the dash switch, brake light switch, all of that. I didn't test the wiring and I probably should before I get to the point of putting the body on, but it's all pretty straightforward. Turn signal wiring also is done, and I got the turn signal stalk wired up, with the push button for the horn.

Then I started looking at the windshield wiper motor, and the mounting for it. And I looked more at the instructions, and decided that this was probably a feature that wasn't worth adding in in the end. I've already drilled the hole for the wiper motor switch, but I think that location will be a good spot for the push-pull cable for the heater valve. So I'll plan to remove that switch and install the cable, which I then will have to figure an appropriate routing for, and cut to the appropriate length.

By deciding to omit the windshield wipers, that leaves the wiring on the car as "done", or at least as done as it can be. I had thought about adding some dome/footwell lights. The light switch I bought allows for that, but I just don't think it's likely worth doing. I doubt I'll be driving it that much at night, and if I am and really need a light, that's what cell phones are for.

I had originally hoped to mount the dashboard yesterday, but I'm not quite ready to do that. It'll make more sense for me to run the wire looming (was waiting on that until after all the wires were run) and I've also got one more aluminum panel to rivet in before it gets covered up by the dashboard. But, I'm basically there, which is pretty satisfying and gives me more motivation.

The next steps will be looming the wires and getting these couple more aluminum panels on. Then, the dash can get attached (along with connecting the HVAC vents and mounting the driver's side floor vent). From there, it will basically be going over the suspension and then the car should be ready for its first "go-kart" drive, after which it becomes a matter of body work.

 

[Half Fast]

By deciding to omit the windshield wipers,...

Is that legal for the street in your area?

Back in the ‘70s, rail dune buggies were popular in my area. Florida law at the time required working windshield wipers, and they were checked during inspections. But the law didn’t require windshields. So there were buggies running around on the streets with no windshields, but they all had working wipers.

Gov’t at work...

 

[Ted]

Is that legal for the street in your area?

I'd had that thought and wanted to make sure the Kansas inspectors wouldn't raise any issues if I didn't have wipers installed, so I asked on the regional Cobra group. The response was that they don't care about wipers when doing the inspection.

What some have done in states where they care about wipers (but don't specify that there must be two or power) is attach a manual wiper to the top of the windshield that can be moved from a lever on the inside. So if they do care, I could always add that.

 

[GaryM]

If they give you a hard time at inspection, just explain that most light planes don't have windshield wipers, and that the car is faster than many of them...so the slipstream is all you need to keep the windscreen clear.

 

[Ted]

If they give you a hard time at inspection, just explain that most light planes don't have windshield wipers, and that the car is faster than many of them...so the slipstream is all you need to keep the windscreen clear.

I could pull that off with some cars, but not the Cobra. While its 0-60 time should be very good, as they get above about 120 they prove to have aerodynamic characteristics roughly equivalent to the broad side of a cow with a jet engine strapped to its back.

 

[Craig]

I could pull that off with some cars, but not the Cobra. While its 0-60 time should be very good, as they get above about 120 they prove to have aerodynamic characteristics roughly equivalent to the broad side of a cow with a jet engine strapped to its back.

MMMMMMM...self cooking steaks!

 

[SoonerAviator]

MMMMMMM...self cooking steaks!

Cook on Mach 1.8 for 6 minutes per side . . .

 

[Bill]

It’s like Omaha steaks, except they arrive cooked to order!

 

[Zeldman]

Back in the ‘70s, rail dune buggies were popular in my area. Florida law at the time required working windshield wipers, and they were checked during inspections. But the law didn’t require windshields. So there were buggies running around on the streets with no windshields, but they all had working wipers.

Texas was the same way.

Then a few years later Michigan moved to Texas. A lot of Michigan folks were pee'd off to find out their car won't pass a safety inspection. Seems like doors, fenders, floor boards and other metal parts were required to be attached along with headlights, brakes, seatbelts and windshield wipers but windshields not required...

 

[Ted]

It's been a while, but I finally got some time to work on the Cobra today.

My goals were to try to get the dashboard on the car, steering wheel on/hooked up, and some of the wiring loomed up. This gets it a couple steps closer to driving while also making things look prettier.

Getting the dashboard on and the steering wheel lined up was a bit of a challenge. One of the popular modifications I've done from stock on this car is add a traditional turn signal stalk. In its normal trim there is no turn signal stalk, turn signals are manually activated with a switch that you place somewhere. I believe if you follow the instructions, you actually take the Mustang turn signal stalk, shorten it, and then put it behind the dashboard. There's a person who takes a VW Bug turn signal stalk and machines the Factory Five hub to make it fit and work properly, so that you have normal canceling turn signals. An added bonus is that the turn signal stalk has a button on the end, which I'm using for a horn. Some people use it to toggle low and high beams, but some of the Jaguars I used to work on had the horn in that location, so I figured I'd go with it.

I had to cut off part of the factory steering wheel mount to make this modified turn signal mount fit (the instructions didn't say anything about this). And then, because I have HVAC hoses to route through, I also had to cut off another metal support to make room for that. But in the end, all of the HVAC hoses are mounted, the dash is attached, and the steering wheel is on.



Unfortunately the steering wheel does block a good portion of the speedo and the tach. This is just the nature of the beast with this car basically no matter what you do for gauges. But the parts that matter are visible, specifically high RPMs (where you need to shift) and high speeds (where you'll get pulled over).

After that I did some more details. The wiring harness was still a rats nest full of wires all over which needed to get put in looms. I got almost all of the wiring in the engine bay worked out, and then started running the looming over the main backbone wiring harness that goes down the transmission tunnel towards the battery in the back.

I had one moment of panic when I opened the radiator cap and saw no water. But it didn't take very much, well under a pint to fill. So I think that with the temps dropping the water just shrunk some, and maybe there were some air bubbles that worked their way out. So nothing to be concerned about there. However I do still have water in it, and I should change that over to proper coolant since this is going to be a street car.

I need to finish up the wire looming and do some other mounting details, and then it'll be ready for its first proper go kart drive.

 

[asicer]

It's been a while, but I finally got some time to work on the Cobra today.

Glad to hear you're making progress.

Getting the dashboard on and the steering wheel lined up was a bit of a challenge. One of the popular modifications I've done from stock on this car is add a traditional turn signal stalk. In its normal trim there is no turn signal stalk, turn signals are manually activated with a switch that you place somewhere. I believe if you follow the instructions, you actually take the Mustang turn signal stalk, shorten it, and then put it behind the dashboard. There's a person who takes a VW Bug turn signal stalk and machines the Factory Five hub to make it fit and work properly, so that you have normal canceling turn signals. An added bonus is that the turn signal stalk has a button on the end, which I'm using for a horn. Some people use it to toggle low and high beams, but some of the Jaguars I used to work on had the horn in that location, so I figured I'd go with it.

My 7 had the 3 position toggle switch for turn signals. It was placed just behind and to the outside of the right hand side of the steering wheel. To signal, I'd just flick it with my right pinky and then flick it back after the maneuver. I don't think it ever bothered me at all doing it that way rather than using a stalk. Of course, given the visibility issues I'd always back it up with hand signals anyway.

However, the horn button was an entirely different story. It was a momentary toggle switch next to the turn signal switch. Whatever the reason, it was always a pain for me to find it and actuate it. I wish it were a button on a stalk, like you're setting up.

 

[Ted]

That's an interesting setup on the 7. I put a lot of thought into the position of switches and buttons to try to make it both look good aesthetically and also be simple and functional.

It would be nice if the gauges were more visible, but that's just how the car is. Smaller gauges placed closer together might be better. But again, the gauges will be visible in the important parts, so I'm still happy enough with what I'm doing.

Having the steering wheel actually on and then turning the wheel (remember this is manual steering) I don't think the assist required is too high at all. Of course the floor of my shop is more slippery than asphalt, but I don't see a problem.

If I can get some more days working on it over the winter, the body should be on it for when the days get nice.

 

[asicer]

It would be nice if the gauges were more visible, but that's just how the car is. Smaller gauges placed closer together might be better.

Yeah, the early 7's and I think original early AC Cobras had the speedo in the center between the seats or in front of the passenger off to the right. Logically speaking, makes sense since speed is probably the easiest piece of data to infer by sight/sound/feel. But in real life probably the most jarring with respect to what's customary placement.

 

[Ted]

Yeah, the early 7's and I think original early AC Cobras had the speedo in the center between the seats or in front of the passenger off to the right. Logically speaking, makes sense since speed is probably the easiest piece of data to infer by sight/sound/feel. But in real life probably the most jarring with respect to what's customary placement.

When I made the decision to use the 5" tach and the 3 or 3.5" (I forget the exact size), I got comments from a lot of other Cobra builders that I should reverse that because the speedo matters more. I disagree strongly.

 

[SoonerAviator]

When I made the decision to use the 5" tach and the 3 or 3.5" (I forget the exact size), I got comments from a lot of other Cobra builders that I should reverse that because the speedo matters more. I disagree strongly.

Just depends on how it's being driven. If it's 95% a street car, having the speedometer as the primary makes sense. If you weight it heavier towards track-use, the speedometer means next to nothing and the tach is the primary. Heck, if you rig up a shift light, the tach isn't of much concern on the track, either, as you're shifting by sound/feel and the shift light is giving you the meaningful data on desired peak rpms.

 

[charheep]

I dont see the AOA indicator. Is it even legal to drive without it?

 

[Half Fast]

Just depends on how it's being driven. If it's 95% a street car, having the speedometer as the primary makes sense. If you weight it heavier towards track-use, the speedometer means next to nothing and the tach is the primary. Heck, if you rig up a shift light, the tach isn't of much concern on the track, either, as you're shifting by sound/feel and the shift light is giving you the meaningful data on desired peak rpms.

And if it's being used for timed rallies, the navigator needs to see the speedometer clearly.

 

[TCABM]

And if it's being used for timed rallies, the navigator needs to see the speedometer clearly.

Make a remote indicator for the navigator.

 

[SoonerAviator]

Make a remote indicator for the navigator.

Or just give him a GPS tablet, lol.

 

[asicer]

Just depends on how it's being driven. If it's 95% a street car, having the speedometer as the primary makes sense.

Even as a street car, someone that really knows the car can figure out speed from gear and RPM. Or sight/sound/feel.