DuPuis Family Cobra Build

[3393RP]

Why would an air pocket in the heater hose matter? It won't affect flow through the heat exchanger.

 

[3393RP]

I’d just route it to the fender straight off the water pump and keep it out of the valley. No need to add a bunch of stuff into the valley. Pic for reference.

How odd.

Shock tower stiffeners with spherical rod bearing ends kinda defeat the purpose. They're supposed to provide torsional rigidity, and the bearings prevent that.

 

[SoonerAviator]

Lol yeah I didn’t even look at the rest of the pic, just searched for a 351w/302 with the heater hoses running on the side. From the looks of it, there are some brace pieces missing from the “system” that’s shown. Probably a cross-brace in there. Maybe the tie-rod ends are just supposed to limit major flex and not eliminate it, I dunno.

 

[Ted]

I did some more looking at the passenger side of the engine bay. I do think it’s doable to have the coolant hoses there. I’ll plan on routing them somewhere or another.

Spark plug wires are installed. I need to get separators to make that prettier but they’re in and should work. Made the adapter (if you want to call it that) for the crank sensor, which is now installed and properly spaced.

The girls helped me paint some more panels, and I got the e-brake handles clipped in, although I now realize I’ll have to reroute one and I do still need to put in some clamps to hold them where they belong.

After that I started looking at the dashboard more and figuring out where I want to put the switches and vents. In the end it’s going to be reasonably clean and I think will look nice. I haven’t drilled anything because I want to spend more time thinking about where everything is going, but I think I have a good idea and plan.

Also got the MAP sensor location figured out and installed.

Doesn’t sound like a lot but feels like I’ve made a lot of progress today. The big question I’m thinking about now is whether I want to add an Air/Fuel Ratio gauge or not. I feel like I do, but I also want something that looks appropriate with the rest of the gauges in the system. As I recall the Sport Comp ones were either expensive or there was something I didn’t like about them. I need to look more.

I am going to put the switches for the seat heaters near the shifter above the transmission. I’m debating if I want to put anything else there to clean up the dash. I could put the HVAC controls there, for instance. I actually did that on my ‘82 Jag XJ-S, on which I made a completely custom dash and transmission tunnel cover/center console. It’s not a bad spot for them and might add some interest there while also separating the switches so that they’re not so easy to confuse. More thinking is required.

I still feel like I’m close to starting wiring, but I also see how far away I am from being truly ready to start wiring. I still need to weld in the support for the AC compressor and mount that, get the hoses made and run those, run the hoses for the heater, install the HVAC box and run those hoses, and I suppose finish getting the dash assembled, plus other things I’m forgetting about. Still, it’s coming along nicely. Date for first start? Who knows. But it’ll be fun when it gets there.

 

[Hang 4]

My $.02 on the O2 sensor. Definitely have one, the Megasquirt can tune to a tune to a target A/F ratio which works great. I'd not waste the panel space with a gauge. If I remember correctly, there is way to get your MS info onto a phone through bluetooth. You can use that as a temporary gauge for the times you want to tune. Once you get it dialed in, you will have a gauge in some pretty prime real estate, that will just be a distraction.

 

[Ted]

My $.02 on the O2 sensor. Definitely have one, the Megasquirt can tune to a tune to a target A/F ratio which works great. I'd not waste the panel space with a gauge. If I remember correctly, there is way to get your MS info onto a phone through bluetooth. You can use that as a temporary gauge for the times you want to tune. Once you get it dialed in, you will have a gauge in some pretty prime real estate, that will just be a distraction.

I agree with you, and the more I think about it the more I don't think I'd rather just leave it out.

One thing with this project is it's been interesting to look at the scope creep over time. Originally I'd planned significantly more switches and a few extra gauges than what I'm putting in. For example I was going to have a separate switch for the water pump and a manual override for the electric fan. I've decided neither of those make sense - the water pump will be tied to the ignition relay (after all - engine running = need water pump) and I'll let the MegaSquirt take care of the fan based on an appropriate temperature with one of its outputs.

By comparison, I've definitely had scope creep in terms of making it far more complicated - going from the original concept of a carb and distributor, proper old school, to EFI, distributorless ignition, air conditioning, electric water pump, electric air conditioning compressor, etc. My electrical system will not be simple like the original "I want 3 wires on this car" that I had planned.

It's all fun. When my wife gets back home in a couple days I'll go do the weekly shopping for the household and grab the square steel tubing I need to make the mount for the AC compressor, then ideally weld it in and mount the compressor so that I can then go to the hose shop and get the AC hoses made up before she heads back to work. I doubt I'll get that far, not like that would really hold me up given everything else there is to do on the car.

I thought some more about the switches and I do think I want to put the HVAC switches on the transmission tunnel. I think that will help keep the dashboard cleaner, group things together in a nice manner, and add some interest to the transmission tunnel. Since I'm going to put the heated seat switches there anyway it makes sense. I also was going to add a couple of USB charging ports just for good measure, so that's probably a good spot for them.

I will need to check the inventory of what the kit came with, but. I think the transmission tunnel is normally covered in carpet like the rest of the interior. If so I'll probably get some black vinyl instead.

And once I finalize what I want to do on the dashboard, then I can cut the holes I need and start wiring up the gauges, etc. That'll be an important step to help get me towards starting electrical.

 

[Ted]

So now another thing came to mind on the gauges. I will be putting in a USB power port. Many of those come with built-in voltmeters, so I could opt to have that be my voltmeter and then use one of the gauges for something else.

I think I'm still better off just sticking with what I have (if nothing else, I already have the voltmeter). But something to consider briefly at least.

 

[Greg Bockelman]

So now another thing came to mind on the gauges. I will be putting in a USB power port. Many of those come with built-in voltmeters, so I could opt to have that be my voltmeter and then use one of the gauges for something else.

I think I'm still better off just sticking with what I have (if nothing else, I already have the voltmeter). But something to consider briefly at least.

I think you have considered it. Think no more of it. Move on. LOL

 

[Ted]

I think you have considered it. Think no more of it. Move on. LOL

That's probably what I'll do.

 

[SoonerAviator]

Yeah, I'd skip that idea. Heck, may be better to just wire a 12V outlet and use one of the 12V USB receptacles instead of wiring them specifically. Might enable you to use a 12V tire pump or something like that in a pinch.

 

[Ted]

Yeah, I'd skip that idea. Heck, may be better to just wire a 12V outlet and use one of the 12V USB receptacles instead of wiring them specifically. Might enable you to use a 12V tire pump or something like that in a pinch.

I do think I want to have a dedicated USB charger port, but I have also considered adding a cigarette lighter (even as a non-smoker) because of that added versatility. Nobody's allowed to smoke in my car.

 

[Matthew]

This is one of the finishers at Le Mans in 1966 (the basis of the Ford v Ferrari movie). This one came in 3rd. It was up for auction a couple years ago and sold for around $9.8 million. The instrument cluster looks pretty plain.

https://rmsothebys.com/en/auctions/mo18/monterey/lots/r0073-1966-ford-gt40-mk-ii/692159

 

[Ted]

This is one of the finishers at Le Mans in 1966 (the basis of the Ford v Ferrari movie). This one came in 3rd. It was up for auction a couple years ago and sold for around $9.8 million. The instrument cluster looks pretty plain.

https://rmsothebys.com/en/auctions/mo18/monterey/lots/r0073-1966-ford-gt40-mk-ii/692159

That's good reference, and really not too far off from what I'm doing in general. My switches will be in a different layout than what they have, but the Cobra has a completely different dashboard from the GT40. I suppose I could build mine differently if I really wanted, but don't think I will.

Interesting that they upgraded the tach to the same one I'm using, and I don't see a speedo.

 

[-KLB-]

Generally the few places/conditions that have speed limits are handled by knowing the appropriate gear and RPM for pit row, etc. so no speedo.

 

[Ted]

Generally the few places/conditions that have speed limits are handled by knowing the appropriate gear and RPM for pit row, etc. so no speedo.

It makes sense, I just hadn’t previously thought about it.

Funny thing - several people on the Cobra Facebook group said I should swap the speedo and tach because the speedo would get partially blocked by the steering wheel and be hard to read. Tells me what kind of drivers they are - I don’t care about the speedo being harder to read, the tach is what matters!

 

[Hang 4]

Tach front and center. The speedo will not prevent over-rev. Speed costs a ticket, over-rev can cost an engine.

 

[Ted]

Tach front and center. The speedo will not prevent over-rev. Speed costs a ticket, over-rev can cost an engine.

Exactly why I’m putting the tach where it is, where I’ll be able to easily see it.

The Factory Five group has a lot of low performance drivers.

 

[FormerHangie]

Exactly why I’m putting the tach where it is, where I’ll be able to easily see it.

The Factory Five group has a lot of low performance drivers.

You can add a rev limiter if you think you're likely to overspeed the engine, or you can install an upshift light. Chances are that you'll know from the sound that it's time to upshift, and you won't need either.

A rev limiter won't help if you miss a 5 - 4 shift and make it a 5 - 2, of course.

 

[Ted]

You can add a rev limiter if you think you're likely to overspeed the engine, or you can install an upshift light. Chances are that you'll know from the sound that it's time to upshift, and you won't need either.

A rev limiter won't help if you miss a 5 - 4 shift and make it a 5 - 2, of course.

I've never needed or felt I needed a rev limited or shift light. I just want to have the tach where I can see it. Like you said, you can normally just hear.

 

[Hang 4]

You can add an RPM based fuel cut off in Megasquirt. Think I set it for 500rpm over factory redline. I occasionally bounced off it in 2nd gear in my 911.

 

[Ted]

You can add an RPM based fuel cut off in Megasquirt. Think I set it for 500rpm over factory redline. I occasionally bounced off it in 2nd gear in my 911.

I do plan on doing that. The way I’ve built the engine I figure 6k or so will be about redline, so maybe set for 6500. Which supposedly the EDIS runs out of steam about them anyway.

 

[Ted]

Listening to the "Ford v Ferrari" soundtrack while working, makes me want to get this engine running and screaming...

On today's grocery/supply run I'll get a few more of the things I need to keep moving forward.

 

[Ted]

Got the mounts welded in for the AC compressor today.



along with a few other details.

Next is riveting in a few panels, and then starting to think about wiring.

But I also decided that I need a 3 3/8” speedometer instead of a 5” (more on why in the video below). I think that’s going to look better anyway, but now I need to order one. Basically the 5” won’t fit well and as I think about it more the 3 3/8” will look better.

 

[charheep]

I will admit I missed it, but why are you putting in an A/C? Do you think it will get much use? Please dont make me read all 35 pages to find the answer...

 

[-KLB-]

I think it was pretty similar to why I keep the AC on in my convertible with the top down, mostly to increase comfort at stop lights. It can be amazing how much difference some lower humidity air blowing on you can make.

 

[Ted]

I will admit I missed it, but why are you putting in an A/C? Do you think it will get much use? Please dont make me read all 35 pages to find the answer...

Here in Kansas we have a lot of very hot days. In the summer it hits 90F one day in June and then after that 90+ is the high for a few months. Plus we have high humidity.

When I had my BMW convertible, I found that I used the AC quite a bit with the top down, especially when sitting in traffic. So, I figured I would find similar here. My wife especially doesn't like to be too hot. Plus I've wanted to play with these electric compressors for a long time, so this gives me a good opportunity to (even though it adds a lot of complexity and cost).

 

[jsstevens]

Here in Kansas we have a lot of very hot days. In the summer it hits 90F one day in June and then after that 90+ is the high for a few months. Plus we have high humidity.

When I had my BMW convertible, I found that I used the AC quite a bit with the top down, especially when sitting in traffic. So, I figured I would find similar here. My wife especially doesn't like to be too hot. Plus I've wanted to play with these electric compressors for a long time, so this gives me a good opportunity to (even though it adds a lot of complexity and cost).

I ran the A/C in my Mini Cooper S convertible with the top down frequently. And I do the same in my 370Z convertible along with the cooled seats. It greatly expands the convertible weather window.

 

[Ted]

I ran the A/C in my Mini Cooper S convertible with the top down frequently. And I do the same in my 370Z convertible along with the cooled seats. It greatly expands the convertible weather window.

Exactly. Very few people put AC in their Cobras, I think largely because of the added cost and complexity. Heaters are more common (and easier/cheaper) but still not super common.

Sort of like a motorcycle - gear and heated items (heated grips, heated seats, heated gear, etc.) extend the motorcycle season.

 

[Hang 4]

When I did my 911, I took out the AC. It never worked and was a lot of weight and took up a lot of space in the engine compartment. If there was an option to replace it with something that worked, I would have done it in a heartbeat, for the reasons Ted mentioned.

 

[Ted]

My first car, an '82 Jaguar XJ-S, had the HVAC removed from it when I bought the thing. The guy I bought it from had intended on turning it into a race car (by the way, the XJ-S is a terrible race car) and so he'd started stripping it of unneeded items. I drove it without AC or heat for a while. Somewhere in the first winter I decided "This is stupid" and built a heater box in true college form - dryer ducting from the blower motors (the car had two), 10 cent household light switches for power, a cardboard box (literally) to hold the heater core, cheapest heater core I could get at Advance, and then some duct tape and chop sticks to hold it all together. Total cost was probably around $20, but I had heat.

Next summer I raided the parts shelf above the office in the Jag shop and got some used bits I needed to add A/C. Was that ever worth it.

I'm mostly a windows down person, but there are times and days when AC is still nice to have.

 

[Ted]

Today the kids helped me paint a couple more panels. I only have one panel left to paint of the big ones that came attached to the car that needs to get painted. That's the panel behind the seats and I have to cut a hole in it to mount the power disconnect first.

So it's time to rivet some panels in place and then it's time to start running wires. And then comes the question of which wires I run first - do I start with the EFI/ignition or some of the main ones for the car as a whole. I'll think on it some more, but I'm thinking the answer is probably the EFI and ignition wires as those are the most critical and everything else is pretty minor. Originally I'd planned on running all of the wires before first start, but maybe... maybe I want to do first start before I run some of the other wires that aren't critical like turn signal and horn. We'll see.

 

[Ted]

The Microsquirt can drive a few "Spare" outputs. I'm planning on having one of those drive the electric cooling fan since that will let me vary what temperature I want it to turn on, plus then I don't need to mess around with having a thermostatic switch.

But then the kit comes with a red indicator light on the dash (idiot light). I don't have to install it, but it's probably not a bad idea. MicroSquirt lets you program the outputs based on a number of parameters, so I could use it as a shift light, coolant overtemp light, or all different sorts of logic could be used.

The other option that came to mind for that would be a light to let me know if the electric water pump wasn't getting power (i.e. if the fuse blew). But that wouldn't necessarily tell me if it had died, whereas a coolant overtemp light would. Now if I'm paying attention to my gauges I'll notice such a thing, but if it died while I was racing I could imagine the engine would get hot very quickly, so having something I could set to a caution temperature, especially with the aluminum heads, would be nice. I have to give it a bit more thought, but I think this is what I'll do.

 

[jsstevens]

The Microsquirt can drive a few "Spare" outputs. I'm planning on having one of those drive the electric cooling fan since that will let me vary what temperature I want it to turn on, plus then I don't need to mess around with having a thermostatic switch.

But then the kit comes with a red indicator light on the dash (idiot light). I don't have to install it, but it's probably not a bad idea. MicroSquirt lets you program the outputs based on a number of parameters, so I could use it as a shift light, coolant overtemp light, or all different sorts of logic could be used.

The other option that came to mind for that would be a light to let me know if the electric water pump wasn't getting power (i.e. if the fuse blew). But that wouldn't necessarily tell me if it had died, whereas a coolant overtemp light would. Now if I'm paying attention to my gauges I'll notice such a thing, but if it died while I was racing I could imagine the engine would get hot very quickly, so having something I could set to a caution temperature, especially with the aluminum heads, would be nice. I have to give it a bit more thought, but I think this is what I'll do.

Can you set it up to kill the engine or go into a limp mode before it breaks something expensive?

 

[Ted]

Can you set it up to kill the engine or go into a limp mode before it breaks something expensive?

I could set it to shut off fuel if coolant temp gets above a certain number. My general preference is to let me handle that decision so that it doesn't shut off at a bad time (like let's say I'm overheating going around a blind corner and need a safe place to pull off).

I try to make the idiot behind the wheel the safety feature.

 

[jsstevens]

I could set it to shut off fuel if coolant temp gets above a certain number. My general preference is to let me handle that decision so that it doesn't shut off at a bad time (like let's say I'm overheating going around a blind corner and need a safe place to pull off).

I try to make the idiot behind the wheel the safety feature.

I'm with you! My Mini went into limp mode a couple of times and it was dramatic! Glad I wasn't on the highway when it did.

 

[Ted]

I'm with you! My Mini went into limp mode a couple of times and it was dramatic! Glad I wasn't on the highway when it did.

Exactly. I prefer to have most of the passive safety features like that deactivated, or at least something I can switch off/override. I also don't like features where you have to hold the clutch for the starter to engage - been a few times where the ability to crank the car over with it in gear has saved my bacon.

 

[Ted]

I went ahead and ordered the 3 3/8" Autometer Sport Comp speedometer that I need to match the Cobra. This will hopefully arrive by the weekend, so I can work on finishing drilling the holes and getting the vinyl on the dashboard to get that going.

 

[Ted]

Last night I spent a bit of time riveting in some of the cockpit area panels. This is the sort of thing where the panels will get in the way of some things now that they're riveted in, but you eventually just have to decide to move forward on something, because it will get in the way of other things no matter what.

I think this is a good decision to do before wiring since I've left the transmission tunnel top off. This will let me make sure I'm routing the wires in the appropriate places, and I can make sure I'm using pass-throughs in appropriate places since I will need a few of those.

I'm really trying to figure out where to mount the MegaSquirt. It needs to not be under the hood. Somewhere in the general cockpit area is considered to be ideal overall. Trunk would be more sealed, but also get more hot and I'm not sure what sort of temperature resistance this box has. It's certainly not designed to DO-160 levels like our avionics.

But in the cabin/cockpit area the primary places to put it are going to be in the footwell areas. The passenger footwell is pretty small overall. The driver footwell area is larger, but of course has the pedals to consider. So really, I think I need to put the seats in (temporarily) and start to play around with locations to decide for sure.

This will drive me to do the ignition wiring first, since that's more straightforward and the ignition module is specifically designed to live under the hood of the car. I have everything I need to perform that wiring other than the noise-suppression capacitor, which is on its way.

I also started playing with TunerStudio, the programming software for MegaSquirt. It is a very functional program, and also includes a lot of help bubbles to explain what various parameters mean and why. That's useful since the nomenclature they use is a little different than what I'm used to and it has some features that, even as someone who programmed engines for a living in the past, is different.

A lot of little things that should come together. I've figured out what I need to finish up the coolant hose plumbing and when my wife gets home I'll get the AC hoses measured and made, buy some more coolant hose and a couple more 90 degree fittings to install all of that. And really, once the ignition and EFI are wired, I can do a first start... although gauges do also need to be wired/plumbed.

 

[Hang 4]

I had my Megaquirt under the passenger seat. It was pretty protected there and allowed easy access to the connector for tuning.

TunerStudio is awesome and they do a good job of continuing updates with new features. This is reaching back into the dim recesses of my memory, but there were also two different MS "firmwares". One was vastly more supported than the other. Think it was B&G and the other was MS extra. The latter had much more flexibility and more active user forums. Not sure where you are sourcing your MS from, but do your firmware homework. One cool thing you can do is build a "dashboard" on a laptop to monitor real time engine parameters. Gives you an option to keep your permanent dash cleaner and more spartan.

 

[Ted]

I'm not sure which firmware is on it right now, but that's a good tip, thanks. There are a lot of features I'm seeing that I could see having impacts on some of the areas that are of interest to me.