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Cimbria SS

Brett Proctor

Well-known member
I will have it in go-kart state, running and driving before the body goes back on it for the final time. The oem harness was modified and tested few years back so not much to do there. All controls were working and I cleared all errors codes related to bypassed emission functions.
Cool
I couldn't do that with my car
I had almost everything integrated into the body (gas,clutch, brake pedals, gas tank,ECU, Wiring, etc.)
The thinking behind that was(besides the ease of wiring) if I had to remove the body for any reason, All I had to do was disconnect items from just the engine and I could pull the body off.
I'm assuming your using the subaru gears mod to the Subaru manual transmission. If your using a ECU that came out of an automatic car you'll get an error code for that. there is a fix for that if you have that issue.
 

sector

Member
And my setup will be the complete opposite, to lift the body I will only need to disconnect lights.
Yes, I am using subarugears conversion. My harness is from a manual WRX, so no codes.
 

islandman

Member
Wow, you really did get lucky with that dash fitting as it does, just the loss of the passenger side vent and all else pretty much lines up. I ended up doing a lot of cut n shut with my Subaru dash and then made a buck for it, which as Brett will attest to is a ton of work (he inspired me to give it a go). I guess the confines of the Cimbria are a bit different from a Sterling / Nova. So is the plan to end-cap the passenger side and cover it with material / leather, or just end-cap as neat as possible and leave the OEM finish?
 

sector

Member
At least for now, the plan is to only make the custom end cap and leave oem finish on the dashboard.
Your observation is correct, only the end passenger vent was lost, but since there are two center vents, the cooling/heating should not be a problem.
This approach allows me to keep all oem subaru components from drivetrain to all electronics and HVAC.
 

islandman

Member
At least for now, the plan is to only make the custom end cap and leave oem finish on the dashboard.
Your observation is correct, only the end passenger vent was lost, but since there are two center vents, the cooling/heating should not be a problem.
This approach allows me to keep all oem subaru components from drivetrain to all electronics and HVAC.
You must have so much more space in the Cimbria than the Sterling if you can keep the OEM HVAC....I'm jealous!
 

sector

Member
You should have similar space as on our cars the front bulkhead is so much further forward than on subaru. You can almost put another HVAC behind the oem one.
 

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Brett Proctor

Well-known member
Changing out the dash for a more modern one has increased the room under the dash in my car.
Issues for my oem dash were height and the pocket for the wiper motor got in the way. That restricted the length.
With the new dash I got the room needed to put the HVAC unit under there now with space to spare.
 

islandman

Member
You should have similar space as on our cars the front bulkhead is so much further forward than on subaru. You can almost put another HVAC behind the oem one.
I guess a lot has to do with the height of the dash. For me being 6' 4" my feet go all the way to the bulkhead, so any HVAC has to sit higher above my toes, which doesn't leave a lot of room
 

Brett Proctor

Well-known member
I guess a lot has to do with the height of the dash. For me being 6' 4" my feet go all the way to the bulkhead, so any HVAC has to sit higher above my toes, which doesn't leave a lot of room
I suppose it all depends on what HVAC that your using.
The system that I'm using is no wider than the center tunnel so its mounted there. Clearance over your legs is not an issue with that unit.
 

sector

Member
Same with my setup, the entire HVAC is outside of the driver's compartment so no impact on the legroom.

If you have limitation with under dash space, perhaps you should consider full length drop floor.
 

islandman

Member
I've got the same system Brett uses (haven't played with it properly yet) as an option for the scooby Nova, and I've got an aftermarket for the Alfa Nova, which is sort of fitted, but not connected fully to the dash vents yet. The pandemic put a stop to trips to the UK for a couple of years, so lots to catch up on
 

sector

Member
For the first ime this year, I was finally able to allocate a day to work on my project. Chassis was painted last year and now it's being assebled . Yesterday I was able to install suspension and mount engine with transmission. Next will be floors, steering column and wiring harness. My plan is to have a running and driving chassis before I mount the body.
 

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sector

Member
I am at the point where I am ready to install cooling system. I am planning on using 2" O.D. x 1/8" wall aluminum tubing to connect radiator located at the front. Would that diameter tubing be sufficient?
 

Brett Proctor

Well-known member
Depends.

First lets look at structural integrity.
2" 6061 aluminum tubing with a wall thickness of 0.125 has a burst pressure rating of around 937 PSI. Way above the rating that the cooling system is capable of. The radiator cap is around 15 psi I think.

Now With a wall thickness of 0.125 that calcs out that you'll have a 1.75 id.

In my car I used 1.75 od 6061 with a wall thickness of 0.065. Thats rated at 557 psi burst pressure. ( run to and from the radiator) . Went with 1.75 od to get more ground clearance.

At idle the stock water pump ( thats all I have to circulate the water) doesn't circulate the coolant that well (radiator is up front). temps start to rise a little but if I bring the rpm's up to over 1000 rpms it circulates the coolant well enough that the temps start to come down. (fan still hasn't come on). This test was done with the car at a stand still and engine ran for around 30 minutes with no air being blown over the radiator. (forgot what the outside temps were at the time of this test)

If your going to use the 2 inch tubing I'd go with a wall thickness of 0.065 (burst pressure of around 500 psi) and get a larger id for more coolant to flow. And if your worried about debris from the road damaging the lines make a cover to protect them.

My 2 cents.
 

sector

Member
Thanks for that detailed explanation. I also read on the gt40 forums that it's better to have smaller diameter pipe for the inlet and larger for the outlet. The new GT-40 uses 1 1/2" inlet and 2" outlet. Interestingly enough my radiator fittings are also two different sizes, 1 1/2" inlet and 1 3/4" outlet with the 1/8 wall. This arrangement supposed to increase flow velocity in the smaller pipe. Not sure how critical that is. Any thoughts?
 

Brett Proctor

Well-known member
Interesting read.

I think there are a lot of things to look at when designing a cooling system, and I'm guilty of cutting corners.

Water pump, how many gallons per minute it can pump

distance it has to pump the coolant.

Size of the pipe, how many gallons per minute of coolant you can pump through it or suck through it at the distance it has to pump it.

The height the pump has to pump the coolant to.

Bottom line, the pump that's in these engines wasn't designed to do what we are asking it to do.

When I built my cooling system I just stuck with the oem size of pipe. Mainly because of keeping the system compact and able to make tight turns around things.
If you can have a 2" suction side and a 1-3/4" pressure side I think you'll be ok. Just as long as you have some back pressure I don't think you'll have any problems with cavitation.

Don't forget to make sure the heater line circulates coolant other wise the thermostat wont open
 

sector

Member
I was going to use seats from the Smart ForTwo car, which fit very nicely, but after installing them I just could not find a comfortable position. This is mainly due to incline angle that puts seat back relative to seat bottom at awkward angle. I tried lifting seat at the front to minimize the angle, but lower back support never felt right. This is probably because in Smart ForTwo the seat is very upright and not meant for such tilt. In fact, I even had remove stopper that limits the incline.
As many others, I kept on searching for another viable solution and came across 2021 Mazda Miata seats that look very promising. Initial measurements indicate they would fit in my chassis without any modifications. They feel very comfortable even at high incline angle and the best part is that head rest is tilted forward which provides excellent head support. Will report back once I install them in the car.
 

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