VTEC-E in custom built car....

[Unforgiven]

Nice thinking here, good luck on the task ahead. One thing I saw that makes me wonder, how about a scoop or ports on the underside for taking up the airflow for cooling?

[rkcarguy]

I'm playing with that right now. So far I have the radiator mounted flat in front of the engine just higher than the valve cover, drawing some air from the channel that has to be deflected around the engine anyway.
I've drawn the shape of the radiator and fan and have been moving it around a bit playing with options.
My other thought was to put it in the back and draw air thru it as the cars rearend terminates. Kinda like if you disguised a boatail with radiators under the end...

[rkcarguy]

I had a friend over during the weekend and we made several changes to the design. We took and leaned the rear firewall back further and took 2 inches off of the top of the car, at the same time rolling the top to ease the transition from winshield-top-rear hatch. The local college's VRI has a small wind tunnel we can test models in if it comes to that.
I have moved the radiator to the rear of the vehicle. I plan to use it in the tail and have openings top and bottom to encourage the air to suck thru the radiator and into the low pressure zone at the termination of the body. While there will be increased drag with the air going thru the radiator, it should be less than having it tumble off the end of the body.
Trying to make the windows roll up and down is really controlling my door design and I'm not pleased with it. I'm fooling around with having a part of the window hinge open instead, this will also eliminate the exposed edge of the window channels being in the airflow.
The latest tally has this thing at 12'-8" long, 5'-6" wide, and 38" tall plus 4" of ground clearance. The headlights have to pop up at nearly a 45* angle to be 24" on center from the road surface to meet state and federal "safety" requirements(can't have us getting too good of mileage), and I drew in the flattest common ones I could find to minimize exposure.
Exterior door handles are being omitted opting for a alarm with keyless entry(already have NIB sitting here getting dusty why not?)

[Christ]

If security isn't really a concern, you can just mount a solenoid in the door with a finger-contact switch in the sheet metal/whatever of the door skin. Saves weight at only 1 lb or so.

Remember those stupid toys that would chirp when you touched the metal contacts on the bottom of them? That's exactly what happens here. You touch the contacts, the door opens.

[theunchosen]

RK, are you sticking with the slightly sloped up rear section for a boat-tail effect?

If so there are two possible options for the radiator that would increase the effectiveness of both. If the bottom of the car expands up away from the road it will create a slightly low pressure zone and if you have a kammback/boat-tail top that will be low pressure as well.

Depending on which has a greater low pressure mount the radiator along that slope. The heat dumped into the flow will do 2 things on a very small level.

1.) It should decrease density of the flow because its expanding(slightly).
2.) It should decrease(or rather increase pressure) the low pressure by adding a little Q back into the flow to cause the cooling expansion to become simply expansion.

The cooling densification process is what causes the drag on the rear of your car. If you can take that heat and dump it there usefully it will decrease your drag(how much I can't tell you). Any sloped low pressure area will have that effect with the radiator but obviously the best place is the one with the lowest pressure.

It would also be beneficial for the radiator because instead of facing regular air temps it will face cooler temps(slightly).

The other thing is as speed increases the radiator will cool better but the drag "scavenging" will decrease because your car isn't really producing a linear(to match the ramping heat exchange) amount of heat.

Something to consider if you aren't already doing this.

My older friend with the Turino did this on his Thunderbird(mounted to the trunk along with his pre-cooler for a turbo, built in flush) and he said it was somewhat noticeable. IT might have been a firebird. He has/had alot of cars. I've seen a couple of instances where this is done in racing applications like the Bentley Speed 7&8 and a few others with the pre-coolers and radiators mounted in low pressure spots to "soften" them.

[rkcarguy]

From the roof the rear window spans downward at an angle to the termination of the body.
Underneath I am installing a rolled boattail(imagine a river boat style) that starts at the back of the oil pan and ramps up to the termination point. This piece will be pretty swiss cheesed with openings for the exhaust system and cooling system, and a baffle to keep the exhaust heat from the cooling system. I am unsure at this point if the cooling air will be drawn from top or bottom. It may end up being something I have to fine tune once it's actually done, but I'm betting it will draw from the bottom due to flow thru the "tunnel".
The exhaust is turning out very simple, right off the cat it will dump at a 90* angle right into the center of a long glasspack to which I will weld 90* elbows on each end and be done. Summit has a nice long stainless one I could hole saw into off center a little and get some swirl effect inside, hopefully it won't be too loud.
The last difficult part is separating the engine bay from the pass compartment, I'm stuck with making a whole hatch and then an engine cover, or having a vertical window behind the driver followed by the hatch window, but I am concerned with the two windows doing weird things with reflections and such. The 2nd option would look much cooler but not like I'm showing off a quad turbo V12 or anything either.
Another idea my friend offered that was really cool is subframing the entire rear end with cooling system such that the whole thing drops out in one piece with no fluid loss. Then I could have one with the econo motor and another with a nice B-series beast

[theunchosen]

Sounds good.

As long as you are dumping heat into a low pressure area where there is vacuum dragging it sounds good by me.

[evolutionmovement]

Roll down windows are a PITA for aero and engineering. I also like the flip up as you can make them flush and it's a light, simple mechanism. Another option, probably even lighter, is to have sliding window-within-a-window like some of the old GT race cars, but sealing wouldn't be as good.

[rkcarguy]

thought I'd toss in an update.
I've moved further along in my design and got the point where I was laying out the metal panels in the drawing per each piece and nesting them into availiable sheet size of aluminum. I also had a friend who had his engine out of his Civic so I got to take measurements off the frame rails and subframe to pick up the suspension mounting points, and ran a string thru the hubs while the car was sans axles to get a relation of the holes compared to center line.
Last week I came home to find my computer non-functioning, it has a dead motherboard. The drawing was saved from the hard drive but I'm stuck with a old non-autocad capable computer for a few weeks until mine comes back from warranty repair
My engineering degree'd friend and I agreed that as long as the window or window section opens enough to get a fast food bag and super size drink thru it's all good lol

[rkcarguy]

Computer is back and working. I've been working on wiring up the shop so I haven't done much on the drawing. I did end up getting a 94 Civic coupe EX with a tired engine that I'm replacing, and it had a VX tranny in it, so I have my last piece of the drivetrain puzzle! I also dug thru my junk bin and located a full set of Civic pedals which will help in the design process.