CAS clearance

[belize1334]

So with my new AWIC install the clearance between the intercooler, the strut tower, and the CAS is tight.



Now, officially I can't change engine parts for my class but I can alter anything related to engine control. That means that the CAS - which is ultimately a component of the EFI system - is a little bit of a gray area. I'm thinking of exploiting this to see if I can get a bit more clearance. The question is, based on the above image, might I get a little more wiggle room by switching to a black_top? I know they have a domed top which may help since the interference is only over about a third of the current CAS. But, does anybody have one of each to compare the overall mounting depth? Or would somebody with a black_top be willing to take a careful measurement of it's thickness from flange to dome peak? If the black top is not only domed but also lower in overall profile then that'd be a double win...

 

[bazeng]

Modify the water to air tank???

There isn't much you can do to the CAS unless you run a crank mounted trigger and rewire everything to work from there.

 

[belize1334]

I'm just thinking that if a black-top is a little lower in profile it might give me an extra few mm so that the tank isn't so tight in there. It sits without an issue now but I'd just like a little more clearance so that it doesn't heat soak right next to that hot steel plate. To that end, even if the black-top doesn't improve the clearance, given that it's plastic it'd probably have less thermal emission. Hm... maybe I'll just go ahead and try it out...

 

[belize1334]

Nobody has one of each to put side-by-side and measure their profiles? /ubbthreads/images/graemlins/dunno.gif

 

[curtis]

Don't have a green top but as for the black I do.

Ok back now from the shop. Finally found it. /ubbthreads/images/graemlins/grin.gif

from top of flange where the 12mm headed nut is to the top of the screw heads. 47mm
from top of flange where the 12mm headed nut is to the top black cover dome is. 51mm
flange thickness to make sure its the same as a green top is 10.12mm

Your welcome

 

[89Mirageman]

I always thought the black top cas was thicker. I guess we'll see.

 

[belize1334]

So I understand Curtis, does that make the total thickness 51mm or 61.12mm? Either way, I make the total thickness of the green at 45mm so I'm not gaining anything. I found a picture to help illustrate the point...
click

Looks like a tight fit is gonna be as good as it gets unless I want to modify the end tanks to move the core farther forward in the bay. Here's a zoomed out pic so you can see what I'm talking about. It's a good thing the washer reservoir is plastic and a little bendy...

My other option is to try to use one of these offset silicon couplers... click which would shift the whole business forward and out about an inch. They come in 2.4x3 and 3x3. I've had 2.5" silicon over my 2.75" n/t throttle-body but 2.4" might be pushing it. Also, the guys at AP implied that they're actually more like 2.2" (not sure about that). If I went 3x3 I'd need a sleeve over the tb or else a different tb... hm.

 

[curtis]

There is plenty different things to do but all requires a tig welder which I have and if you want some chopping done yell.

One you could cut off the rear end tank and slide the IC forward a few inches over a couple and box back in.
Another is rotate the IC 90 degrees weld on an elbow to the rear one now and a 90 on the bottom and mount standing up.
Use the rear end tank as the hot side and weld on a couple of 90's


Or have you removed the cas cover . You might be able to re move it and install a flat plastic one. /ubbthreads/images/graemlins/dunno.gif

Just yell if you need some help with it.

 

[belize1334]

I didn't realize the cover could be removed without damage. Maybe I should investigate that. I don't want to get too drastic with cutting if I can avoid it but I suspect that if I use one of those offset couplers it'll behave as a restriction. One thing that's just recently occurred to me is to use an "S" shaped piece of 2.75" aluminum pipe off of the tb and then remount the unit forward and out. But, the cleanest option may just be modify the rear end tank. I'll think on it.

 

[curtis]

Something else you could do is cut 2 flanges from a 1st gen elbow. I have a few if you need some. Then remote mount the TB. with a piece of Pipe. This will enlarge the plenum volume but may not be legal for class rules. /ubbthreads/images/graemlins/dunno.gif

 

[belize1334]

I can do anything with the manifold or TB. I was actually thinking that I could switch back to a turbo TB with a custom elbow that would let me run that 2.4"x3" offset coupler. But, by the time I've sold my na tb and bought a turbo unit I might just as well get one of the 3" ones that's on the market now. I'm gonna go home and fiddle with the CAS a bit and see if replacing the cover would buy me anything. That'd be the simplest and most elegant solution. I'd really like to keep the IC as close to it's current location as possible 'cause I think the routing is very clean this way.

 

[RedTwo]

You can pop the top off the CAS and gain a little space there but if you get some debris in there....

 

[belize1334]

I just pulled my '90 CAS apart and also popped the top off of my '91 CAS for comparison. There is nearly half an inch to be gained by pulling the cover and replacing it with one that domes up for the sensor but is otherwise lower profile. The problem is in the distinction between '90 and '91. The '90 has the sensor on the extreme forward side of the CAS, well clear of my fitment issues. The '91 reverses it on the extreme aft side, right in the way of my IC. So, I could make a new cover for the CAS and gain a fair bit of breathing room, but only if I also swapped '90 for '91 and made a wiring harness adapter for it. Not at all sure it's worth the trouble...

 

[belize1334]

f*** it. I'm just gonna slot the holes in the washer reservoir and slide it back half an inch. It's not legal but nobody will ever notice and it'll save me a huge headache messing around with end-tanks and wiring and all that. Then I'll radius the edge of the water jacket so that there's a little more room at the strut tower and call it a day.