AAZCD said:
I hope stafford1500 takes his rolls of yarn and painters tape to challenge. it'd be interesting to see how much air is making it back to the rear spoiler in this "configuration". You might take some spare sheet if he's got some ideas for tweaks that you could do on-site to facilitate that.
That would be awesome if he has time to go over some of it with me. This car is about physically experimenting with ideas, not so much about applying my limited knowledge. Imagination more than engineering.
The thought was not to have the two working in conjunction. I removed the stock spoiler mechanism and put in a light fixed spoiler. Less weight, same funtion. After I removed the heavy convertible top and mechanism, I thought it would be nice to have a lightweight top that I could easily remove. Temps were in the high 90s and I was removing the AC. With the modest flap on the roof, it feels like I have less tubulent air blowing around my face. Maybe windows will be a better strategy.
I actually used some yarn and tape when I made the louvers in the hood and blew air across them with a fan. Louvers that stick up seems better than flush for getting hot air from the radiator out of the frunk. I plan to do some yarn on the car with an 'action cam' to record it if I get some time. The problem is I really won't know what 'good' looks like. Timed runs under near identical conditions are probably going to be my best way to know improvement vs detriment.
Many posts back, on 10 and 11 Sept, there was some discussion of the roof. I'm hoping to reduce drag from turbulence more than create aerodynamic force. My expectation is that it will not have any significant effect on performance, but will be awesome if there is rain or a hot, sunny day.
Here's a comparison of turbulence at 180 kmph (111 mph), topless vs standard hardtop. Note, the spoiler seems ineffective with the top open:
I may be able to be convinced...
Your driving impressions will give you a good idea of how much the flow comes back to the driver/windshield.
With the sides effective open the spoiler should see pretty good flow.
For you Boxster guys that are following this thread, you should check out the old forum thread where I got the pics from. The thread went a little sideways at one point, but lots of great info there. Fred made a lot of cool stuff for the 986 community.
AAZCD said:For you Boxster guys that are following this thread, you should check out the old forum thread where I got the pics from. The thread went a little sideways at one point, but lots of great info there. Fred made a lot of cool stuff for the 986 community.
Hah!, went to the thread and I'm subscribed. Love your 914 roof.
Here's my aero tester, good for well over 100 mph. I was at a hot rod show last weekend and a glass cutting guy showed me where and how to cut the windshield to rake it back. This will allow a lower and flatter roof and allow a good flow to the rear (hopefully).
stafford1500 said:I may be able to be convinced...
Your driving impressions will give you a good idea of how much the flow comes back to the driver/windshield.
With the sides effective open the spoiler should see pretty good flow.
How about this... There is some airflow under the roof. What if I move the flap to the bottom side of the roof? It may still reduce some of the turbulence, and also improve the effectiveness of the spoiler on the back.
The roof may actually be beneficial for more than my comfort. Whether or not I put any sort of cowling on the roof support is still TBD, but I think I should if I commit to running with the roof.
In reply to AAZCD :
I think I prefer the gurney on top of the roof. If you get air over the top of the car moving up, then more air will get pulled in from the sides to go over the rear of the car... IITC (if I'm Theorizing Correctly)
a more radical idea is to filling in the air at the back of the cabin from the front of the car, but it's too crazy for now
I would leave the wicker/gurney on the top trailing edge of the roof panel. For the same reasons as SleepyHead noted, you want to avoid trying to get the air to turn down toward the spoiler as that would result is a small amount of lift locally, even if it is offset by extra downforce on the spoiler. You have to think of the whole thing as a system.
Fairing in the area behind the seats would help flow to the spoiler as well, if there is time and cheap material.
Sweet Boxster! I've always like them but I am afraid to dive into a Porsche.
"Five-point roll bars meeting item 4:10 of the NHRA's general safety regulations are mandatory in all open-top cars running a 13.49 E.T. or faster."
As I read through 4:10 and the rest of the rules, my car will not meet the NHRA Safety requirements to run faster than 13.49. The factory roll bar falls short of the requirement and even with my improvised roof, this car should be considered "open top". I bought a 5-point harness and window net, but I now see little need to install them in the car this year. Staying slower than the 13.49 threshold makes prep a lot easier. I have no idea how fast the drag time will be with this car or how much the nitrous will improve it. It may not be 'safe' to destroy my engine. ...or it may blow up with just a normal run. I'll put the Sparco R100 (not really a racing seat) back in. The safety gear will all be brought along to keep configuration options open and have it available to loan as needed.
I worked on the cooling system yesterday improving the mounting and checking for leaks. I spent most of an hour looking for a lost radiator cap. Found it just after I bought a new one. It was under the radiator.
"a more radical idea is to filling in the air at the back of the cabin from the front of the car, but it's too crazy for now"
I may be addressing this with a quick mod to the roof. I should have decent painting weather tomorrow to finish the hood and roof, so any more mods to them need to be done today. AC compressor is coming out today and I hope to get the exhaust done.
Wow, just the AC Compressor is 14 lbs. The rest of the hoses are next.
AAZCD said:Sleepyhead said:
"a more radical idea is to filling in the air at the back of the cabin from the front of the car, but it's too crazy for now"
I may be addressing this with a quick mod to the roof. I should have decent painting weather tomorrow to finish the hood and roof, so any more mods to them need to be done today. AC compressor is coming out today and I hope to get the exhaust done.
My crazy idea involves sizeable holes into the cabin, and probably hvac ducting, and no longer needing vents in the frunk bonnet
In reply to sleepyhead the buffalo :
We can look at it in Gainesville. I am officially not worrying about aero any more for the next week. After a drive around town yesterday, I'm focusing back on just having a running car that doesn't dump it's coolant on the course once it warms up.
Next year, I'll try for this, but in black with an Audi V8:
sleepyhead the buffalo said:AAZCD said:Sleepyhead said:
"a more radical idea is to filling in the air at the back of the cabin from the front of the car, but it's too crazy for now"
I may be addressing this with a quick mod to the roof. I should have decent painting weather tomorrow to finish the hood and roof, so any more mods to them need to be done today. AC compressor is coming out today and I hope to get the exhaust done.
My crazy idea involves sizeable holes into the cabin, and probably hvac ducting, and no longer needing vents in the frunk bonnet
I am not sure if SleepyHead will be there, but I think I know what he is getting at with his cryptic post!!! I can talk you through the idea when we have a few minutes between cold drinks...
In reply to stafford1500 :
Nope, I don't think my arms can flap that far. And, yes, I suspect you have an idea what I'm getting at... and how "nuts" it is... and how it's not appropriate to propose for this year. ( which is why I'm being... obtuse)
AAZCD said:
I am officially not worrying about aero any more for the next week.
I fully support this approach. Good luck with the coolant issue!
I got a lot done yesterday. I'll tell you about it later. Taking a short break now and figuring out what's next. Here is what just happened:
I painted the back of the spoiler yellow because I thought it should be painted. It became yellow and I hated it.
That triggered the next step. Painting really didn't need to happen. I already had a uniform black on the hood and roof and it looked decent. It didn't matter that it didn't matter. The yellow was wrong. I had red paint. I Needed to paint the spoiler red and paint red boxes (squares) on the hood. Plan? Purpose? Correct stuff to mix the red paint with? No. No. No. Just do it.
I might like it. Not sure yet. What matters is that it's done and I can move on to 'next'.
I am out shopping with it. Needed some distilled water to keep the coolant topped up. It's very different from driving the Dung Beetle, where everyone smiles and waves.
People look worried. Mothers hold their children tighter...
AAZCD said:In reply to sleepyhead the buffalo :
We can look at it in Gainesville. I am officially not worrying about aero any more for the next week. After a drive around town yesterday, I'm focusing back on just having a running car that doesn't dump it's coolant on the course once it warms up.
Next year, I'll try for this, but in black with an Audi V8:
I will drive to Florida next year, just to see that in person! Best of luck this year Jon! Represent the 986'ers well!
'Muffler': Cut two right angles off of a straight pipe pulled off a scrapped Civic five years ago. Weld on to Boxster C-pipes. Add cross tube for mounting and resonance (left-over pipe from the Dung Beetle project). I forgot to weigh it, but I'll get an estimate later based on the parts and length of pipe. I think stock is about 35 lbs.
Coolant Hoses: Boxster coolant tubes have a fork at the front to go to both side radiators. At first, I just plugged the extra hoses. That was stupid to do on a car that already has a problem over pressurizing the cooling system. Yes, a plug popped out while driving. What I should have done in the first place: cut out the forks, replace with hose.
In other news, I think I accidently overwrote my budget with the blank one when I was transferring files. E36 M3. I still have a partial copy on my computer at work.
The decal layout should balance the red boxes I think.
In reply to AAZCD :
That turned out nice!
I like it as well!
I can't find the bill of sale from when I bought the car. I do have the original Craigslist ad posted in this thread though.
More significantly, I found an Interstellar Sledgehammer sticker when looking for the bill of sale. That alone should be worth 12 concours points.
Oh hell... Let's try that again. How do you say "label" and "inside" in Spanish. This guy usually does great work...
So, yesterday I got the Nitto front tires mounted and convinced the guy at the tire shop to flip the tire so that "outside" was at the out-side of the rim. He was still trying to explain something about front and back tires when I paid and left.
Today we had the dogs (all four) dropped off at the kennel around 9:30 then went home to get ready and load up. I started doing just one more thing to the car. ...and one more thing. Stuff like windows installed and working in both doors -because rain. Hooked up and calibrated the nitrous system. Past lunchtime and still just one more thing to do before I put it on the trailer. How about a passenger seat, just in case, and those wires need to be tucked a little better. Late afternoon. Oh crap, it's getting late. I need to hurry now so we can get on the road.
I rushed to get the trailer from the back yard. Set the ramps. Drove the car on the trailer, then E36 M3. The trailer tipped down at the back and rolled forward. I hadn't locked the hitch. E36 M3.
Not going to buff out. In fact, I'm sure it's over $1,000 damage. On the plus side the only effect is that the hatch won't open and I can still get to the Challenge just as well.
We only got a few hours down the road this evening, but we are on the way. No keys lost, no broken collar bones, or inoperable cars. This year, just getting to Gainsville will be a win.
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