Having problems with windshield upgrade to 964 style.

[Porsche Doc]

Hey Milt,
My 2 cents!
I have tried to put a 964 windshield and seal in early car with NO success. The glass and seal are bigger than the earlier ones.
I have also tried to put a earlier windsield in a 964 too with no luck.
Good luck Man!

[randywebb]

Uh oh -- I swear I saw posts where some had done that....


Jack - in science significant means a 1/20 chance that the event was a random effect. Highly sig. means 1/100 chance...

I figured it was just a common sense usage, but still wanted to track it down.

Also compare the entire Cd reduction for the 964 with the earlier cars -- that includes bumpers, all glass, etc. I'm sure the windshield helps a fair amount tho (and prob. adds some stiffness to the unit body).

[khamul02]

Randy,
Statistical significant has a relationship with an alpha level. The alpha level is predetermined before analysis. It's based on an acceptable level of error. So if a researcher is willing to set that level high, "statistical significant" can be absolutely meaningless. In research we need more reporting than just a significance number. We need the whole story (alpha level, power, effect size).

I play a scientist on TV


No, really I occasionally teach this crap.

More info for the truly sick:

http://www.statpac.com/surveys/statistical-significance.htm

[randywebb]

I am just a humble biologist. 0.05 is typical for us.... there is also a nasty tendency to measure everything you can, toss it into the computer and Hit the Regress button....


Anyway - I hope milt finds his windshield. At least he's getting a lot of bumps to keep the thread live.

Don - note his car is not all that early (his 'new' car).

[khamul02]

Randy, 0.05 is very typical in many disciplines. Back in the day my stats professor would kill us for using it with no justification. But it seems like every journal allows its articles/researchers to use it no questions asked. So we all do.

Milt, Good luck with the window. I'm going to search this topic to find out the details for my SC. Every little bit helps!

[ChrisBennet]

Originally posted by ChrisBennet
My '86 had and now my '80 911 has a 964 seal and windshield.
-Chris

I shoud clarify. The bodyshop that put the windshield in told me that they put in a 964 windsheild and seal. I didn't do it myself and I wasn't there. I do know that it doesn't have the metal trim in it.
-Chris

[304065]

"When Scientists Attack" tonight on FOX.

Bump for Milt. N=26, p=.05

[Zeke]

I don't understand Jack's diagram. Blue seemlingly indicates a high pressure area and red a low. Yet the door windows have a high (blue) area. Is this deflection off the mirrors? What with the rain drip in front of the door glass, I expected to see some turbulance there. AS I said, I don't understand "mach," so maybe that's not what it means.

Anyway, I'm about to give up on this idea. Looks like money could be better spent if I [i]was[/] looking for an aero

Originally posted by randywebb
Uh oh -- I swear I saw posts where some had done that....

Me too, but I also thought it was a slam dunk. One thread dicussed every conceivable combination of seal and glass, not to mention the various installation tricks.improvement.

[jaydubya]

I think the fringe plot shows velocity, not pressure.

[Zeke]

Originally posted by jaydubya
I think the fringe plot shows velocity, not pressure.

OK, and I remember some high school physics rule that said "where velocity is greatest, pressure is least," or the venturi effect. Are they related in the diagram, or not?

[jaydubya]

Looking at the top of the windshield area in that figure, what I see is a high velocity area and a high velocity gradient area along the top seam. High velocity gradient indicates high shear stress on the surface, which I think means high drag force.

It's harder to interpret velocity fringe plots in terms of drag. The headlights are clearly low velocity and high drag areas but the latter is less obvious from the plot. The other aspect of this picture is it is just showing velocity on the surface of the car, so you don't see the gradient in velocity as you move off of the car's surface into the air stream.

[island911]

What jaydubya said.

I'll just add, that CFD CAD model is very crude. It's an 'stl' faceted brick. --It's the equivalent of building a 911 body out of chunks of (flat)plywood, and taking it to a wind-tunnel for testing.

So, don't spend to much time trying to decipher the picture 'details'.

Originally posted by Jack Olsen
Significant is not all that precise a word. But the original 911 design has an aero issue just behind the windshield.



How much would the smoother 964 arrangement help? I don't know.

[Laneco]

Milt,
Tell your insurance company to give you the full cost including installation of the glass for your car. They will only pay stock replacement only (not the 964). Take the money and do what you want.

2nd thing. Beware of extremely cheap windshields. We've had some REAL problems with poorly made windshields for 911's that were made in Mexico. They were un-fittable. Steve cracked a couple of them in succession before he actually thought to remove the mexico-made glass and lay it down on top of the german glass. The mexico-made windshield was almost 1/2 inch narrower at the base and slightly taller. No possible way to get a seal with it.

He was able to get a refund as he could prove they did not fit, but what a huge PITA. He wound up buying a used german windshield. I'm sure there's good aftermarket stuff out there but from first hand experience, there is DEFINATELY some crappola!
angela

[Formerly Steve Wilkinson]

Is there anybody out there who I can pay to make an accurate paper template of a free-standing piece of 964 windshield glass? I'm about to put a 964 seal (which I have) and a 964-size piece of Lexan (which I also have but it needs to be trimmed to size) into my SC.

I can put the empty 964 seal in place and try to measure the difference in size between it and the 911 seal, but having an accurate paper template would be a lot easier and more accurate...

[rdane]

Originally posted by Porsche Doc
I have tried to put a 964 windshield and seal in early car with NO success. The glass and seal are bigger than the earlier ones.
I have also tried to put a earlier windsield in a 964 too with no luck.

My body guy tried the same thing and could not get it to work.

[Formerly Steve Wilkinson]

That's odd, Steve Weiner does it all the time.

[Craig 930 RS]

Mach is air velocity - notice how the windshield to roof join area has the highest measured velocity per the Mach table.

This area also has a large raised gasket right in the critical area, as well as a steep windshield-to-roof join angle.

Smoothing this out will help.......but at what cost?

Yeah I spent time at this:
http://www.boeing.com/news/releases/1998/news_release_980128a.html

[RickM]

Originally posted by rdane
My body guy tried the same thing and could not get it to work.

I recall at least two people on here that tried and no dice. Pretty much boiled down to what Porsche Doc stated.

[81 911 SC]

I have the 964 windshield with the integrated radio antena and had to have extra glue put in to keep the leaks out of my 81. Biggest issue with removing the radio antena and going with the 964 is reception but then again I'd rather listed to the howl of the flat 6 any day.

[CBRacerX]

Originally posted by 81 911 SC
I have the 964 windshield with the integrated radio antena and had to have extra glue put in to keep the leaks out of my 81. Biggest issue with removing the radio antena and going with the 964 is reception but then again I'd rather listed to the howl of the flat 6 any day.

+1 in my '87 - same situation exactly.