Having problems with windshield upgrade to 964 style.
 

A week ago I ran into some accident debris on the freeeway not cleaned up yet. The car in front kicked up a large piece of metal and it smashed my hood and windshield. I've read here all along that the 964 windshield AND seal makes for a very nice installation over the current '88 set up with the metal trim.

I bought a seal and anticipated a more expensive windshield. My problem is, insurance is covering this and the shops won't do it because of liability (I guess). Is this worth all this hassle???

I know I could install it myself, but I can't find a place to buy the damn glass. Well, I could lay down and pay stone retail, but that ain't gonna happen since the ins co is going to give me half of what this will cost.

I would just install a windshield that is easy to install and insurance will pay for, the original.

why not just tell your insurance company the damaged windshield is the 964 version and you want it replaced with the same. The installer shouldn't care as long as they get paid and the installation is easier.

It's my understanding that the trim is supposed to be cosmetically better, quieter and also better at keeping out moisture. I have the upgrade and my w/s STILL leaks ands whistles!

Becasue the claim paperwork identifies the car as an '88 and the '88 w/s is cheaper by at least $100. I asked to upgrade providing my own seal along with the difference in cash and they said no way. Apparently, they would want to back date it to stock, or worse yet, use the smaller 911 glass in my new seal.

I'll have to buy the glass on my own. Another thing, last windshield I had done on a 911 was in '94. The installer insisted on putting te butyl sealant in the seal after installation. Ever tried removing one with that crap in there? I'd rather just put the glass in as the factory did.

Above all, the 964 WS is significantly more "aero"; not just 'internet-discussion aero', but a measurable difference, as this junction is a significant source of drag on earlier 911s.

Hell, I'd give it a try, but have no actual help to offer other than to offer up a bit of information -

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

Chris, is this something you could post a picture? I would really like to go trimless too..

Maybe when it warms up later this week. Right now it's covered with a frozen car cover.
-Chris

I wouldn't be surprised by that, but what is the source for that bit of aero information??

Ah, come on Randy, run your hand over the upper area. If the outside mirrors can make a difference, the lack of metal trim across the top and both sides can too. I don't think it's a lot and that's not why I'm trying to do it.

For the record, there hve been many threads on this. It's all been sorted out in the past. You need a 964 windshield AND a 964 seal to do this. I'm not after that info, I'm after a windshield. Where do they come from?

It isn't a ton - yet that junction is absolutely one of the most critical areas for aero on a car. Yup, it's true.
The CD difference between a 911 and a 964 is quite large - and it isn't all from the front bumper.
That said, I think I'll stay with what I have until, for example, the trim and windshield take a direct hit. Then it makes sense.

Jack Olsen has a place where he gets glass CHEAP, but I can't remember where.

Cheers

Well, I guess anyone asking any questions about this process will come to the same place you are Milt. I've not seen this conversion but it sounds interesting if the glass isn't a pain to find.

And he sent me the number of Gus. But, Gus doesn't answer that number anymore. We are waiting for another Pelican to see if he knows where the guy went.

That having been said, John Walker tells me that early glass w/o a band or antenna, and not German, is very cheap. Like $120 (sometimes installed!!!) TRE has some nice original stuff for the early cars. but, more like 600 for the 964 glass.

not trying to hijack your thread, but he said "significant source of drag"

- if it's supported I'd like to read up on it -- I may learn something, tho I don't play with wind tunnels much anymore.

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

http://forums.pelicanparts.com/uploa...1170211134.jpg

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

Randy, I think he's trying to say our earlier seals look girly. :cool:

FWIW, I wouldn't doubt a lowering of Cd -- i'm amazed at how much wind noise is produced at the WS top edge.

Jack, as pretty as that CFD velocity map/picture is, it's too crude to represent the seal detail. . .. and the associated flow.

Interesting how the flag mirrors affect the surface flow. Neat picture. I always though the headlight would make great air intakes. Guess this proves it, almost full ram pressure recovery (near zero Mach) Should we put the oil cooler there, and move the headlight somewhere else ;)

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!
SmileWavy

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).

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 :D


No, really I occasionally teach this crap.

More info for the truly sick:

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

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).

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!

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

"When Scientists Attack" tonight on FOX.

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

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

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.

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?

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.

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'. :)

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

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...

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

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

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

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

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.