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Bridge spoiler effective?
https://forums.tipec.net/viewtopic.php?f=25&t=21477		 Page 1 of 2
Author:  flt505 [ Thu May 26, 2016 7:49 pm ]
Post subject:  Bridge spoiler effective?
Hi Folks -

The recent topic of painting or otherwise the rear bridge spoiler of late model 944/968s made me thinking: is the bridge spoiler more effective than the older rubber one re. proven aerodynamics? One reason for asking this is that my S2 front end lifted badly at speed but since having fitted a front splitter it is now extremely stable and handling much improved. Porsche never fitted a front splitter, so I'm wandering if the 'bridge' was just cosmetic?

Dave
CT
Author:  briggy [ Thu May 26, 2016 8:06 pm ]
Post subject:  Re: Bridge spoiler effective?
My S2 cab lifted at the front at speed after renewing the suspension. Turns out it had a 2 degree rake, which was sorted by altering the ride heights.
Author:  GlennS [ Thu May 26, 2016 8:19 pm ]
Post subject:  Re: Bridge spoiler effective?
flt505 wrote:
One reason for asking this is that my S2 front end lifted badly at speed...


Define "at speed". I've had no front end lift issues at 130mph... I have heard it suggested that if the engine bay undertray is missing or damaged, lift may occur at 120mph+ but I've not experienced it personally.
Author:  scam75 [ Fri May 27, 2016 11:52 am ]
Post subject:  Re: Bridge spoiler effective?
According to Porsche, in the brochure for the 90 model turbo where bridge debuted, it was claimed the bridge spoiler was superior to the rubber one in aero terms and that it helped plant the back end better at speed.

Also the turbo has 3 under trays and often the 3rd tray, the aluminium one, is missing. This does cause front end lift at speed as the tray is designed to suck the car down at speed as you can see from the aero fins on it. I have no idea if an S2 has the same set up.

My definition of "at speed" is 100mph+ btw! :D

Stuart
Author:  zcacogp [ Fri May 27, 2016 3:22 pm ]
Post subject:  Re: Bridge spoiler effective?
GlennS wrote:
flt505 wrote:
One reason for asking this is that my S2 front end lifted badly at speed...


Define "at speed". I've had no front end lift issues at 130mph... I have heard it suggested that if the engine bay undertray is missing or damaged, lift may occur at 120mph+ but I've not experienced it personally.


I've seen over 140mph on my S2 and it felt very solid and stable at that speed. That's with one (plastic) front undertray fitted and a rubber spoiler.

Instability can be caused by a host of different things, of which aero is only one of many. I'd have thought that bad tracking, worn suspension or steering parts, dodgy road surface, incorrect ride heights (as mentioned) or any one of several other things are more likely to be the cause of problems. Bear in mind that Porsche spent many thousands of hours with a wind tunnel perfecting the body and wing design of the 944 and these parts won't have changed since the car was built. However all the other items in that list may well have changed and worn. (I'd also suggest that adding aero parts that haven't undergone as much testing as Porsche put into the original design are more likely to cause problems than relieve them, but I could be wrong.)


Oli.
Author:  PSH [ Fri May 27, 2016 5:48 pm ]
Post subject:  Re: Bridge spoiler effective?
well just to add, I have been at much higher speeds than 140mph and had no issues with lift whatsoever....car is 86 and thus has the rubber type rear spoiler....

Pete
Author:  flt505 [ Fri May 27, 2016 8:46 pm ]
Post subject:  Re: Bridge spoiler effective?
Hi Folks -

Thanks for your replies. I think my original description of 'the front end lifting at speed' was probably a bit over dramatic and confused the question somewhat! I did have a few issues with the overall stability at speed and it has been rectified, with modifications and upgrades to the suspension system (Koni Sports, 968 springs, new ARB bushes etc), together with that front splitter.

I see it as a benefit to our cars that replacing worn items with more modern and proven products, only enhances what is and very rightly mentioned here, a very stable vehicle platform...

Dave
S2
Author:  pauly [ Sat May 28, 2016 2:25 pm ]
Post subject:  Re: Bridge spoiler effective?
Some time ago I posted about the steering feeling light at speed when I'd removed the under trays to change the belts. I didn't mention the speed but it was a bigger number than has been posted here so far, on a private road. I don't think Porsche fitted the bridge spoiler just because it looks better.
Author:  GlennS [ Sat May 28, 2016 4:44 pm ]
Post subject:  Re: Bridge spoiler effective?
I wouldn't be too negative about the old rubber hatch spoiler, Porsche thought it was good enough for Le Mans ;)
Author:  pauly [ Sun May 29, 2016 5:03 pm ]
Post subject:  Re: Bridge spoiler effective?
GlennS wrote:
I wouldn't be too negative about the old rubber hatch spoiler, Porsche thought it was good enough for Le Mans ;)


Was that back in the days of leather helmets and wire wheels :lol: .
Author:  PSH [ Sun May 29, 2016 9:40 pm ]
Post subject:  Re: Bridge spoiler effective?
continuing on with the downforce generated on our cars, it's not so much the rear wing as it is the diffuser that really plants the car to the road at speed. Some may find this article of interest, the world of motorsport owes a lot to the humble 944 Turbo of 86. http://www.flussigmagazine.com/1/post/2 ... isher.html

Now regarding speeds I've had my speedo bouncing off it's stop, on the continent mind. The car was still pulling like a train too, IIRC GPS recorded 174 mph which I believe is as fast as one can go with the final drive ratio on our cars, I had begun to back off so don't know if she would have gone faster , she got there very quickly though with plenty of power left in reserve.....ok my car is heavily modified but these machines in any form are true masterpieces of German engineering. Better still they are finally being recognised for their true potential, something us faithful long term owners have known for many years....

enjoy your cars guys..they are very special...

cheers

Pete
Author:  Waylander [ Mon May 30, 2016 11:40 am ]
Post subject:  Re: Bridge spoiler effective?
That was an interesting read, just goes to show Porsche knew what they were doing and a lot of boy racerish mods are pointless
Author:  pauly [ Tue May 31, 2016 12:04 am ]
Post subject:  Re: Bridge spoiler effective?
Waylander wrote:

Porsche knew what they were doing and a lot of boy racerish mods are pointless



Such as ?
Author:  Waylander [ Tue May 31, 2016 11:40 am ]
Post subject:  Re: Bridge spoiler effective?
Such as,

Lowering to far so the roll centre ends up below the ground
seen a few really large rear diffusers, fluffy Dice

things along those lines,

there are plenty of mods that are beneficial to the cars, hope you did not take what I said the wrong way
Author:  GlennS [ Tue May 31, 2016 11:44 am ]
Post subject:  Re: Bridge spoiler effective?
I take issue with your assertion that fluffy dice are ineffective.
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