924Board.org

Andrew NZ · Joined: 22 Jun 2004 Posts: 744 Location: New Zealand

Does the 951 rear spoiler make a difference at high speed over the smaller 924 item?

My rally car has no spoiler at the moment and tends to get a little unstable above 100mph at times. Is there a significant improvement with the bigger spoilers, or will a standard size one still make a noticable difference? The types of rallies I do have a 200kph(120mph) speed limit, so I'm not too worried what happens above 200.
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Andrew
1977 RX924 race car
12a bridgeport supercharged
www.race4-dcup.co.nz

Raceboy · Joined: 01 Mar 2004 Posts: 2326 Location: Estonia, Europe

I've used both and stock small spoiler will do the job well and it's A LOT lighter than 944/951 spoiler.
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'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold

'84 924, turbocharged, sold.
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Joes924Racer · Posted: Thu May 28, 2009 4:09 pm Post subject:

get a big one the down force is substantial in other words you will notice the difference i did... splitter and rear spoilers give a strong solid improvement at speeds 75 +.

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1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

morghen · Joined: 21 Jan 2005 Posts: 9082 Location: Romania

i'm sure its quite important.
i didnt have the power to go that fast before...but now i can tell you that the car feels like on rails even at 200+ and i'm sure its because of the front spoiler and the rear one...and the wide tires.
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Supercharger and EFI kits
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924RACR · Posted: Thu May 28, 2009 9:50 pm Post subject:

It's been a very long time since I ran without one, and never at a track where we can get to speed... but I definitely wouldn't run without any!!!

For one thing, the small spoiler actually reduces drag by providing a good separation point for the airflow on the rear hatch - like a Kamm tail.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

tuurbo · Posted: Fri May 29, 2009 1:04 am Post subject:

I put the 944 spoiler on my car and shit man, it lifts off the ground now when I shift into 3rd!

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1980 924 turbo, MSD, Meth. Inj, otherwise stock.

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

There is no doubt in my mind that the rear spoiler adds significant downforce, and I suspect that the 944 spoiler provides more than the smaller 931/924S. The only real way to know would be to setup some Autospeed-style rolling tests with magnahelic gauges.

However, if I had a car without a spoiler already attached to the hatch, I would do something like this:

I don't know if it would be any better than what the factory did, but on a race car, it looks purposeful and bad ass, and if you really knew what you were after, the adjustability would probably be a benefit. Both of my lexan hatches came with rear spoilers (944 style), but I haven't completely ruled out removing one and doing something like this, just because it looks so cool

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erstwhile owner of just about every 924 variant ever made

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

I haven't had my 81 past 100mph, BUT I have had my old early 77 past 120mph on the way between Los Angeles, and San Francisco, and between Los Angeles and Las Vegas.

You can feel the front end getting lighter at 100mph, and it's really touchy at 120mph.

The 81 with factory installed 931/924S small rear spoiler is definitely more stable at 100 than the 77 was.

I would not add a 944 spoiler unless you are going to balance it with front spoiler that will create a matching amount to the larger rear unit.

Joes924Racer · Posted: Fri May 29, 2009 3:39 am Post subject:

yea that funky racing type splitter i made did weird stuff
at high speeds.. best describe it as tracking like an arrow
with a light feeling that was with the rear val. n44 spoiler
in the back of course.
_________________
1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

Andrew NZ · Joined: 22 Jun 2004 Posts: 744 Location: New Zealand

Thanks everybody - there's some really good info here to mull over. Please keep it coming!
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Andrew
1977 RX924 race car
12a bridgeport supercharged
www.race4-dcup.co.nz

FSMITH010 · Joined: 24 Apr 2009 Posts: 101 Location: Los Angeles, CA

Did the GTS have a different rear spoiler than the 944/gct?

924RACR · Posted: Fri May 29, 2009 8:15 am Post subject:

Nobbi · Joined: 24 Aug 2006 Posts: 1394 Location: Germany

i dont think it matters.

my original 924 from april 1977 has no rear spoiler (thank who ever) and it is driving great on the Autobahn even at top speed.(Which is a 210 Km per Hour) For me personly ther is no need for a rear spoiler.

Only thing it does, maybe, is reducing the amount of fuel you need to get to your next cup of coffe in a cool place....

Yeah,common show me that drag figures... bla bla.....
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NA 924 - april/1977- 4-speed-audi gearbox.
500.000 km with fun.....and new toy:Porsche 944 S2 Cabriolet.Other car Daimler c-class cabby,brandnew..Plus : DEUTZ 4005 tractor Built 1969

Khal · Posted: Fri May 29, 2009 9:31 am Post subject:

I can only comment anecdotally but I've had my car well up over 200km/h (~120mph) several times and over a certain speed (I vaguely recall around 130-140km/h and over but it's been a long time so don't quote me on that), I clearly remember having the feeling that the car started "pushing" itself down against the road, "settling", in a sense. Another mate of mine who took it up over 200km/h commented that he had a similar feeling. My car is an '81 924 Turbo so it has the (smaller than 944) Turbo rear spoiler but I have absolutely no empirical evidence to prove the spoiler is working or not. But I suspect it is... Just a feeling...
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'80 924 Turbo

Scorpio · Posted: Fri May 29, 2009 9:58 am Post subject:

any speed 40km over the speed limit and we lose our license for 6 months and they throw a $1000 fine in just for good measure..
So the maximum speed we can travel here before losing our licence in one fine is 150km/hr
Ive got a nice big rubber 944 spoiler just incase....and i dare say ill never have the opportunity to really test its downward force.
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1979 NA
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