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Dutch924-racer · Joined: 23 Jul 2007 Posts: 1081 Location: The Netherlands

What is the distance between the ground and your car front and rear ?

And what kind of suspension/ springs are you using.

_________________
937 trackday car
Series 2 engine
951S turbo and intercooler
Fast road camshaft
Forge recirculation valve + boost controller

924RACR · Posted: Wed Feb 27, 2008 5:50 am Post subject:

5.25" over here - with 660# front springs, 34mm hollow rear torsion bars. Ran the same with the 400# front spring, 30mm t-bar combo, but that would sometimes bottom out. Even this setup, so low, can bottom out I think until I cut my rear bump stops in half.

I should add, when I take the measurements as you have them, I do not include the pinchweld - the little vertical lip at the bottom of the sheetmetal. I measure up to the first flat surface.

The car gets real squirrely (loose - oversteer) when the rear hits the bumpstops!!!

_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

Dutch924-racer · Joined: 23 Jul 2007 Posts: 1081 Location: The Netherlands

I measeared it from the points as shown in the picture. The picture is before lowering the rear.

front distance : 12,5 cm = 4.9 inch
rear distance : 13cm = 5.1 inch

Should I lower the rear a bit more to get i equal with the front ?

_________________
937 trackday car
Series 2 engine
951S turbo and intercooler
Fast road camshaft
Forge recirculation valve + boost controller

924RACR · Posted: Wed Feb 27, 2008 7:23 am Post subject:

What you should do is get the car on scales and corner-balance it. Can you get access to scales?

Generally one would want the car to be level, to get equal front/rear weight distribution.

Refresh my memory, what spring rates/torsion bars are you using?

If you don't have a very big rear torsion bar and/or rear coilover spring rate, I would be very concerned about bottoming out the rear suspension on track. When the car bottoms out the car will tend to snap oversteer. If you hit the bump stops, no problem, but if you don't hit them, there's a possibility you could damage your shocks (if those are bottoming out).
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

Neil924 · Joined: 18 Mar 2003 Posts: 4225 Location: Canada

924RACR · Posted: Wed Feb 27, 2008 10:05 am Post subject:

Yes.
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

Neil924 · Joined: 18 Mar 2003 Posts: 4225 Location: Canada

Dutch924-racer · Joined: 23 Jul 2007 Posts: 1081 Location: The Netherlands

I don't know anybody with car scales.

Spring rates is unknown, In Holland they just say -30mm springs for 924/944. Torsion bars ar 23mm. I have koni gas shocks at the rear (yellow).

Do you have a picture of the side of your car ? So I can see the difference.
_________________
937 trackday car
Series 2 engine
951S turbo and intercooler
Fast road camshaft
Forge recirculation valve + boost controller

PORSCHEV · Posted: Wed Feb 27, 2008 9:13 pm Post subject:

Most race tracks should have scales. Our local track has 4 corner scales.
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1976 924
5 lug conversion, 17'C2 wheels,custom body work,327 vette engine.

1978-#53 "D" track racer.

924RACR · Posted: Thu Feb 28, 2008 6:06 am Post subject:

There may be some pics out there on my website showing the side of the car... yes, you'd need to make a connection with a speed shop or racer who has such scales...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype