Coilovers?
08-07-2002, 07:30 PM
#16
Have read on this board and other places that the shock mounting points on the body will fail over time because they are not engineered to take the load of a full coilover setup. That's why some folks use coilovers as helpers to suppliment the torsion bars.
The fact that Kokeln offers a t-bar elimination kit tends to make me doubt that though.
Oh, and with this post I am a Senior User. Yippee.
The fact that Kokeln offers a t-bar elimination kit tends to make me doubt that though.
Oh, and with this post I am a Senior User. Yippee.
08-07-2002, 07:43 PM
#17
Race Director
From what I've been told, only eliminate the T-Bars if you aren't planning on driving it on the street. Bumps, pot-holes, etc are rougher on the rear suspension mounts than DE's or track.
Tifo
Tifo
08-07-2002, 08:28 PM
#18
Three Wheelin'
Thread Starter
Yeah, I just got the same response from my PCA racer friend. It makes sense, Porsche designed the spring loads to be supported at the torsion bars, and the shock loads at the shock mounts.
Back to an old question, does anyone know where to find the proper HAL coilover setup? It was mentioned earlier but I still haven't found them for 944s anywhere. Are they just universal and I just have to match up my measurements to them?
... oh yeah, Tifo, great looking car! Very clean.
Back to an old question, does anyone know where to find the proper HAL coilover setup? It was mentioned earlier but I still haven't found them for 944s anywhere. Are they just universal and I just have to match up my measurements to them?
... oh yeah, Tifo, great looking car! Very clean.
08-07-2002, 10:01 PM
#19
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Hal shocks (Now QA1)
I was holding off with my response. I'm not real happy with the mounting system I used. A bit shadetree. None the less. The shocks are solid and work well. 12 position adjustable (13 if you count the starting position). <a href="http://www.halshocks.com" target="_blank">http://www.halshocks.com</a>
Doing it the right way will require Racers Edge mounts at $150 pr. Still the upper mounts need a perminant fix.
Here is the write-up on my experiences and data gathered.
<a href="http://members.rennlist.org/dan10101/chapter_20_-_coil_overs.htm" target="_blank">HAL rear coil over shocks</a>
The Huntley setup isn't that much more than I ended up spending. And they are engineered to fit. That said, I probably saved $200-300 on the rear shock setup over Huntley's price. Take the $150 off that and it's not a big difference.
I'm running 400# front and 300# rear springs along with the 25.5 torsion bars. The combination could be run without the torsion bars if the spring rates were changed.
BTW, I'm running the Paragon 2.5 coilover kit with Koni struts on the front.
Hope this isn't too confusing...
DanD
I was holding off with my response. I'm not real happy with the mounting system I used. A bit shadetree. None the less. The shocks are solid and work well. 12 position adjustable (13 if you count the starting position). <a href="http://www.halshocks.com" target="_blank">http://www.halshocks.com</a>
Doing it the right way will require Racers Edge mounts at $150 pr. Still the upper mounts need a perminant fix.
Here is the write-up on my experiences and data gathered.
<a href="http://members.rennlist.org/dan10101/chapter_20_-_coil_overs.htm" target="_blank">HAL rear coil over shocks</a>
The Huntley setup isn't that much more than I ended up spending. And they are engineered to fit. That said, I probably saved $200-300 on the rear shock setup over Huntley's price. Take the $150 off that and it's not a big difference.
I'm running 400# front and 300# rear springs along with the 25.5 torsion bars. The combination could be run without the torsion bars if the spring rates were changed.
BTW, I'm running the Paragon 2.5 coilover kit with Koni struts on the front.
Hope this isn't too confusing...
DanD
08-07-2002, 11:24 PM
#20
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One more additional piece is that we have the damping levels changed to match the 944 rear end bigger, run a custom length not available retail from QA1, make our own metric scherical bearings and run 2.25" springs on custom perches not the 2.5" which are heavier and bulkier. It is actually a very good deal getting our packadge. <img src="graemlins/jumper.gif" border="0" alt="[jumper]" />
08-08-2002, 03:23 AM
#21
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[quote]Originally posted by DanG:
<strong>So I'm presented with the question, why not return the bars, and use ONLY coilovers for the rear suspension.</strong><hr></blockquote>
Certainly an option - but consider your usage carefully. Competitive classing will most certainly change as a result. SCCA IT/SP won't allow it, PCA requires you at least retain the stock spring type (though, they can be "turned-down" to an uneffective rate - ~10mm). Candidates for torsion bar removal are: dedicated club race car in GT or equivalent modified class, dedicated Driver's Education car, street car with no intention of competing.
Also, it's recommended that you take steps to restore the rigidity lost from removing the torsion bars - this comes in the form of Delrin or Metal bushings for the spring plate, and possibly metal spherical bushings in the trailing arm (attaches to the torsion tube, inboard).
Not trying to talk you out of them, just presenting the facts. Also, still haven't heard a bonafide story of trailing arm failure at the lower load point due to coil-over use (not attributed to other extraneous circumstance)
Good luck with your decision...
Skip
<strong>So I'm presented with the question, why not return the bars, and use ONLY coilovers for the rear suspension.</strong><hr></blockquote>
Certainly an option - but consider your usage carefully. Competitive classing will most certainly change as a result. SCCA IT/SP won't allow it, PCA requires you at least retain the stock spring type (though, they can be "turned-down" to an uneffective rate - ~10mm). Candidates for torsion bar removal are: dedicated club race car in GT or equivalent modified class, dedicated Driver's Education car, street car with no intention of competing.
Also, it's recommended that you take steps to restore the rigidity lost from removing the torsion bars - this comes in the form of Delrin or Metal bushings for the spring plate, and possibly metal spherical bushings in the trailing arm (attaches to the torsion tube, inboard).
Not trying to talk you out of them, just presenting the facts. Also, still haven't heard a bonafide story of trailing arm failure at the lower load point due to coil-over use (not attributed to other extraneous circumstance)
Good luck with your decision...
Skip
08-09-2002, 03:42 PM
#22
Advanced
Dan,
My friend Chris Cervelli at Technodyne always seems to have 944 race parts lying around his shop. His URL is <a href="http://www.technodyneracing.com" target="_blank">http://www.technodyneracing.com</a>
He had several sets of 968 TurboRS rear coilovers in his shop a couple of years ago.
You may also want to try my buddy Dave at TRE Motorsports (http://www.tremotorsports.com), he seems to always have 944 parts lying around as well.
Derek at Huntley Racing has very good parts for very good prices. I've personally used his coilover setup and Carrera shocks with very good results. If we can only get Derek to bring out the zebra car once again!
As far as your setup is concerned, you're currently set up for understeer. If you ask a dozen racers what they recommend for your car, you'll get a dozen different answers. Changing springs and swaybars will tune in different elements of handling much like caster, camber, etc.
The proper way to set up your car is to perform controlled testing. Big teams will rent out race tracks for the day or weekend to test their cars and make adjustments. Our team goes to open test days or attends open track events to do the same. I assume you're not taking your driving that seriously, nor do you have that kind of budget, so here's how I would sum it all up:
Think of your car as a "teeter totter" set, it's a constant compromise and the best compromise between the different factors nets the best setup. The general rule of thumb is that you want to soften the side that needs more grip (weight equals grip). You can achieve this by either softening the spring/dampening rates on that side or increasing the same on the other side. My crew chief prefers to tune throttle exit understeer/oversteer with swaybars and run the softest spring rates he can get away with. We found this especially true with the 924/944/968 chassis. We also found that the 944 could improve with a slight change in the roll center biased towards the front and wider front track for better turn-in. I'm assuming you're already running poly bushings or monoballs.
As far as the decision to change to rear coilovers or larger torsion bars is concerned, both choices reap benefits and deficits.
Torsion Bars are a solid design that will not slip, and need little to no maintenance. For street use, I highly recommend this setup. The 30mm torsion bars might be a bit too much with your 250# front springs, I'd go with maybe 28-29mm at most. Unfortunately, this setup is a one time adjustment.
Rear coilover helper setup is a great way to be able to include some adjustability into your rear supension and still have the fullproof setup of the t-bars. However, this setup up has been known to reap some innacurate readings and adjustments as you now have 2 different factors to motivate the suspension. The coilovers are also not designed for daily driving abuse and may slide or wear out prematurely.
A full rear coilover setup gives the most immediate feedback and allows for the most direct adjustments. However, this type of suspension requires more maintenance as the parts are not designed for daily driving abuse and the more moving parts, the more chances of things changing on you. Unless you truly understand suspension dynamics, having all those adjustments can actually lead you too far in the opposite direction.
If you have questions or want feedback from other 944 racers, feel free to also visit our Message Boards (we have a 944 racing section) at: <a href="http://forums.realride.com" target="_blank">http://forums.realride.com</a>
Regards,
David
PENNYWEB/REALRIDE.COM RACING
<a href="http://www.RealRide.com" target="_blank">http://www.RealRide.com</a>
My friend Chris Cervelli at Technodyne always seems to have 944 race parts lying around his shop. His URL is <a href="http://www.technodyneracing.com" target="_blank">http://www.technodyneracing.com</a>
He had several sets of 968 TurboRS rear coilovers in his shop a couple of years ago.
You may also want to try my buddy Dave at TRE Motorsports (http://www.tremotorsports.com), he seems to always have 944 parts lying around as well.
Derek at Huntley Racing has very good parts for very good prices. I've personally used his coilover setup and Carrera shocks with very good results. If we can only get Derek to bring out the zebra car once again!
As far as your setup is concerned, you're currently set up for understeer. If you ask a dozen racers what they recommend for your car, you'll get a dozen different answers. Changing springs and swaybars will tune in different elements of handling much like caster, camber, etc.
The proper way to set up your car is to perform controlled testing. Big teams will rent out race tracks for the day or weekend to test their cars and make adjustments. Our team goes to open test days or attends open track events to do the same. I assume you're not taking your driving that seriously, nor do you have that kind of budget, so here's how I would sum it all up:
Think of your car as a "teeter totter" set, it's a constant compromise and the best compromise between the different factors nets the best setup. The general rule of thumb is that you want to soften the side that needs more grip (weight equals grip). You can achieve this by either softening the spring/dampening rates on that side or increasing the same on the other side. My crew chief prefers to tune throttle exit understeer/oversteer with swaybars and run the softest spring rates he can get away with. We found this especially true with the 924/944/968 chassis. We also found that the 944 could improve with a slight change in the roll center biased towards the front and wider front track for better turn-in. I'm assuming you're already running poly bushings or monoballs.
As far as the decision to change to rear coilovers or larger torsion bars is concerned, both choices reap benefits and deficits.
Torsion Bars are a solid design that will not slip, and need little to no maintenance. For street use, I highly recommend this setup. The 30mm torsion bars might be a bit too much with your 250# front springs, I'd go with maybe 28-29mm at most. Unfortunately, this setup is a one time adjustment.
Rear coilover helper setup is a great way to be able to include some adjustability into your rear supension and still have the fullproof setup of the t-bars. However, this setup up has been known to reap some innacurate readings and adjustments as you now have 2 different factors to motivate the suspension. The coilovers are also not designed for daily driving abuse and may slide or wear out prematurely.
A full rear coilover setup gives the most immediate feedback and allows for the most direct adjustments. However, this type of suspension requires more maintenance as the parts are not designed for daily driving abuse and the more moving parts, the more chances of things changing on you. Unless you truly understand suspension dynamics, having all those adjustments can actually lead you too far in the opposite direction.
If you have questions or want feedback from other 944 racers, feel free to also visit our Message Boards (we have a 944 racing section) at: <a href="http://forums.realride.com" target="_blank">http://forums.realride.com</a>
Regards,
David
PENNYWEB/REALRIDE.COM RACING
<a href="http://www.RealRide.com" target="_blank">http://www.RealRide.com</a>
08-09-2002, 04:09 PM
#23
Three Wheelin'
Thread Starter
Thanks to everyone for their input. I'm most interested in the project DanD posted. I have access to an excellent machine shop (CMU's mech e dept shop) and can obtain the delrin, aluminum, or steel necessary to fabricate the required mounts for free. I can also mill and lathe the parts myself or have the machinists lend me a hand. So from a pure cost basis, that is my best option. However, I'd be using the same springs no matter what setup I bought, and the HAL shocks seem to be of acceptable quality as they are used by Huntley Racing. So I am going to work toward building up a setup similar to that.
DanD, I'll be sending you a personal email shortly.
DanD, I'll be sending you a personal email shortly.
08-31-2002, 01:18 PM
#24
Three Wheelin'
Thread Starter
Just an update...
I went to the drivers ed, and had an absolute BLAST. By far the best money ever spent on the car. I've decided to leave the car alone and spend the money on track events. And tires.
Anyway, I took some pictures and thought some of you might be interested. Click the pic to see more...
<a href="http://www.p-caronline.com/stuttgart/gielamonster/nl02.htm" target="_blank">
</a>
I went to the drivers ed, and had an absolute BLAST. By far the best money ever spent on the car. I've decided to leave the car alone and spend the money on track events. And tires.
Anyway, I took some pictures and thought some of you might be interested. Click the pic to see more...
<a href="http://www.p-caronline.com/stuttgart/gielamonster/nl02.htm" target="_blank">
</a>
08-31-2002, 03:04 PM
#25
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Rennlist Member
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DanG,
Excellent choice. Just go have fun!
(I had to skip the last 2 events due to low funds. No fun!)
<img src="graemlins/burnout.gif" border="0" alt="[burnout]" />
Excellent choice. Just go have fun!
(I had to skip the last 2 events due to low funds. No fun!)
<img src="graemlins/burnout.gif" border="0" alt="[burnout]" />
