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Raceboy
Joined: 01 Mar 2004
Posts: 2326
Location: Estonia, Europe
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 Posted: Fri Aug 03, 2007 5:16 am Post subject: Teaser pics (some performance eyecandy) |
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Finished rear alloy arm and 951 brake conversion (plus torsion bar carrier swap for rear sway bar and yellow 951 M030 Konis) today and installed sandblasted & powdercoated struts w/ yellow Konis.
Tomorrow I'm finishing front end by installing spindles with 951 calipers and discs.
Quality is not the greatest (taken with cell phone) but you'll get the idea.
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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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Chrenan
Joined: 15 Jan 2003
Posts: 3903
Location: Canada
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| Posted: Fri Aug 03, 2007 5:27 am Post subject: |
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Well done!
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1987 951 - M193 Version for Japan |
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Raceboy
Joined: 01 Mar 2004
Posts: 2326
Location: Estonia, Europe
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| Posted: Fri Aug 03, 2007 5:36 am Post subject: |
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Should just add that all brake stuff sans calipers (though soft sandblasted and painted) are brand new: discs are Zimmermanns, pads are Ferodo DS Performance, brake lines are steel braided and fluid is Ate Super Racing Blue.
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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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Min
Joined: 04 Nov 2002
Posts: 2368
Location: Vernon, British Columbia, Canada
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| Posted: Fri Aug 03, 2007 6:43 am Post subject: |
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Very nice, someone's been busy!
Min
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Custom means it didn't come from a box.
1980 n/a with EDIS and Megasquirt II Injection. 7 different colors and counting. |
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macBdog
Joined: 16 Aug 2004
Posts: 1111
Location: Brisbane, Australia
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| Posted: Fri Aug 03, 2007 9:02 am Post subject: |
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Nice work! Whats the philosophy behind drilled rotors and not slotted?
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1979 931 with a 350 chev
1973 911E with EFI
| p-talk wrote: | I'm still convinced the word 'Porsche' makes people crazy in all kinds of ways  |
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!tom
Joined: 28 Aug 2006
Posts: 1931
Location: Victoria, BC Canada
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| Posted: Fri Aug 03, 2007 9:28 am Post subject: |
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| macBdog wrote: | | Nice work! Whats the philosophy behind drilled rotors and not slotted? |
I like how you ask about the philosophy, rather than the science.
Seems I've heard a few people debate the science, but I'd expect the far greater surface area on the inside edges of the holes would provide superior cooling than slots or a uniform surface.
I know the holes sound neat on my motorcycle front disk brake, but that's a solid rather than vented rotor that's been drilled (from the factory).
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78 924 NA
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Raceboy
Joined: 01 Mar 2004
Posts: 2326
Location: Estonia, Europe
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| Posted: Fri Aug 03, 2007 2:28 pm Post subject: |
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These discs are drilled already from the factory.
I would choose non-drilled and non-slotted discs but they weren't available at the time for '86 951. I think I can live with that and being used drilled and solid rotors, it's actually pretty hard to tell the difference.
What matters with cross-drilled rotors is the proper pad selection and heat-cycling, that prevents it cracking prematurely.
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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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morghen
Joined: 21 Jan 2005
Posts: 8879
Location: Romania
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| Posted: Fri Aug 03, 2007 4:18 pm Post subject: |
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very nice looken and i'm sure..very nice drivin' 
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Raceboy
Joined: 01 Mar 2004
Posts: 2326
Location: Estonia, Europe
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| Posted: Sat Aug 04, 2007 3:37 am Post subject: |
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Hehee, right now the ride is terrible because of the totally f***d up alignment.
I finished the front axle today and too some photos of it.
These are fronts:
These are rears:
Rear axle:
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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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Hoboceratops
Joined: 16 Aug 2006
Posts: 156
Location: Atlanta, GA
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| Posted: Sat Aug 04, 2007 3:35 pm Post subject: |
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Older brake pads would expel gases at high temperatures which could form a layer between pad/rotor and lower braking power. For more recent brake pads this is much less of a problem. The idea of slots and holes is to get these gases out from between the pad and rotor, and holes are supposedly better at this, but slots are more than adequate for todays brakes. Slots also have the bonus of scraping the pads off, which can form a sort of glaze that hurts baking [left this typo in because I think it's funny that glaze made me hungry for some baked goods].
Holes/Slots do nothing for cooling, in fact lowering the total mass will make the rotors worse off in terms of cooling.
Drilled holes are pretty good at making stress points for the rotors to crack though, and most companies that sell them do not recommend them for track use. Basically all they're good for is looks.
So in terms of performance, Slotted > Solid > Drilled
Edit: This is for normal iron rotors/brakes. Dunno how different materials will behave.
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1987 924S: Very much in love with it, even if it's all finnicky |
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!tom
Joined: 28 Aug 2006
Posts: 1931
Location: Victoria, BC Canada
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| Posted: Sat Aug 04, 2007 4:20 pm Post subject: |
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| Hoboceratops wrote: | | Holes/Slots do nothing for cooling, in fact lowering the total mass will make the rotors worse off in terms of cooling. |
A solid rotor (as in, no holes or slots in the friction surface; a vented rotor is obviously far superior to the solid 4 bolt rotors on our 924's) would have a higher heat capacity than an otherwise similar slotted or drilled rotor, due to the fact that there is more material.
However, I disagree with your conclusion that a solid rotor would cool better than a slotted or drilled rotor (assuming a conventional arrangement). A higher surface area will promote a higher rate of heat transfer from the rotor to the atmosphere, and of the 3 discussed arrangements, a drilled rotor would have the highest surface area.
I'm not saying that drilled is best, nor am I saying that people justify drilling their rotors due to the higher surface area hence rate of heat transfer, but I am saying that a drilled rotor will cool faster than a solid or slotted rotor.
The drilled and slotted rotors will also have less surface area acting against the brake pad, which will in and of itself decrease braking performance. However, the above mentioned justifications for holes and slots may or may not counteract the decrease in available surface area.
If you take cars that are identical in all ways other than their rotor arrangements, and stop each of them from the same speed in the same distance on the same road, the car with solid rotors would have the lowest rotor temperature once stopped due to the higher heat capacity of the solid rotor.
However, if you're driving all three cars down a very steep mountain and really use the brakes a whole bunch, the increased cooling capacity of the drilled rotors would ensure those brakes were the coolest, and the solid rotors would be the hottest. In both cases the slotted would be in between the two extremes.
They (drilled rotors) look novel, and they sound kind of neat, but I'd expect if they were all that much better, they'd be far more common than they are.
They are common on motorcycles which do not have vented rotors -- and they tend to be steel.
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78 924 NA
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Hoboceratops
Joined: 16 Aug 2006
Posts: 156
Location: Atlanta, GA
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| Posted: Sat Aug 04, 2007 4:56 pm Post subject: |
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Cross-drilling is really only a way to make the brakes lighter because out-gassing isn't a problem; and while I know the surface area to mass ratio makes sense, by all reports cross-drilled rotors run as hot or hotter than vented solid rotors.
Cross-drilling does make rotors the lightest of all the methods though, and I guess some think they look cool (I think they look goofy, slotted imo).
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1987 924S: Very much in love with it, even if it's all finnicky |
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morghen
Joined: 21 Jan 2005
Posts: 8879
Location: Romania
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| Posted: Sat Aug 04, 2007 7:08 pm Post subject: |
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oh i love those wheels....can we get a picture of the car?
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ihatesissycars
Joined: 14 Jan 2008
Posts: 17
Location: Uk, Hampshire
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| Posted: Mon Jan 21, 2008 1:08 am Post subject: |
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Did the ally arms widen the track of your car by any amount?
I'm having a problem with my own car after swapping the rear beam!
http://www.924board.org/viewtopic.php?p=204344#204344
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When will the endless repairs end!!!!!!! |
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924RACR
Joined: 29 Jul 2001
Posts: 8804
Location: Royal Oak, MI, USA
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| Posted: Mon Jan 21, 2008 1:47 am Post subject: |
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We did recently refit the stock steel rear trailing arms to a 924 (early) racecar which had been fitted with the 924S alloy arms (for numerous reasons); I can confirm that there was a loss of track (having now the steel arms), perhaps 20mm per side?
OTOH, having read your other post - these were 924S alloy arms, interchangeable with the steel ones; not sure why on your car they're not apparently interchangeable, if you've already tried all the adjustments...
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Vaughan Scott
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'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
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