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Aussie Jase
Joined: 16 Jan 2015 Posts: 17 Location: New York
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Posted: Mon Feb 01, 2016 2:09 am Post subject: What are my 924 caliper options? |
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Hi guys,
Is there a bigger caliper option for the 924? I need to stay with the narrow body and wheels so I can't go to 4 piston calipers.
Is there a bigger single or twin piston caliper I can bolt onto or adapt to the 924 and remain on original narrow body wheels? The braking power of the car isn't too bad but the problem is (as you all know) the pad size is just too small for endurance racing on sticky tires. Anyone know if a Toyota or Honda or whatever larger caliper could fit on the front?
Cheers, Jason. [/list] _________________ 1987 924S 24hr LeMons car |
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ideola
Joined: 01 Oct 2004 Posts: 15548 Location: Spring Lake MI
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Posted: Mon Feb 01, 2016 2:21 am Post subject: Re: What are my 924 caliper options? |
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Aussie Jase wrote: | I need to stay with the narrow body and wheels so I can't go to 4 piston calipers. |
Not true.
BTW, is your car 5-lug already?
Source a set of spindles, strut housings, and hubs from a 1986 951, and you are good to go with Brembos. You run most high-offset (>50mm) 16" rim you want, and some 15ers will work too. The 86 951 has the "early offset" control arms, so the front setup works perfectly on a 924/931. 87-onward 951 stuff will not work (at least not well or easily) on narrow body cars.
Rear Brembos will bolt right up, assuming you already have 5-lug. If you don't just get the alloy trailing arms from an 86 951 or from a 86-88 924S.
Only drawback to this setup is the 951 spindle doesn't have the hole for the speedometer cable. You have three options here:
1. have a machinist drill the 951 spindle
2. rig up a wheel speed sensor and a compatible speedometer
3. install a GPS-enabled speedometer
I've done #3 and it works quite well.
Here's another alternative: Wilwoods
Get a set of these and a set of these. You will still need to find a solution for the rear brakes, either bolting up standard 951 brembos or sticking with the single piston floaters that you already have; but in either case will likely need a brake bias adjuster to get a mismatched setup dialed in.
Regardless of which approach you take, be aware that your car comes with an X-split. For running any of these setups, you should switch to a front-rear split, and you should consider swapping in the correct-sized master cylinder at minimum, and ideally the matching brake booster. _________________ erstwhile owner of just about every 924 variant ever made |
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Aussie Jase
Joined: 16 Jan 2015 Posts: 17 Location: New York
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Posted: Mon Feb 01, 2016 3:36 am Post subject: |
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Thank you ideola! Car is a 1987 924S.
So in summery, these 4 piston calipers will fit behind the early offset 924S 15 inch wheels and suit the OEM sized rotor? Could be a winner.
Would a 944 turbo master cylinder and brake booster suffice? _________________ 1987 924S 24hr LeMons car |
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ideola
Joined: 01 Oct 2004 Posts: 15548 Location: Spring Lake MI
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Posted: Mon Feb 01, 2016 4:03 am Post subject: |
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Brembos will most likely require 16" rims. I can't say on the Wilwoods.
Regarding the offset discussion, I prefer to use the term "high" vs. "low" offset, rather than "early" vs. "late". The reason is that most people talking "early offset" are referring exclusively to the 944 line, forgetting about the early 2.0L 924 platform.
To illustrate:
The early 2.0L cars with five lug require an offset in the 50-60mm range (52mm is stock), depending on tire and rim width. The early (1982-86) 944 required an offset in the 20-30mm range (23mm is stock). When the late (1987-onward) 944 and 951 came out, the hub moved outboard by about 22mm, requiring the additional offset (23+22 = ~55ish). So it's misleading to say "early" or "late" offset, and better to say "high" vs. "low".
On your 924S, you need "high" offset of ~52mm, which will work with 6", 7" and 8" rims front and rear. You already have the alu trailing arms in the rear, which are setup to take high offset rims with NO spacer. (Note that early 2.0L 924 came with steel arms, and the 5-lug setups required a 22mm spacer to use the same rim that goes on the later 924S setup). For the front, simply swap on the 86 951 spindle-strut-hub assembly, and you're good to go, it bolts right up to the steel A-arms. You will then only need to worry about the speedometer, as the 924S didn't get the updated electronic speedos of contemporary 944/951.
As for rotors, you MUST get the correct rotor for the Brembos, so if you source bits from an 86 951, make sure to get the 86 951 rotor. It is UNIQUE to that year, and other setups will not work correctly.
A 944 turbo master and booster would be ideal. _________________ erstwhile owner of just about every 924 variant ever made |
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nickthompson
Joined: 26 Mar 2013 Posts: 873 Location: Central Georgia
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Posted: Mon Feb 01, 2016 3:33 pm Post subject: |
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Volvo 240 calipers will work. They are four piston calipers. Make sure you get the vented brake calipers. If you get early ones you have to get a split line because they have two inputs. The later ABS equipped cars have a single input. They aren't as pretty as the 951 calipers but they are cheaper, designed to stop a heavier car, can be bought anywhere and have a wide range of pads available. |
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Rasta Monsta
Joined: 12 Jul 2006 Posts: 11724 Location: PacNW
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Posted: Mon Feb 01, 2016 3:36 pm Post subject: |
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P.S. There is absolutely NOTHING wrong with the factory floating calipers. Hundreds, if not thousands of people race on them every weekend without issue. Properly functioning, and with a good set of pads, they will displace organs with sticky tires.
Oh, and not really sure how "pad size" comes into it? _________________ Toofah King Bad
- WeiBe (1987 924S 2.5t) - 931 S3
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jason c
Joined: 13 Jan 2014 Posts: 1018 Location: Nwi
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Posted: Mon Feb 01, 2016 4:23 pm Post subject: Re: What are my 924 caliper options? |
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Aussie Jase wrote: | The braking power of the car isn't too bad but the problem is (as you all know) the pad size is just too small for endurance racing on sticky tires. [/list] |
Larger pads do last longer. Have you tried an endurance pad? |
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Aussie Jase
Joined: 16 Jan 2015 Posts: 17 Location: New York
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Posted: Mon Feb 01, 2016 10:52 pm Post subject: |
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I agree that the standard floating calipers are better than most. I have been running hawk endurance pads and they've been reliable but the pedal gets long during the day. When flushing the fluid out between days it's almost black which tells me I'm pumping too much heat through them.
I was actually considering pulling the 2 piston caliper off my Scion FR-S and seeing what kind of bracket I would have to fabricate as the rotor thicknesses are the same and the diameters are only 6mm different (FRS being the larger) _________________ 1987 924S 24hr LeMons car |
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fiat22turbo
Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR
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Posted: Tue Feb 02, 2016 1:09 am Post subject: |
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If they are overheating, either you need to adjust your driving style or add cooling via cooling ducts from the front of the car.
For example:
http://www.pelicanparts.com/More_Info/PELPEOSBPAZK.htm?pn=PEL-PEOSBPAZK&SVSVSI=944M
Also the titanium brake pad backing plates should help reduce heat transfer to the calipers:
http://www.pelicanparts.com/More_Info/PELSSTBS2.htm?pn=PEL-SS-TBS2&SVSVSI=944M
More braking options:
http://www.pelicanparts.com/catalog/SuperCat/944M/POR_944M_BRKprf_pg1.htm
Multi caliper pistons won't really help your overheating issue, nor will adding more pad area. You have to reduce the thermal load in the system. If you're not providing cooling of some sort then you're going to continue to have the same issue at perhaps different points in time.
Ensuring there is a way to evacuate the heat from the wheel wells helps. Ensure the leading edge of the quarter panel/nose extends past the outer edge of the wheel to provide a low pressure area near the wheel center. A splitter helps as you can use it to extend the leading edge of the quarter panel and force air into the cooling ducts.
Wheel choice matters as well, wheels with larger openings or aerodynamic designs in the spokes can help greatly as well.
Good luck. _________________ Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose) |
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Cedric
Joined: 27 Aug 2004 Posts: 2614 Location: Sweden
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Posted: Tue Feb 02, 2016 3:18 am Post subject: |
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With that kind of weight/power i can't see endurance would be a problem. Are the calipers regularly serviced? That makes night and day difference in racing, they heat up quickly if there is friction keeping the pads from retracting. I assume cooling ducts are already there since it's an endurance racer? _________________ 1980 924 Turbo
www.instagram.com/garagecedric/ |
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KDJones2000
Joined: 14 Sep 2010 Posts: 322 Location: Phoenix, AZ
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Posted: Tue Feb 02, 2016 7:15 am Post subject: Re: What are my 924 caliper options? |
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Aussie Jase wrote: | Hi guys,
Is there a bigger caliper option for the 924? I need to stay with the narrow body and wheels so I can't go to 4 piston calipers.
Is there a bigger single or twin piston caliper I can bolt onto or adapt to the 924 and remain on original narrow body wheels? The braking power of the car isn't too bad but the problem is (as you all know) the pad size is just too small for endurance racing on sticky tires. Anyone know if a Toyota or Honda or whatever larger caliper could fit on the front?
Cheers, Jason. [/list] |
I run this same car in Chumpcar and 944SPEC. All you need to do is to put some cooling hoses on the brakes and use some good racing grade compound pads, and you will have brakes coming out of your ears.
We have used this for 24 hour and double 7 race weekends without any issues. Porterfield R4-E, Hawk Blue and the like pads will last multiple weekends. _________________ 1987 924S SPEC car
Team Toofah Racing
1988 944 Turbo S |
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gabo931
Joined: 26 Feb 2015 Posts: 21 Location: Puerto Rico
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Posted: Wed Feb 10, 2016 1:50 am Post subject: |
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nickthompson wrote: | Volvo 240 calipers will work. They are four piston calipers. Make sure you get the vented brake calipers. If you get early ones you have to get a split line because they have two inputs. The later ABS equipped cars have a single input. They aren't as pretty as the 951 calipers but they are cheaper, designed to stop a heavier car, can be bought anywhere and have a wide range of pads available. |
Are these worth the upgrade? Or the standard 5 lug 931 brakes work better?
I know that for the price, 240 calipers are a steal. But how much better are they? _________________ 1980 931 M471 LSD |
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daniel
Joined: 18 Jun 2009 Posts: 670 Location: Sydney, Australia
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Posted: Wed Feb 10, 2016 11:46 am Post subject: |
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Calipers from a early 90's A4 audi (also used on a golf GTi?) will bolt right up, Hawk also has some excellent pads for them. This allows you to keep your 4 lug setup _________________ Over the top of skyline, total brake failure.... hit the wall at over 200 kp/h at the dipper, so anyone who has to brake for the esses is a pussy.
1977.5 Race Car, CAMS Group S Spec
1989 944 Cabriolet |
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gabo931
Joined: 26 Feb 2015 Posts: 21 Location: Puerto Rico
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Posted: Fri Feb 12, 2016 2:38 am Post subject: |
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daniel wrote: | Calipers from a early 90's A4 audi (also used on a golf GTi?) will bolt right up, Hawk also has some excellent pads for them. This allows you to keep your 4 lug setup |
Thanks for the response! But my car has the factory 5 lug setup, and I am not sure if the 240 brakes will be a substantial upgrade. _________________ 1980 931 M471 LSD |
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fiat22turbo
Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR
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Posted: Fri Feb 12, 2016 4:37 am Post subject: |
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gabo931 wrote: | nickthompson wrote: | Volvo 240 calipers will work. They are four piston calipers. Make sure you get the vented brake calipers. If you get early ones you have to get a split line because they have two inputs. The later ABS equipped cars have a single input. They aren't as pretty as the 951 calipers but they are cheaper, designed to stop a heavier car, can be bought anywhere and have a wide range of pads available. |
Are these worth the upgrade? Or the standard 5 lug 931 brakes work better?
I know that for the price, 240 calipers are a steal. But how much better are they? |
At the limit, they'll have better feel, therefore potentially providing better threshold braking. The drawback being that there isn't a similar upgrade available for the rear aside form 944 Turbo Brembo calipers (which bolt right up).
This is similar to the Wilwood front caliper upgrade from Rennbay (which weighs much less than the cast iron caliper options), but is only available for the front. _________________ Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose) |
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