Cal Poly Zmanaustin Posted February 22, 2006 Share Posted February 22, 2006 Check out these adaptors for using larger rotors on a Z32. It appears to be a nice kit with one exception: notice the uneven arc on the pad. The originator of the kit states the Z32 caliper was designed for a 11 inch rotor and the brackets move the rotor further from the hub for a 12.8 in rotor. My question: is this kit designed correctly? I think the brackets are moving the caliper about 4 or 5mm too far from the hub. Please enlighten/correct me if I am mistaken. http://s95014253.onlinehome.us/63104/104050.html?*session*id*key*=*session*id*val* Quote Link to comment Share on other sites More sharing options...
Kennysgreen280zt Posted February 22, 2006 Share Posted February 22, 2006 My guess, is the caliper doenst have enough clearance to sit all the way down on the rotor like it should.... or it doenst have enough pad area to cover the whole rotor surface. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 22, 2006 Share Posted February 22, 2006 I think you're right, but I don't think it would matter unless you ran the pads all the way down and the edges hit in the middle before the pads were all the way worn out. Even then, it doesn't look like enough pad material. Looks like it would probably break off if that happened. Quote Link to comment Share on other sites More sharing options...
evildky Posted February 22, 2006 Share Posted February 22, 2006 I think the object of that kits isn't really to improve braking (but it seems logical that the larger rotor would give graater leverage and could also spread the heat across a larger surface area), rather that kit is to allow people with big blinging wheels to fill some of the gap with some big blingin caliper and rotor Quote Link to comment Share on other sites More sharing options...
Cal Poly Zmanaustin Posted February 22, 2006 Author Share Posted February 22, 2006 Jon, If I want to be critical it would have less clamping force due to less pad material contacting the rotor. Probably would work okay unless the pad material is worn all the way (I think this is what you were eluding to if I understood you correctly). Just makes me wonder about the overall final QA of the kit and the effective planning of it. Just wanted to know if others think this is still a good kit or if the defect in aligning/measuring the pad/rotor contact area would make you shy away from the kit. Quote Link to comment Share on other sites More sharing options...
Cal Poly Zmanaustin Posted February 22, 2006 Author Share Posted February 22, 2006 I think the object of that kits isn't really to improve braking (but it seems logical that the larger rotor would give graater leverage and could also spread the heat across a larger surface area), rather that kit is to allow people with big blinging wheels to fill some of the gap with some big blingin caliper That is kind of what I am wondering. I want function over appearance. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted February 22, 2006 Share Posted February 22, 2006 The master cylinder brace in that write up is truely laughable. He is trying to keep the firewall from flexing by pushing on the far end of an aluminum MC. The problem isn't the arc in the pad doesn't match the rotor. The problem is the caliper isn't mounted correctly on the rotor. Quote Link to comment Share on other sites More sharing options...
Cal Poly Zmanaustin Posted February 22, 2006 Author Share Posted February 22, 2006 The master cylinder brace in that write up is truely laughable. He is trying to keep the firewall from flexing by pushing on the far end of an aluminum MC. That was something else I was looking at (not for purchase) and wondering if I was ignorant. I kept thinking how can that do anything and if there is that much flex than that is the last place you would want it since it would crush the MC. I agree and this was my original question. I just wanted to make sure I was viewing it correctly. I can see where this could happen placing a caliper made for larger rotors onto a smaller rotor, but not vice versa. As the rotor increases in size the arc would be less gradual not more pronounced. That being the case it should line up fine. Makes me wonder if multiple sets had already been made and they are just trying to sell the kit with the inherent flaw. Quote Link to comment Share on other sites More sharing options...
2126 Posted February 22, 2006 Share Posted February 22, 2006 From the photos and explanations provide by the seller, it appears he is trying to off a poorly thought out and executed brake conversion. Don't waste your $$$. The M/C brace should give you some insight into the sellers mindset!!! It appears that the caliper mounting bracket demensions are a bit fat and have positioned the caliper/pads too far out....hence the untouch portion of pad material. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted February 22, 2006 Share Posted February 22, 2006 The master cylinder brace in that write up is truely laughable. He is trying to keep the firewall from flexing by pushing on the far end of an aluminum MC. I dunno about that, but there are several companies out there making these I think. Some people do claim it works. One person at zcar.com machines and polishes this style of brace and they look really nice. Who knows, maybe they have week firewalls? Mario Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 22, 2006 Share Posted February 22, 2006 Have you ever checked your firewall for flex? We ALL have weak firewalls... Quote Link to comment Share on other sites More sharing options...
johnc Posted February 22, 2006 Share Posted February 22, 2006 Earthing kit, poorly designed brake upgrade, and a bolt head pushing on the MC. Internet automotive engineering at its best! Quote Link to comment Share on other sites More sharing options...
Dan Baldwin Posted February 23, 2006 Share Posted February 23, 2006 That "fix" would be welcome on my 240! My M/C moves at least 1/8" with my foot hard on the pedal. This solution may appear crude, but should be effective. I hear tell a similar fix is very common on 914s/914-6s. Why they couldn't get the caliper bracket machined to correctly locate the caliper on the rotor is beyond me. I kind of like to use hardware that I KNOW has been proved by engineering analysis and testing, anyway. Quote Link to comment Share on other sites More sharing options...
kcelectronics Posted February 23, 2006 Share Posted February 23, 2006 If the caliper should fit a smaller disk than the arc insice the caliper is a smaller diameter! so if the caliper is fitted to a larger disk then the front and rear edges would be closer to the new larger disk causing the center (pads to be further out causing the pad problem see below. Quote Link to comment Share on other sites More sharing options...
fastzcars Posted February 23, 2006 Share Posted February 23, 2006 For person on a budget, That brake "kit" wouldn't be that bad. I would trust is better if the adapter was machined in steel though. As far as the placement of the caliper to the disc, you really can't get it any closer since because the pads where designed for a 10.8 inch disc and they'r installing them to a 12.8 disc. Quote Link to comment Share on other sites More sharing options...
Cal Poly Zmanaustin Posted February 23, 2006 Author Share Posted February 23, 2006 If the caliper should fit a smaller disk than the arc insice the caliper is a smaller diameter! so if the caliper is fitted to a larger disk then the front and rear edges would be closer to the new larger disk causing the center (pads to be further out causing the pad problem see below. That is what the designer of the kit is saying. When I asked him if he could correct his CAD drawing this was his response... "There isn't a way to correct for that given the way the bolt spacing works out - its not possible to get the caliper to sit much further "down" on the rotor." I looked at your drawing and I understand the issue, but I would have thought that would only happen if you go to a smaller rotor, not bigger. Since the radius is larger the curve is less pronounced and more gradual. I would think there are a few more mm left to correct. I am guessing the difference in the hub spacing was designed into the CAD drawing, but not the difference in radius' arc. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted February 23, 2006 Share Posted February 23, 2006 So you guys honestly think turning the MC into a structural, load bearing part of the chassis is a good idea? No one is worried about chassis flex causing a single point of failure in the braking system? Or what type of stresses that aluminum MC might experience in an accident? If the firewall flexs, why not run a support rod from the firewall itself to the fender? I would suggest a person on a budget would do better to spend his limited money on parts that are known to work. Not some poorly engineer collection of mismatched parts. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 23, 2006 Share Posted February 23, 2006 I'm not saying that the bolt head is the best solution for the firewall flex issue, just that we all have a firewall flex issue. I think the best thing would be a cage with a knee bar that had braces to the firewall on both sides of the master. If you don't have or want a cage, then you have to figure something else out. A bar from the front strut back to the firewall might work too. A PDK strut tower bar might also reduce that flexing with its braces to the firewall. I'm sure that the bolt head works as well. Not the best way to do it, but I'm sure it works. And for those worried about collapsing the master, I think you'd be far more likely to collapse the sheet metal brake booster than the aluminum master. Potential damage to the master or the booster depends on how much stress the master is handling, and how much gets transferred to the bolt head and the strut tower, but frankly I don't really see that being a huge issue, since they're designed to withstand you slamming your foot on it repeatedly forever. Was thinking about this, I have a CA car that has rust, but not a whole lot. Check out this thread on my cowl rust: http://forums.hybridz.org/showthread.php?t=106849 That's right above where the master bolts in. I'm betting the rust repair will help a lot, and I'm betting I'm not the only one with this problem... Quote Link to comment Share on other sites More sharing options...
bjhines Posted February 23, 2006 Share Posted February 23, 2006 My 1995 Toyota Land Cruiser does this to it's front pads...as they wear down they form a lip that overhangs the rotor....It bothered me at first... but it has never caused any problems... The brake system on my Land Cruiser is COMPLETELY STOCK... and it does this... If this problem bothers you... shave the outer portion of the pad down with a band saw...grinder... or a hack saw... Quote Link to comment Share on other sites More sharing options...
Dan Baldwin Posted February 24, 2006 Share Posted February 24, 2006 Trying to brace to the firewall would be problematic, once you get around the vac booster, you're pretty far removed from the line of action of the force on the piston. I don't like the bolt head in this particular instance, I'd rather see a spherical button, with maybe .015" static clearance. I would be surprised if the Z32 has enough firewall flex to warrant this. Like I said, I've only heard of it on 914s. A quick search yielded this GRM archive: http://www.grmotorsports.com/archives/914.html Holy crap, that's ugly! I would suggest a person on a budget would do better to spend his limited money on parts that are known to work. Not some poorly engineer collection of mismatched parts. I totally agree. You can get a HELL of a lot out of stock brakes with appropriate pads and fresh high-temp fluid. And if a brake setup has not been developed and tested by qualified automotive engineers, I wouldn't spend money only to find out the balance is ruined, or risk structural failure of a bracket or such. Generally I recommend against brake mods (other than pads and fluid). If a hp mod goes wrong, so what. If a BRAKE mod goes wrong.... Quote Link to comment Share on other sites More sharing options...
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