Just wondering why everyone uses different rotors that have to be drilled and hacked for the big brake upgrade when the 1999-2005 Jetta has 12" or the 13" upgraded rotors that are already 5x100? Are the rotor hats too deep to use for the Fiero?

I've wondered about this for the pre-05 subaru STI's as well. With a little custom bracketry a stock brembo setup from them would be a pretty slick upgrade.

I have the Audi TT setup sitting on my bench waiting for me to get a day to put them on the VR6 Fiero. There are some mods that will need to be done. The lug bolt holes are too big and need a ring welded to them or the hub to keep the disc in perfect alignment. Otherwise, the hub is perfect.
Dave

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www.hausofguru.com

I've got a set of used Audi TT rotors kicking around too just for measurements. I'm pretty sure they're 12" dia though, not 13". The offset of the rotor from the hub mounting surface is very shallow, something like 0.5" to 1.0". I'm not sure how you could make the right bracketry to mount a caliper with these. I'll post some pics later today.

They are roughly 12.5" inches. I plan on using the Audi calipers.
Dave

quote Originally posted by IMSA GT: Just wondering why everyone uses different rotors that have to be drilled and hacked for the big brake upgrade when the 1999-2005 Jetta has 12" or the 13" upgraded rotors that are already 5x100? Are the rotor hats too deep to use for the Fiero?

Excellent point. After surfing NAPA parts online which does the exceptional service of providing specs for the parts, I've found that the 2005 Subaru Impreza has probably the best options for making its brake parts a better swap than the Corvette's.

84-87 Fiero

Frt rotor ht: 3.41", Diameter: 9.68, Thickness: .44, hole diameter: 2.28
Rear rotor: 1.81, Diameter: 9.7, Thickness: .50, hole diameter: 2.28

2005 Subaru Impreza
Frt rotor ht: 2.23, Diameter: 11.54, Thickness: .950, hole diameter: 2.29
Rear rotor: 2.65, Diameter: 12.43, Thickness: .790, hole diameter: 2.29

Compared to the 88 Vette rotors if those are the ones used they'll move the caliper a little further away from the wheel as well as eliminate the need for a hub centric ring.

[This message has been edited by Joseph Upson (edited 07-25-2010).]

quote Originally posted by bmwguru: They are roughly 12.5" inches. I plan on using the Audi calipers. Dave

I'll be curious to see how you do that.

quote Originally posted by IMSA GT: Just wondering why everyone uses different rotors that have to be drilled and hacked for the big brake upgrade when the 1999-2005 Jetta has 12" or the 13" upgraded rotors that are already 5x100? Are the rotor hats too deep to use for the Fiero?

According to NAPA, the 12.3" rotors ( for an '04 Jetta ) are more likely too shallow. The height is listed as 1.35". But I have a few ideas not yet listed. I'll post if any pan out.

The '04 Jetta is a 5x112 bolt pattern if I remember correctly. The -'02 is 5x100.

The calipers need a spacer bracket similar to the lebaron brake upgrade to make them work. I have never worked on a Suburu, so I never thought to go in that direction. I think the best option for a brake upgrade are two piece rotors to keep the weight down, but that will drive the cost up.
Dave

I appreciate the input guys. I am just not a big fan of having a rotor look like swiss cheese with 10 holes drilled in them to adapt them to the Fiero. Although, from what I understand, none have ever failed, it just seems like such a weak point to remove that much metal from an item that is supposed to stop your vehicle.

quote Originally posted by IMSA GT: I appreciate the input guys. I am just not a big fan of having a rotor look like swiss cheese with 10 holes drilled in them to adapt them to the Fiero. Although, from what I understand, none have ever failed, it just seems like such a weak point to remove that much metal from an item that is supposed to stop your vehicle.

The clamping force resulting from the wheel being installed makes the extra holes irrelevant as it is unlikely that the bolt holes have any shearing load on them once the wheel is properly torqued given the amount of surface area the force is distributed over. Your concern would be more relevant for a dual bolt patterned aftermarket wheel which is subjected to more shear and leverage loads and are almost always aluminum for added weakness compared to a steel wheel.

bmwguru is correct about the two piece rotor which I was considering but the machine work that would go into modifying a stock rotor to accept some of the Coleman racing bolt on rotors plus the cost of the rotors made it unreasonable.

If the 2000 Impreza rear rotors will fit on the rear without interference from the permanent hard parts it is the most practical since its thickness is .030 less than the Fiero's rear rotor. The problem is that it is only a slight improvement in size at 10.47" in dia vs. the Fiero's 9.7".

If I recall correctly the Fiero's brake pad lining is not positioned at the maximum outer limit of the rotor surface which would provide a little more stopping leverage so in repositioning the stock caliper to take advantage of that fact with the Impreza rotor which I believe you can expect an appreciable improvement. The question is whether or not there is enough room for the rotor to be moved inward by a half inch which I doubt, leaving the thicker front rotors as the swap option and a caliper change as well.

[This message has been edited by Joseph Upson (edited 07-25-2010).]

Now that I have been under the car doing my suspension mods I got to see the brakes up close and personal. To say that they are lacking is an understatement. They are not even vented and the calipers are pretty weak....... I think a nice brake upgrade is on the horizon. SO won't you smart fellows hurry up and figure out a way to easily and cheaply build a better brake system..... !! There has gotta be a larger vented disc that is available for another car that will just bolt on and then a simple bracket to accept the appropriate caliper. I read thru the lebaron upgrade but it would be nice to have a truly bolt on setup..... keep up the good work guys!!! peace

The Grand AM brake upgrade is as close as truely "bolt-on" as you're going to get for the '84 - '87's. It's also significantly cheaper than if you were to replace the brake parts with stock Fiero.

quote Originally posted by Bloozberry: The Grand AM brake upgrade is as close as truely "bolt-on" as you're going to get for the '84 - '87's. It's also significantly cheaper than if you were to replace the brake parts with stock Fiero.

Agreed. I understand the allure and some benefits of these "big brake" upgrades, but the Grand Am upgrade on all 4 corners with drilled/slotted rotors and ceramic pads combined with the S10 booster upgrade is plenty for easy modulation and tire smoking lock ups if needed (not that you should need that.)

lebaron upgrades are available from vendors that are bolt on .the only thing that needs machining is the cutting off of the stock fiero front disc to turn it into a hub .or you could get a custom hub and drop spindle from people like street dreams by ross .he will also make hubs with the corvette bolt pattern too .archie , RCC ,west coast fiero and held motor sport all sell upgrade kits .