Best modern braking system upgrade? (Page 3/4)
skywurz OCT 31, 07:06 AM
Does your track not have a long exit for the 1/4? I've not had issues slowing down from those speeds in a straight line unless the headlights popped up and dropped unevenly.

Where did op go? Started a best oil debate and ran

[This message has been edited by skywurz (edited 10-31-2020).]

theogre OCT 31, 04:38 PM
84-87 Fiero Brake Bias has Little to Nothing to do w/ the Prop-valve unless you're Panic Stopping or close to it all the time.
Most Bias for daily driving is "Hard Bias" built into the system's hydro for Fiero w/ different piston diameter.
Unlike most others even today have "Hard Bias" w/ different hydro and mechanics w/ smaller "weaker" pads etc on rear as said in the cave "upgrade" page.

If you run out of shut off space at Drag track very likely something is wrong w/ the car, the track, or maybe both.
Examples:
  • Pads could drag for several reasons and heat up cause "Fade" problems. Doesn't help for low time for a run either. Big engine and low gearing can hind brake problems more easily.
  • "Cheap" pads may out gas stopping at high speeds and cause true Fade problems even when not overheated. This is partly why Drilled/Slotted rotors were made but that has large problems and not needed by most pads even in the 80's and not recommended by Wilwood and other real Engineers.
  • If Fiero rear brake have piston problems or you're dumb enough to "Power Brake" to spin the rear wheels then often the Rear brakes get hot or overheat and worse often Glaze the pads and do very little or nothing after. Glazing problem is close to Fade problem but Doesn't go away when brakes are cool/cold. Front brakes dragging pads can have same Glaze problems. You might be able to sand/grind the pads to remove Glazing but not a good idea for many reasons. (Brake Dust doesn't have Asbestos now but still can hurt you and more. Is Why some states and others restrict Copper etc in pads/shoes. see https://www.counterman.com/...ppearing-brake-pads/ )

    Some Tracks have problems but not getting into that.
    1 Quick Example: Driving over X speeds and/or < Y seconds put many "Street cars" in another Class w/ more rules how the car is built, safety equipment required, etc. but some tracks ignore that w/o NHRA etc in town. Or NHRA etc won't use a track at all like F1 etc left Watkins Glen many years ago then went bankrupt because of many big problems there. (Not only the track was in very poor shape at that time.)
    • DimeMachine NOV 01, 07:52 AM

    quote
    Originally posted by skywurz:

    Does your track not have a long exit for the 1/4? I've not had issues slowing down from those speeds in a straight line unless the headlights popped up and dropped unevenly.

    Where did op go? Started a best oil debate and ran




    Yes, there is a short and a long one. It shuts down fine using the longer exit - but clearly could be better. Might be in my head, I also take my C5 there and perhaps I am contrasting the how much more confident the C5 stops from 130 than the Fiero does from 115. It also sticks in my mind that you don't see too many cars with solid rotors at the track (or on the street even).

    P.S. 1. At the starting line I do a very short screech in the Fiero to clean of the rear tires (not heat them up) so the rotors are leaving the starting line at room temp.
    P.S. 2. I am seriously considering the 4 wheel GA setup with larger master to make up for the larger volume of fluid to move the larger caliper pistons and keep my larger S10 booster. If anyone could tell me specifically what they find hackish about it I would appreciate it. The rear seems solid - direct bolt on. I do have some concerns about having the front rotor perfectly centered on the Fiero hub as that part does seem like it could be an issue to me. From those that have the front GA set up - have you had any issues with the GA roter being perfectly centered on the fiero brake "modified hub"?

    Thanks Guys!!

    ------------------
    84/87 NB, 3800SC, E-85, VS Cam, 2.8 Pulley, 4T65E-HD, HP Tuners, AEM Wideband, Regal GS Gauges, S-10 Brake Booster. 1/4 mile -11.85 at 114mph

    [This message has been edited by DimeMachine (edited 11-01-2020).]

    pmbrunelle NOV 01, 09:23 AM

    quote
    Originally posted by DimeMachine:
    If anyone could tell me specifically what they find hackish about it I would appreciate it.



    No parking brake is pretty hackish. That's about it in my book.


    quote
    Originally posted by DimeMachine:
    I do have some concerns about having the front rotor perfectly centered on the Fiero hub as that part does seem like it could be an issue to me.



    On most cars, the hub has a small-diameter (57.1 mm in the case of Fiero) stub protruding outwards. This is used to pre-center the wheels before the lug nuts are tightened.

    In cars with divorced discs (or drums), the disc or drum is also centered on the stub before it is sandwiched in place by the wheel.

    The modification done to the Fiero rotor is to part off the braking surface on the periphery. The centering stub remains factory, and therefore, centering of the GA rotor remains as per a factory install.

    I don't remember if the Fiero stub is long enough to pre-center the wheel once the thickness of an additional rotor hat has been added. Personally, I don't find the pre-centering of the wheel to be a strict requirement, since you can center via the tapered-seat lug nuts, but the most detail-oriented car modders will consider the loss of wheel pre-centering to be hackish. This obviously will depend on the wheel you choose; some have bigger chamfers than others.
    DimeMachine NOV 01, 10:09 AM

    quote
    Originally posted by pmbrunelle:


    On most cars, the hub has a small-diameter (57.1 mm in the case of Fiero) stub protruding outwards. This is used to pre-center the wheels before the lug nuts are tightened.

    In cars with divorced discs (or drums), the disc or drum is also centered on the stub before it is sandwiched in place by the wheel.

    The modification done to the Fiero rotor is to part off the braking surface on the periphery. The centering stub remains factory, and therefore, centering of the GA rotor remains as per a factory install.

    I don't remember if the Fiero stub is long enough to pre-center the wheel once the thickness of an additional rotor hat has been added. Personally, I don't find the pre-centering of the wheel to be a strict requirement, since you can center via the tapered-seat lug nuts, but the most detail-oriented car modders will consider the loss of wheel pre-centering to be hackish. This obviously will depend on the wheel you choose; some have bigger chamfers than others.



    Thanks for your response!

    In MN, due to rust, most of the fiero's brake cables corroded stuck years ago and almost nobody has a working parking brake. Plus I live in a flat area, the car is an auto and this is a toy for me so I don't care about the PB. If I lived in a state that deemed my car not roadworthy due to a bad parking brake, that would be a deal breaker for sure.

    Not talking about the wheel centering - I totally get what you are saying about the tapered lug nuts doing that. Seems like it might be possible for the GA rotor to not be perfectly centered as the holes on the studs allow it to move around a touch prior to tightening the wheel. This is the area of concen in my mind that I want worked out prior to pulling the trigger $$$
    skywurz NOV 01, 10:25 AM

    quote
    Originally posted by DimeMachine:


    Yes, there is a short and a long one. It shuts down fine using the longer exit - but clearly could be better. Might be in my head, I also take my C5 there and perhaps I am contrasting the how much more confident the C5 stops from 130 than the Fiero does from 115. It also sticks in my mind that you don't see too many cars with solid rotors at the track (or on the street even).

    P.S. 1. At the starting line I do a very short screech in the Fiero to clean of the rear tires (not heat them up) so the rotors are leaving the starting line at room temp.
    P.S. 2. I am seriously considering the 4 wheel GA setup with larger master to make up for the larger volume of fluid to move the larger caliper pistons and keep my larger S10 booster. If anyone could tell me specifically what they find hackish about it I would appreciate it. The rear seems solid - direct bolt on. I do have some concerns about having the front rotor perfectly centered on the Fiero hub as that part does seem like it could be an issue to me. From those that have the front GA set up - have you had any issues with the GA roter being perfectly centered on the fiero brake "modified hub"?

    Thanks Guys!!



    I had a z06 C5... The Fiero will never be a Corvette. You could swap the brakes engine trans body it will still be a Fiero.

    Honestly the stability control in the C5 saved me a couple times but really didn't make me a better driver. It made me a lazy less respectful (of the machine) driver.

    Learn the car you are driving and make sure the equipment you have currently is functioning. Thats my advice.
    pmbrunelle NOV 01, 11:17 AM

    quote
    Originally posted by DimeMachine:
    Not talking about the wheel centering - I totally get what you are saying about the tapered lug nuts doing that. Seems like it might be possible for the GA rotor to not be perfectly centered as the holes on the studs allow it to move around a touch prior to tightening the wheel.



    Slip-on brake rotors are centered by the stub on the hub; the same stub that centers the wheels. Sometimes the stub is stepped with two different diameters.

    Rotors are NOT centered by the lug studs. The holes need to be big enough to let the studs pass through, but that's about it. The brake rotor holes can be drilled in an imprecise manner, and that's fine.

    I was assuming that the GA rotor has a precise slide-fit on the Fiero rotor stub. If that's not the case, I'd be shocked that people do this... that would be really hackish.

    If there is a gap between the stub and rotor hole, this could be rectified with a Speedi-Sleeve:
    https://www.realfierotech.c...a66c840ffee0#p159322
    https://www.skf.com/ca/en/p...es/skf-speedi-sleeve

    A good machinist could be handed Fiero rotors, GA rotors, and told to make the two fit each other, with machining for a Speedi-Sleeve if necessary.

    [This message has been edited by pmbrunelle (edited 11-01-2020).]

    fieroguru NOV 01, 03:11 PM

    quote
    Originally posted by pmbrunelle:


    Slip-on brake rotors are centered by the stub on the hub; the same stub that centers the wheels. Sometimes the stub is stepped with two different diameters.

    Rotors are NOT centered by the lug studs. The holes need to be big enough to let the studs pass through, but that's about it. The brake rotor holes can be drilled in an imprecise manner, and that's fine.

    I was assuming that the GA rotor has a precise slide-fit on the Fiero rotor stub. If that's not the case, I'd be shocked that people do this... that would be really hackish.

    If there is a gap between the stub and rotor hole, this could be rectified with a Speedi-Sleeve:
    https://www.realfierotech.c...a66c840ffee0#p159322
    https://www.skf.com/ca/en/p...es/skf-speedi-sleeve

    A good machinist could be handed Fiero rotors, GA rotors, and told to make the two fit each other, with machining for a Speedi-Sleeve if necessary.




    The issue is most hubs (including the 84-87 rear and 88 front hubs) have 2 pilots, a slightly larger one for the rotor and a slightly smaller one for the wheel. For FIeros and Grand Ams the rotor pilot is 0.71mm or 0.20" larger than the wheel pilot.

    Since the 84-87 front hubs never had slip on rotors, they do not have the slightly larger rotor pilot, just the smaller wheel pilot. This means that all brake kits designed for the 84-87s should have different concentric rings for the front vs. the rear. In regards to the grand am, there isn't room for concentric rings so when you install the rotor there ends up being 0.020" more sloppiness than the rear.

    One method to reduce the sloppiness is to get some 0.010" shim stock and cut it in a 1/4" strip and insert it between the rotor and the wheel pilot area.

    [This message has been edited by fieroguru (edited 11-01-2020).]

    Will NOV 02, 09:07 AM

    quote
    Originally posted by fieroguru:

    The issue is most hubs (including the 84-87 rear and 88 front hubs) have 2 pilots, a slightly larger one for the rotor and a slightly smaller one for the wheel. For FIeros and Grand Ams the rotor pilot is 0.71mm or 0.20" larger than the wheel pilot.

    Since the 84-87 front hubs never had slip on rotors, they do not have the slightly larger rotor pilot, just the smaller wheel pilot. This means that all brake kits designed for the 84-87s should have different concentric rings for the front vs. the rear. In regards to the grand am, there isn't room for concentric rings so when you install the rotor there ends up being 0.020" more sloppiness than the rear.

    One method to reduce the sloppiness is to get some 0.010" shim stock and cut it in a 1/4" strip and insert it between the rotor and the wheel pilot area.




    And the wheel pilot bores typically have a lead-in chamfer that results in little to no contact between the wheel pilot journal and the wheel pilot bore when the journal is shorter due to adding the brake rotor.
    Squall86GT NOV 05, 05:59 PM
    I am replacing my rear calipers. Is there a such thing as a plug-and-play new set of rear calipers that is slightly better breaking power than stock?