Brake bias issues
10-14-15, 04:00 PM
#26
Rotary Freak
Well, I don't think the OP will have to worry about premature brake lock up now. After about 3 laps, the front pads will be heat saturated and stop working. The rears should be as well by then. I don't know of anyone who has used the HPS or HP+ pads on track during a dry race and had good results. If you find they are working for you, I would suggest you aren't braking hard enough.
A decent race setup on my buddy's FB was Hawk Blues on the front and Blacks on the rear. He ducted to the front and rears and they worked well and lived a decent amount of time. He never complained about premature lock up.
Eric
A decent race setup on my buddy's FB was Hawk Blues on the front and Blacks on the rear. He ducted to the front and rears and they worked well and lived a decent amount of time. He never complained about premature lock up.
Eric
10-16-15, 09:09 PM
#27
Keep in mind this is a street driven car used for Track days and not full blown races. Twenty minute sessions on street tires would have to be generate less heat than a bonifide race car on slicks used for full length races.
Given, now that I've tried the HP + I would agree that the HPS pads have no place on the track, I will see how the HP + holds up next week end at AMP, if not I will step up once more till I find something that works for me and just switch over for track days then back again for the street.
Given, now that I've tried the HP + I would agree that the HPS pads have no place on the track, I will see how the HP + holds up next week end at AMP, if not I will step up once more till I find something that works for me and just switch over for track days then back again for the street.
10-19-15, 12:16 PM
#28
Update:
Well after driving the car some I was able to come to the following conclusions:
Firming up the shocks and lowering the rear have definitely helped, the brake hop has disappeared, even when the rears lock up first. Thank you mustanghammer.
And, installing the more aggressive pads just on the front fixed the bias issues, but like most systems, when you change one thing it affects others. In this case it made the brake peddle too sensitive. Before the peddle was very firm, which made it easier to heal toe, now when I heal toe the it causes enough variation of brake peddle pressure that the braking varies uncontrollably, makes controlling the braking impossible. So I have reinstalled the old pads until I can come upon a proper fix.
I think this means I need to install a master with a larger bore to firm up the peddle so the braking is more controllable when heal towing, so that is the long term plan, switch to a later year model master with the larger piston, and possibly an
aftermarket proportioning valve as suggested by Large Orange Font, although I am still curious about the function of the bypass valve in the stock prop valve
I have a track day this weekend and don't have the time for a proper fix so I am considering a band aid. I am thinking of reducing the area of the rear pads by trimming them back, just to get me through this last track day of the season, then going back during the off season and fixing the system properly.
What do you guys think? Stupid Idea?
Firming up the shocks and lowering the rear have definitely helped, the brake hop has disappeared, even when the rears lock up first. Thank you mustanghammer.
And, installing the more aggressive pads just on the front fixed the bias issues, but like most systems, when you change one thing it affects others. In this case it made the brake peddle too sensitive. Before the peddle was very firm, which made it easier to heal toe, now when I heal toe the it causes enough variation of brake peddle pressure that the braking varies uncontrollably, makes controlling the braking impossible. So I have reinstalled the old pads until I can come upon a proper fix.
I think this means I need to install a master with a larger bore to firm up the peddle so the braking is more controllable when heal towing, so that is the long term plan, switch to a later year model master with the larger piston, and possibly an
aftermarket proportioning valve as suggested by Large Orange Font, although I am still curious about the function of the bypass valve in the stock prop valve
I have a track day this weekend and don't have the time for a proper fix so I am considering a band aid. I am thinking of reducing the area of the rear pads by trimming them back, just to get me through this last track day of the season, then going back during the off season and fixing the system properly.
What do you guys think? Stupid Idea?
10-19-15, 01:46 PM
#29
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it sorta works. we've got a bunch of stuff like that in a box somewhere, theres a prop valve that has the big bolt replaced with a nut and bolt to make it adjustable, stuff like that.
plan B would be to drive it a little differently. maybe brake a little earlier, and less "jumping" on the pedal. it is possible, you could brake earlier, straighter, and then be braking less at turn in. one of the easy data logs to interpret is braking. our fast drivers brake pressure trace is basically square, high and short, and then there is a pause and then the accelerator goes WOT. so he brakes as hard and fast as possible, but he's also braking in a really short amount of time, then there is a release, and he doesn't hit the gas until it can be matted. compared to our slower driver the faster one brakes sooner, and his mid corner speed is the same or slower, but he's faster because he spent less time braking, and then he goes WOT faster, and for longer
oh and just to be pedantic, its a brake pedal. peddle is like; to sell.
plan B would be to drive it a little differently. maybe brake a little earlier, and less "jumping" on the pedal. it is possible, you could brake earlier, straighter, and then be braking less at turn in. one of the easy data logs to interpret is braking. our fast drivers brake pressure trace is basically square, high and short, and then there is a pause and then the accelerator goes WOT. so he brakes as hard and fast as possible, but he's also braking in a really short amount of time, then there is a release, and he doesn't hit the gas until it can be matted. compared to our slower driver the faster one brakes sooner, and his mid corner speed is the same or slower, but he's faster because he spent less time braking, and then he goes WOT faster, and for longer
oh and just to be pedantic, its a brake pedal. peddle is like; to sell.
Last edited by j9fd3s; 10-19-15 at 01:53 PM.
10-21-15, 10:43 AM
#31
The HPS pads were so crappy you could get away with slamming on the pedal anywhere because they had no feel or bite. When you jump on the brakes with HP+ pads you get a ton of bite and feel which you are not used to.
I am glad you are headed in the right direction, but still get a full disc brake MC and prop valve setup on the car. A larger MC will help you. I put a larger 929 master and booster on my FC and am very happy with the change.
10-21-15, 11:04 AM
#32
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we've tried a few different pads over the years, and the drivers go for feel/modulation over just about everything else.
10-23-15, 09:28 PM
#33
Glad the shock settings worked for.
While I have had street brake pads that felt spongy this is not a PSI issue. The newer pads have better initial bite on the rotor.
It really seems like the new pads are providing improved braking. Once you get used to them and learn how to utilize the improvement, you'll be faster.
Peddle....usually I see "breaks" and have to shake my head!
Keep us posted on your results
While I have had street brake pads that felt spongy this is not a PSI issue. The newer pads have better initial bite on the rotor.
It really seems like the new pads are providing improved braking. Once you get used to them and learn how to utilize the improvement, you'll be faster.
Peddle....usually I see "breaks" and have to shake my head!
Keep us posted on your results
10-24-15, 10:11 AM
#34
Glad the shock settings worked for.
While I have had street brake pads that felt spongy this is not a PSI issue. The newer pads have better initial bite on the rotor.
It really seems like the new pads are providing improved braking. Once you get used to them and learn how to utilize the improvement, you'll be faster.
Peddle....usually I see "breaks" and have to shake my head!
Keep us posted on your results
While I have had street brake pads that felt spongy this is not a PSI issue. The newer pads have better initial bite on the rotor.
It really seems like the new pads are providing improved braking. Once you get used to them and learn how to utilize the improvement, you'll be faster.
Peddle....usually I see "breaks" and have to shake my head!
Keep us posted on your results
10-25-15, 11:58 AM
#35
My track day at AMP was good. Plan B worked well. As long as I was smooth with the original application of the brake I could still end up standing on the pedal hard without total rear lock up and by the end of the day could even turn in with a little brake, creating a momentary and subtle oversteer that I could control into the apex and then accelerate from there. I had a very good day and ran down some very fast cars, granted with slow drivers, but fun to do anyway!!
The only down side is that I could tell some other cars were out braking me, letting me know that my setup was not getting enough braking out of the fronts.
Any way I am considering what direction to go for the final remedy.
I sought out the local brake expert at the track who happen to be in his 240Z race car with brake upgrades that were similar to mine. He is an engineer and had tried many various setups to give the right balance.
He is steering me in the direction of double masters with a balance bar. I am considering this as other solutions seem to me to be experiments, and the double masters, with a little tweaking of master bore should work very well, with less guess work.
My concern is how such a setup would work for the street, can I find a pad that will do double duty? Some of these newer compounds you guys have experience with makes it sound doable.
What do you guys think?
and btw, thanks for your help!!! I have driven this car for years and done a lot of autocrossing, but the track thing is relative new to me, been doing it about a year and a half now and am just now getting to the point that I am not totally ham fisted, and with the higher level of driving I am uncovering issues, such as these brakes, and I am having a ball, not only with the driving but with engineering solutions for the problems, so once again THANKS!!!
Now off to figure a fix for fuel starvation under braking for Weber 36 DCDs!
The only down side is that I could tell some other cars were out braking me, letting me know that my setup was not getting enough braking out of the fronts.
Any way I am considering what direction to go for the final remedy.
I sought out the local brake expert at the track who happen to be in his 240Z race car with brake upgrades that were similar to mine. He is an engineer and had tried many various setups to give the right balance.
He is steering me in the direction of double masters with a balance bar. I am considering this as other solutions seem to me to be experiments, and the double masters, with a little tweaking of master bore should work very well, with less guess work.
My concern is how such a setup would work for the street, can I find a pad that will do double duty? Some of these newer compounds you guys have experience with makes it sound doable.
What do you guys think?
and btw, thanks for your help!!! I have driven this car for years and done a lot of autocrossing, but the track thing is relative new to me, been doing it about a year and a half now and am just now getting to the point that I am not totally ham fisted, and with the higher level of driving I am uncovering issues, such as these brakes, and I am having a ball, not only with the driving but with engineering solutions for the problems, so once again THANKS!!!
Now off to figure a fix for fuel starvation under braking for Weber 36 DCDs!
Last edited by rwatson5651; 10-25-15 at 12:07 PM.
10-25-15, 12:51 PM
#36
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JGrewe has posted the dual master sizes...
10-26-15, 07:12 AM
#37
Rotary Freak
My track day at AMP was good. Plan B worked well. As long as I was smooth with the original application of the brake I could still end up standing on the pedal hard without total rear lock up and by the end of the day could even turn in with a little brake, creating a momentary and subtle oversteer that I could control into the apex and then accelerate from there. I had a very good day and ran down some very fast cars, granted with slow drivers, but fun to do anyway!!
The only down side is that I could tell some other cars were out braking me, letting me know that my setup was not getting enough braking out of the fronts.
Any way I am considering what direction to go for the final remedy.
I sought out the local brake expert at the track who happen to be in his 240Z race car with brake upgrades that were similar to mine. He is an engineer and had tried many various setups to give the right balance.
He is steering me in the direction of double masters with a balance bar. I am considering this as other solutions seem to me to be experiments, and the double masters, with a little tweaking of master bore should work very well, with less guess work.
My concern is how such a setup would work for the street, can I find a pad that will do double duty? Some of these newer compounds you guys have experience with makes it sound doable.
What do you guys think?
and btw, thanks for your help!!! I have driven this car for years and done a lot of autocrossing, but the track thing is relative new to me, been doing it about a year and a half now and am just now getting to the point that I am not totally ham fisted, and with the higher level of driving I am uncovering issues, such as these brakes, and I am having a ball, not only with the driving but with engineering solutions for the problems, so once again THANKS!!!
Now off to figure a fix for fuel starvation under braking for Weber 36 DCDs!
The only down side is that I could tell some other cars were out braking me, letting me know that my setup was not getting enough braking out of the fronts.
Any way I am considering what direction to go for the final remedy.
I sought out the local brake expert at the track who happen to be in his 240Z race car with brake upgrades that were similar to mine. He is an engineer and had tried many various setups to give the right balance.
He is steering me in the direction of double masters with a balance bar. I am considering this as other solutions seem to me to be experiments, and the double masters, with a little tweaking of master bore should work very well, with less guess work.
My concern is how such a setup would work for the street, can I find a pad that will do double duty? Some of these newer compounds you guys have experience with makes it sound doable.
What do you guys think?
and btw, thanks for your help!!! I have driven this car for years and done a lot of autocrossing, but the track thing is relative new to me, been doing it about a year and a half now and am just now getting to the point that I am not totally ham fisted, and with the higher level of driving I am uncovering issues, such as these brakes, and I am having a ball, not only with the driving but with engineering solutions for the problems, so once again THANKS!!!
Now off to figure a fix for fuel starvation under braking for Weber 36 DCDs!
The reason I am asking is that there are so many other things to do to maximize your braking performance before you throw parts at a car. It may be my history of coming from showroom stock and World Challenge style racing, but the stock brake setup can be made to work extremely well and usually is only a problem when you exceed the heat shedding capabilities of the rotor, hub and calipers. If you are not melting seals, then you aren't exceeding the thermal capacity of the setup. That means the rest comes down to setup. Setup includes Front to Rear brake bias, pressures, alignment settings and tire size and grip. Sometimes if you are tire limited then you need to adjust the camber to maintain a flatter front tire contact patch and sacrifice some potential cornering grip for braking grip. If you aren't, then go grippier or wider until you exceed the braking capability of the front caliper and rotors. Also, In my opinion, unless you have huge front rotors and large calipers, there is no such thing as a dual duty brake pad. If you are able to drive around all day long with a under 12" front rotor and a pad that works on the street, then you aren't going hard enough. If you are exceeding the heat shedding capabilities of your front rotors or fading the pads (exceeding their capabilities) then you need to go to a higher heat stable material and more ducting. Only after you grossly exceed the capabilities of the stock setup, should you look at upgrading.
My race RX7 has won many races, has finished first in class in the last 2 years 3 Hour Enduro's at Mosport, set the overall 3rd fastest race lap in the 2015 race, runs on slicks and 15x7 inch rims and still uses the stock single piston, single master, non vented rotor setup from a standard 1988 RX7. The brakes work great and with careful pad management, the brakes last hours with no issues. I am just trying to say that sometimes if you think intelligently about the situation and adjust your driving a bit, your setup a bit and watch the wear, you don't need to spend cubic dollars on rebuilding something that works absolutely fine.
Eric
10-26-15, 09:20 AM
#38
if you think intelligently about the situation and adjust your driving a bit, your setup a bit and watch the wear, you don't need to spend cubic dollars on rebuilding something that works absolutely fine
To your question about getting out braked it was from watching cars close in on me at the end of the longest straight. Prior to the braking zone I would have four or five car lengths on them that would go away. They were braking later and harder than I was. Keep in mind that I was trying to be smooth because I definitely have a brake bias problem and if I brake harder the rears lockup. More evidence came when I examined the video I took with my new iphone app that gives g force information. The braking g s appeared to be modest to me. The reading were in the .5 range. I not sure but I think I should be able to have much greater deceleration than that. I had to be careful not to get too much rear lock up. The last time it happened I was in way too hot and had no choice but to brake as hard as I could and I got severe brake hop that bent my rear end housing. I also was concerned about losing the rear end and trying out the gravel pit, so I was intentionally braking a little early and trying to be smooth. I eventually got to where I was consistently able to brake with the rears beginning to lock up but I was still not getting the braking I think the car is capable of. Also I spoke to the other drivers who told me about how they were braking much later than I.
So the whole issue to me is fixing my bias problem. It is of my own making cause I upgraded my brakes to a non stock setup so Im having to come up with a master / prop valve combination that will give me a better balance. I had no choice but to upgrade somehow has the stock SA setup was so bad that It would never handle anything beyond modest auto cross use. Here is a link to my brake setup:
https://www.rx7club.com/1st-generati...twist-1029145/
The bore sizes on this setup are identical to a turbo II setup and the 3rd gen brakes (I think) so Im thinking I can use a proportioning valve from a turbo II car , or go with the dual master setup.
I don't enjoying wasting money, but if I have to spend some to get this right I will.
Last edited by rwatson5651; 10-26-15 at 09:22 AM.
10-26-15, 09:54 AM
#39
Rotary Freak
Why don't you just add an in car adjustable brake bias valve? This has been used on many many race cars and street cars to adjust the rear brake pressure to a point that make sense to you. You can do it in car while driving as the point that you need to pick will change depending on temps, tire types and weather. I have them on both cars and use it a fair bit. My Cougar has the balance bar set up and 2 masters and I adjust the balance bar to get the better braking effect, but I use the adjustable bias valve to set the max braking effort to the rear brake circuit. Think of it as a manual bias valve. Good ones are just over $100, easy to plumb in and you can play with it from where you are right now to a point where you like the rear braking effect.
After you install it into the rear pressure line, it splices in, you can set it at wide open then slowly restrict the flow to the rear until you get to a point that works for you on that day. Its not rocket science at all and most race cars have them as you need something that can adjust to the different rear loading as the fuel runs out. I use it and the balance bar, all the time in my Cougar to effect maximum braking effect as the fuel and track conditions change in longer races.
If you look at the attached picture, the blue **** is the balance adjuster, there is a small **** between the blue adjuster and the seat where I can adjust the pressure. The black gated **** is for the in-car adjustable bars that the Cougar has.
Eric
After you install it into the rear pressure line, it splices in, you can set it at wide open then slowly restrict the flow to the rear until you get to a point that works for you on that day. Its not rocket science at all and most race cars have them as you need something that can adjust to the different rear loading as the fuel runs out. I use it and the balance bar, all the time in my Cougar to effect maximum braking effect as the fuel and track conditions change in longer races.
If you look at the attached picture, the blue **** is the balance adjuster, there is a small **** between the blue adjuster and the seat where I can adjust the pressure. The black gated **** is for the in-car adjustable bars that the Cougar has.
Eric
10-26-15, 09:57 AM
#40
Rotary Freak
Oh and yes, I was one of the 7 people who purchased the Platinum coloured harness that Racequip were selling.... I thought that they would look cool and not LAVENDER!!!!!!!
Eric
Eric
10-26-15, 10:47 AM
#41
That's where I am now, trying to evaluate my situation so I can go in the right direction. Don't want to go off half cocked and waste time and money.
To your question about getting out braked it was from watching cars close in on me at the end of the longest straight. Prior to the braking zone I would have four or five car lengths on them that would go away. They were braking later and harder than I was. Keep in mind that I was trying to be smooth because I definitely have a brake bias problem and if I brake harder the rears lockup. More evidence came when I examined the video I took with my new iphone app that gives g force information. The braking g s appeared to be modest to me. The reading were in the .5 range. I not sure but I think I should be able to have much greater deceleration than that. I had to be careful not to get too much rear lock up. The last time it happened I was in way too hot and had no choice but to brake as hard as I could and I got severe brake hop that bent my rear end housing. I also was concerned about losing the rear end and trying out the gravel pit, so I was intentionally braking a little early and trying to be smooth. I eventually got to where I was consistently able to brake with the rears beginning to lock up but I was still not getting the braking I think the car is capable of. Also I spoke to the other drivers who told me about how they were braking much later than I.
So the whole issue to me is fixing my bias problem. It is of my own making cause I upgraded my brakes to a non stock setup so Im having to come up with a master / prop valve combination that will give me a better balance. I had no choice but to upgrade somehow has the stock SA setup was so bad that It would never handle anything beyond modest auto cross use. Here is a link to my brake setup:
https://www.rx7club.com/1st-generati...twist-1029145/
The bore sizes on this setup are identical to a turbo II setup and the 3rd gen brakes (I think) so Im thinking I can use a proportioning valve from a turbo II car , or go with the dual master setup.
I don't enjoying wasting money, but if I have to spend some to get this right I will.
To your question about getting out braked it was from watching cars close in on me at the end of the longest straight. Prior to the braking zone I would have four or five car lengths on them that would go away. They were braking later and harder than I was. Keep in mind that I was trying to be smooth because I definitely have a brake bias problem and if I brake harder the rears lockup. More evidence came when I examined the video I took with my new iphone app that gives g force information. The braking g s appeared to be modest to me. The reading were in the .5 range. I not sure but I think I should be able to have much greater deceleration than that. I had to be careful not to get too much rear lock up. The last time it happened I was in way too hot and had no choice but to brake as hard as I could and I got severe brake hop that bent my rear end housing. I also was concerned about losing the rear end and trying out the gravel pit, so I was intentionally braking a little early and trying to be smooth. I eventually got to where I was consistently able to brake with the rears beginning to lock up but I was still not getting the braking I think the car is capable of. Also I spoke to the other drivers who told me about how they were braking much later than I.
So the whole issue to me is fixing my bias problem. It is of my own making cause I upgraded my brakes to a non stock setup so Im having to come up with a master / prop valve combination that will give me a better balance. I had no choice but to upgrade somehow has the stock SA setup was so bad that It would never handle anything beyond modest auto cross use. Here is a link to my brake setup:
https://www.rx7club.com/1st-generati...twist-1029145/
The bore sizes on this setup are identical to a turbo II setup and the 3rd gen brakes (I think) so Im thinking I can use a proportioning valve from a turbo II car , or go with the dual master setup.
I don't enjoying wasting money, but if I have to spend some to get this right I will.
I left my prop valve under the hood for a simpler setup.
Last edited by LargeOrangeFont; 10-26-15 at 10:50 AM.
10-26-15, 11:29 AM
#42
You know what, I'm going to do just that. I have thought about it till my head hurt and I have decided to rely on your experience. The only additional change I shall make is going to a larger bore master cylinder so I can have a firmer pedal with pads that have more bite than the wimpy street pads that I have ran in the past. I will have to decide on which of the newer pads to install that will have better bite than the HPS pads I have now, and are not as rough on the rotors as the HP Plus pads that I have tried recently.
Do you have a recommendation on a brand for the proportioning valve?
Do you have a recommendation on a brand for the proportioning valve?
10-26-15, 12:27 PM
#43
Rotary Freak
You know what, I'm going to do just that. I have thought about it till my head hurt and I have decided to rely on your experience. The only additional change I shall make is going to a larger bore master cylinder so I can have a firmer pedal with pads that have more bite than the wimpy street pads that I have ran in the past. I will have to decide on which of the newer pads to install that will have better bite than the HPS pads I have now, and are not as rough on the rotors as the HP Plus pads that I have tried recently.
Do you have a recommendation on a brand for the proportioning valve?
Do you have a recommendation on a brand for the proportioning valve?
Eric
10-26-15, 01:53 PM
#44
My research says, and my understanding is that a larger bore master will give a firmer pedal with less absolute braking capability and a smaller bore will give a less firm pedal with more absolute braking capability. Braking capability meaning more PSI in the hydraulics.
The master in it now is the stock one, which is the smallest bore ever on a Rx-7, and also it was originally a drum brake car so I'd like to get rid of it and get one that will yield a firmer pedal.
The master in it now is the stock one, which is the smallest bore ever on a Rx-7, and also it was originally a drum brake car so I'd like to get rid of it and get one that will yield a firmer pedal.
10-26-15, 02:56 PM
#46
You know what, I'm going to do just that. I have thought about it till my head hurt and I have decided to rely on your experience. The only additional change I shall make is going to a larger bore master cylinder so I can have a firmer pedal with pads that have more bite than the wimpy street pads that I have ran in the past. I will have to decide on which of the newer pads to install that will have better bite than the HPS pads I have now, and are not as rough on the rotors as the HP Plus pads that I have tried recently.
Do you have a recommendation on a brand for the proportioning valve?
Do you have a recommendation on a brand for the proportioning valve?
I would do the Flyin Miata prop valve kit (it is what I used). It comes with the generic Wilwood prop valve and the standard to metric conversion fittings. I used premade metric brake lines from the auto parts store to replumb from the master to the valve, and that was it.
https://www.flyinmiata.com/complete-...oning-kit.html
Last edited by LargeOrangeFont; 10-26-15 at 02:59 PM.
10-26-15, 04:50 PM
#47
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10-26-15, 08:03 PM
#49
Absolutely do the larger master, just be aware of the port configuration. On the 929 MS I used, it only had one fort for the front brakes, so I had to get the dual banjo fitting you see in the picture. The FC master cylinders have 2 front ports.
I would do the Flyin Miata prop valve kit (it is what I used). It comes with the generic Wilwood prop valve and the standard to metric conversion fittings. I used premade metric brake lines from the auto parts store to replumb from the master to the valve, and that was it.
https://www.flyinmiata.com/complete-...oning-kit.html
I would do the Flyin Miata prop valve kit (it is what I used). It comes with the generic Wilwood prop valve and the standard to metric conversion fittings. I used premade metric brake lines from the auto parts store to replumb from the master to the valve, and that was it.
https://www.flyinmiata.com/complete-...oning-kit.html
I will do research to try to guesstimate what diameter bore to try first.
My heal toe style is probably unorthodox as I brake with my heal (read stand on the pedal with all I've got) and throttle with my toe and it all works best with a very firm pedal. I've been doing it this way for so many years that I shant try to change now, so I will probably go with as large a bore as I can find to start, if I have to trial and error the size I will. I have found willwood prop valves that come with 10 x 1 mm threads eliminating the need for adapters AND they even have one configured to split the front line so I can use a two port MC if I need to without adapters, giving a neat install hopefully.
I am more concerned with the mounting lugs. It will be easier if I can find a large bore MC with lugs at 12 and 6 rather than 6 and 9. If I can it may bolt right onto my booster, easy peasy. I remember seeing some threads about the different possibilities, I will search. The largest MC I have found so far with vertical lugs has a 7/8 in bore, do you guys think this is big enough? All the FC cylinders are larger (maybe 15/16 ?) but have horizontal lugs that will not bolt up. I will continue to search.
10-27-15, 09:11 AM
#50
You may want to change the booster along with the MC if feasible. I do not know what the FB booster mounting pattern looks like. If it is the same as the newer Mazdas, this gets very easy. When I swapped mine I put in a 929 booster as well as the MC. The 929 MC is 1 inch. The FC, 929, FD all have the same mounting setup, as well as many others.
Subaru has some 1 1/16 MCs that bolt right on to the Mazda boosters with horizontal mounts.
Clockker on this forum has posted tons of information about the MC and booster swaps.
Subaru has some 1 1/16 MCs that bolt right on to the Mazda boosters with horizontal mounts.
Clockker on this forum has posted tons of information about the MC and booster swaps.