Sirion M100 Brake pad upgrade

#1

Hi there, im currently swapping my L700 to be powered by a k3ve2. So ill also swap the brakes.
Point is last time i drove on track i had allot of brake fade due to overheating of my brake pads.
So on my new sirion brakes i want track oriented brake pads.
I cant find any online, ferodos, ebc nothing.
I hope that someone here has encountered the same issue and found a fix for it :smiley:

#2

do you mean you got fade from the L700 brakes?
The k3ve2 version brakes are pretty good on an L700!

I think i last got ferodo
But havent hammered them on the track

If you want heaps of options then go for the YRV k3vet issues versions
Or also issued with the L880k Copen
then you can get copen pads to match - and they’re a step up again

But you will need to run 14" wheels which are much more a stretch on the L7 guards

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#3

Patrick has some good info in the post above. Only thing I can add is that I have used the Ferodo racing pads on track and experienced no fade with them.

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#4

Yes, i had fade with the L700 brakes.
The disks from the sirion are vented wich should help.
Youre saying that the brakepads from a YRV fit the sirion caliber? Or do i need the calibers from the YRV?
And could i upgrade the rear drums?
Btw already running 14" BMW E30 wheels with a 35 offset. Rolled the fenders out a bit.
But thanks for the quick reply already!

#5

YRV and Copen breaks have bigger rotors and slightly different calipers vs m100. You would have to remove the dust shield to fit them, but, otherwise they would just bolt up.

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#6

There are plenty from yahoo auctions japan.
Just make sure from the manufactures websites that the part #'s match up and then you should be good to go.

There are various 3rd parties to purchases from the auctions like Buyee.com etc etc.

There are several track orientated Project Mu pads for example.

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#7

My experience is that they can do with more rear brake bias too. Bigger rear slave cylinders will give more power. However, you might just find you go deeper under brakes and still end up with heat problems. Rear discs and the K3 fronts are fantastic. I also run an adjustable bias valve (went to a single brake line to the rear).

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#8

Awesome guys! Thanks for the great help.
What rear disc brakes fit on a L700?

#9

Here one grabs Applause caliper brackets, rear disc and caliper. Then get a Charade rear drum with integral bearing. Machine off the drum while leaving the flange to mount disc/wheel. Swap the inner bearings. Hub sans drum goes back on and applause disc goes over the drumless flange (note: caliper gets spaced out from the bracket about 10mm). Caliper bracket gets center hole bored OS and mounting holes redrilled. You can make a long spacer up that goes in the Appluase handbrake brackets so the handbrake cable works. Or if no brackets or to reduce weight I welded some tubes onto the trailing arms at the right distance so the handbrake works. Check Mazda MX5 rear discs and calipers they appear to be an alternative (one version of the Mazda is an identical casting but might have a diff bore size)
.

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#10

Wow nice! Sounds like a nice project after the engine swap! Ill make a build thread later!

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#11

@Roffelkut as above
But if you get stuck or want something custom - my brother and i are sending stuff around the world fairly often if you need anything bespoke
If you want very serious, then our mates in Japan have the ultimate set ups, if you’re feeling very rich …but you can get into endless 6 pot calipers and the types of AP racing and willwood

Rear’s is a bone of contention!!! :smiley:
Personally I don’t touch them - only to get cool enough
I think in a fwd they’re basically useless and i can never get them hot enough and have all bias forward
in the wet it’s worth considering …sometimes …but again you can get aftermarket shoes if you want them …otherwise i’ve only ever run stock stuff in the rears …but some believe that having something there is better for balance … :man_shrugging:

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#12

Thanks for the help mate, for the time being ill keep it stock. We will see in the future.

#13

If one becomes a left foot brake user then good rears are essential.

If you are to motokhana or khanacross / autocross there will be a need for a hydraulic handbrake and good rears.

If a good rear set-up is pointless then any top category with fwd would not bother with good rear setups (note btcc cars especially)

#14

Yep. No one is building at BTCC spec tho
My point is that they rarely need an upgrade

#15

Note this is a track build. The question was about brake improvements. My btcc example was real world evidence. My experience is rear discs make a worthwhile difference and I am certain that if we tested drum VS rear rear (even with factory bias valve) that in all forms of club motorsports (except 1/4 mile sort of stuff) that there is sufficient benefit to notice a difference. Can you say whether you have done a rear disc swap on a Dai? If so on what grounds is it not worthwhile when the aim was all round brake improvement? Let’s say one gets a 5% improvement in cold stops, which I’d say is easily realistic. How many times are brakes applied in an event? My local hillclimb has six brake areas, heck I’d do the rear brakes for a 2% improvement in brake zones if I could shave my time from 52.05to 51.95. Then at sprints I have won my fair share of battles because I still have brakes on the last couple of laps. Maybe your comment concerns driving on the road, but even then why wouldn’t anyone want the best brakes possible. Remember the last sentence of the lead post was about competition and brake fade.

#16

Good points, though i mostly drive on the street.
When i drive on track, mostly the nürburgring/nordschleife wich is really hard on brakes, i dont want to lose my brakes halfway through the lap. Also im not so focused on time and defenitly not on tens of seconds.
For now ill keep it stock but it wont be long before i have to rebuild the rear brakes, then ill go for better brake shoes. If the improvement is to little i can go for discs.
But i cant say it enough, thanks for the support its extremly helpfull!

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#17

Gornsby means well but his replies can seem like a personal attack …often
But he has a head on his shoulders

I think the rear disc conversion is too far
If you find you want more rears then the copen/yrv turbo conversion is straight forward

personally I dont go for more rear brakes because it events in rear locking too easily with weight transfer mainly forward
Road and wet track = flatter set up could see some gains …but not nearly as much as stiffer front end suspension and decent front end pads

In my opinion :smiley:

good luck out there!
enjoy it!

#18

No personal attacks intended. More like thorough thought on a subject needs to be talked out. I am keen to learn and if I say something technically wrong I want to understand so do tell me off if you have data contrary to anything I say.

Why though would rear discs be “to far”?

You mention “wet track” and “stiffer front end suspension”. The end you make “stiffer” is the end you take grip away from. So yeah you could transfer weight to the back to make the brakes work better. It is a rare circumstance when grip would ever be taken from the front of a fwd as a overall performance solution.

Bigger diameter rear does not mean things lock easily. Locking up the rears is either an issue with to much pressure to the rear slave cylinders, as in wrong bias or poor rear tires (only running good ones on the front) .

#19

lots to discuss here
i too are very keen on the facts and the data
i feel we need to pm @Mr_Gormsby but you don’t reply to them?

so the issue i have - well myself and all othes i’ve worked with and pitted with really - is that in heavy braking the rear is light and the front end is doing the lion share of the braking action
so even with factory bias, the rears lock almost all the time
so i’ve only really worked to decrease bias to the rear
never gone to add more braking effort to the rear

addressing tyres - i’ve only ever run same sets all around - nothing junky at the rear
i am to blame for running too heavy a spring set in the rear - possibly - something i’ve been challenged over recently by a chassis technician - but not convinced this would change much here

my example is different to what the common questions are based around here - possibly different to your experiences too mr_G - as i know when i’ve done a few smaller speed events / tighter events the rears were different

also as mentioned, in the wet i try to allow much more flex in the set up - or less stiff front end as i said - more roll / less roll bar action, which asks more for rear end effort

i know i spurt out info too quickly sometimes - so i do appreciate the questions to clarify - maybe i’ve done a bit better this time :stuck_out_tongue:

#20

“i feel we need to pm @Mr_Gormsby but you don’t reply to them?”

I do seek to reply to everything sent to me. Apologies if I missed something. If this does seem to happen at any time just remind me.

“so the issue i have - well myself and all othes i’ve worked with and pitted with really - is that in heavy braking the rear is light and the front end is doing the lion share of the braking action
so even with factory bias, the rears lock almost all the time”

Consider the front brakes for a moment. With a small front brake it is hard to get the modulation required for “high” foot pressure control. As such it can be easy to lock a front wheel. So we may go to bigger brakes to get more sensitivity and thus allow our right foot (or left foot in my case and a few others) to push hard without locking up. Well the same goes for the rear, taking the same sort of approach to front upgrades being applied to the rear gives better modulation. Bigger rears can help reduce lock up.

“i am to blame for running too heavy a spring set in the rear - possibly - something i’ve been challenged over recently by a chassis technician - but not convinced this would change much here”

99% of what I have seen run too soft in the rear and to hard of a spring in the front. Soft front means that is where the grip is. Stiff rear makes weight transfer to the front. Lets say under hard brakes you can end up with 90% of the mass going to the front and then still have the benefit of 10% over the rear wheels. So it is still worth sorting the rears to take advantage of that traction. To oversimplify that let’s say the percentage equate to stopping distance. Without those rears one might take 100m to stop intead of 90m in a given situation.

“also as mentioned, in the wet i try to allow much more flex in the set up - or less stiff front end as i said - more roll / less roll bar action, which asks more for rear end effort”

In wet front and rear spring rates need to be dropped. Personally I believe there is an over reliance on sway/roll bars. They are best when as small in diameter as possible. Yes they correct an issue, however, why would anyone want to link either side of a car with a sway bar if they didn’t have to? Independent suspension works best when it remains independent. I rely on my roll bars where fitted to allow for track day adjustments that fall outside the scope of tire pressure alterations.

“i know i spurt out info too quickly sometimes - so i do appreciate the questions to clarify - maybe i’ve done a bit better this time”

We all spurt out stuff at times. What is good is the dialogue and thinking things through in a rigorous manner. For me there is no desire to “win” and have my ideas make me look good (in my mind). I want the Dai community as much as possible to move beyond stance, slam, cool, “the look”, bolt ons, and so on for a David and Goliath type outcome when our marque is pitched against the competition.

Sorry Roffelkut, no more hi jacking your thread. We’ll just respond to your questions. Hope all is moving along well.