Jump to content
SAU Community

Recommended Posts

Does anyone out there know for a fact the point where you should be looking at an aftermarket master cylinder etc because of bigger brakes.

Say if you were to run big ass 6 pots on the front, with big ass 4 pots in the rears (std Nissan 4 pots - possibly aftermarket 4 pots) with something like 355 front rotors and 324 rears.

Im expecting for such an over engineered braking setup you would need to do somthething about the std Nissan mater cylinder, perhaps bigger piston AP type setup or equiv? Std Brake booster ????

I know in a RWD car that weighs 1400kg this sort of system isnt warranted but im askign all the same. :D

Link to comment
https://www.sau.com.au/forums/topic/40164-overkill-brake-setup-question/
Share on other sites

I have friends who have done an r33 front brake swap onto a silvia/180 and found that by using the original master cylinder thay have a very spongy feeling pedal but the car stops ok. They have then installed an s14 master cylinder and booster as the s14 has 4 pot fronts and similar rears and the pedal feel improved, probably improved the bias too.

In all honesty i'd think that if you are changing one component in the system so dramatically then the others should be changed as well to make the most of it, otherwise you won't get the most of the new calipers. Bias is something important in all of this too.

Yeh i expect to have to play with bias, and i seem to recall the R32 has a 32mm diam piston in master cylinder.

Whilst that std 32mm piston does a fine job at moving the std brakes 12 pistons within the std calipers (2 x 4pot fronts and 2 x 2 pot rears) i would expect it to run into trouble when expected to displace 20 pistons, may of which are a larger diam then std caliper pistons (ie 2 x6 pot fronts and 2 x 4pot rears)

Looking at some engine bays of Jap cars with massive brake upgrades (time attack or whatever they call them), many still seem to run std master cylinder setups etc, doesnt seem right to me... just wondering where the limits are, especiually since you look under the bonnet at circuits around the traps on circuit cars, and some/many run aftermarket setups when the calipers themsleves may not be dramatically different to std, ie a late model WRX with AP 6 piston fronts and std 2 pot rears?

this sounds reasonable, but in my limited understanding of physics, isnt pressure distributed evenly over all area in fluid? so the number of pots would not be so relevant as the size of the piston itself, the pressure exerted on the pistons would be the same? does this make sense?

Then again, theory and the real world often seem to clash:)

I have seen vacuum bottles fitted to brake boosters - this was mainly because of the lack of vacuum at low revs due to large cams, but I suppose theoretically extra vacuum would be beneficial?

sorry for the red herring.

??? I dont know, as for the pressure being equal you are right, but thing to remember is if you increase the volume of fluid in the brake lines, then only have the same displacement of the piston in the master cylinder, then the overall pressure applied will be reduced due to the increased volume of fluid in the system, you may need a 40mm piston to get the same percentage in volume change... make sense? (Actually its not really a volume change, more a displacement of volume...as the brake fluid isnt compressible.)

a drip under pressure!!!

???  I dont know, as for the pressure being equal you are right, but thing to remember is if you increase the volume of fluid in the brake lines, then only have the same displacement of the piston in the master cylinder, then the overall pressure applied will be reduced due to the increased volume of fluid in the system, you may need a 40mm piston to get the same percentage in volume change... make sense?  (Actually its not really a volume change, more a displacement of volume...as the brake fluid isnt compressible.)

You need help Roy, and unfortunately the people who know enough to stop you slamming into a wall will want to charge you for it...

Find out your nearest brake guru, and you will find your answer. What you pay in quality advise, deduct from your T & E bill and you'll more than likely brake(sic) square.

TT

a drip under pressure!!!

You need help Roy, and unfortunately the people who know enough to stop you slamming into a wall will want to charge you for it...

Find out your nearest brake guru, and you will find your answer. What you pay in quality advise, deduct from your T & E bill and you'll more than likely brake(sic) square.

TT

The brake kit i was looking at getting ended up selling for a grand more then i was willing to pay, so for the moment brakes are fine...will have to see how they handle the big stops at Sandown at the end of the month, sonce now i have a bit more power then before and no speed limiter.

The brake kit i was looking at getting ended up selling for a grand more then i was willing to pay, so for the moment brakes are fine...will have to see how they handle the big stops at Sandown at the end of the month, sonce now i have a bit more power then before and no speed limiter.

What is the event Roy? I have 200litres of elf I need to use...

TT

MSCA Multiclub Sprint on 30th May @ Sandown www.cm510.com/msca/

OR

PIARC are holding a sprint weekend at the Phillip Island on the 29th/30th. www.piarc.com.au

Im thinking Sandown, because its closer, a few other Vic guys ive met are going, and i want to scare myself stupid on the back straight kink.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Driveline vibration is resolved. I ended up loosening all my engine mount and trans mount bolts, giving it a good shake then retightening everything and it's gone... Let's just say I was surprised that fixed it.  I've been happily driving it around again but unfortunately put zero time into my direct port/constant pressure WMI setup. I'm on vacation next week, so I'll try and finalize it then.  On a different note, I spent all week fuel/ignition mapping 2x 216L V16 engines. Turbo's were burning glycol and we swapped them out for larger units. We also had planned emissions testing on site, so I figured I'd be there the same week to use their instrumentation and massage any emissions issues out if needed. This was a first for me. Fuel management is similar in certain ways to automotive (i.e air density as load variable) but very different in others. It's all PLC based and AFR's are controlled by air and not fuel. They use a control valve between the turbo and air manifold to control pressure which in turn controls AFR's. Due to this, target AFR tables supplied by the OEM are in pressures and not mass which really through me off. They use air pressure vs fuel pressure tables. I also relied on an O2 concentration sensor the emissions team had in the exhaust. Ignition timing was also all over the place and we were losing a fair bit of power. They're now happily sitting at 16-40BTDC depending on load. We were making about 1600kw at 900rpm at 90% load. Engines were running a lot smoother as well.    
    • heh, aint no R32 ever meeting modern targa cage rules unless the driver is veeeery short OP, good luck with the sale, since its already in the land of freedom I'm sure you will find a good buyer.
    • meh, it was a good video, clear about the issue and how he dealt with it. A bit heavy on the RTV and very brave to put an RB in anything without rebuilding it first, but otherwise I thought it was good Dose, I'm not sure that having the pickup forward is a big issue; yes of course the oil could shift under brakes but the sump should never be empty enough for that to be a problem (unless you also have a higher volume oil pump, and that oil can't return from the head to the sump quickly enough)
    • I can donate $100 to your upgrade fund. So long as you can donate the IC7 my way....
    • I'd love a Haltech ECU, and Haltech 10 dash. Was having a chat with Rob and Andy @ Haltech when Rob put one in his MR2. First one I'm kind of interested in too, as you can dim it RIGHT down. Andy was saying bright dashes is one of his peeves too!
×
×
  • Create New...