Brakes: j30 vs q45 vs m30

[SketchyRollin564]

im looking into j30 or Q45 brakes, since they are easy and cheap to find at a junk yard, and from what ive heard are significantly better than the stock brakes, and are a worthwhile upgrade, especially in my case since my stock brakes pretty much dont do anything at all

ive heard the 97-01 q45 brakes are bigger than the 91-96, and you have to modify the bracket or some holes to make it fit. Im going for the cheapest and easyest installation, without cheaping out, so ill pass on those

my question is, are there any real differences between the 91-96 Q45 brakes and the J30 brakes? Ive read the j30 brakes are slightly smaller, but ive also read that Q45 brakes throw off your brake bias, so maybe the smaller j30 brakes would actually be better? Anyone got any input on this?

the other thing im wondering is what have you 4 lug guys that have done this upgrade done for the rotors? From what i know theres 4 options
1: re-drill the rotors i get from the junk yard
2. buy em new for $30 at advanced and re drill them
3. buy brand new cross drilled and slotted 4/5 lug interchangable rotors (i dont know where they sell these but i know they exist)
4. use the rotors from the 95ish altimas, which have the same diameter, but are slightly thinner (would this be safe?)

and does anyone have any info on the M30 brakes? from what i know these are 4 lug rotors, but the caliper is only a single piston "floating" design, which i have no idea what that means

supposidly they still have a lot of stopping power, evern though they are single piston

thanks in advance for any helps


edit: apparently another option is the "180sx spec upgrade"
which is basically 3rd/4th gen maxima brakes with 94 altima rotors

...and according to this guy, the q45 brakes clamp too hard and are liken on/off switch
http://www.sr20forum.com/240sx/180348-q ... -ever.html

[Razi]

Q45s with stocks in the rear throw the braking bias off like crazy.
I'd lock up the fronts before the rears felt like they did anything.
I actually regretted doing it.

Now I'm enjoying it after upgrading the rear to Z31 bracket + Altima rotors though.

But really, stock brakes with good pads are pretty much good enough for daily driving.

[AZ89two4Tsx]

I disagree with Raz man about regretting it. I had Q's in the front, stock rears, and they felt fine. Sure they would lock up pretty easily, but it was definitely a small price to pay. MUCH more bite.

As far as which upgrade to choose though, definitely go with the direct bolt in G50 Q brakes. The Q was the biggest car out of them all. MAKE SURE TO GET THE CALIPER MOUNTING BOLTS. They're a b**** to find at the dealer. J30 bolts will work as well.

And don't risk your car using used junkyard rotors, not smart. Get some new rotors/bad at an autoparts store. They're cheap dude. And be sure to have a machine shop re-drill those holes. Unless you have a drill press.

[SX APPEAL]

But really, stock brakes with good pads are pretty much good enough for daily driving.

True, but the minute you show them some real action, they warp so damned easy... I'm currently looking for parts to do that Z31/altima swap you mention, so if you happen to come across more brackets please let me know

[DanThaMan]

I have re-drilled 4-lug q45 front brakes and I love them, they are great for daily and a huge improvement over stock, I havn't had any problems with locking them up, but then again I don't track my car ever...

[turbonxsx]

I have J30 brakes up front on my hatch 5-lug and just installing the brakes you go from a one-piston to a two-piston set-up it's a nice cheap upgrade just dont paint them red lol they feel stronger but i havent installed new brake lines to take full advantage yet...

[costa_rican13]

But really, stock brakes with good pads are pretty much good enough for daily driving.

True, but the minute you show them some real action, they warp so damned easy... I'm currently looking for parts to do that Z31/altima swap you mention, so if you happen to come across more brackets please let me know

DO IT.... It's awesome ^_^ defintely evens out the bias!

[allenms240]

Why do you want your front ones to lock up first, I'm curious.

I run Z32 fronts with drilled 4lug and 5lug drilled and slotted rotors up front, and stockers in the back with stock BMC and Booster.
I love the way it feels and how fast I can stop

[SX APPEAL]

Well ideally you don't want them to lock up at all do you? but that represents the limits of most people's knowledge on brake bias, just "which end locks up first." You have to do some serious custom work (dual master cylinders etc..) to be able to adjust the brake bias in any kind of meaningful way to tune the car's handling. But in professional motorsports the adjustment is used to tune the way the car responds under braking turning into a corner. The more rearward bias you have, the more tail happy the car will be under braking, more more forward bias, the car will tend to understeer more under braking. But without the ability to adjust it properly, its basically just a crap shoot of trying to find the right combination of parts to achieve the balance you want. Personally I don't get why so many people make such a big deal about it on street driven cars, where 99.9% of the time any hard braking is done in a straight line and bias doesn't really count for anything. Either way the car's going to stop, no matter which, if any, wheels lock up.

[Fenris]

...and according to this guy, the q45 brakes clamp too hard and are liken on/off switch
http://www.sr20forum.com/240sx/180348-q ... -ever.html

If you read, the car he was driving was using the wrong rotors, so there must have been no room for anything other than on-off.

I have Q45 front brakes on mine and have heard not but praise for them, they seem to work well enough.

As soon as the car is back from its cancer treatment i will give a full eval.