5-lug and J30 brake upgrade questions

MX500 · 06-27-2009, 05:58 PM

I already searched, if you know of a helpful thread please throw in a link.

Backround info: I just recently got my coupe back together with a ported and rebuilt head. I ported and polished it myself with the advice of my engine builder friend who did the majority of the actual rebuild. The car now has a huge difference in torque starting at 2500+. I didn't really notice an increase in top end power, but the torque curve is much broader which makes the car deceptively fast. This is why I want the brake upgrade...

I'm thinking of upgrading to J30 front brakes but I am unsure if they will clear my 15x7 wheels. Does anyone have a definative answer? I have 15x7 minilites with a +15 offset. If the brakes won't clear, I'll just save up more cash and 5-lug the front and rear while I do the brake upgrade.

Can J30 hubs be used for a 5-lug swap? my local junkyard has a few j30s and I may as well get the VLSD, 5-lug hubs, and brakes while I'm there if everything is compatable.

Thanks guys.

MX500 · 07-01-2009, 10:36 PM

Figures... It looks like I'm on my own as usual. This forum has too many people talking and not enough people that have actually worked on their own car... I guess I'll have to start with the brakes and see if they clear.

allwayzsidewayz · 07-01-2009, 11:55 PM

They should clear I'm not 100% on that but its worth a try if they dont just buy some wheel spacers and you should be good to go.

MX500 · 07-02-2009, 08:08 PM

I don't think spacers would help, I alteady have +15 offset and the drop center isn't near the stock brakes. I'll see how it works after I get everything.

cervasa · 07-03-2009, 04:59 PM

i had 15x6.5 black racings witch cleared and i currently run 16x8.5 watans on the front that also clear both are simular wheels so i would say most likly clear but since i have not tried those exact wheels i wouldnt give you a 100% yes

MX500 · 07-04-2009, 11:04 AM

SWEET! I love my minilites and would like to keep them. I'm off to the junkyard to go scavenge for calipers...

MX500 · 07-05-2009, 01:51 PM

Snagged a set of Q45 calipers. They are made by sumitomo for Nissan but look nearly identical to the J30 brakes. Same rotors too. I'm off to the driveway for a test fit.

MX500 · 07-05-2009, 03:48 PM

Shitty! They rub on the spokes of my wheels. I did as much grinding on the caliper bracket as I am comfortable doing but it still wont quite clear. I'm going to try them with spacers and see if they clear. Btw, for those of you interested in the u[grade ROCKAUTO.com has Q45 front pads for under $10!!

cervasa · 07-05-2009, 10:36 PM

that sucks man i guess there is a bigger difference between the wheels than i would have guessed unless the q45's are bigger

daverussell · 07-06-2009, 01:29 PM

It isn't just offset that allows clearances, spoke design comes into play as well. I have 5Zigen FN01R-C's (17x8 +35) and they clear 30mm Z32 4 piston front calipers perfectly. Also, when you do a brake upgrade, just bolting on more pistons is not going to help you stop better. The Q45 brakes are not a good upgrade imho (flame suit on for all the people running them). The proportioning with the stock BMC is not right for those front calipers. If it were me, get SS lines, Hawk pads and new rotors for all four corners. That will be the best option if you are on a budget.

cervasa · 07-06-2009, 07:06 PM

ive done that and ran j30's which work much better stopping distance isnt always the issue but fade.......

daverussell · 07-06-2009, 11:18 PM

I understand that. Also using an improper sized caliper for your car. Your brakes may not fade as much, but if your master cylinder is pushing the same amount of fluid to a bigger caliper than it used to, than it isn't squeeze as hard which is why your rear wheels will lock up. I had Q45 calipers on my car back in the day and will NEVER go back. A full Z32 setup is WAAAAAY better as far as stopping power and feel. Like I said before, even a good pad/rotor upgrade with SS lines will help fade.

MX500 · 07-10-2009, 11:40 AM

I had stainless lines. They started leaking within a month. The manufacturer wouldn't honor their warranty. I already have EBC green stuff rear pads. Doesn't the proportioning valve just vary the pressure, not the volume? A smaller master cylinder and more surface area on the brake pistons would give your more braking for the same pressure on the pedal. Either way I'm planning on getting an aftermarket adjustable proportioning valve sooner or later. I've had my stock brakes boil over on me on the street and I NEVER want that to happen again. 115-20 is not so easy when your brake pedal turns to mush. I couldn't find Z32 calipers so I got the Q45's. An upgrade is an upgrade in my book.

daverussell · 07-10-2009, 10:16 PM

I guess it is all a matter of opinion then. good brake fluid will keep you from boiling your fluid. Also, EBC pads are not an upgrade imho. If they work for you then awesome. Good SS lines should not leak. I have had mine for almost 2 years and no leaks.

MX500 · 07-11-2009, 11:59 AM

I'm aware that brake lines shouldn't leak. My leaky lines were bought from SilverstoneMR on Ebay. They were very shitty to deal with. I was running castrol synthetic Dot 4 fluid and have since switched to ATE blue brake fluid which has the highest wet boiling point I've found.