Booster delete with stock master cylinder S30

[RebekahsZ]

Anybody got any info on a booster delete conversion?  I saw one at an autocross on an F-prepared 240z that was fast as hello.  He had no trouble stopping.  I only got to talk to him briefly-stock master cyl with relocation of the push-rod hole in the pedal.  He was in a hurry and I didn't get to study it much.  My master is leaking (again) and I never got the booster-to-master rod adjusted correclty, so it is a good time for me to do this mod in conjunction with the Wilwood 1" master conversion.  Anybody?

[socorob]

It will be pretty hard to push a 1" master without power assist. If you look at older cars that came with manual brakes only most seemed to be around 3/4ish big. 

[zukboi2004]

I would also like to know more about this topic....

 

Whoa!!! My first post!!!

[74_5.0L_Z]

I have the stock master (15/16") cylinder and no booster.  My car stops great, the pedal effort is not too heavy, and I have great modulation.

 

That being said, the master cylinder is the only stock component in the brake system.

 

11.75" x 0.081 Coleman machine vented rotors
Outlaw 2800 series 4 piston calipers (1.75" pistons)
Hawk HB237 HP-plus pads

On the rear, I have
1985 modified maxima rotors (10.75" x 0.81)
Outlaw 2800 series 4 piston calipers (1.38" pistons)
Hawk HB237 HP-plus pads
 

 

 

In the picture below you can see the adapter plate that bolts where the booster would have been and has provisions for the master cylinder.

 

Edited May 10, 2013 by 74_5.0L_Z

[RebekahsZ]

Thanks!!!! Did you buy the plate or order it? How thick is it? Wanna sell one?

[74_5.0L_Z]

I made it from some 1/4" 6061 T6 aluminum that I had laying around (about ten years ago).  It's amazing what you can do with a hole saw and some drill bits.

[RebekahsZ]

Yeah, I know. I'm just trying to avoid being down any more than I have to until winter. But I've got a seeping master cyl so I may be forced to pull something together. Did you relocate the pivot hole in the pedal to increase the leverage ratio?

[xtreme_240z]

im running the willwood mast unsure or bore dia tho. took out stock booster make and alum plate.

although you will need to change the leave point on the pedal to achieve the correct ratio 

 

 

and were running the biggest set up AZC sells for the 240z

no issue with it locking up or sudden hard stops. works great. and not that much modifying . at least not to our standers 

[RebekahsZ]

Now we are talkin'. What thickness plate? And how much did you raise the leverage hole on the pedal? Did you raise the master cyl or just let the pushrod just come in at an angle?

[xtreme_240z]

Um keep in mind we did this last winter. The plate if I remember correct is around 3/4-7/8. We mounted in the same location holes as the factory had. If I remember correct the hole was raised maybe 1/2 of and inch, to give the 7:1 ratio WillWood wanted. For the push rod im thinking I had to modify the length of the stock one, but not by much. I don't have pics on that part. If there is anything else I can go take pictures of it, car sitting in the garage now.

[RebekahsZ]

Man, I appreciate it. I've already bought a 1" tandem MC but I just took it off my booster and there is no leaking to be found! Can't figure out how I'm cleaning fluid off the bottom of the booster every couple weeks(???). Anyway this is gonna be a winter project for me. You've given me the ratio that I was looking for. I don't think you'll be able to get any good photos under the dash unless you took any of the project in-progress. Did I understand you correctly-you used the Datsun pushrod, not the wildwood pushrod?

[xtreme_240z]

Yes i used the existing 240z push rod. Not sure how much I modified it but I can try for iPhone pictures under the dash. we never got the WillWood push rod. And im pretty sure it was a 7:1 ratio I believe it was in the instructions.

[RebekahsZ]

Ok thanks for being so nice. I am wondering what kind of mods you did to the pushrod-lengthened it? When I did a tilton clutch MC, the tilton rod was longer but had the wrong thread pitch for the clevis. When I go to the trouble of wrestling the pedals down this winter, I'm gonna weld and redrill all the pivot holes (they feel pretty egg-shaped) and change all the weld nuts on the clevises (clevi?) to SAE so I can use the longer aftermarket rods. I've warned my wife that there is gonna be a lot of profanity from the garage. I'm really just sourcing parts and making my plan out right now.

[ablesnead]

Chase Boys in Alabama have the complete kit about 250.00 .

[ablesnead]

Sorry its Chasebays , and the kit is 269.00 including the mc

[RebekahsZ]

I just might love you....thanks!

[Xnke]

The ChaseBays kit has been discussed before...it removes/eliminates the rear brakes!

[RebekahsZ]

Why?  they have both a single circuit kit and a dual (front/back) kit using the same 1" wildwood MC that is discussed in the stickies.  How does that eliminate the rear brakes?

[m1ghtymaxXx]

What are you running for calipers? I just had my ass kicked at autocross last weekend by my combination of 1" Wilwood MC, Stock calipers and drums, Hawk HP Plus pads and Hankook Z214 slicks. I had been running the 1" MC and stock brakes with unknown stock replacement pads for a while without issue, however the aggressive pads make it too easy to lock up the wheels with the very little pedal travel the big MC provides. The issue was much more exaggerated with the R comps since there's no warning of wheel lockup until you see the plume of tire smoke or realize you have no steering. I ran some fun runs on street tires and found the issue to be much less severe.

 

I'm curious to see what's involved in changing the pivot location of the pedal. I bought the Wilwood MC because the the one in the car when I bought it was shot and saw big brakes in my near future, however I've been having second thoughts about the big brakes because of the balance issues that everyone seems to be having, and the fact they just don't seem necessary. I bought the HP+ because I'll be running a road rally school in September and wanted some heat capacity. The format for the driving portion is 2 two hours sessions around a course closed off through a town on a small island near where I live. You can line up to run as frequently as you want, but I didn't want to be held up by cooked brakes.

[RebekahsZ]

I am sorry mightyMax, but I am just a fellow clueless traveler on the road to ruin. I am not an automotive engineer-at best I am just a copy cat. Im not really qualified to give advice. The only advice I know is to only change one variable at a time. My brakes worked fine until they disintegrated. I don't really need better stopping, I just need them to be as bullet proof and durable as possible. If you have a L6 you don't need as much brakes as a V8, but 2 hours of race level driving is gonna be rough on them. Can you stop in the pits every now and then and check pad wear? Could you slap together some sort of ducting for cooling? Can you bring some spare rotors and pads? And some mechanics gloves cause the hardware will be hot. You may have to brake earlier and less aggressively if you want the car to hold up... Ask the ITS Enduring guys for advice.