CANTONRACER

My new setup is not going to make much vaccum and I know the car will not stop well, if at all.

So I am considering going to a manual setup and in the process eliminate the ABS also.

So how bad is it?

I figured if it is properly setup, it should be ok.

NOVA5

To test how it would be get on a safe road get to 40MPH, cut off your engine, but do NOT turn to off and lock your colume. Now try braking. thats what nonpower brakes will feel like.

CANTONRACER

That would be how a power-assisted brake system without power would feel.

I would think that a properly setup manual brake system would work ok?

respectirocz

the vacuum brake booster stores vacuum, so if u produce very little vacuum it will take longer for the booster to "fill up" so if you're going 40 and kill the engine u still have one or two good asssted pumps, after that the pedal will be pretty stiff and u cant push it farther than an inch or so

revtime

It will work ok. But just like manual steering it will take a bit more effort.
I would think with the 4 wheel discs a manual setup would not be bad at all.
Just more work, people have gotten soft with all the creature comforts we take for granted nowadays.

Turbo6

I just can't see going manual when people making well over 1,000rwhp have kept power brakes without difficulty. So, unless you are building an 8k rpm motor that needs a huge cam, why do it?

CANTONRACER

The guys making that power are not trying to make a lot of power on motor only...which changes the cam and vaccum.

A cam with 104 CL will be a different animal than a cam with a 114 CL.

thom1

Must be a lot of cam in that car

You also have the option of adding an additional vacuum reservoir (sp)

JEGS sells them specificaly for your purpose

CANTONRACER

I am looking at an additional reservoir...maybe an electric unit?

Thanks for the replies guys.

Injuneer

Baxter kept his booster with the 1,125HP LT1. When he went to the Gen 1 SBC setup, and wanted to get the weight of the car under 3,800#, he pulled the booster out. Even at 3,525#, and using some really skimpy Mark Williams drag brakes, he had no problem pulling the car down from 160MPH trap speed with "manual" brakes. He preferred NOT to pull the chute, because it took us so long to pack it.... . He did totally replace the master cylinder though, with one better suited to the brakes he had and the fact they were manual. I don't recall the brand of the master.

96speed

On the track, they are great! Nice and even and you can really "feel" the car. However, big difference in manual brakes in a track car vs. a street car. They suck in a street car. Totally unresponsive. I personally ran a manual brake setup, but convereted back to a power setup because they felt too dangerous.

For a track car or a car you drive once every couple of weeks, its probably fine. You definitely cannot "lock" the wheels up with a manual brake setup, not even close.

What kind of cam are we talking about here? I'm running > 250/260 and its never been a problem with the power brakes.

Edit: Manual master cylinder, LS1 front brakes, stock rear brakes.

Ryan

captaindbol

I think the biggest problem with manual brakes on a late model car is the car was never designed for such a thing. Yes you can run without the booster-(super white trash), or get a manual brake master cylinder but the brakes will never stop to their potential. The problem lies in the pedal ratio or lack of to be exact. If any one can remember back to the 60's & 70's or has ever worked on a car of that vintage, you will remember that some cars had manual brakes from the factory while others were optioned out with power assist. Under the dash the cars were the same, there were two sets of holes in the brake pedal arm for the master cylinder pushrod to attach to. The upper hole being for manual brakes with a higher ratio and the lower hole being for power assist with a lower ratio. Problem is that Detroit forgot about manual brakes about 20 years ago and our 4th gens don't have the extra hole needed to run manual brakes effectively. A pedal ratio between 6 and 7 to 1 should provide the pressure needed to run a 4 wheel disc manual system. Where this involves relocating a hole on a 4th gen I don't know or care to do the math on but I'm just throwing this out there for all the people that want to jump on the manual brakes suck bandwagon. I have personally adapted a manual 4 wheel disc system on my 68 truck using all gm brake components and a mp brakes master cylinder with a wilwood proportioning valve. This 4400 pound truck will white smoke tires in a panic stop situation and that is with components that are most likely not as good as those found on a stock z28. I'm sure that a well sorted out manual 4th gen with aftermarket brakes would change a lot of peoples minds.

Re-invent the wheel or get a vaccum pump

96speed

I relocated the hole up about ~2.5" as per the instructions from the chassis builder:

www.smithperformance.com

I think the issue is that manual brakes (on a 4th gen) don't really offer much other than a little weight savings and a little freed up engine room. Not much altogether, except for race cars where the brakes don't have to lock up the wheels.

Unless you need the extra room or need to lose 5-10 lbs, keep the power brakes. They are nice to have when you need them. However, there is a HUGE difference in power assisted brakes without power vs. a true manual brake setup.

Ryan

IrocSS85

Im goin to vote for a elec. vac. motor. I know there are some aftermarket systems out there, but theyre kinda pricey. but they pull a consistent 20psi so you'll always have the best brakes possible. Ive been eyeballin the ones on the new denali's at work and I think one day I'll get one of those pumps and get some sort of hobs switch to keep it automatically on/off to keep a good vac.. but a vac. cannister will be good enough for me right now. if you do this post up about it so we can learn from how/what you do.
chrhis

kevm14

Even with a cam that doesn't develop quite enough vacuum on the street would work fine at the track for vacuum. I mean, at the end of the timed run, you let off the gas with the car in gear. This should build plenty of vacuum, even with a really, really hot cam.