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sedition88

StreetFighter 620

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Not with this kit. I also got the bias valve for it (not shown) Their systems are tried and true in race cars of all types. Not worried.

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I don't have a problem with deleting the booster. Many much heavier vehicles did not come with boosters. I've even deleted a few myself.

 

What I do have a problem with is the single circuit master cylinder. That's a flat out safety hazard. You really couldn't fit a dual circuit master in there?

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Why is it not a problem with that system? Is it in fact a dual circuit master? It looks like a single circuit master.

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It is a single circuit... I appreciate the feedback, but there's no need to argue this at all...  From the company...

 

"A common misconception is to believe this causes a higher risk of failure due to a lack of a back up line should one line fail. Most OEM master cylinders are still single feed internally and have the same assumed “risk” to our Master Cylinder. Always use good quality brake lines that are clear of moving parts."

"Brake pressure output is determined by the master cylinder bore size. Vehicles with up to 4 outputs on the master cylinder have a pressure output that is controlled internally by the bore size. The increased number of outputs does not translate to more braking power. This does have a single exit but it will not translate into any less braking pressure or performance."

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26 minutes ago, sedition88 said:

It is a single circuit... I appreciate the feedback, but there's no need to argue this at all...  From the company...

 

"A common misconception is to believe this causes a higher risk of failure due to a lack of a back up line should one line fail. Most OEM master cylinders are still single feed internally and have the same assumed “risk” to our Master Cylinder. Always use good quality brake lines that are clear of moving parts."

"Brake pressure output is determined by the master cylinder bore size. Vehicles with up to 4 outputs on the master cylinder have a pressure output that is controlled internally by the bore size. The increased number of outputs does not translate to more braking power. This does have a single exit but it will not translate into any less braking pressure or performance."

 

Not the same thing. Their assurances are aimed at OEM single masters and meaningless compared to a dual system. If you have a single master to work both front and rear brakes ANY failure in the system is a failure in the entire system. I'll bet you any amount that converting to a single is as illegal as fuck. Think about someone else's life in the event of an accident. Here, if there is a fatality in an accident the vehicle is put through a safety check. Brakes are almost certainly the first thing they look at. You could loose everything in a suit.

 

A dual master separates front from rear and in the event a line failure from say hitting a piece of road debris or just a leaking wheel cylinder that causes you to pump one system dry, you will still have braking in the other. Your braking will be reduced but there is a pressure differential switch in the dual system that warns that pressure is lost on one of the systems. I have had this happen in my '79 Bronco. Rear line torn off. Noticed right away the spongy pedal and longer stopping distance.

 

My first car was a 4 year old '64 Dodge with a single master, which was the norm back then. When I was a kid you used to often hear later that the cause of a fatal accident, or any collision was brake failure. With the introduction of dual masters you NEVER hear this any more.

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Which is also the reason I bought the bias valve to be able to control the front and rear

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23 minutes ago, sedition88 said:

Which is also the reason I bought the bias valve to be able to control the front and rear

 

Bias valve just controls how much fluid goes where. Any system pulling from one reservoir has the potential for catastrophic failure. Even a double outlet master since its pulling fluid from the same place, so a leak anywhere in the system can drain the whole system...

 

I can also speak from experience where my 510 had a rear leak... and had no effect on the front fluid... and my 620, same thing... rear leak drained all the rear fluid but no change to the front 

 

I have no doubt that their system is good... but would sketch me out on a street car/truck... and for the record i just deleted my booster and am very happy with it, but kept the stock master.

 

Just make sure your ebrake is GOOD. Any bd careful at any sign of a leak, low pedal pressure, air in the system...

Edited by demo243

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1 minute ago, demo243 said:

 

Bias valve just controls how much fluid goes where. Any system pulling from one reservoir has the potential for catastrophic failure. Even a double outlet master since its pulling fluid from the same place, so a leak anywhere in the system can drain the whole system...

 

I have no doubt that their system is good... but would sketch me out on a street car/truck... and for the record i just deleted my booster and am very happy with it, but kept the stock master.

 

 

 

Yes, it's comparable to any other single master such as the 521 truck. You'll note that all hydraulic systems started with a single and progressed to dual and not the other way. This is a very very bad idea.

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19 hours ago, sedition88 said:

It is a single circuit... I appreciate the feedback, but there's no need to argue this at all...  From the company...

Not arguing, just pointing out the dangers of  a single circuit master. I don't care what the company tells you, a single circuit master is simply not as good as a dual circuit master. I get why they make it that way, because racers used to do it that way, and it looks cool. Sometimes looking cool is not good enough reason to make a modification. Besides, I'm sure there are plenty of dual circuit options that would bolt to that firewall plate. Like a generic Wilwood master. Wilwood bought Tilton years ago and folded the Tilton lineup into their brand. Tilton and Datsun have massive racing history, so there's your racing precedent.

 

Don't misconstrue our advice for bashing. I like what you're doing, but I'm offering ways for you to do it better with advice learned the hard way. Yes, I've blown single circuit masters before and coasting to a stop after blowing through a stop sign is not a lot of fun.

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19 hours ago, datzenmike said:

 

Not the same thing. Their assurances are aimed at OEM single masters and meaningless compared to a dual system. If you have a single master to work both front and rear brakes ANY failure in the system is a failure in the entire system.

This quote - "Most OEM master cylinders are still single feed internally and have the same assumed “risk” to our Master Cylinder. "

 

What they are trying to explain is that most new OEM masters utilize a single reservoir. If the reservoir leaks, you lose fluid to both circuits, got it. What they fail to explain is if the reservoir fails, you will still have enough fluid in the system for a panic stop. This is not the same as having a leak or failure with the cylinder or any other part after the cylinder. Their logic is faulty.

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The "risk of failure"  as your instructions state, is no different with a single or dual master, but the risk of not having brakes after you develop a system leak is significantly higher.   Master cylinder failure on a new unit can happen no matter what style of master.  They're using semantics to make a false argument.  They're saying the master isn't any more likely to have a seal fail because it only has one circuit, which is true, but it leaves the system compromised because one seal failure causes a complete braking system failure.  In a dual system, 2 seals have to fail to compromise the whole system, and that's truly rare.   

 

Racing Bonneville, we have the option of running only front or rear brakes, mostly to reduce drag.  If you wander through the pits, the most common master cylinder you'll see is a dual-circuit Wilwood, the one you can pick up for $200.  Its what I installed in my truck, for the safety of the driver.  A single master may be smaller and lighter, but it also has to provide ALL the fluid for your braking system through a single circuit.  2 circuits double the amount of fluid you can provide to the calipers by effectively pumping fluid through 2 separate ports/chambers/circuits.  2 circuits give you a functional "back-up system".  2 circuits allow you to run a lot more fluid and help prevent fluid boiling if you brake hard.  

Eliminating the booster in a boosted system results in a very hard pedal feel, ask me how I know.  Most power brake systems have a 4:1 pedal ratio, while non-power systems are near 7:1, meaning the pedal itself amplifies the power you put into it.  100 lbs of pressure from your leg applies 700 lbs of pressure to the pushrod in the master.  At the very least, you'll want to modify the master cylinder attachment point at the pedal  to improve the pedal ratio to closer to 6:1 as a minimum.  I've driven my truck with no booster and the stock pedal ratio.  I feared for the lives of anyone near me.  Completely unsafe, since it could never have stopped in the same distance as the soccer moms on the road ahead of me.  I can't leg press 1200 lbs anymore, and the effective pedal pressure required to stop in a hurry at 4:1 is over 600 lbs, with a stock or larger sized master cylinder.  

The emergency brake isn't designed to stop the truck at speed.  Its there to keep the truck from rolling when parked.  It only provides 30-ish % of your braking, since there's no weight over those braking wheels.  They'll just skid and slide, and once you lock them up, its time consuming to get them to release.  Even our race truck with 54% rear weight bias stops like shit and skids when only using the rear brakes, despite switching to what's essentially a high-traction snow tire.  

 

I can also tell you that in many states (all the ones with inspections), it is illegal to downgrade to a single master cylinder.  They were outlawed in production cars for a reason.  A single leak anywhere results in no brakes.  A leak in one line of a dual-system leaves you with half a system AND your emergency brake, so you can stop safely.  

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I agree with everything except the booster delete argument. Downsizing the master can give you the leverage required for ample brake pressure. Sure, there is a risk of running out of pedal travel, but not likely if you go down one or two bore sizes.

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