No Brake Booster In A Road Car???

[Duk]

To the best of peoples knowledge, is it legal to create a brake system in a road car that does away with the original booster?

The brakes are intended to be significantly more capable than standard.
At a bare minimum they would be the existing 284mm 164 rotors and Volvo 240 4 piston calipers.
But I'm looking to do either a Series 4/5 (FC3S) RX7 Turbo rotor (again about 284mm) and matching 4 piston caliper, or the Series 6 (FD3S) 295ish rotor and bigger 4 piston calipers.
Rear's would be 275mm vented rotors and Series 4/5 RX7 Turbo vented single piston caliper (MUCH bigger pad surface area than the Alfa calipers).
I'm looking to reduce weight, make space for chassis bracing and to simplify.

Yes I continue to wallow around in the 'I'm still not sure what to do with the engine', but I'll put target power between 250 and 400hp (OK, 400hp would be a built bottom end with chunkier rods and pistons) and weight just south of 1300kg.

Also, something that oz3litre said about putting the car back togther, made sense (not that I'm anywhere near that!).
My argument against it, tho, is the fence sitting that I'm still doing and basically revolves around deciding on a warmed up NA engine or shoving some boost into it.
And a big bug bear is removing the passenger side head.
If I went force fed, I'd want to keep combustion chamber volume as large as possible. But if I went for a warmed NA engine, machining the heads for extra compression would be needed.
The heads and inlet runners are all ready ported and the valve seats modified with Richard Jemmison valve seat angles.
With the booster removed, removing the passenger side cylinder head can be done without taking the engine out, if I decide on staying with a warmed NA engine! 

Piccies to help give clarity. Pics from post on this forum by our esteemed members.

[bonno]

Hi Duk
I assume the brake booster has been done away with, because of insufficient room in engine bay. If this is the case and it is a legal requirement to fit, then try a remote mounted unit located in the boot (refer to the following link on available kits).
http://techtalk.mpbrakes.com/boosters/remote-mounted-brake-boosters-vacuum-booster-solutions-for-cramped-engine-compartments

[Craig_m67]

Googling suggests it may all need a Safety Cert - Best to talk to the person who will do that for you


NATIONAL CODE OF PRACTICE for LIGHT VEHICLE CONSTRUCTION and MODIFICATION (VSB14)
^this may be completely the wrong VSB - i was just googling outta interest^

1.1 MODIFICATIONS NOT REQUIRING CERTIFICATION
The following modifications may be performed without certification:
- Fitting a manufacturer's optional braking system for the particular make/model; and
- Fitting of additional or substitute in-line brake boosters to pre-ADR 31/35 vehicles.

1.2 MODIFICATIONS REQUIRING CERTIFICATION UNDER LG CODES
The following modifications may be performed under LG Codes:
- Fitting disc or drum brakes that are not a manufacturer's option;
- Substituting brake master cylinders, wheel cylinders or calipers;
- Fitting or modifying brake balance and pressure limiting devices;

When the brake system of an early model vehicle is modified, a dual or split circuit brake system
should be fitted. Disc brakes are highly recommended on the front and generally should be
power assisted.



That's a cool link above - you could fit the boosters off a 105
(don't do it!)

[Duk]

Cheers Craig_m67.
I'm in SA, so I don't know how much diffenece that causes. Certainly the rules around the country do vary a lot.
But it looks like I'm staring down the barrel of an Engineer's approval.

So if I need to get Engineer's approval for that, maybe it's worth while going with outboard rear brakes too............... Hmmmmmm.

[Colin Edwards]

Hi Duk,

Will your non-servo'd / non boostered brake system develop the required line pressure?  Have you measured the respective servo'd / non-servo'd brake line pressures?
As others have suggested, may need to consider a remote booster.

I'm interested to see what comes of this.  Doing some relatively minor brake development work on my own 75 V6.

Colin

[Duk]

Hi Colin,

others have done it, so it does work.
However, who can drive the car might be a bit different. Leg muscle strength requirements would be significantly higher than standard.
From what I understand, car brakes are suppose to be specified so that the driver of modest strength can still stop the car if the booster fails.

I've got no intentions to run a remote servo. There's no point. The existing servo works and very well. The idea, as mentioned is to reduce weight and give more space (tho I don't actually need any more space, it does mean the chassis brace will be easier to make).

From MD's build thread: http://www.alfaclubvic.org.au/forum/index.php?topic=7616.15

"The original pedal box was altered to accommodate a 4 bolt 25mm Toyota tandem master cylinder. The brake foot lever was reworked to provide a 6.5 lever ratio as there was no boost."

[LukeC]

In short:

You will need an engineering certificate when removing a booster.

You need to be able to demonstrate the vehicle will continue to meet the technical and performance requirements to which applied to the vehicle when first certified (later, more stringent standards may be applied).

Braking tests comprised of achieving a minimum deceleration with a maximum force applied to the control. This also applies to the secondary brakes (when each circuit fails). When significant power outputs are made, endurance tests must also be made.

[Citroënbender]

From memory there were/are constraints on physically altering brake pedals in some states too, I mention this in light of the referenced article apparently having the lever length of the pedal altered.

[105gta]

From my understanding of local qld laws and NCOP regs
If the vehicle was released with a booster it must retain a booster. I'm sure you could find an engineer who could find a way around this and pass it without a booster.
That being said. It's not hard to still fit a booster in the engine bay if wanted?  and keep it serviceable and looking factory which always helps with the local law enforcement on the side of the road. (As soon as it looks modified they want to dig deeper!)
Btw. I'm assuming you're fitting a 24v and that's what this is about.

[Duk]

The reasons for removing it are in my first post.
Probably no 24V engines.

[julianB]

I'm planning on it (removing the booster).

I'll be running a pedal box, probably a floor mounted Tilton unit.
I'm expecting to have to fine tune cylinder sizing after doing the maths, with the idea that full pedal pressure locks the fronts towards the end of a big stop.

Of course, I'll have the car engineered and completely legal.
I've driven an E30 with a pedal box and no booster and found it fine to drive (running GTR brembos up front on E46 M3 discs).

The engine bay can get pretty crowded with these things, and by the time I have an ITB 24v in there, the last thing I want crowding the bay is a booster and that huge cross over bar.

[Duk]

A quote from the first post
"With the booster removed, removing the passenger side cylinder head can be done without taking the engine out"


Just move the booster and pull the head you need to move it to pull the motor

Cylinder head removal without removing the engine is an added bonus. Removing the booster is a bit of a PITA. Desturbing all of the hydraulics is a major PITA.
And the biggest goal is the reduction of weight that is high in the car.

[Duk]

It's the same reason why I struggle with adding a supercharger or a pair of turbos. It's not so much the amount of weight, but where the weight is. Up high and far forward.

No you won't notice any 0-100km/hr improvements by this change alone.
You would notice much more acceleration improvements by lightening the engine and clutch flywheels and you wouldn't be removing 12odd Kgs in the process.

By making a series of incremental improvements, I expect the car to have better turn in, less lateral weight transfer and ultimately be a much more agile and responsive car.
This change goes along with moving the battery, windscreen washer bottle and charcoal canister to the boot, using the TS/2.5 litre type bumpers (maybe a custom made Veloce style fiberglass bar), either a carbon fiber or fiberglass bonnet, maybe fiberglass front guards and moving the engine back as much as I can.

There are a bunch of suspension and chassis changes I'm making too, but that's another subject all on its own. I will say that it is (well, will be) a road car.
Spring and anti roll bar rates are intended to be for a road car and to not overly stress the poor old Alfa chassis.
Tho significant chassis regidity improvements are on the cards, I still plan on keeping suspension natural frequencies at 2Hz or lower (around 1.8Hz front and 2Hz rear) with suitably matched, digressive piston equipped dampers.

I don't subscribe to the notion that "This is all the Alfa 75 is, like it or lump it!" philosophy.
Nor do I accept that these sort of changes are only for pure track cars.

[Colin Edwards]

A little bit off topic, however lowering the drivers seat a tad and moving it back as far as ergonomically feasible will improve weight distribution, COG and polar moment. 

Given the V6's marginal engine cooling, a more efficient and lighter radiator moved rearwards as much as possible would also assist.  I'm looking at locally made aluminium radiator holding half the coolant, 30% more efficient and 40% lighter. 

[Duk]

A little bit off topic, however lowering the drivers seat a tad and moving it back as far as ergonomically feasible will improve weight distribution, COG and polar moment. 

Given the V6's marginal engine cooling, a more efficient and lighter radiator moved rearwards as much as possible would also assist.  I'm looking at locally made aluminium radiator holding half the coolant, 30% more efficient and 40% lighter.

The radiator is definitely an area to look at.
I got an aftermarket aluminium radiator for the VL to VS V8 Commondores, but it's a lot thicker than I really need. It has very good surface area, but would hold more coolant and so would be heavier than I really want.
Any suggestions on a suitable, thin but large surface area aluminium radiator would be great. Moving plumbing is no big deal, but it would have to be a fabricated aluminium radiator not a crimped on end tank rad.

Moving the radiator back a bit would help, but you are limited in how far you can move it because of the cross member.
You could tilt it backwards at the top and then make a nice, light weight duct.
A large, non Alfa Romeo ducted fan that grabs air from the entire core's surface area is the key to making it work at low air flows.
Like the 14" Spal unit I have