VN Brake Test

[88GreenVN]

Took the V8 VN in for a brake test today at the local Repco reps. Stock pads and calipers, VT booster and M/C non abs.

The car was 1570kgs (full tank 80l) heavy.

Front: 5087 left, 5350 right
Rear: 1512 left, 1675 right

Front to Rear:
10437 = 76% front
03187 = 24% rear

Footbrake peak = 81%
Footbrake Avg = 75%
Parkbrake = 21%

[Zuicider]

time for new fluid and a good bleed?

[bmxj6]

hi there, am trying to fit vp switch blocks, in a vn wagon, witch has a calais series 3 loom & dash already fitted & was told your the one to talk to, any help would be great. CHEERS.

[greenfoam]

What's this brake test mean, I just want to know how many G's it pulls slowing down

[fnlow1]

Those numbers don't mean much to me mate. Care to shed some light?

[strgas]

time to upgrade to VT calipers and rotors

[88GreenVN]

This is the VZ:

Front: 4425 left, 4325 right
Rear: 2625 left, 2750 right

Front to Rear:
08750 = 61% front
05375 = 39% rear

Footbrake peak = 83%
Footbrake Avg = 77%
Parkbrake = 51%

[88GreenVN]

Those numbers don't mean much to me mate. Care to shed some light?

It's a special skid plates thing that records the bakes on the car. Bloke drives onto it and brings the car to a stop. Computer spits out the balance between all 4 wheels.

the numbers are brake force on each wheel in "Newton"

[levymetal]

so the VN has better front brakes than the VZ? amazing! i need to get myself a vt booster and master

[88GreenVN]

so the VN has better front brakes than the VZ? amazing! i need to get myself a vt booster and master

You wont regret it I can tell you

[levymetal]

do you need to change the lines or something, and would that be hard to do?

[88GreenVN]

do you need to change the lines or something, and would that be hard to do?

Modded booster rod and mount braket. PM Markovr for some ideas/cost. Really is worth the effort and the V8 is a bolt up job as the brake lines are the same (no adapters needed like on the V6)

[Cheap6]

Before anyone gets carried away with fitting a new master cylinder or booster it's worth pointing out that neither of these items will improve brake performance. All each of them will do is alter the relationship between the force on the pedal and the force the wheel cylinders apply to the discs i.e. if you can push harder on the pedal you don't need the master or booster.

You can't say that a VN has better front brakes than a VZ either, only that the front brakes do more work, at least in this test. That stands to reason as the VN (V8) is a smaller car (= likely higher CoG, more effect of engine weight on CoG) with a shorter wheelbase, and a heavier engine. All of these will tend to put more weight on the front wheels as well as cause more dynamic weight transfer.

Note that the peak and average G's are virtually the same for both cars.

The most useful thing from the tests would appear to be checking that the brakes are even left to right (they are).

[immortality]

we do this brake test every 6moths when we get a WOF done. really it's just to check the ballance.

[88GreenVN]

Well yesterday I had to "test" the brakes for real. I stopped way short of what I thought I was going to. (small car stopped on the yellow in front of me at 60 kph) No skidding or noise from the tyres - but the old VN just about chucked everything out of the boot and over the car.

All in all I'd still recommend upgrading the booster and m/c even if it's only pedal feel - now I think I need to fix the front shocks

[immortality]

Well yesterday I had to "test" the brakes for real. I stopped way short of what I thought I was going to. (small car stopped on the yellow in front of me at 60 kph) No skidding or noise from the tyres - but the old VN just about chucked everything out of the boot and over the car.

All in all I'd still recommend upgrading the booster and m/c even if it's only pedal feel - now I think I need to fix the front shocks

i've found mine to border on the side of dangerous with the current combo of stock VN V6 rotors/calipers and VT style M/C+booster. it does stop really well unfortunately i have issues with rear wheel lock up when braking real hard. the one time i did have to stop when some old suicidal nanna ran out in front of me i came to a full stop sideways because the rear locked fully and even stalled the engine. the only difference i can see is the manual trans which engine brakes much better then the auto. i'm either going to have to alter my driving style or fit a proportioning valve to reduce rear brake bias. (proportioning valve sounds better)

no matter what the numbers say. the car pulls up way better then it did before with the standard MC/booster

[88GreenVN]

i've found mine to border on the side of dangerous with the current combo of stock VN V6 rotors/calipers and VT style M/C+booster. it does stop really well unfortunately i have issues with rear wheel lock up when braking real hard. the one time i did have to stop when some old suicidal nanna ran out in front of me i came to a full stop sideways because the rear locked fully and even stalled the engine. the only difference i can see is the manual trans which engine brakes much better then the auto. i'm either going to have to alter my driving style or fit a proportioning valve to reduce rear brake bias. (proportioning valve sounds better)

no matter what the numbers say. the car pulls up way better then it did before with the standard MC/booster

Do you have V8 calipers? maybe it's the V8 weight and finned calipers + 225/16 tyres.

I had no lockup at all and the car just stopped dead - well short of the car in front - to the point of did I over react a little. But no I was impressed no end on my cars brake performance in the dry. Wet may be different tho - we shall see.

[immortality]

Do you have V8 calipers? maybe it's the V8 weight and finned calipers + 225/16 tyres.

I had no lockup at all and the car just stopped dead - well short of the car in front - to the point of did I over react a little. But no I was impressed no end on my cars brake performance in the dry. Wet may be different tho - we shall see.

nahh mate, stock V6 callipers. i also have fairly new shockers and good 235/45/17's all round

the fronts did not lock and the car pulled up real good. fact is, if it had happened with the stock brakes the suicidal nanna would have been dead as it would never have stopped in time, as it was i pulled up with probably less then a meter to spare.

to be honest, the more that i think about it. the more that i think it's related to my driving style/transmission setup. becuase the VN's have such poor brakes i use the transmission a lot to brake. where the nanna stepped out is on my is on my regular route home, it was at the top of the crest of a hill where i normally change down a gear and let the car run down the hill without using the brake pedal. that morning i was in a hurry and had let the engine rev out a little in 2nd coming to the top of the crest ready to change into 3rd to let it run down the hill like i normally do, however the nanna stepped out onto the road without warning and i had to hit brakes hard i think i also popped the clutch out at the same time which caused a compression lock up on the rear wheels and the car going into a slide/spin. some quick fanny footwork on the brake pedal and wheel stopped the back end coming completely around and killing the stupid bitch.

i'm definitly going to fit VT style rotors and calipers as it will improve the situation again over what i have now