mx5cartalk.com

Guys,

I was reading another thread that mentioned the NA8 has a front / rear bias valve. I havn't seen it before, is it worth chucking some more load to the rear brakes?

Cheers -Mike

All NA & NB models have a proportioning valve. (Except the ABS equipped cars)

Yes, more rear bias is goodly. Willwood, Tilton, or NB, or most extreme, get the (non-biasing) distribution block off an ABS car (but don't call me if you leave the road arse first).

Matty wrote:All NA & NB models have a proportioning valve. (Except the ABS equipped cars)

Yes, more rear bias is goodly. Willwood, Tilton, or NB, or most extreme, get the (non-biasing) distribution block off an ABS car (but don't call me if you leave the road arse first).

Yep - I've been in a car with waaaay to much rear bias and it scared the pants off me.

Where do I find the factory installed valve? Any hints as to adjustment?

Cheers- Mike

All cars have a brake proportioning valve fitted,it is not actually a Bias valve.

The job of the proportioning valve is to stop the rear brakes looking up so the car does not spin around under heavy braking.

I would say it is not worth playing around with it...fitting a good set of brake pads will give a MX5 more than enough braking.

It's right next to the master cylinder.
It's not adjustable.
You can either replace it with one with more rear bias (eg the NB one), or fit an adjustable aftermarket unit (cheaper but DIY plumbing)

Swapping from the 1600 PV to an NB one made a noticeable difference on my car.

Our 89 NA6 feels like it has way to much front bias. Is it a recommended mod to stick the NB proportioning valve in to fix it? Any idea what I should pay for one?

adfox wrote:Our 89 NA6 feels like it has way to much front bias. Is it a recommended mod to stick the NB proportioning valve in to fix it? Any idea what I should pay for one?

Yes and yes. Mine cost $235, but the dealer didn't want to do it that cheap really (but they'd already quoted that, so they did)

You're probably better getting a Tilton, they make them with the right M10 threads now - and a union fitting for the rear line that is no longer used in the PV. Cheaper, and fully adjustable.

I see on the flying miata website they sell an adjustable one for $43 US. Looks like it might be a good option http://www.flyinmiata.com/index.php?dep ... r=14-76250