mr2 brake and suspension questions

[gasman]

so heres the story, ive gone and bought a dirt cheap auto 1990 mr2 auto and plan on doing some work to it.

ive been trolling mr2oc.com and mr2.org.nz and cant quite seem to find a definitive answer regarding brake differences between the years.

for the first generation sw20's is there any difference between turbo and non turbo brake rotors and calipers?

at which point do the so called larger brakes start coming in and are they on both na and turbo models?

if i change the brakes to the larger ones is it worth swapping the bias valve or will the stock one still be proportioned correctly?

whats the going rate for the larger brake calipers and rotors? one goon/con-artist wants $400 for just the fronts.


now onto the suspension, according to wikipedia 92+ have the suspension geometry that is less likely to "snap oversteer". is it worth swapping in the latter suspension parts over into my older chassis or just leave it as is? if the answer is yes what would i need to buy to make it work?

[thegreatestben]

When I was looking for later model rear calipers I was told the "bigger" ones were on turbo models. As it turns out they are the same between n/a and turbo.

Hope this helps, can't be much help on other points

[fivebob]

Pads, rotors and calipers are the same on all models of the same series. There is no difference between turbo and NA models.

[Akane]

at the point for end of 91~ onwards, they're the second revision MR2's

They have factory 15" alloy wheels because 14" don't fit the bigger brakes.

and $400 just for the fronts? Wow. another grand you'll almost get some second hand 4 pot love.

[iOnic]

for the first generation sw20's is there any difference between turbo and non turbo brake rotors and calipers?

Nope - no difference between Turbo/Non-Turbo brakes on SW's of any generation

at which point do the so called larger brakes start coming in and are they on both na and turbo models?

All SW's made after Dec 91 - Chassis numbers SW20-00059266 onwards have the larger brakes. Both Turbo and Non Turbo have them.

if i change the brakes to the larger ones is it worth swapping the bias valve or will the stock one still be proportioned correctly?

Not sure on this one but I changed the whole system over (master cylinder, brake booster, lines, prop valve etc) when I did mine. I've heard of them working fine on the Gen1 valve though. Whether they're as effective is a mystery - as a general rule of thumb you want to use the valve/cylinders that are matched to the brakes you're using.

whats the going rate for the larger brake calipers and rotors? one goon/con-artist wants $400 for just the fronts.

Not a lot. Pretty much any second hand brake setup that old will require a rebuild/new rotors/new pads etc anyway so you should be able to get the lot for $400

now onto the suspension, according to wikipedia 92+ have the suspension geometry that is less likely to "snap oversteer". is it worth swapping in the latter suspension parts over into my older chassis or just leave it as is? if the answer is yes what would i need to buy to make it work?

Drive a Gen1 and a Gen2+ and see which you prefer first. Some people (me included) feel that the Gen1 has a more "raw" feel and is less forgiving to inexperienced drivers. The Gen2+ feels like it's been made to suit a wider variety of drivers and is "easier" to drive. There is no such thing as "snap oversteer" so you can remove that one from your vocabulary quickly As for whether it's worth swapping in the later suspension - I'd say no, learn to drive what you have and you'll find it more fulfilling than swapping in the "MR2 for dummies" suspension setup. Gen1 has more options for adjustment in terms of wheel alignment as well.

[fivebob]

Drive a Gen1 and a Gen2+ and see which you prefer first. Some people (me included) feel that the Gen1 has a more "raw" feel and is less forgiving to inexperienced drivers.

Examine the rear suspension changes and you'll see that there is no real difference in the suspension geometry in 99% of the situations. The main change was to remove the tendency of the rear wheels to go toe out when they were at extreme movements, usually on off camber bumpy surfaces.

Having driven quite a few of both varieties, and some that have been converted, I think it's a myth that there is any difference in feel between Series 1 & Series 2 rear suspension in most situations. There's more difference to be felt in changed alignment settings on the same model than there is between different models with the same settings.

The major change, and it's one that most people seem to gloss over, is the removal of the adjustable caster at the front that really took away the ability to tune the suspension, and did affect the feel of the suspension.

There is no such thing as "snap oversteer" so you can remove that one from your vocabulary quickly

There is, it's just that you haven't experienced it yet. As noted above the tenedency for the rear wheels to go toe out can cause the snap oversteer to occur, but in saying that I've also experienced snap oversteer on Series 2 suspension. Generally speaking this situation occurs when the rear wheels become unloaded when you already traction limited at the rear. In a lot of cases it's due backing off, either due to driver error or the situation requiring it, sometimes it's due to the change on camber of the road surface, which is what happened the time I experienced it in the Series 2. General rule is not to back off if you can avoid doing so.

As for whether it's worth swapping in the later suspension - I'd say no, learn to drive what you have and you'll find it more fulfilling than swapping in the "MR2 for dummies" suspension setup.

Firstly I'd say the spirited driving in MR2s is not for dummies, secondly if only the rear suspension is changed then I doubt that more than 1% of drivers would be able to detect that change. It's the old placebo effect. If I gave you two cars to drive, one with the changes and one without and told you the opposite of what they were, you'd be convinced that the one I told you had the changes somehow felt less precise, it's just human nature to prejudge

Gen1 has more options for adjustment in terms of wheel alignment as well.

Only at the front, and most people, if they have any sense, only swap the rear.

[gasman]

when swapping the brakes do i need to swap the hubs over or are the caliper brackets different and place the pistons further out but use the same hub as the older ones?

are the piston sizes the same and will the older piston part of the bracket bolt onto the newer bracket? if so then that would save me from buying the piston half of the calipers.

[fivebob]

when swapping the brakes do i need to swap the hubs over or are the caliper brackets different and place the pistons further out but use the same hub as the older ones?

The hubs are a different part #, but I'm not sure if there are any changes to the brake mounting points on the hub, the caliper brackets are definitely different.

are the piston sizes the same and will the older piston part of the bracket bolt onto the newer bracket? if so then that would save me from buying the piston half of the calipers.

The fronts use the same pistons for all model SW20s, the rears are a different caliper and I don't know if the older rear calipers would fit on the bracket for the newer ones.

[KinLoud]

Based on no facts I that can lay my hand on at the moment...

I think the suspension mounting points were moved when they changed the rear geometry.

Some test drivers have said that the original suspension is slightly faster if you know what you are doing.

Based on facts I know...

If you drive mr2s a lot (and vigorously!) your brain will be wired into the little signals the car gives you as it begins to let go.
Because you can detect it early you only need to make a small correction to "catch it" before it tries to point 180degrees the other way!

If you don't drive MR2s a lot (like me) the first indication something is wrong is at the point when it's beyond recovery!
At this point you might have a spare braincell that will remind you to take your thumbs out from the inside of the steering wheel, put your foot either full on the brake OR full on the accelerator and try to decide what corner might hit first.

Don't worry about what suspension you have (early or late) just make a real effort to (at an appropriate venue) take it to the limit so you brain can wire itself properly!

Ken
Auck
021 408 863

[85AW20v]

From what I've experienced on the racetrack in my AW, it's braking and turning at the same time that upsets the MR2. The demon late braking move doesn't work!! Straight line braking and then powering through the corner works well as the car is settled and weight distribution is right. Brake and turn and it'll feel OK until about 2/3's of the way through the corner when the rear will try to meet the front.

If you know it's going to happen and are able to control it, it's handy sometimes to frighten your competitors into backing off coming through the last corner on your way to the finish line, especially when they've got more grunt then you

[Adamal]

If you drive mr2s a lot (and vigorously!) your brain will be wired into the little signals the car gives you as it begins to let go.
Because you can detect it early you only need to make a small correction to "catch it" before it tries to point 180degrees the other way!

Yup. This is why good tyres are a smart choice on an MR2. Those little signals have a bit more leaniancy to them, and if you do go beyond them, its still doable to pull things back into line.

..... With a big grin on your face

[iOnic]

Having driven quite a few of both varieties, and some that have been converted, I think it's a myth that there is any difference in feel between Series 1 & Series 2 rear suspension in most situations.

There shouldn't be much/any difference between the two in most situations. The changes were implemented to aid stability and predictability in extreme situations as you pointed out and most people will never find themselves in such situations. Having driven various factory examples of both revisions on the track and on sealed hillclimbs I can definitely feel the difference between the two. It's not as "night/day" as it's made out to be but if you know what to feel for, it's quite evident.

There is, it's just that you haven't experienced it yet.

I've spun my MR2 more times than I'd admit to - and every single time I can say with absolute certainty that it was my fault and my fault alone. I've never been in a situation where my car just suddenly oversteered with no warning. These sentiments are echoed by Jeff Fazio here

http://www.jekylhyderacing.com/snapoversteer.htm

[Akane]

As Tsuchiya Keiichi have said, with the MR2 you have to react fast.

http://www.youtube.com/watch?v=FeHaMdset9Y explains a lot

[Adamal]

Yep, after that, oversteer in anything else feels like you've got enough time to make a spot of tea.

And have scones.

[Toby]

From my experience with a gen 1 sw20 you have to be going pretty $&#$% fast before you reach the "snap oversteer" limit. Even full tit through Waipu Cove/Langs beach roads I always felt that I was driving fully within the chassis and my survival instinct kicked in well before any negative reaction from the car.

"Brake on the straight, before it's too late"
"Don't lift off unless you want to die in a horrible cliff/tree/car mess"

Some rules to go by although I'm sure others can think of a few.