Attn NB racers: front neg camber question(s)

[NMX516]

Hi guys,

I took the NB8B in for a wheel alignment yesterday, and was told that there wasn't enough adjustment on both front wheels to get as much neg camber as my alignment guy wanted to get out of it. In fact, there was less than has been set on my NB8A... He said there is more adjustment on the RH front than the left. He said there is no damage etc to the car, it is the way it is made.

Now, I don't know the numbers he was trying to achieve, but we were trying to set it up for "fast road" with maybe 6 track days per year, so nothing too drastic, but some good neg camber none the less.

So, to all those who race NB8B's, have you encountered this problem too? I assume you would be wanting a couple degrees neg camber on the front on a race 5. If so, can you get around it and how?

Thanks in advance

[greenMachine]

Well, simplest way of doing it is to fit new bushes with adjustable pins. These give a bit more neg camber, when you install them put a small blob of weld on the face of the front ones to stop them rotating under the forces fed in from the lower arm. BTDT

I used superpros, the harder of the two that are available.

Good luck

[Cal]

^ What he said. -2 all round works pretty well for fast road/track. That is what I run on BRG.

[CT]

Hi guys,

I took the NB8B in for a wheel alignment yesterday, and was told that there wasn't enough adjustment on both front wheels to get as much neg camber as my alignment guy wanted to get out of it. In fact, there was less than has been set on my NB8A... He said there is more adjustment on the RH front than the left. He said there is no damage etc to the car, it is the way it is made.

Now, I don't know the numbers he was trying to achieve, but we were trying to set it up for "fast road" with maybe 6 track days per year, so nothing too drastic, but some good neg camber none the less.

So, to all those who race NB8B's, have you encountered this problem too? I assume you would be wanting a couple degrees neg camber on the front on a race 5. If so, can you get around it and how?

Thanks in advance

Is your car lowered? If not, forget getting maybe more than 1/2 deg neg on the front of an NB. As you lower the car, the camber angle actually increases naturally. With offset bushes, you can then get more. My road car can get -2 without offset bushes. As for what us racers do, well, we move the lower ball joint out 15mm by modifying the lower control arm. Then, with offset bushes, -6 is achievable.

[NMX516]

Thanks guys!

greenMachine, what are the other brand of bushes which are available?

CT, the car is lowered to some extent, but not massively. I have Tein SS's which were set to give 100mm ground clearance on the NB8A, but I just swapped them straight into the 8B and haven't measured the clearance since... The 8B seemed fairly low at the front to start with, so doesn't seem to have dropped much since fitting the Teins. The difference between the Teins on the 8A was more pronounced than on the 8B at the front... I'll do some measuring on the weekend and see if I can get away with lowering it further.

[greenMachine]

Have you seen Boyracer's post http://mx5cartalk.com/phpBB-3.0.2/viewtopic.php?f=44&t=34505? This photo shows the offset pins to good effect.

I don't know who else makes them, there is Nolathene locally they might do MX5 bushes, or try the 949Racing site, IIRC they have some. Goodwin Racing ....

However, everyone I know is happy with the Superpros.

[CT]

Thanks guys!

greenMachine, what are the other brand of bushes which are available?

CT, the car is lowered to some extent, but not massively. I have Tein SS's which were set to give 100mm ground clearance on the NB8A, but I just swapped them straight into the 8B and haven't measured the clearance since... The 8B seemed fairly low at the front to start with, so doesn't seem to have dropped much since fitting the Teins. The difference between the Teins on the 8A was more pronounced than on the 8B at the front... I'll do some measuring on the weekend and see if I can get away with lowering it further.

Just make sure you the lower control arms are parallel to the ground via an imaginary line through the ball joint and subframe mounting bolts otherwise you will induce bump steer - which is bad. Too low is not better. More camber is not always better either. 1-2deg neg with zero toe and 4+ castor for a mostly road dríven car is plenty good.

[NMX516]

Thanks guys!

greenMachine, what are the other brand of bushes which are available?

CT, the car is lowered to some extent, but not massively. I have Tein SS's which were set to give 100mm ground clearance on the NB8A, but I just swapped them straight into the 8B and haven't measured the clearance since... The 8B seemed fairly low at the front to start with, so doesn't seem to have dropped much since fitting the Teins. The difference between the Teins on the 8A was more pronounced than on the 8B at the front... I'll do some measuring on the weekend and see if I can get away with lowering it further.

Just make sure you the lower control arms are parallel to the ground via an imaginary line through the ball joint and subframe mounting bolts otherwise you will induce bump steer - which is bad. Too low is not better. More camber is not always better either. 1-2deg neg with zero toe and 4+ castor for a mostly road dríven car is plenty good.

Yeah I don't want it too low. From memory the height of the NB8A was dropped about an inch, maybe inch and a quarter, but not more than that. I spoke to my wheel alignment guy today, and the NB8A had 1.25 deg neg camber on the front, the 8B he managed to only get 0.75 deg... He said he would like to get 1.5 on the front for my purposes, so I'm going to give these Super Pros a try. Hopefully they will be able to give enough adjustment to get to at least 1.5. It seems like it could be an experiment of sorts, as he said he has fitted them to some makes before, and the manufacturers claimed amount of adjustment has been far too optimistic.

[16bit]

i got an alignment yesterday and holy shite was it out. check out the before and after!!!!


garage.php?mode=view_image&image_id=564

[NMX516]

i got an alignment yesterday and holy shite was it out. check out the before and after!!!!


http://www.mx5cartalk.com/phpBB-3.0.2/g ... age_id=564

Have you been bouncing off too many ripple strips?!

[16bit]

funnily enough no. i think when I lowered the car and didn't get another alignment it went all wrong. the car feels soooooooooooooooo much better now. it turns in a million times better now. its just brilliant. can't wait to get on the track.

[greenMachine]

... he said he has fitted them to some makes before, and the manufacturers claimed amount of adjustment has been far too optimistic.

At the risk of stating the bleeding obvious ....

When installing these adjustable offset bushes, with all that horrible moly grease on everything, it is easy for the bushes to rotate before they are tightened up. All it takes is some rough handling as the lower arm is installed.

IIRC it is possible to eyeball them to verify that the offset is fully outboard of the centre of the bush. If not, and the camber is not what you expect/want, its easy enough to drop the arms at the inboard end and check the position of the bush.

And to repeat my earlier comment, don't forget to get the dob of weld to keep the bush from rotating even when tightened.

[NMX516]

I'll keep an eye on him greenMachine thanks

Anyone have any clues on what I should expect to pay for this exercise, incl fitting?

16bit, how much neg camber have you got on yours? Any need for adj lower control arm bushes on yours?

I can't believe how much different the 1.25 on the 8A is to the 0.75 on the 8B...

[Guran]

I've read that increasing the castor angle naturally increases the negative camber.

[CT]

I've read that increasing the castor angle naturally increases the negative camber.

Opposite actually - increasing castor decreases available camber. Quite often you have to dial castor back to maintain camber angles in the MX5.