bluesmoke Posted January 25, 2011 Report Share Posted January 25, 2011 Hi folks, I was hoping Tony may get a chance to look at this, but in truth anybody knowledgable could probably help. There are a few of us on the MR2OC who are about to fit RCAs to our cars, as per this topic: http://www.mr2oc.co.uk/forum/mk2/roll-cent...me-141550.html/ I'm wanting to fit mine, which are the Tom's camber adjustable RCAs, and have the car set to Dinos MR2 alignment settings. What I don't know is whether I should have any camber adjustments made via the RCAs or if it should be done via camber adjustment bolts at the back and camber adjustment bolts and/or adjustable top mounts at the front? My biggest worries are: 1. I'm not sure where the adjustment bolts in the RCAs go, i.e. do they bolt into something or do they just push up against something, altering the angle of the hub the more they are screwed in? And if they just push up against something, does that make the hub unstable going over bumps? 2. I intend to go to Nigel Lang in Bolton when I get the alignment done, as I am in West Yorkshire. I'm concerned that they either won't know how to adjust the camber using the RCAs or they won't even have encountered them before. Is this likely? Thanks in advance for any help Quote Link to comment Share on other sites More sharing options...
CIH Posted January 25, 2011 Report Share Posted January 25, 2011 Hi BS! TBH I'm not really sure how those roll centre adjusters (RCAs) function. It looks like they reposition the steering arm which would be an anti-bumpsteer measure and not really an RCA. It would help if you could clarify. What I do know for sure is in the Nissan Silvia/200SX world they have either taller lower control arm balljoints or an extended section to the hub. In either case it re-establishes the lower control arm in a (more or less) horizontal position. I personally am generally inclined to adjust camber with the topmounts as it's the least likely to encounter any prolems. I don't know if Langs are familiar with them but no one can hnestly say they've seen everything. Oh and I saw on the MR site they wanted kpi/sai & camber for an SW20; Jap Rev 1 = C -0.55 SAI 13.35 All UK and Jap Rev 2 & 3 = C -1.00 SAI 13.50 Quote Link to comment Share on other sites More sharing options...
Tony Posted January 25, 2011 Report Share Posted January 25, 2011 Welcome to wim If you need to correct the roll centre you wouldn't fit the adjusters in the lower ball joint and steering arm, nor do i understand why the camber position is mentioned other than the camber curve on bump. Historically the new track-rod end adjuster will increase the radius of the arms curve to within the curve of the wishbone, the camber curve is totally beside the point at this time. Quote Link to comment Share on other sites More sharing options...
bluesmoke Posted January 25, 2011 Author Report Share Posted January 25, 2011 Welcome to wim If you need to correct the roll centre you wouldn't fit the adjusters in the lower ball joint and steering arm, nor do i understand why the camber position is mentioned other than the camber curve on bump. Historically the new track-rod end adjuster will increase the radius of the arms curve to within the curve of the wishbone, the camber curve is totally beside the point at this time. Cheers guys. I'm really confused now lol. These RCAs are meant to put the lower arms back to stock position. I'm not sure really how much you need to know before installing them. It's when trying to work out how to use the camber adjustment element that I get a bit lost. Quote Link to comment Share on other sites More sharing options...
Tony Posted January 25, 2011 Report Share Posted January 25, 2011 That's fine but you don't need both, if the car is staying low your wise to use the track-rode end adjuster. The camber change is a consequence of changing the roll centre but it's an easy fix and another story. Quote Link to comment Share on other sites More sharing options...
Tony Posted January 25, 2011 Report Share Posted January 25, 2011 Additional reading..> http://www.wheels-inmotion.co.uk/forum/ind...?showtopic=3337 Quote Link to comment Share on other sites More sharing options...
nikk1877 Posted January 25, 2011 Report Share Posted January 25, 2011 That's fine but you don't need both, if the car is staying low your wise to use the track-rode end adjuster. The camber change is a consequence of changing the roll centre but it's an easy fix and another story. The parts that we are intending to fit (in the above link to the MR2OC thread) are being marketed as 'roll centre adjusters'. Perhaps that would be an inacurate product description but that aside, we are aiming to use them to correct our SAI. Me and many others have been under the impression that the additional bump steer we experience after lowering our vehicles, is due to inclined suspension arms (raised SAI?) adding positive camber through the upward stroke of the suspesion (bump?). By fitting this 'spacer' between the lower arm and ball joint we are hoping to correct the SAI and reduce said bump steer. I think a few people have become confused with the static camber adjustment offered on some of these 'RCA's'. Although it has been confirmed above, that the best way to do this would be through camber bolts or adjustable topmounts. So, with that out the way we'd like your thoughts and wisdom on the following: Are the components in question really suitable for what we are aiming to achieve? With regards to changing the roll centre and it's effect on camber, I'm all ears (or eyes) for the whole story and how we may apply it to the SW20, if you are willing to tell. Obviously I'd love to bring my car and components to WIM for a full calibration but I'm at the other end of the country. Quote Link to comment Share on other sites More sharing options...
Tony Posted January 26, 2011 Report Share Posted January 26, 2011 That's fine but you don't need both, if the car is staying low your wise to use the track-rode end adjuster. The camber change is a consequence of changing the roll centre but it's an easy fix and another story. The parts that we are intending to fit (in the above link to the MR2OC thread) are being marketed as 'roll centre adjusters'. Perhaps that would be an inacurate product description but that aside, we are aiming to use them to correct our SAI. Me and many others have been under the impression that the additional bump steer we experience after lowering our vehicles, is due to inclined suspension arms (raised SAI?) adding positive camber through the upward stroke of the suspesion (bump?). By fitting this 'spacer' between the lower arm and ball joint we are hoping to correct the SAI and reduce said bump steer. I think a few people have become confused with the static camber adjustment offered on some of these 'RCA's'. Although it has been confirmed above, that the best way to do this would be through camber bolts or adjustable topmounts. So, with that out the way we'd like your thoughts and wisdom on the following: Are the components in question really suitable for what we are aiming to achieve? With regards to changing the roll centre and it's effect on camber, I'm all ears (or eyes) for the whole story and how we may apply it to the SW20, if you are willing to tell. Obviously I'd love to bring my car and components to WIM for a full calibration but I'm at the other end of the country. 1: The bump-steer is due to the difference between the wishbone/ steering arm radius on bump, this can be solved by fitting the track-rod end. 2: The camber curve on bump will be negative because the suspension leg is perpendicular to the vertical. 3: SAI projection and camber position taken at the wheels centre produces the scrub radius, this point should be a the steering axis pivotal point, if it not then the handling is pants. 4: The SAI projection is adjustable contrary to what people think, it's adjusted by tilting the hub which is achieved by fitting EZ adjuster bolts in the suspension leg. Quote Link to comment Share on other sites More sharing options...
bluesmoke Posted January 26, 2011 Author Report Share Posted January 26, 2011 Tom's rear RCA fitted without the camber adjustment bolt: Quote Link to comment Share on other sites More sharing options...
Tony Posted January 26, 2011 Report Share Posted January 26, 2011 It's changing the angle of the lower arm but the SAI will be the same. Quote Link to comment Share on other sites More sharing options...
CIH Posted January 26, 2011 Report Share Posted January 26, 2011 It just so happens the 200SX peeps are discussing Roll centre too. I whipped up a little picture as most diagrams use double wishbones and the principals aren't quite the same. Dig this; Quote Link to comment Share on other sites More sharing options...
Tony Posted January 26, 2011 Report Share Posted January 26, 2011 Shame it's pointing at the strut for SAI rather than the hub As you should know spacing the lower arm will only change the perpendicular angle of the arm, it will not change the SAI or the camber curve. To change the SAI or curve a movement in the camber at the strut anchor points or a change in the length of the lower arm is required. I honestly feel peeps in the 200SX forum are over analysing the problem. If there is steer on bump the steer radii needs to be lowered, if there's wayward looseness at speed ( 50mph+ ) the SR is an issue via the SAI. Quote Link to comment Share on other sites More sharing options...
CIH Posted January 26, 2011 Report Share Posted January 26, 2011 Shame it's pointing at the strut for SAI rather than the hub It's pointing at the axis between botom balljoint and topmount Quote Link to comment Share on other sites More sharing options...
phipck Posted January 27, 2011 Report Share Posted January 27, 2011 so an adjustable top mount would alter SAI in this scenario then as it would change the possition of the top strut anchor point? Quote Link to comment Share on other sites More sharing options...
Tony Posted January 27, 2011 Report Share Posted January 27, 2011 You would get more correction from the strut pintch bolts at the hub. Quote Link to comment Share on other sites More sharing options...
phipck Posted January 27, 2011 Report Share Posted January 27, 2011 very interesting stuff! Quote Link to comment Share on other sites More sharing options...
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