Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: TheBoy on 12 September 2011, 21:20:24
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We know WIM use a baseline of 1'10 for camber for standard Omegas, was wondering what the recommendations would be for an Irmscher sprung car.
Irmscher springs are obviously stiffer, and lower by approx 30mm...
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Irmscher quote something like -1'30 don't they?
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Interesting.
Its the stiffer bit that I suspect may have the bigger impact (although the different static wishbone angle may well affect the KPI slightly.
So given that we are trying to limit the max camber yet camber is good for cornering, I would guess at a little more static camber than a standard setup e.g. the -1.30 previously mentioned.
Would be interesting to hear Tonys thoughts.
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Indeed. Irmscher quote -1.40.
I suspect you'll end up near that figure. Maybe not immediately...But once a set of tyres get half worn
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Indeed. Irmscher quote -1.40.
I suspect you'll end up near that figure. Maybe not immediately...But once a set of tyres get half worn
Although having said that, the suspension fitted is used.
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Good topic TheBoy
Lowering the car one would assume the coil rates are higher than OEM, in this case you can afford a deeper camber because the dynamic camber gains will be less, but there's a problem.
The end position for the front camber depends on where the rear is sitting. Lowering the car will naturally migrate the rear camber negative ( top leaning in toward the car ) A 30mm drop will add around 45' leaving the non-adjustable rear camber around -2 degrees 20' +- 30'.
Setting the front depends on where the rear is, if in this case the rear is -2 degrees 20' the front needs to be around -1 degree 40' +- 10'. This allows the front camber migration during a turn better control under thrust, less camber under thrust will push and the car understeer.
The end camber positions are for handling balance only, tyre wear may be an issue because on a lock the front camber gains will be very deep.
It has to be said no modification is without consequence.
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as said, it's all about the utilisation of camber-thrust.
Part of the reason why I'd never consider lowering one of these.
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So we have a 30 mill lower car. What tyre wear will we expect to see? Assuming something like -1.40 is dialed in.
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So we have a 30 mill lower car. What tyre wear will we expect to see? Assuming something like -1.40 is dialed in.
Guessing that amount of camber would give inner shoulder?
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Problem with my type of reply is it's a global assessment of worst case. I don't know what the coil rates are so unless i can test "bump and droop" camber migration then at the moment i'm speculating.
Historically -30mm is not end of days but as said the rear camber being fixed is the dictator for where the front will be set ( for handling )
If there's an expectable element of front inner tyre wear then welcome to the modified world.
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My thinking being weather the driver actually needs the set up for the benefit of performance, rather than purely appearance.
If appearance then I'd expect to see all inside edge wear, but if he chucks it about to a level that's worthy of the set up, will we see more even shoulder wear on the outside edge as well, or merely increase the inside edge more...?
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Btw we're talking 15 mill lower than the factory spec face lift mv6 with lowered sports chassis... Which might sag that much over time anyway.
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:-/
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My thinking being weather the driver actually needs the set up for the benefit of performance, rather than purely appearance.
Are you implying something there Mr G?
You know the roads around my way - I do cover a lot of motorway/dual carriageway.
After a disappointing, albeit extreme fun, 7000 miles from a set of Sport Maxx TT's, I need a more durable compromise I think :'(. And no, Michelin do not make anything useful to anyone.
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My thinking being weather the driver actually needs the set up for the benefit of performance, rather than purely appearance.
Are you implying something there Mr G?
You know the roads around my way - I do cover a lot of motorway/dual carriageway.
After a disappointing, albeit extreme fun, 7000 miles from a set of Sport Maxx TT's, I need a more durable compromise I think :'(. And no, Michelin do not make anything useful to anyone.
Implying? Me? :-?
It's a difficult conversation to have without imPlying something.
We know camber can be set according to wear.
Driver a can have vary differant tyre wear to drivet b for the same base setting. Same as the vast majority of drivers will find Michelins suit their purposes fine. Thing is their purposes are vey differant to yours/mine/and anyone else who drives, well, like a tw@. (sorry but there we are)
Mine is currently set to -1.20 on 30 mill drop. I am experiencing outside edge wear as well as slightly less inside edge wear. This was apparent very early on in fitting the current tyres. Seems to me 1.40 would be more appropriate.
But then somebody who just plods around bring patient and not upsetting their passengers may not have the same issue. Thereby -1.20 might be fine for them...?
So q is, given I have outside edge wear at -1.20 will 1.40 give more even tyre wear ? Or all on the inside edge wear?
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But then somebody who just plods around bring patient and not upsetting their passengers may not have the same issue. Thereby -1.20 might be fine for them...?
Surely, those people would be better served by standard suspension :-/ - whilst the lowered, stiffer setup remains a comfortable ride while being more capable, it is still compromised compared to std... ...imho of course.
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But then somebody who just plods around bring patient and not upsetting their passengers may not have the same issue. Thereby -1.20 might be fine for them...?
Surely, those people would be better served by standard suspension :-/ - whilst the lowered, stiffer setup remains a comfortable ride while being more capable, it is still compromised compared to std... ...imho of course.
Seems so to me too. But was hoping to hear it from the hoarses mouth...
And also advise more clearly to those who want to "lower the car purely for appearance".
To me the lower set up is far far more comfortable than any stock set up. If that's purely because it's stiffer, or because it's lower as well...? I don't know. It's a vast improvement for me though. Job done. :y
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To me the lower set up is far far more comfortable than any stock set up. If that's purely because it's stiffer, or because it's lower as well...? I don't know. It's a vast improvement for me though. Job done. :y
I guess that is the human diversity that I sometimes struggle with.
To me, the std Elite suspension is an absolutely fantastic comfortable cruiser. Just shite when it sees the slightest deviation in direction.
The sports setup, *seems* to be a massive improvement (not had chance to play, as still struggling a bit with my hoof), without overly compromising the comfort. But bumps are still noticable.
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To me the lower set up is far far more comfortable than any stock set up. If that's purely because it's stiffer, or because it's lower as well...? I don't know. It's a vast improvement for me though. Job done. :y
I guess that is the human diversity that I sometimes struggle with.
To me, the std Elite suspension is an absolutely fantastic comfortable cruiser. Just shite when it sees the slightest deviation in direction.
The sports setup, *seems* to be a massive improvement (not had chance to play, as still struggling a bit with my hoof), without overly compromising the comfort. But bumps are still noticable.
The price I guess will be slightly less comfort and tyre life due to uneven wear. And that wear I presume will be more aggressive on the inside edge the slower it's driven. I.E. Drive faster and roll the tyre onto it's outside shoulder more...?
By that I mean slightly more bump intrusion. But Elites are way too soft IMO. Difficult to keep straight above er .... 80 :-X
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To me the lower set up is far far more comfortable than any stock set up. If that's purely because it's stiffer, or because it's lower as well...? I don't know. It's a vast improvement for me though. Job done. :y
I guess that is the human diversity that I sometimes struggle with.
To me, the std Elite suspension is an absolutely fantastic comfortable cruiser. Just shite when it sees the slightest deviation in direction.
The sports setup, *seems* to be a massive improvement (not had chance to play, as still struggling a bit with my hoof), without overly compromising the comfort. But bumps are still noticable.
The price I guess will be slightly less comfort and tyre life due to uneven wear. And that wear I presume will be more aggressive on the inside edge the slower it's driven. I.E. Drive faster and roll the tyre onto it's outside shoulder more...?
Depending on the cars use that's going to be a compromise at best. throwing the car around the twisties is going to even out the wear but if your car spends a lot of time as a motorway / dual carriage way cruiser then the balance of wear shifts...
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To me the lower set up is far far more comfortable than any stock set up. If that's purely because it's stiffer, or because it's lower as well...? I don't know. It's a vast improvement for me though. Job done. :y
I guess that is the human diversity that I sometimes struggle with.
To me, the std Elite suspension is an absolutely fantastic comfortable cruiser. Just shite when it sees the slightest deviation in direction.
The sports setup, *seems* to be a massive improvement (not had chance to play, as still struggling a bit with my hoof), without overly compromising the comfort. But bumps are still noticable.
The price I guess will be slightly less comfort and tyre life due to uneven wear. And that wear I presume will be more aggressive on the inside edge the slower it's driven. I.E. Drive faster and roll the tyre onto it's outside shoulder more...?
Depending on the cars use that's going to be a compromise at best. throwing the car around the twisties is going to even out the wear but if your car spends a lot of time as a motorway / dual carriage way cruiser then the balance of wear shifts...
Yeah I guess that's a factor too ...
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So the trade off from fitting and setting up the OOF spec lowered sports chassis is increased tyre wear and more noticable issues with bumps / speedbumps?
So then the issue becomes what tyres meet the requirements but either don't wear so fast (oh dear, harder compound :-X) or are cheaper so outweigh the wear rate issue on a £ for wear equation.
What will be the difference in tyre wear between different wheel size / sidewall (thinking flex here) combinations? Significant or not?
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If driving to a level that needs the set up then softer tyres will be needed to make use of it. With that goes initial extra cost of a sport Orientated tyre, AND the wear to follow.
If fitting 30mill drop and driving like miss daisy I guess any old shite rubber will do...? :-/
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If driving to a level that needs the set up then softer tyres will be needed to make use of it. With that goes initial extra cost of a sport Orientated tyre, AND the wear to follow.
If fitting 30mill drop and driving like miss daisy I guess any old shite rubber will do...? :-/
Agreed, the second point is the issue that isn't worth investigating IMHO, far better to buy an MV6 setup if you want some middle ground.
The point TB raised and I think KW has mentioned in other threads is that the cost V performance V longetivity balance of a perfomance tyre is something that isn't sustainable to a fair few of us so a compromise needs to sought on an individual basis, that compromise comes down entirely to the weighting we put on each of the three factors.
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Problem you all has is there's no absolute law on where the geo will be set.
As said for handling the end rear camber positions rule because it's not adjustable and it sets the tyres "saturation limit". Once know the front camber/ castor and toe can be calibrated.
If on the other hand the lowering is simply for looks then it's an open book geo wise.
Another consideration that can reflect owners reporting back after lowering is the dampers.
Lowering coils tend to be of a higher rate due to the fact each helix has less space to compress, there are other factors like maintaining the dampers "bump/ droop" activity within the working range, albeit at the lower end.
Point is, is if the dampers are tired then the coil re-bound is not controlled which is detrimental to the handling.
As negative as this reads i personally feel lowering the sprung chassis is wise? The Omega has a remarkably long suspension stroke and a very high roll centre, the length of the anti-roll bar drop-link is a visual clue.
Lowering the sprung chassis will improve the ride, not necessarily body roll but the general ride.
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Agreed, the second point is the issue that isn't worth investigating IMHO, far better to buy an MV6 setup if you want some middle ground.
The point TB raised and I think KW has mentioned in other threads is that the cost V performance V longetivity balance of a perfomance tyre is something that isn't sustainable to a fair few of us so a compromise needs to sought on an individual basis, that compromise comes down entirely to the weighting we put on each of the three factors.
Indeed. And driving style plays a big part. FWIW I think there's a limit to how fast you want to drive an Omega on the road anyway, and therefore how much you actually want it to stick.
I was struck by that today when I did my commute in the MX 5 for the first time in a very long time. I drive it a lot quicker than the Omega, and enjoy it more. :-/ Maybe because I haven't got 1.7 tonnes to haul up every time I meet someone coming the other way, maybe because it doesn't take up as much road, or it has a nice manual gearbox, or you can start to approach the limits of adhesion and feel what's going on without risking it getting messy. OK, I personally tend to only play on twisties and get bored and ease up when the corners get fast and sweeping or there are roundabouts everywhere. YMMV.
I certainly wouldn't change a thing about the MV6+KU31s setup at the moment, although having rear subframe bushes with rubber attached to them has improved it a lot. ;D
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The Omega has a remarkably long suspension stroke and a very high roll centre, the length of the anti-roll bar drop-link is a visual clue.
don't suppose you know where the Omega roll centres are front and rear do you ?
that would save me a whole lot of measurement.
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it'd different things for different people really....
I'm driving my '02 MV6 at the moment and find that excellent - maybe just a little too hard for my liking, but excellent all the same. The thrill of driving for me is to balance the motor car into, through and out of bends, so I generally find lower spring rates give me more controlleability, even on my track cars. Those who know me know that I'm hardly miss daisy. Indeed, I've just recorded my first full week at less than 20mpg when out in the sticks.
I find with pretty much all motor cars that once the roll centres have been moved around, they rarely handle as well as they did before, so this means sticking to the standard ride height at all costs. I haven't done the calsulations yet for Omega B, but I'd be willing to guess that even though the roll moment is resuces, a lower car will skew it's roll centres to such an extent that it'll roll more.
Because so many of my cars have this suspension system on them, I'm toying with the idea of building a proper geometry map for them. So, if anyone does know what the "official" roll centres are, I'd be glad to hear from them.
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For 30mill drop, suspect a basic camber guide might be...
Miss daisy or steady a to b driving 1.10 to 1.20
Fast motorway with enthusiastic slip roads and roundabouts 1.20 to 1.30
Fast twisties included 1.30 to 1.40
Maybe?
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For 30mill drop, suspect a basic camber guide might be...
Miss daisy or steady a to b driving 1.10 to 1.20
Fast motorway with enthusiastic slip roads and roundabouts 1.20 to 1.30
Fast twisties included 1.30 to 1.40
Maybe?
Provided the rear will match the front I guess. I still don't understand the rear tie rod mechanics of affecting toe and camber. Probably because I haven't had to do any work in that area.
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I have learned the hard and expensive way with the Omega ;)
If you don't wont to go all the way when lowering your Omega, don't!
Mine is lowered 40mm, and when going for 30 or 40mm lowering, the firs thing to pay your attention to is the camber in the back. There is a camberkit on the marked, from Austalia.
It's for the Holden, but it has the same chassi as the Omega.
They reccomend a camber setting for 1.55 and the combined toe for 0.20 in the rear.
The next thing is the donuts, this is what's holding the rear suspension in place, but they will flex a lot when phussing the car in turns.
So change them with polys from the same company. BIG change in drivability!!!
Then the shock's and springs. I'l rather go for sports shocks and standard sports springs then standard shocks with lowering springs. It's essential that when you lower the Omega more then 20mm, that you go for shocks that are rated for that, like the bilstein B6 or B8 and the yellow KOni.
Anyway, this is the setup for my car, and there is no unewen tyrewear :)
Poly camberkit in the rear, poly donuts, Cobra 40mm lowering springs and Yellow Koni's, adjusted to one turn in the front and 0 in the rear.
Camber 1,26 in the front. Toe combined 0.10
Camber 1.56 in the back. toe combined 0.20
The car is neutral in corners, before the rear end is starting to drift out, and it's very stable in hig speeds. A benefit from this setup is that the car is hardly roling in the turns, and it feels like you removed 300kg from the car :)
And the comfort, well, it's better then a corsa or Astra ;)
This is a setup for the driver, for the looker, just chop the springs :)
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just remember if you use the camber-correction kit from Pedders or Whiteline, you MUST discard the camber-correction bar and fit a Carlton / Omega A inner rear wishbone bush.
if you don't your semi-trailing arm will be wanting to pivot in an entirely different way to the camber-control rod wants it to. The result is a suspension bind-up.
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Chris - the essence of the rear set-up is this.
it's a semi-trailing arm with a twist....
semi-trailing arm rear suspension is great for packaging because you the manufacturer can get it all under the rear seat. That's why Omega has the minibloc spring, a neat design which keeps the same rate over it's whole range, yet folds up inside itself.
it's also good for comfort.
what it's not too hot on is maintaining a constant roll height over its operating range and maintaining consistent camber over the range.
THEREFORE.....
they like to be kept to the same inclination angle as they're designed ( rear same ride-height ).
and in the case of Omega B (and some Omega A), they have a camber-correction bar in them, which coupled with an especially floppy inner bush, allows the camber to be kept more steady over the full operating movement.
The bar sort of forces the semi-trailing arm into an illogical path in the name of better and more predictable handling, especially on lift-off. kind of like a rudimentary multi-link system.
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That all makes sense as we have discussed previously on other threads.
But to confirm, the rear track rod merely forces the trailing arm over within the natural play of the bushes.... Trailing arm only? (I don't think I'll fully sus the geometry of those pivot points until I take it to bits and look.) ... Seems a bit Micky though.
Donuts and rear dif blocks purely for comfort ? (sure I can feel it slop over in corners)
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This is a setup for the driver, for the looker, just chop the springs :)
Pmsl ;D ;D ;D
Of course we would never recommend such silly behaviour. Funny though. ;D
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My thinking being weather the driver actually needs the set up for the benefit of performance, rather than purely appearance.
Are you implying something there Mr G?
You know the roads around my way - I do cover a lot of motorway/dual carriageway.
After a disappointing, albeit extreme fun, 7000 miles from a set of Sport Maxx TT's, I need a more durable compromise I think :'(. And no, Michelin do not make anything useful to anyone.
In the late 80s early 90s Michelin bike radials were the best available
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That all makes sense as we have discussed previously on other threads.
But to confirm, the rear track rod merely forces the trailing arm over within the natural play of the bushes.... Trailing arm only? (I don't think I'll fully sus the geometry of those pivot points until I take it to bits and look.) ... Seems a bit Micky though.
Donuts and rear dif blocks purely for comfort ? (sure I can feel it slop over in corners)
... And to achieve better set up to match the front would an adjustable eccsentric inner lower trailing arm pivot help? Provided it doesn't bind? Think I'm getting it?
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My thinking being weather the driver actually needs the set up for the benefit of performance, rather than purely appearance.
Are you implying something there Mr G?
You know the roads around my way - I do cover a lot of motorway/dual carriageway.
After a disappointing, albeit extreme fun, 7000 miles from a set of Sport Maxx TT's, I need a more durable compromise I think :'(. And no, Michelin do not make anything useful to anyone.
In the late 80s early 90s Michelin bike radials were the best available
Yes they do! If you call mega mileage and hence no grip useful. Some people do you know. If you where a fleet manager or used your vehicle for business. :P
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Last set of PS2 on the Elite lasted less than 15k before the canvas poked out.
So, zero grip, and poor life. To quote wankwordbingo, that isn't a blue sky scenario.
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Last set of PS2 on the Elite lasted less than 15k before the canvas poked out.
So, zero grip, and poor life. To quote wankwordbingo, that isn't a blue sky scenario.
J pull the other one. Your not ment to drive it with weds night bangers and hoodies in the local village hall car park. Drive it sedately and you'll get 30k from primacy.... You'll also be late alot, but you'll get 30k. ;D
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Last set of PS2 on the Elite lasted less than 15k before the canvas poked out.
So, zero grip, and poor life. To quote wankwordbingo, that isn't a blue sky scenario.
J pull the other one. Your not ment to drive it with weds night bangers and hoodies in the local village hall car park. Drive it sedately and you'll get 30k from primacy.... You'll also be late alot, but you'll get 30k. ;D
Trouble with Primacy and Pilot Sport is that you start to get a slippery 'sheen' on the surface, that if you don't scrubb off, gives similar grip to Linglongs in the wet on an M40 roundabout.
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Last set of PS2 on the Elite lasted less than 15k before the canvas poked out.
So, zero grip, and poor life. To quote wankwordbingo, that isn't a blue sky scenario.
J pull the other one. Your not ment to drive it with weds night bangers and hoodies in the local village hall car park. Drive it sedately and you'll get 30k from primacy.... You'll also be late alot, but you'll get 30k. ;D
Trouble with Primacy and Pilot Sport is that you start to get a slippery 'sheen' on the surface, that if you don't scrubb off, gives similar grip to Linglongs in the wet on an M40 roundabout.
Your not wrong there. Some people do drive slower than my Mrs. :-/
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Last set of PS2 on the Elite lasted less than 15k before the canvas poked out.
So, zero grip, and poor life. To quote wankwordbingo, that isn't a blue sky scenario.
J pull the other one. Your not ment to drive it with weds night bangers and hoodies in the local village hall car park. Drive it sedately and you'll get 30k from primacy.... You'll also be late alot, but you'll get 30k. ;D
Trouble with Primacy and Pilot Sport is that you start to get a slippery 'sheen' on the surface, that if you don't scrubb off, gives similar grip to Linglongs in the wet on an M40 roundabout.
Your not wrong there. Some Most people do drive slower than my Mrs. :-/
Fixed that for you ;) ;)
As an aside, those Neutons I've stuck on the back seem pretty good (for a budget tyre) so far... Really need to get them onto the front to see about braking traction but are a definite possibility for me while still messing about with setup ;)
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just remember if you use the camber-correction kit from Pedders or Whiteline, you MUST discard the camber-correction bar and fit a Carlton / Omega A inner rear wishbone bush.
if you don't your semi-trailing arm will be wanting to pivot in an entirely different way to the camber-control rod wants it to. The result is a suspension bind-up.
I dont remember tha name of the manufacturer, but my kit contain's both inner and outher adjustible bushings.
When adjustet corectly, tha trailing/toe rod must be set to zero when car is set to ground.
I have checked the travel witout the spring, and there is no binding i the suspension.
The rod's function is mostly correcting the toe. Just look at the inner bushing, it can only move slightly in a front-back movement.
So the camber cant be adjusted as normal in the back, just the toe.
That's my experience on my 4 last Omegas, all modifyed, bringing me to the point where I'm at to day :)
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the bar moves both toe and camber when the semi-trailing arm moves.
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the bar moves both toe and camber when the semi-trailing arm moves.
As stated in my post: The rod is mostly there for adjusting and controlling the toe, but yes, the camber wil be afbreakted. But in such a small ammount that you cant realy adjust it.
From my papers, it looks like the camber moves like +/- 0.30 at maks. when adjusting the toe.
When lowering the car, the adjustable range you need is in the neiborhood of +/- 0.80 or moore. Mine was at -2.60 before adjustment, at 40mm lowering, and after the adjustment 1.56. Thats the differense of wearing the rear tyres out in one month instead of having them for two sesons ;)
The other thing to remember here is setting the toe to arround 0.20 or more, to help for a more even wear of the rear tyres.
As said before, works as a charm on mine :y