Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: feeutfo on 19 October 2010, 04:49:00

Title: 30 mill lowering, experiences please.
Post by: feeutfo on 19 October 2010, 04:49:00
Certainly with the irmscher body kit on mine the air dam rubs the floor down the far side of speed bumps with 15 mill lower mv6 suspension, and am resigned to never riding over or parking right up to a curb... :(

30 mill is quite a drop, but I love the ride, lack of body roll, and stance this particular suspension kit set up offers  :-*  :y, but will it muller the under side of the car should I fit similar to my new black pride and joy? There are some quite severe speed bumps on my commute... :'(

Anyone else on here got 30 mill drop? And is it a pita?

Ta.
Title: Re: 30 mill lowering, experiences please.
Post by: Kevin Wood on 19 October 2010, 09:42:47
Looks like a choice. Irmscher bits or lowered?

How much rear camber do you end up with after 30mm lowering? There's quite a lot on my MV6 setup, especially if it's fully loaded.

Kevin
Title: Re: 30 mill lowering, experiences please.
Post by: F1 9LFG on 19 October 2010, 09:50:56
hi chris, i dropped my omega when i brought it, had a broken spring so thought it was the perfect time!

i lowered by 40mm and have only rubbed a speed bump once, that was the exhaust catching, and it was a large bump.

i only have stock body parts and being a cdx, not mv6 the ride height was quite high before.

makes a big difference to looks and handling, though oddly the front is lower than the back when the back seats are empty, by a fair amount too.

 :y
Title: Re: 30 mill lowering, experiences please.
Post by: aaronjb on 19 October 2010, 10:00:34
Depends if you ever go down Telford Drive in Slough (or anywhere with 'speed cushions' but in by the same people) - they were all but impossible to navigate in the MR2 with it lowered 30mm :-/ it was a case of stop, crawl over hump, drive, stop, crawl over hump, drive.

Really annoyed the 4x4 owners who could go over them at 40mph (did I mention it was a 20 limit outside a school, put there because of the 4x4 owners dropping their kids off? No, that didn't annoy me at all, as you can tell).
Title: Re: 30 mill lowering, experiences please.
Post by: 2woody on 19 October 2010, 10:26:23
I'd say you'd need to go "off-piste" with the suspension settings if you were to lower beyond the "standard" MV6 spec.

it is highly likely that the roll-centre changes resulting from the lowering will make the handling worse rather than better.

the suspension geometry relies on how the wheels move in relation to the body when in roll. If,for instance, the static position of the lower wishbone is altered at rest (through lowering), the amount that the camber changes with roll will be different that Opel intended, probably incompatible with the roll angle, thereby reducing grip.
Title: Re: 30 mill lowering, experiences please.
Post by: F1 9LFG on 19 October 2010, 10:37:21
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I'd say you'd need to go "off-piste" with the suspension settings if you were to lower beyond the "standard" MV6 spec.

it is highly likely that the roll-centre changes resulting from the lowering will make the handling worse rather than better.

the suspension geometry relies on how the wheels move in relation to the body when in roll. If,for instance, the static position of the lower wishbone is altered at rest (through lowering), the amount that the camber changes with roll will be different that Opel intended, probably incompatible with the roll angle, thereby reducing grip.

What you say is all very true, however i had full suspension geometry adjusted to suit the 40mm drop and cant say i have noticied any problems in grip, only improvement, even in the wet it is far better on the roundabouts
 :y
Title: Re: 30 mill lowering, experiences please.
Post by: serek on 19 October 2010, 14:21:43
got irmscher springs -30mm on mine and dont have any problems with drive over speed bumps :y
Title: Re: 30 mill lowering, experiences please.
Post by: feeutfo on 19 October 2010, 15:07:38
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Looks like a choice. Irmscher bits or lowered?

How much rear camber do you end up with after 30mm lowering? There's quite a lot on my MV6 setup, especially if it's fully loaded.

Kevin
A phone call to wim is on my list of jobs, the car it's currently fitted to has visibly more camber than mine at the rear!

 Question is why? did the owner not set it correctly? even though the suspension turrets are emblazoned with yellow irmscher stickers announcing a new setting of 1.40 is required? Front looks to be set correctly afaict, so why not adjust the rear? Because it compromises the toe setting excessively? or just didn't bother the with the rear? Or just seized track rods possibly?  :-/

I do wonder if the the toe setting would be miles out if the camber was set with such a low ride hight....? I'll get my head round that piece of geometry one day. The car has a history of tyre wear advisories on the rear... :-/

Title: Re: 30 mill lowering, experiences please.
Post by: Kevin Wood on 19 October 2010, 16:09:11
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Question is why? did the owner not set it correctly? even though the suspension turrets are emblazoned with yellow irmscher stickers announcing a new setting of 1.40 is required? Front looks to be set correctly afaict, so why not adjust the rear? Because it compromises the toe setting excessively? or just didn't bother the with the rear? Or just seized track rods possibly?  :-/

I do wonder if the the toe setting would be miles out if the camber was set with such a low ride hight....? I'll get my head round that piece of geometry one day. The car has a history of tyre wear advisories on the rear... :-/


The camber/toe are a combined "setting" on the track control rods at the rear, so you have a choice of the right camber or the right toe. ;)

The suspension geometry gives extra dynamic camber as it is compressed (designed to keep the tyre contact patch parallel'ish to the road when it rolls during cornering) so by lowering the ride height you are also adding camber which you can't adjust out without bu66ering up the toe.

As 2woody says, you might need to make some changes to make it handle right afterwards.

The reason I mention it is that I know when I get mine aligned they are never happy about the amount of static camber at the rear wheels (well over 2 degrees) but can't do anything about it (and that's with a completely standard MV6 setup).

Having said that, the rear end on mine positively refuses to let go, so something's working OK. :)

Kevin
Title: Re: 30 mill lowering, experiences please.
Post by: feeutfo on 19 October 2010, 17:32:39
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Quote
Question is why? did the owner not set it correctly? even though the suspension turrets are emblazoned with yellow irmscher stickers announcing a new setting of 1.40 is required? Front looks to be set correctly afaict, so why not adjust the rear? Because it compromises the toe setting excessively? or just didn't bother the with the rear? Or just seized track rods possibly?  :-/

I do wonder if the the toe setting would be miles out if the camber was set with such a low ride hight....? I'll get my head round that piece of geometry one day. The car has a history of tyre wear advisories on the rear... :-/


The camber/toe are a combined "setting" on the track control rods at the rear, so you have a choice of the right camber or the right toe. ;)

The suspension geometry gives extra dynamic camber as it is compressed (designed to keep the tyre contact patch parallel'ish to the road when it rolls during cornering) so by lowering the ride height you are also adding camber which you can't adjust out without bu66ering up the toe.

As 2woody says, you might need to make some changes to make it handle right afterwards.

The reason I mention it is that I know when I get mine aligned they are never happy about the amount of static camber at the rear wheels (well over 2 degrees) but can't do anything about it (and that's with a completely standard MV6 setup).

Having said that, the rear end on mine positively refuses to let go, so something's working OK. :)

Kevin
Aeye, but provided the tyre ware is within "a set or tyres", ie progresive inside edge ware throughout the tyres life with more ware on the inside by the time it's replaced, that will be ok to my thinking, what the limit of that setting is I will discuss with  I guess, if 2degrees gives grip and straight-line stability like yours does i be well happy......
.....what are your rears like across the tread at the end of their life? If excessive camber ends my rear tyres life prematurely then that would be unacceptable obviously  :)    
Title: Re: 30 mill lowering, experiences please.
Post by: Kevin Wood on 19 October 2010, 17:36:32
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Aeye, but provided the tyre ware is within "a set or tyres", ie progresive inside edge ware throughout the tyres life with more ware on the inside by the time it's replaced, that will be ok to my thinking, what the limit of that setting is I will discuss with  I guess, if 2degrees gives grip and straight-line stability like yours does i be well happy......
.....what are your rears like across the tread at the end of their life? If excessive camber ends my rear tyres life prematurely then that would be unacceptable obviously  :)    

Generally, they wear in the centres more than either edge, as if over inflated, despite running them at about 30-32 PSI.

Kevin
Title: Re: 30 mill lowering, experiences please.
Post by: feeutfo on 19 October 2010, 17:37:57
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hi chris, i dropped my omega when i brought it, had a broken spring so thought it was the perfect time!

i lowered by 40mm and have only rubbed a speed bump once, that was the exhaust catching, and it was a large bump.

i only have stock body parts and being a cdx, not mv6 the ride height was quite high before.

makes a big difference to looks and handling, though oddly the front is lower than the back when the back seats are empty, by a fair amount too.

 :y
Promissing with ground clearance then, there is one big speed hump on my commute that worries me though...
Title: Re: 30 mill lowering, experiences please.
Post by: feeutfo on 19 October 2010, 17:40:21
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Depends if you ever go down Telford Drive in Slough (or anywhere with 'speed cushions' but in by the same people) - they were all but impossible to navigate in the MR2 with it lowered 30mm :-/ it was a case of stop, crawl over hump, drive, stop, crawl over hump, drive.

Really annoyed the 4x4 owners who could go over them at 40mph (did I mention it was a 20 limit outside a school, put there because of the 4x4 owners dropping their kids off? No, that didn't annoy me at all, as you can tell).
Tellford drive? I 'll look into that one with a view to avoiding, my problem will be peters field avenue in slough  >:(. Big sb is outside a school though to be fair.
Title: Re: 30 mill lowering, experiences please.
Post by: feeutfo on 19 October 2010, 18:07:52
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Quote
I'd say you'd need to go "off-piste" with the suspension settings if you were to lower beyond the "standard" MV6 spec.

it is highly likely that the roll-centre changes resulting from the lowering will make the handling worse rather than better.

the suspension geometry relies on how the wheels move in relation to the body when in roll. If,for instance, the static position of the lower wishbone is altered at rest (through lowering), the amount that the camber changes with roll will be different that Opel intended, probably incompatible with the roll angle, thereby reducing grip.

What you say is all very true, however i had full suspension geometry adjusted to suit the 40mm drop and cant say i have noticied any problems in grip, only improvement, even in the wet it is far better on the roundabouts
 :y
There will be a proper set up at wheels in motion as usual when ever I play with set up components...

....some thinking on all this set up business...without fully understanding roll centres it has to be said....roll centre, as I vaguely understand it, the  static(?)point the chassis rolls around when cornering, same motion controlled by anti roll bars? So draw a line starting at the roll centre, (i imagine this point to be somewhere along the center line of the crank perhaps? ) outboard towards the wheel and finishing at, I guess, the steering knuckle on the wishbone or just above? If lateral forces are not to affect suspension squatting, then this drawn line needs to have the suspension joints almost exactly along that line taking into account the weight of the car pressing down on it...?

Otherwise, Wang round a corner, sideways motion alone would quat the suspension even without body roll doing the same as well? Or am I way off?

So lowering excessively would move the suspension joints (the wishbone bush joints) off this drawn line.....er.... And basically cocking it all up. But given the various engine weights and ride heights on various models, there must be some leeway?


Title: Re: 30 mill lowering, experiences please.
Post by: feeutfo on 19 October 2010, 18:11:49
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got irmscher springs -30mm on mine and dont have any problems with drive over speed bumps :y
Thanks serek, good news, do you have the front air dam fitted as well?
Title: Re: 30 mill lowering, experiences please.
Post by: aaronjb on 19 October 2010, 18:14:10
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Depends if you ever go down Telford Drive in Slough (or anywhere with 'speed cushions' but in by the same people) - they were all but impossible to navigate in the MR2 with it lowered 30mm :-/ it was a case of stop, crawl over hump, drive, stop, crawl over hump, drive.

Really annoyed the 4x4 owners who could go over them at 40mph (did I mention it was a 20 limit outside a school, put there because of the 4x4 owners dropping their kids off? No, that didn't annoy me at all, as you can tell).
Tellford drive? I 'll look into that one with a view to avoiding, my problem will be peters field avenue in slough  >:(. Big sb is outside a school though to be fair.

I think I've been down that way once - looked at a house off Wexham Road (decided the place looked like a dive though ;D ).. Telford Drive is a ways a way, by the Asda (where I used to live .. I didn't move away to get away from the speed humps, honest! ;D )
Title: Re: 30 mill lowering, experiences please.
Post by: TheBoy on 19 October 2010, 19:14:32
chrisgixer - nah, give yourself ride height.

Now I can think of a good home for those springs ::) :P
Title: Re: 30 mill lowering, experiences please.
Post by: feeutfo on 19 October 2010, 20:06:32
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chrisgixer - nah, give yourself ride height.

Now I can think of a good home for those springs ::) :P
Yeah, been waiting for that one.   :P
Title: Re: 30 mill lowering, experiences please.
Post by: 2woody on 20 October 2010, 10:50:47
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I'd say you'd need to go "off-piste" with the suspension settings if you were to lower beyond the "standard" MV6 spec.

it is highly likely that the roll-centre changes resulting from the lowering will make the handling worse rather than better.

the suspension geometry relies on how the wheels move in relation to the body when in roll. If,for instance, the static position of the lower wishbone is altered at rest (through lowering), the amount that the camber changes with roll will be different that Opel intended, probably incompatible with the roll angle, thereby reducing grip.

What you say is all very true, however i had full suspension geometry adjusted to suit the 40mm drop and cant say i have noticied any problems in grip, only improvement, even in the wet it is far better on the roundabouts
 :y
There will be a proper set up at wheels in motion as usual when ever I play with set up components...

....some thinking on all this set up business...without fully understanding roll centres it has to be said....roll centre, as I vaguely understand it, the  static(?)point the chassis rolls around when cornering, same motion controlled by anti roll bars? So draw a line starting at the roll centre, (i imagine this point to be somewhere along the center line of the crank perhaps? ) outboard towards the wheel and finishing at, I guess, the steering knuckle on the wishbone or just above? If lateral forces are not to affect suspension squatting, then this drawn line needs to have the suspension joints almost exactly along that line taking into account the weight of the car pressing down on it...?

Otherwise, Wang round a corner, sideways motion alone would quat the suspension even without body roll doing the same as well? Or am I way off?

So lowering excessively would move the suspension joints (the wishbone bush joints) off this drawn line.....er.... And basically cocking it all up. But given the various engine weights and ride heights on various models, there must be some leeway?




not bad..... :y

different springs are usually fitted to different models to correct the ride height for different configurations.

In production, this was probably about 10 different springs for the various Omega B variants, although in the aftermarket (even through GM dealers) there's only two I think.

the angle of the lower wishbone to the ground is the most critical thing.
Title: Re: 30 mill lowering, experiences please.
Post by: feeutfo on 20 October 2010, 18:00:00
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I'd say you'd need to go "off-piste" with the suspension settings if you were to lower beyond the "standard" MV6 spec.

it is highly likely that the roll-centre changes resulting from the lowering will make the handling worse rather than better.

the suspension geometry relies on how the wheels move in relation to the body when in roll. If,for instance, the static position of the lower wishbone is altered at rest (through lowering), the amount that the camber changes with roll will be different that Opel intended, probably incompatible with the roll angle, thereby reducing grip.

What you say is all very true, however i had full suspension geometry adjusted to suit the 40mm drop and cant say i have noticied any problems in grip, only improvement, even in the wet it is far better on the roundabouts
 :y
There will be a proper set up at wheels in motion as usual when ever I play with set up components...

....some thinking on all this set up business...without fully understanding roll centres it has to be said....roll centre, as I vaguely understand it, the  static(?)point the chassis rolls around when cornering, same motion controlled by anti roll bars? So draw a line starting at the roll centre, (i imagine this point to be somewhere along the center line of the crank perhaps? ) outboard towards the wheel and finishing at, I guess, the steering knuckle on the wishbone or just above? If lateral forces are not to affect suspension squatting, then this drawn line needs to have the suspension joints almost exactly along that line taking into account the weight of the car pressing down on it...?

Otherwise, Wang round a corner, sideways motion alone would quat the suspension even without body roll doing the same as well? Or am I way off?

So lowering excessively would move the suspension joints (the wishbone bush joints) off this drawn line.....er.... And basically cocking it all up. But given the various engine weights and ride heights on various models, there must be some leeway?




not bad..... :y

different springs are usually fitted to different models to correct the ride height for different configurations.

In production, this was probably about 10 different springs for the various Omega B variants, although in the aftermarket (even through GM dealers) there's only two I think.

the angle of the lower wishbone to the ground is the most critical thing.
Hmmm, that aside though, the quality of ride and lack of roll purely down to quality of damping and springs would, on the face of it, be an improvement on that front. Something that would be felt at all times, where as the roll centre issue would only be felt in cornering, possibly only during extreme cornering?....
....wonder if it's possible to add a 15 mill spacer to the bottom of the spring in the suspension cup....? Need a bloody big washer.  ;D
Title: Re: 30 mill lowering, experiences please.
Post by: Jimbob on 20 October 2010, 18:07:34
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I'd say you'd need to go "off-piste" with the suspension settings if you were to lower beyond the "standard" MV6 spec.

it is highly likely that the roll-centre changes resulting from the lowering will make the handling worse rather than better.

the suspension geometry relies on how the wheels move in relation to the body when in roll. If,for instance, the static position of the lower wishbone is altered at rest (through lowering), the amount that the camber changes with roll will be different that Opel intended, probably incompatible with the roll angle, thereby reducing grip.

What you say is all very true, however i had full suspension geometry adjusted to suit the 40mm drop and cant say i have noticied any problems in grip, only improvement, even in the wet it is far better on the roundabouts
 :y
There will be a proper set up at wheels in motion as usual when ever I play with set up components...

....some thinking on all this set up business...without fully understanding roll centres it has to be said....roll centre, as I vaguely understand it, the  static(?)point the chassis rolls around when cornering, same motion controlled by anti roll bars? So draw a line starting at the roll centre, (i imagine this point to be somewhere along the center line of the crank perhaps? ) outboard towards the wheel and finishing at, I guess, the steering knuckle on the wishbone or just above? If lateral forces are not to affect suspension squatting, then this drawn line needs to have the suspension joints almost exactly along that line taking into account the weight of the car pressing down on it...?

Otherwise, Wang round a corner, sideways motion alone would quat the suspension even without body roll doing the same as well? Or am I way off?

So lowering excessively would move the suspension joints (the wishbone bush joints) off this drawn line.....er.... And basically cocking it all up. But given the various engine weights and ride heights on various models, there must be some leeway?




not bad..... :y

different springs are usually fitted to different models to correct the ride height for different configurations.

In production, this was probably about 10 different springs for the various Omega B variants, although in the aftermarket (even through GM dealers) there's only two I think.

the angle of the lower wishbone to the ground is the most critical thing.


just checked tradeclub - 12 different rear springs available currently :o

be nice to see em all in a lineup for the differences
Title: Re: 30 mill lowering, experiences please.
Post by: feeutfo on 20 October 2010, 19:18:24
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I'd say you'd need to go "off-piste" with the suspension settings if you were to lower beyond the "standard" MV6 spec.

it is highly likely that the roll-centre changes resulting from the lowering will make the handling worse rather than better.

the suspension geometry relies on how the wheels move in relation to the body when in roll. If,for instance, the static position of the lower wishbone is altered at rest (through lowering), the amount that the camber changes with roll will be different that Opel intended, probably incompatible with the roll angle, thereby reducing grip.

What you say is all very true, however i had full suspension geometry adjusted to suit the 40mm drop and cant say i have noticied any problems in grip, only improvement, even in the wet it is far better on the roundabouts
 :y
There will be a proper set up at wheels in motion as usual when ever I play with set up components...

....some thinking on all this set up business...without fully understanding roll centres it has to be said....roll centre, as I vaguely understand it, the  static(?)point the chassis rolls around when cornering, same motion controlled by anti roll bars? So draw a line starting at the roll centre, (i imagine this point to be somewhere along the center line of the crank perhaps? ) outboard towards the wheel and finishing at, I guess, the steering knuckle on the wishbone or just above? If lateral forces are not to affect suspension squatting, then this drawn line needs to have the suspension joints almost exactly along that line taking into account the weight of the car pressing down on it...?

Otherwise, Wang round a corner, sideways motion alone would quat the suspension even without body roll doing the same as well? Or am I way off?

So lowering excessively would move the suspension joints (the wishbone bush joints) off this drawn line.....er.... And basically cocking it all up. But given the various engine weights and ride heights on various models, there must be some leeway?




not bad..... :y

different springs are usually fitted to different models to correct the ride height for different configurations.

In production, this was probably about 10 different springs for the various Omega B variants, although in the aftermarket (even through GM dealers) there's only two I think.

the angle of the lower wishbone to the ground is the most critical thing.


just checked tradeclub - 12 different rear springs available currently :o

be nice to see em all in a lineup for the differences
Got 4 sets in my garage, all very different...