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Posted

I've been following this thread for some time and really appreciate the attention to detail.

I am a spirited street/road driver and plan to autocross more frequently as time goes. My track days are still off in the future. Given that I also use the car for daily driving, I don't want to lower the car. I do want to decrease body roll, so will add stiffer anti-roll bars. I currently have 18" wheels.

My shop guy/friend sugested using 17" wheels with lower-than-stock profile tires for autox because it would lower the car's C-G and slightly improve throttle response with a smaller wheel to turn. I can get a second set of wheels for autox pretty easily and keep the 18s for street/road (future track - maybe 19s for track) driving.

Also - reading more about anti-roll bar stiffness, even thought the base Boxster has a larger diameter on the rear bar than the S model, I think the wall thickness on the S model is thicker making it a torsionally stiffer bar.

Two questions:

1) any thoughts about the smaller wheel set up?

2) What differences exist between the Porsche M030 sway bars and other brand after market bars? How stiff is too stiff?

David

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Posted (edited)

the RoW doesn't lower the car that much. unless you have an aftermarket bumper, i'd go ahead and lower it with the RoW. not sure how the idea with the smaller wheel diameters will work. as for the sways:

the base M030 rear sway is 19.6mm thick with a 2.6mm wall, making it 24.6% stiffer than stock

the S M030 rear sway 19mm thick with a 2.7mm wall, making it 14.5% stiffer than stock

you are correct that the S sway has a thicker wall, but not enough to make it stiffer than the base bar (which is 18.5mm / 2.5mm for the base AND the S).

Edited by insite
Posted
the RoW doesn't lower the car that much. unless you have an aftermarket bumper, i'd go ahead and lower it with the RoW. not sure how the idea with the smaller wheel diameters will work. as for the sways:

the base M030 rear sway is 19.6mm thick with a 2.6mm wall, making it 24.6% stiffer than stock

the S M030 rear sway 19mm thick with a 2.7mm wall, making it 14.5% stiffer than stock

you are correct that the S sway has a thicker wall, but not enough to make it stiffer than the base bar (which is 18.5mm / 2.5mm for the base AND the S).

Why are you changing the rear sway bar for the M030 S Model package??? I have been reading and almost every body talks about this setup as a system that works best when not changed. So by changing the rear sway bar from the original kit you are altering something; Are you trying to make the car to oversteer??? how did you come to this change in rear sway bar???

Thanks

Posted
Why are you changing the rear sway bar for the M030 S Model package??? I have been reading and almost every body talks about this setup as a system that works best when not changed. So by changing the rear sway bar from the original kit you are altering something; Are you trying to make the car to oversteer??? how did you come to this change in rear sway bar???

not trying to make it oversteer; trying to make it understeer less. porsche dials more understeer into the S M030 package to create a safety margin for the larger motor breaking the tires loose. to good drivers, this understeer is not desirable. i have run the car with the following combos:

base front w/ M030 base rear

S front w/ base rear

S front w/ M030 base rear

M030 S front w/ M030 base rear

the last combo, in my opinion, is most preferable. the M030 base front sway is exactly the same as the S (non M030) front sway, btw, so the base M030 package really includes the base S front sway and the M030 base rear sway. handling was good here, but a tad darty at speed for me. using the M030 S up front and M030 base in rear w/ adjusted tire pressures to me feels optimal.

Posted
Why are you changing the rear sway bar for the M030 S Model package??? I have been reading and almost every body talks about this setup as a system that works best when not changed. So by changing the rear sway bar from the original kit you are altering something; Are you trying to make the car to oversteer??? how did you come to this change in rear sway bar???

not trying to make it oversteer; trying to make it understeer less. porsche dials more understeer into the S M030 package to create a safety margin for the larger motor breaking the tires loose. to good drivers, this understeer is not desirable. i have run the car with the following combos:

base front w/ M030 base rear

S front w/ base rear

S front w/ M030 base rear

M030 S front w/ M030 base rear

the last combo, in my opinion, is most preferable. the M030 base front sway is exactly the same as the S (non M030) front sway, btw, so the base M030 package really includes the base S front sway and the M030 base rear sway. handling was good here, but a tad darty at speed for me. using the M030 S up front and M030 base in rear w/ adjusted tire pressures to me feels optimal.

So, you are saying that by using a stiffer sway bar in the rear makes the car will experience less understeer??? Could we also say that if we use a stiffer sway bar up front, will the car tend to oversteer more??? I have never had this concept clear. Thanks

Posted
So, you are saying that by using a stiffer sway bar in the rear makes the car will experience less understeer??? Could we also say that if we use a stiffer sway bar up front, will the car tend to oversteer more??? I have never had this concept clear. Thanks

from a balance perspective, increaing the stiffness of a swaybar will reduce the grip limit of that axle relative to the other. so, if you increase the front sway, the front tires will slip sooner, hence increased understeer. increase the rear sway, the rear tires slip sooner, so DECREASED understeer. to an extent, the loss in grip can be regained by manipulating tire pressures. so, you want thicker sways because they reduce body roll, improve transient response and high speed stability. you can then reduce tire pressures slightly to increase grip.

if you go too thick on the sways, you lose your independant suspension (one side is linked to the other). this results in poor performance over rough or bumpy surfaces. it also results in unpredictable tire breakaway at the limit. since sways are so easy to change, a lot of people try to stiffen the car using this route, which is fine to an extent. often they go overboard and ruin the handling of their cars; they might feel stiff and crisp, but driven at the limit, they are unpredictable and darty. ideally, roll stiffness should be controlled by springs and dampers, then supplemented and fine tuned for balance by using the sways. the factory sways on the box are tuned to heavily favor understeer and comfort. the M030 option dials out some of this understeer (desirable for the enthusiast) and adds some roll resistance at the expense of comfort.

the added roll stiffness helps vehicle control at high speeds and helps the vehicle change direction better (i.e. quick left to quick right) by limiting motion caused by lateral weight transfer. this comes at a sacrifice to ultimate grip. with the M030 options, the best set of comprimises, in my opinion, come with the S front bar and the base rear bar with slight changes to tire pressures. configured this way, i am actually achieving higher grip limits with the thicker sways because of the lower tire pressures, but the car is much more controllable at speed. it will break away more sharply, though, than the stock setup.

Posted
So, you are saying that by using a stiffer sway bar in the rear makes the car will experience less understeer??? Could we also say that if we use a stiffer sway bar up front, will the car tend to oversteer more??? I have never had this concept clear. Thanks

from a balance perspective, increaing the stiffness of a swaybar will reduce the grip limit of that axle relative to the other. so, if you increase the front sway, the front tires will slip sooner, hence increased understeer. increase the rear sway, the rear tires slip sooner, so DECREASED understeer. to an extent, the loss in grip can be regained by manipulating tire pressures. so, you want thicker sways because they reduce body roll, improve transient response and high speed stability. you can then reduce tire pressures slightly to increase grip.

if you go too thick on the sways, you lose your independant suspension (one side is linked to the other). this results in poor performance over rough or bumpy surfaces. it also results in unpredictable tire breakaway at the limit. since sways are so easy to change, a lot of people try to stiffen the car using this route, which is fine to an extent. often they go overboard and ruin the handling of their cars; they might feel stiff and crisp, but driven at the limit, they are unpredictable and darty. ideally, roll stiffness should be controlled by springs and dampers, then supplemented and fine tuned for balance by using the sways. the factory sways on the box are tuned to heavily favor understeer and comfort. the M030 option dials out some of this understeer (desirable for the enthusiast) and adds some roll resistance at the expense of comfort.

the added roll stiffness helps vehicle control at high speeds and helps the vehicle change direction better (i.e. quick left to quick right) by limiting motion caused by lateral weight transfer. this comes at a sacrifice to ultimate grip. with the M030 options, the best set of comprimises, in my opinion, come with the S front bar and the base rear bar with slight changes to tire pressures. configured this way, i am actually achieving higher grip limits with the thicker sways because of the lower tire pressures, but the car is much more controllable at speed. it will break away more sharply, though, than the stock setup.

Thanks Insite for your replay, that clarifies my confusion. One another note, remember that you are running a 911 staggered wheels setup. Not all of us Boxster owners out there have this setup. I have the factory 18" wheels for the Boxster with 225 in front and 265 in rear. Would you still recommend the Base M030 ROW sway bar for the rear axle??? By you having the wider rear tires, you will definitely experience more understeer then us. What are your thought on this????

Thanks

Posted
Thanks Insite for your replay, that clarifies my confusion. One another note, remember that you are running a 911 staggered wheels setup. Not all of us Boxster owners out there have this setup. I have the factory 18" wheels for the Boxster with 225 in front and 265 in rear. Would you still recommend the Base M030 ROW sway bar for the rear axle??? By you having the wider rear tires, you will definitely experience more understeer then us. What are your thought on this????

actually, i run 225/265 on my car. i thought the factory 18" boxsters ran either 245/265 or 235/255. anyway, my wheels are certainly different widths; i have 7.5" up front and 10" in back. this doesn't really effect the footprint, though. i still say run the S front w/ base rear. the base front / base rear will understeer even less. for grins, try upgrading just the rear sway first and go for a drive. it's actually really fun, but too easy to provoke a slide at speed if you're not careful.

Posted
i still say run the S front w/ base rear. the base front / base rear will understeer even less. for grins, try upgrading just the rear sway first and go for a drive. it's actually really fun, but too easy to provoke a slide at speed if you're not careful.

It's also a matter of driving style and preference, right. Some drivers like more rotation than others and the track that you drive will also change your preference. The Porsche "system" was probably set up to the preferences of their test drivers. Everybody's going to like things a little different.

Also, because insite's got different tire sizes and manufacturer's than stock, there's going to be some handling differences between his car and those of a stock wheel/tire package.

If you're not interested in lowering your car, the US M030 keeps ride height the same as US stock but uses the increased spring and damping rates of the M030 suspension. You won't get the negative camber that you can with the lowered car.

Posted
back from the track. no GPS logger; couldn't make the arrangements in time. anyway, here was my setup:

Front:

Cold Pressure: 30psi

Toe: 0

Camber: -1.6

Rear:

Cold Pressure: 32psi

Toe: 1/32" in

Camber: -2.0

the car ran awesome. pyrometer showed even temperatures across both front and rear tires (street tires, race would need more camber). i did notice when aligning the car that the front tires are wearing a bit on the inside, indicating -1.6 might be a little too aggressive for the street. i will dial it back to -1.0 for the street and use -1.6 at the track.

the track is smaller (<2.0 miles) and fairly tight, so the minimal rear toe worked out very well. very easy to rotate the car with a little breathe off the throttle. there is one corner on the track that is a closing radius horse shoe; i was able to trail brake into the corner a little hot and then lift just before the late apex, rotating the car's trajectory to track out. felt very good. there's a longer carousel that i was able to modulate through nicely as well. very neutral car. i really don't think there's anything (from a setup perspective) i'd change on the car.

Thanks for the info insite. I have a couple of questions.

1) I assume that you run without PSM on of course, and you mention the ease of rotating with a breathe. I may be over-reading that comment, but I'm not sure I would want the car to rotate that easily on the street. Would you say that the point at which it will do this is well above even spirited street driving? What affect do you think PSM being on would have (would it upset the car)?

2) Just to be sure I'm reading you well. At this point a super ROW M030 street alignment would be on the order of:

Front:

Cold Pressure: 30psi

Toe: 0

Camber: -1.0 to -1.2

Rear:

Cold Pressure: 32psi

Toe: 1/32" in

Camber: -2.0

Thanks,

Andy

The '99 didn't have PSM as an option.

Posted
1) I assume that you run without PSM on of course, and you mention the ease of rotating with a breathe. I may be over-reading that comment, but I'm not sure I would want the car to rotate that easily on the street. Would you say that the point at which it will do this is well above even spirited street driving? What affect do you think PSM being on would have (would it upset the car)?

blue's right, no PSM on '99. as for ease of rotation, this only occurs when you're at or near the limit of adhesion. it's not like you'd be driving around town, lift, and spin the car. for track use, though, when you're at the limit, you want to be able to easily steer with the throttle. more gas should push you wide, less gas should tighten the line / rotate the car. the M030 sways really improve this. as for the PSM, it's my understanding that it really doesn't kick in until your slip angle is high and still increasing. i don't think it would upset the car.

  • 2 weeks later...
Posted
1) I assume that you run without PSM on of course, and you mention the ease of rotating with a breathe. I may be over-reading that comment, but I'm not sure I would want the car to rotate that easily on the street. Would you say that the point at which it will do this is well above even spirited street driving? What affect do you think PSM being on would have (would it upset the car)?

blue's right, no PSM on '99. as for ease of rotation, this only occurs when you're at or near the limit of adhesion. it's not like you'd be driving around town, lift, and spin the car. for track use, though, when you're at the limit, you want to be able to easily steer with the throttle. more gas should push you wide, less gas should tighten the line / rotate the car. the M030 sways really improve this. as for the PSM, it's my understanding that it really doesn't kick in until your slip angle is high and still increasing. i don't think it would upset the car.

Just thought I'd jump in on the M030 RoW - I also have a '99 and recently installed the M030 Row package. I agree with everything I've seen here and will just add my own observations. First is that I need to experiment with the tires, I was trying to reduce understeer by running the fronts at 32 and the rears at 37 - I have an autocross day Saturday and will try running at 37 all the way around. Also the extent of the lowering is about an inch in front, but this hasn't caused me any daily driving issues at all. The car does seem more stable at higher speeds. Also the setup doesn't fell as stiff as one might expect, just a bit of a stiffer feel but with noticably less body roll. Bought mine from Suncoast in Sarasota FL for 999, even though they were out of stock an order from Germany was at my doorstep in two weeks, maybe a day or two less. When you first see the springs it is surprising how much fatter and shorter they are - inches shorter than what came off my car. I'll see if I can find a post the link to a good article on the PCA website.

Posted
I am also considering getting the ROW MO30 kit for my 02 996 do you know where could I find the alingment setings? do they come with the kit??

Thanks

I didn't get any w/mine

Posted

Insite,

This weekend looks like crappy weather and a good one to put my car back up on the stands and put the ROW M030 suspension on. Can you give me some tips on doing a rough alignment in the garage so it's not too bad to drive to the alignment shop? What would I need ? Any tips on the best way to measure for toe-in, etc......

Andy

Posted
Insite,

This weekend looks like crappy weather and a good one to put my car back up on the stands and put the ROW M030 suspension on. Can you give me some tips on doing a rough alignment in the garage so it's not too bad to drive to the alignment shop? What would I need ? Any tips on the best way to measure for toe-in, etc......

Andy

you don't have to adjust the rear toe-link eccentrics when doing this job, so you won't alter any settings there. the upper control arms (trailing arms), however, can alter toe if you torque the bolts down out of order. when re-installing these, loosely install the bolts on the chassis side of the arm. install and torque the lower control arm side of the links, then torque the chassis side. if you adhere to this order, your toe should be fine.

you will see that the lower control arms (rear) connect to the chassis with eccentric bolts and washers. the washers have little dashes etched into them. mark them with a sharpie so you can match your original camber settings when you reinstall.

up front, you have nothing to worry about except camber. you should see the outline of the strut tower nuts in the paint on the strut tower. just align the nuts with the outlines on the towers and you'll have proper front camber.

the only other advice i can give: remove the sways, then do the struts / springs, then install the new sways. trust me on this. also, don't split any ball joints: remove the lower control arms at the chassis instead. MUCH easier / safer.

Posted
I am also considering getting the ROW MO30 kit for my 02 996 do you know where could I find the alingment setings? do they come with the kit??

Thanks

not sure off hand what they should be on a 996. i do know that the Hunter alignment machines DO have the RoW M030 settings programmed in. tell the alignment tech that you have the Euro spec 'SPORT' suspension. the machine does the rest. i do know that the 996 spec for front camber will be incredibly inadequate, so it may help you to just tell the tech to set the front camber to -0.8 or so. this is a good compromise that won't wear your front tires too badly.

Posted
I am also considering getting the ROW MO30 kit for my 02 996 do you know where could I find the alingment setings? do they come with the kit??

Thanks

Call your dealer and ask them for the suspension spec sheet on your specific car with the specific suspension package you're putting on. They do have it (USA and ROW) so be persistent if you get some resistance.

Posted

Ran into a little snag with the rear suspension when removing the stock struts to put the ROW M030 parts on.

The ball joint nut for the lower control arm does not seem to want to clear the halfshaft housing to come off. I tried jacking up the hub to change the angle, but it still wouldn't clear with the half shaft roughly straight out. Maybe I didn't go up high enough, but I realized a second issue was going to be a problem....even if I get the nut off, the ball joint tool I have (the recommended Porsche type) is not going to be able to sit correctly over the top of the ball joint stud - the arm is too thick. I could use a splitting fork, but I have read that they don't work all that well on the Porsche's and often tear the boot resulting in a new lower control arm. I don't want that. Thought this would be a good point to stop and ask for advice.

SO...how about it, any advice guys? Any tricks I need to know ?

Posted
SO...how about it, any advice guys? Any tricks I need to know ?

good for stopping. a couple of posts ago i listed some tricks for the M030 jobl. one was to NOT split the ball joints. instead, remove the control arms from the chassis. that way, the entire arm with the ball joint and knuckle all come off together. this way, you don't have trouble clearing the halfshafts, you don't rip the boots, etc. let me know if you run into any other issues.

Posted (edited)
SO...how about it, any advice guys? Any tricks I need to know ?

good for stopping. a couple of posts ago i listed some tricks for the M030 jobl. one was to NOT split the ball joints. instead, remove the control arms from the chassis. that way, the entire arm with the ball joint and knuckle all come off together. this way, you don't have trouble clearing the halfshafts, you don't rip the boots, etc. let me know if you run into any other issues.

Worked like a charm insite. Your right, this is a much easier way. Am I correct in assuming that, as long as the eccentrics are put back in the positions that I marked, the current alignment will remain essentially the same, or does the geometry change significantly with the ROW M030 parts anyway ?

Trying to get a feel for how urgent getting it to the alignment shop will be. The weekend is looking like I might want to drive it a little and I probably won't be able to get it into the shop for alignment until next week some time.

.....and for the record, I double checked last night - and there is NO WAY on my '03, that that nut is coming off the lower control arm ball joint with the half shaft in place on the hub side.

Edited by Andy_M
Posted
Worked like a charm insite. Your right, this is a much easier way. Am I correct in assuming that, as long as the eccentrics are put back in the positions that I marked, the current alignment will remain essentially the same, or does the geometry change significantly with the ROW M030 parts anyway ?

glad it worked out for you. did you remove the upper control arms from the chassis, or did you just unbolt them from the lower control arms? i ask because if you removed them from the chassis, you probably threw off your toe a bit. alignment isn't seriously pressing if the car drives ok, but i'd get it done soon none the less.

.....and for the record, I double checked last night - and there is NO WAY on my '03, that that nut is coming off the lower control arm ball joint with the half shaft in place on the hub side.

it's doable. what you have to do is loosen the ball joint nut until it hits the CV joint. then, split the ball joint with a pickle fork. now the nut can be removed. it's a pain in the butt. much easier to remove the control arm from the subframe.

Posted
Worked like a charm insite. Your right, this is a much easier way. Am I correct in assuming that, as long as the eccentrics are put back in the positions that I marked, the current alignment will remain essentially the same, or does the geometry change significantly with the ROW M030 parts anyway ?

glad it worked out for you. did you remove the upper control arms from the chassis, or did you just unbolt them from the lower control arms? i ask because if you removed them from the chassis, you probably threw off your toe a bit. alignment isn't seriously pressing if the car drives ok, but i'd get it done soon none the less.

.....and for the record, I double checked last night - and there is NO WAY on my '03, that that nut is coming off the lower control arm ball joint with the half shaft in place on the hub side.

it's doable. what you have to do is loosen the ball joint nut until it hits the CV joint. then, split the ball joint with a pickle fork. now the nut can be removed. it's a pain in the butt. much easier to remove the control arm from the subframe.

Not sure which is considered the "upper control arm". I assume that the UCA is the control arm that controls the toe, I unbolted and split the ball joint from the hub side and didn't touch the chassis side of that arm. The diagonal arm, I disconnected from the LCA and didn't disturb the chassis side.

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