Confused about suspension? M030, M474, etc..
11-16-2002, 06:36 AM
#16
Sajid,
FYI M474 Konis and M030 Konis are both yellow.
The difference is just that these of the M030 can have their height adjusted.
If your car has the M474 from the start, IMO don't bother upgrading with M030 parts if you plan to drive mostly on the road.
What's more, the full M030 seems to include LOADS of extra bits and pieces (according to the PET)
AFAIAC I'm about to fit M474 Konis (non-adjustable, then
) on my S2; this set-up is IMO well enough for road use 
Talking about the difference between the front and the rear stiffness, did the M474-equipped cars had a stiffer torsion bar at the rear??
It would sound quite logical if one takes account of the stiffer springs at the front, wouldn't it?
Does anyone has any clue on this?
FYI M474 Konis and M030 Konis are both yellow.
The difference is just that these of the M030 can have their height adjusted.
If your car has the M474 from the start, IMO don't bother upgrading with M030 parts if you plan to drive mostly on the road.
What's more, the full M030 seems to include LOADS of extra bits and pieces (according to the PET)
AFAIAC I'm about to fit M474 Konis (non-adjustable, then
) on my S2; this set-up is IMO well enough for road use Talking about the difference between the front and the rear stiffness, did the M474-equipped cars had a stiffer torsion bar at the rear??
It would sound quite logical if one takes account of the stiffer springs at the front, wouldn't it?
Does anyone has any clue on this?
11-18-2002, 02:57 PM
#17
I dug into the M474 issue a bit, since both my '87 with LSD/ABS (now Ryan Gabel's) and my '88 sans LSD/ABS had that option - and I found NO indication that the M474 added anything other than Koni Yellows, front and rear, without external adjustment.
You're right on, the '89 951 M030 added external (top mounted) rebound adjustment. The "rebuilt" units I bought from Paragon have both external rebound AND compression, and the latter helps me control some of the "dipping" that the car does at track with many sharp hills (i.e. Grattan) considering my relatively soft (for hard track use) M030 springs.
So I never saw a difference in front or rear spring rates due to just the M474 option - not even the Parts and Technical Reference manual mentions any change in torsion bar part # for it.
BTW, Sajid's car has the "one white dot" front springs, so they are the softest of the three available within the tolerance range. Still, with soft OEM springs, I was able to outrun another 951 and plenty of Audi S4s at the tight Grattan road course in that exact car, with worn out front struts, no ABS, no LSD and nothing more than MetalMaster pads. That was my only track day in that car, tho, and only because the clutch in my 944S died the day before (and also the day I caught the Turbo bug, since I was suddenly able to run circles around my previous instructors simply by switching from the 944S to the 951).
PS: Can someone confirm that the stock front springs from my non-M030 '91 S2 Cab are actually FIRMER than the '87 951 springs I replaced them with? I thought they were the same . . . but I think Menelaos pointed out that the rate on the '91 Cab is actually HIGHER than the 951 rate?!?
You're right on, the '89 951 M030 added external (top mounted) rebound adjustment. The "rebuilt" units I bought from Paragon have both external rebound AND compression, and the latter helps me control some of the "dipping" that the car does at track with many sharp hills (i.e. Grattan) considering my relatively soft (for hard track use) M030 springs.
So I never saw a difference in front or rear spring rates due to just the M474 option - not even the Parts and Technical Reference manual mentions any change in torsion bar part # for it.
BTW, Sajid's car has the "one white dot" front springs, so they are the softest of the three available within the tolerance range. Still, with soft OEM springs, I was able to outrun another 951 and plenty of Audi S4s at the tight Grattan road course in that exact car, with worn out front struts, no ABS, no LSD and nothing more than MetalMaster pads. That was my only track day in that car, tho, and only because the clutch in my 944S died the day before (and also the day I caught the Turbo bug, since I was suddenly able to run circles around my previous instructors simply by switching from the 944S to the 951).
PS: Can someone confirm that the stock front springs from my non-M030 '91 S2 Cab are actually FIRMER than the '87 951 springs I replaced them with? I thought they were the same . . . but I think Menelaos pointed out that the rate on the '91 Cab is actually HIGHER than the 951 rate?!?
11-18-2002, 03:54 PM
#18
Three Wheelin'
[quote] PS: Can someone confirm that the stock front springs from my non-M030 '91 S2 Cab are actually FIRMER than the '87 951 springs I replaced them with? I thought they were the same . . . but I think Menelaos pointed out that the rate on the '91 Cab is actually HIGHER than the 951 rate?!? <hr></blockquote>
The 944S2 without the M030 or M031 options had 136 pound/inch front springs. This sounds low, but is actually stiffer than the stock 944 and 951 rate of 125 pounds (with or without M474 sport shocks.) Details provided here: <a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=18&t=002622" target="_blank">Front Spring colour codes and specs</a>
The M474 and M030 options both included rebound adjustable yellow Koni's, but the M474 are not height adjustable and are not as stiff as the M030 Koni's. M030 also added thicker rear torsion bars to match the higher rate (160 pound) front springs.
On the '88 951S, the M030 package included an 18 mm rear sway bar, but for mid-'89 and later M030 packages (951 and S2) Porsche used a 16 mm bar to dial in more understeer. As a result, my '89 951 has quite noticeable understeer. I would like to get a 968 M030 19 mm adjustable rear bar to fix this.
The 944S2 without the M030 or M031 options had 136 pound/inch front springs. This sounds low, but is actually stiffer than the stock 944 and 951 rate of 125 pounds (with or without M474 sport shocks.) Details provided here: <a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=18&t=002622" target="_blank">Front Spring colour codes and specs</a>
The M474 and M030 options both included rebound adjustable yellow Koni's, but the M474 are not height adjustable and are not as stiff as the M030 Koni's. M030 also added thicker rear torsion bars to match the higher rate (160 pound) front springs.
On the '88 951S, the M030 package included an 18 mm rear sway bar, but for mid-'89 and later M030 packages (951 and S2) Porsche used a 16 mm bar to dial in more understeer. As a result, my '89 951 has quite noticeable understeer. I would like to get a 968 M030 19 mm adjustable rear bar to fix this.
11-18-2002, 06:47 PM
#19
[quote] On the '88 951S, the M030 package included an 18 mm rear sway bar, but for mid-'89 and later M030 packages (951 and S2) Porsche used a 16 mm bar to dial in more understeer <hr></blockquote>
Thanks! I think I might have THOSE struts rebuilt and stuff them back into my Cab - it's a touch softer then before, I think, and your data confirms that. Is the Cab even stiffer? (I can't get to the link you posted at the moment)
You know, I wonder if JUST adding the 19mm bar would have also "neutralized" my handling on this M030 car . . . hmmm. I put on both the hollow 30mm front AND the proper 19mm rear 968 M030 set, as I had them sitting around anyway. That combined with my 245 tires all around seems to have made the car as neutral as I could ever ask for.
In retrospect, if I had kept the previous tire ratio (225F, 255R), I might have only done the rear bar to make it neutral.
This is what an M030 driven at the limit looks like at full tilt:
<a href="http://members.rennlist.com/pinkpank/GR10Lean.JPG" target="_blank">http://members.rennlist.com/pinkpank/GR10Lean.JPG</a>
<a href="http://members.rennlist.com/pinkpank/GR3Lean.JPG" target="_blank">http://members.rennlist.com/pinkpank/GR3Lean.JPG</a>
<a href="http://members.rennlist.com/pinkpank/GR10Camber.JPG" target="_blank">http://members.rennlist.com/pinkpank/GR10Camber.JPG</a>
<a href="http://members.rennlist.com/pinkpank/GM8in.JPG" target="_blank">http://members.rennlist.com/pinkpank/GM8in.JPG</a>
<a href="http://members.rennlist.com/pinkpank/GM10In.JPG" target="_blank">http://members.rennlist.com/pinkpank/GM10In.JPG</a>
<a href="http://members.rennlist.com/pinkpank/GM3Out.JPG" target="_blank">http://members.rennlist.com/pinkpank/GM3Out.JPG</a>
And I never once got seasick. <img src="graemlins/icon501.gif" border="0" alt="[icon501]" />
Don't fear the lean, folks! <img src="graemlins/xyxwave.gif" border="0" alt="[bigbye]" />
Thanks! I think I might have THOSE struts rebuilt and stuff them back into my Cab - it's a touch softer then before, I think, and your data confirms that. Is the Cab even stiffer? (I can't get to the link you posted at the moment)
You know, I wonder if JUST adding the 19mm bar would have also "neutralized" my handling on this M030 car . . . hmmm. I put on both the hollow 30mm front AND the proper 19mm rear 968 M030 set, as I had them sitting around anyway. That combined with my 245 tires all around seems to have made the car as neutral as I could ever ask for.
In retrospect, if I had kept the previous tire ratio (225F, 255R), I might have only done the rear bar to make it neutral.
This is what an M030 driven at the limit looks like at full tilt:
<a href="http://members.rennlist.com/pinkpank/GR10Lean.JPG" target="_blank">http://members.rennlist.com/pinkpank/GR10Lean.JPG</a>
<a href="http://members.rennlist.com/pinkpank/GR3Lean.JPG" target="_blank">http://members.rennlist.com/pinkpank/GR3Lean.JPG</a>
<a href="http://members.rennlist.com/pinkpank/GR10Camber.JPG" target="_blank">http://members.rennlist.com/pinkpank/GR10Camber.JPG</a>
<a href="http://members.rennlist.com/pinkpank/GM8in.JPG" target="_blank">http://members.rennlist.com/pinkpank/GM8in.JPG</a>
<a href="http://members.rennlist.com/pinkpank/GM10In.JPG" target="_blank">http://members.rennlist.com/pinkpank/GM10In.JPG</a>
<a href="http://members.rennlist.com/pinkpank/GM3Out.JPG" target="_blank">http://members.rennlist.com/pinkpank/GM3Out.JPG</a>
And I never once got seasick. <img src="graemlins/icon501.gif" border="0" alt="[icon501]" />
Don't fear the lean, folks! <img src="graemlins/xyxwave.gif" border="0" alt="[bigbye]" />
11-18-2002, 07:09 PM
#20
Three Wheelin'
Sorry, my bad. Link is now fixed.
[quote] Is the Cab even stiffer? <hr></blockquote>
I haven't seen any specs that show the cab used different springs than the regular 944S2. It might make sense, given the extra weight, but I didn't find any part numbers.
[quote] You know, I wonder if JUST adding the 19mm bar would have also "neutralized" my handling on this M030 car . . . hmmm. I put on both the hollow 30mm front AND the proper 19mm rear 968 M030 set, as I had them sitting around anyway. <hr></blockquote>
I can't answer that, but I think the adjustability of the 19 mm rear bar would allow you to go either way. I will probably keep my 26 mm hollow front and run the 19 mm rear bar on the soft or medium setting. I understand that with the 30 mm hollow front bar, you generally run the rear bar full stiff. Tire size would also make a difference; I have 225 front, 255 rear, so the extra width in the back may add to my understeer (compared to the stock 225/245.)
[quote] Is the Cab even stiffer? <hr></blockquote>
I haven't seen any specs that show the cab used different springs than the regular 944S2. It might make sense, given the extra weight, but I didn't find any part numbers.
[quote] You know, I wonder if JUST adding the 19mm bar would have also "neutralized" my handling on this M030 car . . . hmmm. I put on both the hollow 30mm front AND the proper 19mm rear 968 M030 set, as I had them sitting around anyway. <hr></blockquote>
I can't answer that, but I think the adjustability of the 19 mm rear bar would allow you to go either way. I will probably keep my 26 mm hollow front and run the 19 mm rear bar on the soft or medium setting. I understand that with the 30 mm hollow front bar, you generally run the rear bar full stiff. Tire size would also make a difference; I have 225 front, 255 rear, so the extra width in the back may add to my understeer (compared to the stock 225/245.)
