Hi Guys,

I have a '10 Turbo with PDK. I just got the KW v3 with HLS and PASM bypass. The kit looks great, but was just wondering about the PASM bypass...


Is there any benifit other than not having to shut it off via the PIWIS? I am thinking that I will just shut it off via PIWIS and not install the PASM bypass kit. PIWIS seems the quickest most straight forward solution.

My thought is that the KW PASM bypass is great for someone that does not have access to a PIWIS, but if you do, just turn off PASM via the PIWIS.


thoughts?

(This thread is just about installing KW bypass or not. I will post another about my thoughts on KWv3 in a couple weeks...)

thanks!

'10 997 Turbo PDK - EVOM Tune, Sharkwerks muffler delete, KWv3, Vorsteiner VRT, Centerlocks, Focal/Audison Stereo upgrade

 

I had my local shop turn off PASM with the PIWIS. It worked perfect.

FYI, I had a huge problem with my front suspension. Apparantly the springs rates for the front are different on HLS combo with coilovers compared to the regular V3's non HLS. The spring rate is about 150 pounds. There was less then 1 centimeter of travel in the springs before the coils are fully compressed together. So when I hit a small bump in the road or hit the brakes hard the front end would "bottom out". Because of this lack of travel it put too much stress on my front alluminum droplinks and bent them. KW said this is the way they are designed and not a defect. It's a $hit design. I swapped out the springs with a set of Eibach's with 425 lb spring rate and had to use a set of Tarrett monoball top mounts.

Take a look at your front suspension and it should be the same as mine was.

 

Is this what they told you? Strange. There is something very odd about the KW spring rates that baffles me: the rear is in the 900 (extremely high) and the front if you are correct is so extremely low. I mean 900 in rear is rate you see in cup cars, and 150 in front is something I've never seen in a 911. Maybe it's progressive and one rate is missing, I don't know.

If you compare this with the typical spring rates seen in 911's: front around 350, rear around 550 (commonly the rear is set up to be 150 to 200 higher than the front), then the KW spring rates balance is just totally out of whack. I don't know what I am missing. There was a discussion on rennlist some time ago questioning this oddly very high spring rate of KW system.

Someone on this forum mentioned that his KW dove a lot during braking, consistent with spring/dampening rate that is too soft in front, and consistent with your remark.

 

Yes, we looked at the last section of the part # on the spring and multiplied it by the conversion factor and got approx. 150lbs. We even called KW and they confirmed it was the right spring. At first they said it was the incorrect spring but after they figured out HLS kit combo has different front spring as opposed to non HLS they said everything was correct. My rear spring are at 750lbs. I don't mind a stiffer rear spring. Since the turbo is so heavy in the rear. But yes I get alot of front end dive at the track. I have not tracked my car since installing the new springs. Will have to wait till next season. But as of right now the turbo is much smoother on the road. I don't hear a peep from the monoball top mounts either.

FYI, cup cars at my shop run JRZ 3-ways with 900front spring and 1100 rear springs. I will go that route next year.

 

Cool. I am bypassing my PASM tomorrow.


I will check the spring rate, drive it for a week or so, take it to the track in two weeks, and then start a new thread around my KW experience.


thanks!

 

Yes, bypass the PASM through the PIWIS by disabling it (as if the car did not have that option). You will then need to physically disconnect the unit which resides in the passenger side footwell. In this way the computer does not look for the unit of find that certain parameters are out of wack and the unit is disconnected so it does not put out any false signals.

Looking forward to reading your feedback on the KW as I thought the front/rear spring rates should not be apart by more than about 150-200 lb/in.

Cheers.

 

Thanks Chris; yours is the first post I run across that reveals the spring rates of KW. 150 front/750 rear is indeed very strange for a 911 setup, too soft up front and I could see why you have to change that front spring. I think your report will help a lot of other KW owners.

I recall reading that the rear spring rate of the non-HLS KW V3 is around 920 - isn't that equally puzzling?

JRZ eh? Someone is slipping down the slippery slope?

 

FWIW, I think comparing just spring rates of various AM coilovers can be misleading. KW vs. Bilstein vs. JRZ etc. doesn't tell the whole tale. Valving and internal particulars must be considered too. One manufacturer may choose larger apertures, higher flow rates, lower/higher pressures, smaller apertures, and then specific spring rates to complete the recipe. KW's 920lb. rear may be right for their shock, Bilstein's much lower 565 (or whatever) best for theirs, and so on. As for the lifting unit in front, I've not been able to understand how the spring heights can be so drastically shortened (to accommodate the "lifter" thingie) without adversely affecting overall function of the suspension. Me, I'd invest in spare chin spoilers. Just my .02.

 

Well regardless of internal valving and particulars, does it not come down a single parameter: dampening? I don't know what the KW shock dyno looks like, but I can't believe that it is so revolutionary different as to support a front spring rate of 150 in our 911.

AFAIK, Bilstein, Moton, JRZ, etc. suggest spring rates around the range of 400/600, 600/800, etc., as starting point for 911, primarily because of its specific rear weight bias. Nearly all suspension notes for 911 that I've read suggest a front rear difference of 150-200. For any given car and specific usage, tuners first choose spring rates then **fine tune** using dampening force, not the other way around. This is why irrespective of coilover brands, the spring rates tend to be very similar for same application; 400/600 street, 600/800 moderate track, etc, no?

IMHO: While dampening force, for example compression damping, could be used to assist spring that is too soft, it is NEVER good practice. It would make for an overly stiff/ non-compliant system. It is better to use the correct spring rate to start out with. Anyway, my amateurish speculations aside :-), bottom line is that observation by users is consistent with the implication that spring rate of 150 is simply too soft for the front, regardless of what damper you pair it with.
Interesting thread/discussion - KW owners should take note of TTChris's very good finding.

 

You know, once you see them in all their glory, hold them in your hands, and play with the adjustment ***** you know you just got to have them. It's like a fine timepiece that you decide to try on at the watch store. Once it's on that wrist it's not coming off

 

Can, I do agree with you wholeheartedly that KW's front 150lb. deal for the HLS is most puzzling, but I'm even more stricken, as I said, by the seriously short height of that HLS front spring. I'm left with the conclusion that anybody's (not just KW's) lifting devices must compromise the suspension function to an unacceptable degree. If 997 front coilovers can work well with those oddly short springs, then why doesn't P use them as standard? The weight and space savings would be a boon, if the truncated springs worked as well as those taller OEM-sized springs. I just ain't buying it.
On the other hand, I still do believe there are several ways to skin a coilover cat, in re: spring rates. Bilstein and KW are both highly regarded manufacturers, and both have legions of ardent fans. I should include JRZ (and another few) as well. Yet, they all bake their cakes differently, but we can really only read the differences by their spring rates. All of the forgoing coilover manufacturers make products that undeniably work far better than stock on both street and track. All seem reliable, all are priced in a reasonably close range, all have fans. My conclusion remains that spring rates can not be considered in a vacuum, but should be looked at as one ingredient in the recipe.
Lastly, Can, thank you so much for your erudite contributions to this forum. You are a light, and a pleasure. Thank you again.

 

BP, thanks for the kind words. Regarding the lifting devices, I too am leery of such complex add-on in the suspension and would recommend it only for must-have situation (steep drive way, etc.).

For spring length, I think that the OEM spring is longer simply because that the length it has to fill out? Note that the Bilstein spring is also shorter than stock (but just a little bit) because it is a dual spring arrangement, helper and main. Also a shortened spring could have increased "travel" by decreasing the number of coil per inch (I think, anyone pls correct as needed) - and maybe that's what KW do to solve the coil bind problem with a shortened spring? But bottom line is I am just guessing and one would hope KW has taken care of the design, and true, I've learned to be suspicious of everything I see, even one from a trusted company.

 

i will move this to a new thread so it is easier to find, but just wanted to close out this one.

I talked to KW in Germany and the actual spring rates are (drum roll please):

For the HLS set up (my new set up):

Front: 70= 400 lbs /in Linear
Rear: 130 = 742 lbs/in Linear

For Non-HLS set up:

Front: 37.86nm (- 70 apox) = 216 lbs/in progressive
Rear: 130 = 742 lbs/in Linear


The person I talked to at the head quarters in Germany was extremely knowledgable and helpful and said that if a person had received a kit with different spring rates, they should contact KW to get this corrected.

 

^^Great and helpful detective work. There is something odd going on because although I could be wrong, I am fairly sure that the rear spring rate of 927 was given by one of the US KW dealers (I wasn't the only one wondering about the 900 plus spring rate.). Also the 150 front spring rate apparently was on the spring itself and confirmed by KW USA? Too late now but one of these days it would be interesting to confirm the spring rate on the spring is as KW Germany states.

HLS Kit: the regular kit has progressive spring, but for HLS lift kit KW changes to linear? Did you ask KW why and what change they anticipate as far handling and ride is concerned? Neither is "better" than the other (linear vs. progressive) but I am a little leery that they are different.
The change to linear spring might have to do with the shortened spring length mentioned by bumperpip above. Progressive spring has 2 rates, initial soft rate, then becoming firm (final rate) as spring compresses further. Since a progressive spring would shorten a bit more than linear, it would not work when you don't have the length required as in the HLS kit? Just speculating - but the bottom line is if true 400/742 is much more reasonable, and I would expect the HLS to be quite a bit stiffer than the non-HLS.
Non HLS Kit: 216 progerssive front and 742 rear is indeed an odd combination and would be consistent with car wanting to dive with braking. *If* such problem exists, the spring would be the first thing I would change.

 

Cannga,

I got the run around from KW as well when I first inquired about the spring rates. There seems to be a disconnect in information between KW USA and KW Germany. A 216 front spring and 742 rear is a huge spread. Regardless of what spring rates they label on their springs I have real world proof that the front spring is too soft. Take a look at the attached pic. You can see the top of each coil has contact marks from the spring being full compressed. Terrible. Pictures were sent to KW and they responded with "that's the way they were designed"