Doubt it, no one is a fan of KW quality. They also have the worst customer service reputation known to man across all brands.
I'd say stay away unless you have a very good shop nearby with tons of experience with their products
7
2017 GTi PP at VIR
- Thread starter Mini7
- Start date
I'd say stay away unless you have a very good shop nearby with tons of experience with their products
Mini7
Autocross Champion
- Location
- Charlotte, NC
- Car(s)
- 2017 GTi Sport PP
GMP Performance in Charlotte sell them locally and a buddy has a set on his E92. His car seemed pretty well tied down around VIR. And I’ve also seen two TTRS at VIR running KW’s.
I don’t know much about KW. Also I believe that the adjusters are at the top of the struts. Let easy to make quick adjustments to get them dialed in.
My Mini has AST 5100’s on 450lb square setup. Firm ride but the shock controls the spring really well on the street and is still compliant over the curbs at VIR.
Öhlins US headquarters is 2hrs away.
I will have to add a set of Vorshlag camber/caster plates if I go the Öhlins route.
I don’t know much about KW. Also I believe that the adjusters are at the top of the struts. Let easy to make quick adjustments to get them dialed in.
My Mini has AST 5100’s on 450lb square setup. Firm ride but the shock controls the spring really well on the street and is still compliant over the curbs at VIR.
Öhlins US headquarters is 2hrs away.
I will have to add a set of Vorshlag camber/caster plates if I go the Öhlins route.
Mini7
Autocross Champion
- Location
- Charlotte, NC
- Car(s)
- 2017 GTi Sport PP
Both are excellent choices. At a much higher price point.
The GTi is 350-400lbs heavier than my Mini. The Mini rode surprisingly well on 450lb springs with minimal control arm leverage compared to the GTi
400/450 or 400/500 is still well within reason. Because of the lever action of the lower control arm, the actual rear spring rate is lower on our cars ( 15-20% less, maybe as much as 25%). I want a higher rate at the rear to reduce rearward squat under acceleration to increase front end grip out of corners. Around 0.2g of acceleration weight transfer that I need to counteract. Will need to do some research to find the right equation to do the math.
The GTi is 350-400lbs heavier than my Mini. The Mini rode surprisingly well on 450lb springs with minimal control arm leverage compared to the GTi
400/450 or 400/500 is still well within reason. Because of the lever action of the lower control arm, the actual rear spring rate is lower on our cars ( 15-20% less, maybe as much as 25%). I want a higher rate at the rear to reduce rearward squat under acceleration to increase front end grip out of corners. Around 0.2g of acceleration weight transfer that I need to counteract. Will need to do some research to find the right equation to do the math.
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victorofhavoc
Autocross Champion
- Location
- Kansas City
I spoke with ground control recently about a custom setup with mcs dampeners. They recommended 500# front and 650# rear for my primarily not street driven car. They said this would be okay enough to be street compliant though...
Wouldn't trust their opinion.
victorofhavoc
Autocross Champion
- Location
- Kansas City
Can you qualify or quantify that statement? They're pretty well trusted by most of the people I race with.
Mini7
Autocross Champion
- Location
- Charlotte, NC
- Car(s)
- 2017 GTi Sport PP
I still need to crawl under my car to measure the lower control arm to calculate the motion ratio with the divorced spring.
500/650 sounds very reasonable for the track. Even more so, if you are running slicks. Good quality shocks with the good compression and rebound curves will make stiff springs ride tolerably well on the street.
What did Ground Control say about running a big rear sway bar?
To be honest I would prefer to go back to a stock RSB, while running increased rear spring rate. As long as the car will not revert back to understeer.
Keep me posted on your progress.
victorofhavoc
Autocross Champion
- Location
- Kansas City
I think with slicks it would be better to run 600/800, according to what GC commented. I run either 100tw or 200tw (streetable competition) tires.
Those were the numbers they gave me with my rear bar, but honestly, I agree with you. I'd much rather have more spring than bar. If the rears were a lot higher rate than front, then I'd probably run the biggest front bar i could find and a medium or stock rear with upgraded endlinks.
Typically a sway bar reduces grip across the axle... They're better used for balancing reduction of grip front to rear, but a giant front bar on a fwd car with a mcstrut suspension seems to be the exception due to the increasing positive camber in front due to compression.
Anyway, I'm taking my mods a lot slower this time around. I'm trying to make sure I get good seat time in between each change to see the effects. I've gotten quite fast with just 034 springs, too mounts, tune, and proper consummables. Last DE event I went to a viper acr had trouble keeping up everywhere but the main straight. I'll keep you updated as it goes along.
There's a guy on these forums who did a good writeup of the mk7 GTI suspension and I believe measured the motion ratio:
https://drivetribe.com/p/lets-talk-suspension-Be0oGEQcRYOPzXLs-UfUtw?iid=DoKGUvAKRiOcuqGYUdMgqg
Might save you some trouble. It references some threads on here, but I'm not sure he kept them up to date.
Cliff runs 475/650 from Ground Control on his R with 200tw tires. When I got rides from him on the track, it rode comfortably and seemed very streetable and probably could be much stiffer for a more track dedicated car. I know he was getting some ride height sensor errors recently which caused DCC errors. I don't want to mix up any information, so I'm sure he'll see this thread and comment on it.
Mini7
Autocross Champion
- Location
- Charlotte, NC
- Car(s)
- 2017 GTi Sport PP
AWD needs even more rear spring rate to get the car to rotate vs. FWD
It will be good to get some input from Cliff on this subject.
Thanks for the link, I played around with the calculator and came up with 450/500 based on my average speed around VIR. Still think the rear needs to be a little higher. May still measure that rear arm for myself.
Add slicks and you drop 4-seconds on your laptime, pushing your average lap speed higher. Which translates to even higher spring rate and shocks that have to compress and rebound faster to keep the wheel in contact with the rode.
Mini7
Autocross Champion
- Location
- Charlotte, NC
- Car(s)
- 2017 GTi Sport PP
I think with slicks it would be better to run 600/800, according to what GC commented. I run either 100tw or 200tw (streetable competition) tires.
Those were the numbers they gave me with my rear bar, but honestly, I agree with you. I'd much rather have more spring than bar. If the rears were a lot higher rate than front, then I'd probably run the biggest front bar i could find and a medium or stock rear with upgraded endlinks.
Typically a sway bar reduces grip across the axle... They're better used for balancing reduction of grip front to rear, but a giant front bar on a fwd car with a mcstrut suspension seems to be the exception due to the increasing positive camber in front due to compression.
Anyway, I'm taking my mods a lot slower this time around. I'm trying to make sure I get good seat time in between each change to see the effects. I've gotten quite fast with just 034 springs, too mounts, tune, and proper consummables. Last DE event I went to a viper acr had trouble keeping up everywhere but the main straight. I'll keep you updated as it goes along.
So I subscribe to the theory that pitch and roll should be controlled by spring rate and not sway bars. A friend in a home built Lotus 7 raced his car without any front or rear sway bar and was regularly a race winner. He had his suspension dialed in for sure.
RSB should be used as a tool to fine tune balance. Changing conditions, different track requirements. My 034 RSB is to dial out the inherent understeer.
Get the right spring set-up F/R with a good set of shocks with the right rebound curve.
Swaybars tie independent suspensions together making them not so independent.
More static camber for McPherson style front suspensions. Anyone here running Vorshlag front camber/caster plates?
Most probably going to go -3 degrees Front and -2 degrees rear. Still eating the outer shoulder at -2 degrees.
What RSB are you running? Which is your home track and what is your average speed?
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victorofhavoc
Autocross Champion
- Location
- Kansas City
I agree with you for the most part, but the mcstrut is unique in some ways. This article does a good job of explaining some of the oddities, but it's a long and technical read. You'd probably understand, but a lot of others may have more misunderstanding than understanding after reading, so I don't recommend it for anyone that doesn't know the basic physics of moment arms and vector math.
I added the rear bar to take out understeer, but instead I ended up introducing MORE understeer when I had MSS track springs. The front was stiffer, but the rear was even stiffer, and as a result the front could gain more compression through turns than the rear, thereby reducing front camber more than rear, and resulting in corner out understeer. A stock car with a rear bar will be more neutral, but when you've stiffened up the rear too much you'll gain understeer. I've got the 25mm st rear bar, which is non adjustable and I'm not a fan. I'll probably swap it for a superpro bar at some point. Adding the super pro endlinks was actually very helpful for consistency/solidity from the rear end.
Swaybars work by reducing grip across the axle, so bigger bar generally means less grip on that axle, and that's where the "tuning" aspect you're referencing comes into play. However, again, the McPherson strut is special in that unlike a double-wish it gains positive camber as it compresses, so if you had tons of spring in the front you could essentially perform the same action as an anti-sway bar, but you'd limit some of the needed weight change for maximum grip at corner in and under braking. Fwd has to have a bit of a balance between stiff spring and big front bar with the McPherson setup. Roll isn't necessarily a bad thing!
My home track is Heartland motorsports Park in topeka, Kansas. Last time out, on worn direzza Z3 I was running pretty consistent 1:55-ish, with my fastest lap a 1:53. It was a good day, but cutting through traffic was a pain. With less traffic I'm sure I can cut those times down. I've got better tires coming up, and some fresh rubber should be able to cut me down another 1-2 seconds. You can find the race results here, http://timingscoring.drivenasa.com/NASA_Central_Region/2019 - Official Results/HPT/. Though I'm not racing this year, my car would fall into the TT4 category as it stands, and you can see how my times would compare. Keep in mind the majority of these guys are dedicated cars, not dual purpose-ish like mine. They're pushing for me to do TT, but money and time are key...
Mini7
Autocross Champion
- Location
- Charlotte, NC
- Car(s)
- 2017 GTi Sport PP
Send the link to the article. I would be interested in reading through it.
I’m not too concerned about roll. As long as the car takes a set, you can feel the available grip and drive accordingly.
I’m not too concerned about roll. As long as the car takes a set, you can feel the available grip and drive accordingly.
victorofhavoc
Autocross Champion
- Location
- Kansas City
I linked it to the word "this" above, but not sure if it worked properly... Here's the raw link:
https://nasaspeed.news/tech/suspens...-track-performance-for-strut-suspension-cars/