Car Lowered and Aligned Having VDC issues now
05-22-2009, 04:46 AM
#1
Car Lowered and Aligned Having VDC issues now
Recently had my car at the dealer for new Lower and upper front control arms (bushings went under warranty even though lowered). Since then I brought my car to a Very well known Alignment shop (Guelfies) The Car is lowered on Eibach Pro Kit springs and has a Eibach/SBC rear camber arms and toe bolts. The car was aligned back to factory spec no problem.
Here's my problem... When going over a hill or exiting the Highway and I hit the brakes going left or right (Although right its more noticeable) the Slip Lights go on the car halts gas and proceeds to use ABS. While I still have control of my car its FN Annoying as hell, and scary. Its making the car completely unpredictable and making me hesitant to drive her as I would normally.
Before I call the dealer and make a big stink, the tires are new, any thoughts on what the F is going on here? Its only doing it when turning and braking kinda scary when it happens truthly. Is it possible that I need more camber? Or there an underlying issue with the electronics here? Its getting frustrating as it seems every time I correct 1 issue I have another 1.
Here's my problem... When going over a hill or exiting the Highway and I hit the brakes going left or right (Although right its more noticeable) the Slip Lights go on the car halts gas and proceeds to use ABS. While I still have control of my car its FN Annoying as hell, and scary. Its making the car completely unpredictable and making me hesitant to drive her as I would normally.
Before I call the dealer and make a big stink, the tires are new, any thoughts on what the F is going on here? Its only doing it when turning and braking kinda scary when it happens truthly. Is it possible that I need more camber? Or there an underlying issue with the electronics here? Its getting frustrating as it seems every time I correct 1 issue I have another 1.
05-22-2009, 05:35 AM
#3
245/35/20 front (1 Season Old)
275/30/20 rear (Installed new this season 2 weeks old)
To add to this, it will hit the brakes for me with out me actually braking when cornering. This is the part that scary as FK! Why would the car brake on its own?
275/30/20 rear (Installed new this season 2 weeks old)
To add to this, it will hit the brakes for me with out me actually braking when cornering. This is the part that scary as FK! Why would the car brake on its own?
05-22-2009, 06:57 AM
#5
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Well from a stock 225/45/18 to a 245/35/20...you INCREASED your rolling diameter 0.8" out front and now your speedo thinks you're going ~62mph @ 60.
Out back you went from 245/45/18 to 275/30/20...you DECREASED your rolling diameter only 0.2" so it should be fine, but at 60 your car thinks its doing less than that by a hair.
That's off the assumed base OEM wheel setup...
http://www.miata.net/garage/tirecalc.html - should help you, if you started out with different tires just put them into the left side and put the new size in the right and it will tell you the differences.
I did that for you and the size differences coupled together may likely be enough to throw off your VDC as it keeps reading that your front and rear tires are going different speeds as you increased one size and decreased the other. When your rear tires slip it registers a different "speed" in the system so it cuts power / applies brakes to slow it down, your system likely thinks that you are slipping everywhere.
That's my best guess. Hope this helps, don't let the peanut crew get you down.
Out back you went from 245/45/18 to 275/30/20...you DECREASED your rolling diameter only 0.2" so it should be fine, but at 60 your car thinks its doing less than that by a hair.
That's off the assumed base OEM wheel setup...
http://www.miata.net/garage/tirecalc.html - should help you, if you started out with different tires just put them into the left side and put the new size in the right and it will tell you the differences.
I did that for you and the size differences coupled together may likely be enough to throw off your VDC as it keeps reading that your front and rear tires are going different speeds as you increased one size and decreased the other. When your rear tires slip it registers a different "speed" in the system so it cuts power / applies brakes to slow it down, your system likely thinks that you are slipping everywhere.
That's my best guess. Hope this helps, don't let the peanut crew get you down.
05-22-2009, 07:29 AM
#6
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^^^ That would be my guess as well. Same issue as SnyperZ's thread you posted in RedBull. By shifting the F:R tire ratio you decreased the range in which ABS can operate without tripping. This issue has several causes but the F:R tire ratio change appears to be the most comman.
An easy test: go out and lay down some rubber over the next week or so. Does this problem get worse? I would bet yes. The cure is returning to a ratio more like stock. Go to a 35 series tire for the rear. I run 265/35/18 front and 275/35/18 rear without issues.
An easy test: go out and lay down some rubber over the next week or so. Does this problem get worse? I would bet yes. The cure is returning to a ratio more like stock. Go to a 35 series tire for the rear. I run 265/35/18 front and 275/35/18 rear without issues.
05-22-2009, 09:52 AM
#7
Well from a stock 225/45/18 to a 245/35/20...you INCREASED your rolling diameter 0.8" out front and now your speedo thinks you're going ~62mph @ 60.
Out back you went from 245/45/18 to 275/30/20...you DECREASED your rolling diameter only 0.2" so it should be fine, but at 60 your car thinks its doing less than that by a hair.
That's off the assumed base OEM wheel setup...
http://www.miata.net/garage/tirecalc.html - should help you, if you started out with different tires just put them into the left side and put the new size in the right and it will tell you the differences.
I did that for you and the size differences coupled together may likely be enough to throw off your VDC as it keeps reading that your front and rear tires are going different speeds as you increased one size and decreased the other. When your rear tires slip it registers a different "speed" in the system so it cuts power / applies brakes to slow it down, your system likely thinks that you are slipping everywhere.
That's my best guess. Hope this helps, don't let the peanut crew get you down.
Out back you went from 245/45/18 to 275/30/20...you DECREASED your rolling diameter only 0.2" so it should be fine, but at 60 your car thinks its doing less than that by a hair.
That's off the assumed base OEM wheel setup...
http://www.miata.net/garage/tirecalc.html - should help you, if you started out with different tires just put them into the left side and put the new size in the right and it will tell you the differences.
I did that for you and the size differences coupled together may likely be enough to throw off your VDC as it keeps reading that your front and rear tires are going different speeds as you increased one size and decreased the other. When your rear tires slip it registers a different "speed" in the system so it cuts power / applies brakes to slow it down, your system likely thinks that you are slipping everywhere.
That's my best guess. Hope this helps, don't let the peanut crew get you down.
Thats very useful and I do appreciate it, but if you read my post this has only started happening after an alignment, since getting new camber arms up front. The rims and tires are the same from last year and has never ever done that. For the car to brake on its own leads me to believe theres an electric issue. I could see if it did this as soon as I changed my wheels but it hasnt and I have switched back and forth from stock to the summer wheels 2 seasons in a row now.
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05-22-2009, 10:30 AM
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Thats very useful and I do appreciate it, but if you read my post this has only started happening after an alignment, since getting new camber arms up front. The rims and tires are the same from last year and has never ever done that. For the car to brake on its own leads me to believe theres an electric issue. I could see if it did this as soon as I changed my wheels but it hasnt and I have switched back and forth from stock to the summer wheels 2 seasons in a row now.
I honestly am not that well versed as to why camber would cause such issues. You can get readout sheets as to what your current alignment and camber settings are at each corner...whoever did the work on your car should be able to provide you with the numbers. I would work from there.
If your car handled the tires fine until this, well the adjustment must have done something...too hard to tell without being there. I would go back to where you got it done and see if they can figure it out or if they made a mistake.
05-22-2009, 06:16 PM
#10
Sorry, I've been out working on MY Z all day. Your answer is here...
https://my350z.com/forum/showthread....1&postcount=45
Why is it happening now? I have no idea other than the change of the suspension probably bumped something with the wheel speed sensors.
05-22-2009, 07:41 PM
#11
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Your rear tires (275/30-20”) have an Overall Diameter of 26.49”
So… your rear tires have a smaller overall diameter than your front tires.
VDC always fails when you run taller tires on the front than the rear (which is what you are doing with your current wheel/tire setup).
To fix your problem: Install 245/30-20” tires on the front (or any equivalent OD sized tire).
BTW: Changes you made in your suspension or any adjustments are coincidental and not directly related to the tire-sizing problem.
--Spike
05-22-2009, 08:19 PM
#12
New Member
Please give us a little time here to analyze the question so that we can return an accurate response.
--Spike
05-23-2009, 05:54 AM
#13
You know how something will works fine for years and years then you unplug or touch the connectors and all of a sudden it will start acting flaky? I can't explain it but it does seem to happen regularly.
05-23-2009, 12:11 PM
#17
Check your sensors b4 you go waste money buying new tires that probably aren't even causing the problem. Also try driving without VDC, if the problem occurs when VDC is disabled, it's probably an ABS sensor I would GUESS.
05-26-2009, 05:01 AM
#19
Guys, I appreciate the help I really do, but what you are all failing to understand is that I have ran with these rims and tires for 2 years now with no problems. Since getting a alignment this has been happening.
I hope that I have clarified this as I havent been driving my car because of this issue and its nice out I have the kit on the car the wheels shinny and I just want to enjoy her for these nice warm weather driving.
For the 1 who said I am impatient, sorry your taking it that way. Its not about patience more about how FD up these forums have been becoming. I swear I go to other forums and things are a lil more mature and helpful. my350z.com was once like that however maybe they stopped checking ID at the door I dunno, but check out these threads lately and you tell me.
I can see how a bad sensor can do this, I cant see how an alignment or rime/tire setup that has been used before do this. I guess I can call the Alignment shop and see what the deal is. I'll be doing an oil change and cleaning off my calipers this weekend, Ill see about pulling and cleaning the sensors.
Will keep u posted!
I hope that I have clarified this as I havent been driving my car because of this issue and its nice out I have the kit on the car the wheels shinny and I just want to enjoy her for these nice warm weather driving.
For the 1 who said I am impatient, sorry your taking it that way. Its not about patience more about how FD up these forums have been becoming. I swear I go to other forums and things are a lil more mature and helpful. my350z.com was once like that however maybe they stopped checking ID at the door I dunno, but check out these threads lately and you tell me.
I can see how a bad sensor can do this, I cant see how an alignment or rime/tire setup that has been used before do this. I guess I can call the Alignment shop and see what the deal is. I'll be doing an oil change and cleaning off my calipers this weekend, Ill see about pulling and cleaning the sensors.
Will keep u posted!
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