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View Full Version : Car too Low? '83 GTI ITB car



Ned Stevens
01-04-2006, 09:40 PM
After last year (My 1st year) I was told that my car is too low. I ran the car for four race weekends plus drivers school -first time the car had been on track since '98 and every time I ran it I realigned the car and dropped it down a bit more. I ended up lowering it approx. 2 '' frt. and 2.25'' rear. In my mind I am thinking lower is always better, yes-no-what? I am no where near the 5'' min. ride height. Now to the point- BUMP STEER- at what height is the car too low. Wide open question I realize but, any feedback would be appreciated. Thanks, Al

Greg Amy
01-04-2006, 09:45 PM
Ned, there is such a thing as "too low", especially on a McPherson strut car. As a general rule (VERY general) you're looking to make sure that the car is not dropped so far that your front control arms droop down towards the car. To keep the geometry acceptable, make sure they slope down towards the wheels... - GA

Bildon
01-05-2006, 12:01 AM
Flat A-arms are geometrically optimal. But a slight inclination toward the CL of the vehical is acceptable if your running a stiff spring and the car doesn't roll much. It will get you closer to the CG target I think you're looking for. Also forget about postive rake. VWs are too slow. (You have an air dam?) Drop the rear as far as you can. :119: It's ugly but that's how the factory used to set the cars up back in the day.

Bill Miller
01-05-2006, 12:25 AM
Bill pretty much hit it. It's hilarious to watch some of the street crowd that thinks their slammed cars actually handle. There's so little weight in the back of those cars, you want to get what little is there, as low as possible.

joeg
01-05-2006, 08:19 AM
Rabbits will generally appear to ride higher than a lot of other cars and actually, they need to because of the "bump steer" problem identified above.

Dave Zaslow
01-05-2006, 08:35 AM
Joeg, tell that to the Weisberg/Curry/Washay car. Slammed and very good handling, but tough to drive. Spring rates do matter. That car's are extremely high. No suspension movement means no bump steer.

Ned, what's your suspension set-up?

Dave Z

Bildon
01-05-2006, 09:02 AM
Oh and do a few laps with the car at minimum weight (1/4 tank of fuel) then come in and fill it. Sure you just added 50-70 lbs but it's right where you need it... I bet you go faster ;-)

Knestis
01-05-2006, 01:50 PM
True. I did a 3.5 hour enduro by myself and it was amazing, changing nothing else, how much better it was after the fuel stop. It's hard to notice unless you do it in back-to-back laps.

K

Bill Miller
01-05-2006, 02:21 PM
Originally posted by Bildon@Jan 5 2006, 07:02 AM
Oh and do a few laps with the car at minimum weight (1/4 tank of fuel) then come in and fill it. Sure you just added 50-70 lbs but it's right where you need it... I bet you go faster ;-)

70128



I can attest to this too, especially in an A1 Rabbit GTI. Car always handled better on a full tank than it did when it was close to empty. Fortunately, I never ran it that low, as it would burp on the hard RH turns (like the carousel at Summit Point), due to the pick-up problem in the tank.

Ned Stevens
01-06-2006, 10:37 PM
Thanks for all the responses- At present I am running #350 rates frt. and rear (car came with this) and Bilstein Sport frt and rear-I was just trying to survive my 1st year in one piece, so I really did not touch much- other than the ride height. This year I am thinking more like Koni adjustables on frt- #550 frt and #450 rear springs. Will raise the car in the frt-start with full tank-switch to Hoosiers from TOYOs and see what happens. Thanks again, NED

Bill Miller
01-07-2006, 11:39 AM
Originally posted by Ned Stevens@Jan 6 2006, 08:37 PM
Thanks for all the responses- At present I am running #350 rates frt. and rear (car came with this) and Bilstein Sport frt and rear-I was just trying to survive my 1st year in one piece, so I really did not touch much- other than the ride height. This year I am thinking more like Koni adjustables on frt- #550 frt and #450 rear springs. Will raise the car in the frt-start with full tank-switch to Hoosiers from TOYOs and see what happens. Thanks again, NED

70326


Ned,

You may want to talk to Lee Grimes from Koni, about the specific shocks you're going to use, w/ those springs. He'll be able to tell you if the valving is up to the task, w/ those rates.

GITroadracer
01-17-2006, 05:50 PM
Be careful with the half shaft damaging the seals on the diff. If you lower it too much and run standard length shafts they will, after a while, damage the inner flange seal and let gearbox fluid into your inner CV joints and eventually fail them. You can either run shorter shafts of raise the car to avoid this.

JeffYoung
01-17-2006, 06:12 PM
Well, actually, you can't run the shorter a-arms. Illegal.

Andy Bettencourt
01-17-2006, 10:47 PM
Under what rule would shortening the half-shafts be legal?

AB

JamesB
01-17-2006, 11:46 PM
I think Jeff is thinking control arms not axle shafts.

Andy Bettencourt
01-17-2006, 11:49 PM
Originally posted by JamesB@Jan 17 2006, 10:46 PM
I think Jeff is thinking control arms not axle shafts.

71139

I am referring to the 12th post in the thread and to a car for sale I saw recently. I would think any change to axle shafts/stub axels/half shafts (insert your terminology here) would be illegal as well - I just can't find any reference to it being explicitly called out as an approved change...

...could it be the "change in track to accomodate larger tires" rule is what people are hanging their hat on? Please say it ain't so...

AB

Bill Miller
01-18-2006, 07:49 AM
Andy,

I agree w/ you. I've seen shortened axles available, but I have no idea what rule people are using to justify them.

JLawton
01-18-2006, 08:28 AM
Agreed, I don't see anything that would allow it. Believe me, if I thought I could do it, I would have done it on the GTi....

JamesB
01-18-2006, 10:19 AM
Originally posted by Andy Bettencourt@Jan 17 2006, 11:49 PM
I am referring to the 12th post in the thread and to a car for sale I saw recently. I would think any change to axle shafts/stub axels/half shafts (insert your terminology here) would be illegal as well - I just can't find any reference to it being explicitly called out as an approved change...

...could it be the "change in track to accomodate larger tires" rule is what people are hanging their hat on? Please say it ain't so...

AB

71140


Your right, I didnt even think about it. I just know that there is axle bind if you lower too much on mk1 and mk2 VW's but I dont think thats an issue when your talking about optimum gemoetry vs just slamming the car.

JLawton
01-19-2006, 08:14 AM
Originally posted by JamesB@Jan 18 2006, 09:19 AM
but I dont think thats an issue when your talking about optimum gemoetry vs just slamming the car.

71165



I "think" (I'm no expert) that even at a correct ride height and depending on how you have your camber tuned in: whether it's by the camber plates, which will pinch the axle in, or with the bolts in the strut, which will not push the axle in.
To ge the proper camber on one side of my car, I have to have the camber plate pushed all the way towards the engine, which pushes the axle towards the tranny. I had a CV joint blow up on me and we think it was due to the axle shredding the seal and sending chips into the CV joint.

Hope I'm making sense...........

shwah
01-19-2006, 08:33 AM
Originally posted by JLawton@Jan 19 2006, 12:14 PM
I "think" (I'm no expert) that even at a correct ride height and depending on how you have your camber tuned in: whether it's by the camber plates, which will pinch the axle in, or with the bolts in the strut, which will not push the axle in.
To ge the proper camber on one side of my car, I have to have the camber plate pushed all the way towards the engine, which pushes the axle towards the tranny. I had a CV joint blow up on me and we think it was due to the axle shredding the seal and sending chips into the CV joint.

Hope I'm making sense...........

71226

I always adjust the bottom side towards positive and then use the camber plate to get the camber I want. This keeps the outer CV as far as I can from the trans, hopefully making this 'halfshaft bind' issue less likely for me.

Chris

JamesB
01-19-2006, 11:13 AM
yeah, last night I went to check on my car, your right the driver side lacks nearly all room for play so looseing 30mm on the axle length would be better. But its not binding on my car, its just tight. I have plates.

Bildon
01-19-2006, 12:56 PM
Originally posted by Andy Bettencourt@Jan 17 2006, 10:47 PM
Under what rule would shortening the half-shafts be legal?
AB

71138


Andy, people get confused because certain un-named VW parts purveyors sell them shortened...and they sell them to IT guys too. :blink:

Bill Miller
01-19-2006, 02:05 PM
Originally posted by Bildon@Jan 19 2006, 10:56 AM
Andy, people get confused because certain un-named VW parts purveyors sell them shortened...and they sell them to IT guys too. :blink:

71268



:P

RSTPerformance
01-19-2006, 02:53 PM
I have herd of VW's having short axles to avoid this "loweing" problem... I would be disapointed if any Norhteast cars had this modification as it seems to me like it would clearly be illigal...

Raymond

GITroadracer
02-01-2006, 09:26 PM
"Under what rule would shortening the half-shafts be legal? "

Never said it was legal, just telling what people do to avoid the problem.

Several places sell the shortened shafts.

I prefer the cheaper/easier method of raising the car, helps the geometry with bump steer issues.

Oh ya, its legal too.

eMKay
03-31-2006, 11:39 PM
So what ride height would be optimal? I played with it today and have the rear at 23" (ground to top of wheel well) and the front at 23 7/8" The A arms are slightly angled down toward the center of the car. In the rear it seems that I can drop further, I have another 3/4 of an inch left in the coilovers, and slightly less than that in clearance from the tire to the fender.Will I run into rubbing issues going any lower in the rear?

Picture of front and back...

JLawton
04-01-2006, 01:45 PM
You should base your ride height on having your control arms level and then corner weighing the car........

eMKay
04-01-2006, 06:32 PM
You should base your ride height on having your control arms level and then corner weighing the car........
[/b]

So leave the rear alone for now and crank the front up some more?

Conover
04-01-2006, 10:57 PM
No, get that rear as low as you can.

msogren
04-02-2006, 11:47 PM
You may use ecentric control arm bushings to move the wheels out and reduce the axle interferance. This also helps by needing less camber adjustment at the strut. When at all possible, add camber at the bottom of the car, not the strut tops. This widens the car, (often more better.)
Anyplace where there are bolts that hold the control arm, should be optimized. That is ,the balljoint bolts should be pulled out as far as you can, before tightening. the control arm bolts, etc.
You may also shove the engine away from the short axle side to keep it from hitting the end, with a stay bar or creative slotting of the mount areas. Most often the short axle breaks. The lowest the car should be is the axle hits the body/fender well. at full down. You may find that A 1 axles are shorter than A2. Check the part #. Most are not the same, yet fit the car.
WFM,,, MM

I foregot; the rear height determines the inside front wheel traction, also turn in push. raising the rear gives a better turn in , but also lifts the front wheel and will go slower. I predict that you will go slower with the rear any higher than needed to keep the tires off the fender. MM

joeg
04-03-2006, 07:19 AM
Mike--How the heck you been? Long time no see.

This guy knows his VW(S)!

Bildon
04-04-2006, 10:05 AM
>> I predict that you will go slower with the rear any higher than needed

I can support that prediction with testing. Our setup runs the cars with the rear lower than the front.
(as per VWM) See the Blethen photo above... notice the "rake" here at Pocono is probably not optimal due to the large amount of time spent at high speed. But on most other tracks it's proven better.

RSTPerformance
04-04-2006, 11:05 AM
You may use ecentric control arm bushings to move the wheels out and reduce the axle interferance. This also helps by needing less camber adjustment at the strut. When at all possible, add camber at the bottom of the car, not the strut tops. This widens the car, (often more better.)
Anyplace where there are bolts that hold the control arm, should be optimized. That is ,the balljoint bolts should be pulled out as far as you can, before tightening. the control arm bolts, etc.
You may also shove the engine away from the short axle side to keep it from hitting the end, with a stay bar or creative slotting of the mount areas. Most often the short axle breaks. The lowest the car should be is the axle hits the body/fender well. at full down. You may find that A 1 axles are shorter than A2. Check the part #. Most are not the same, yet fit the car.
WFM,,, MM

I foregot; the rear height determines the inside front wheel traction, also turn in push. raising the rear gives a better turn in , but also lifts the front wheel and will go slower. I predict that you will go slower with the rear any higher than needed to keep the tires off the fender. MM
[/b]


Does anyone think some of these recomendations are illigal??? Just wondering others opinions....

ecentric control arm bushings

A 1 axles are shorter than A2. Check the part #. Most are not the same, yet fit the car

creative slotting of the mount areas

Bill Miller
04-04-2006, 03:51 PM
Does anyone think some of these recomendations are illigal??? Just wondering others opinions....

ecentric control arm bushings

A 1 axles are shorter than A2. Check the part #. Most are not the same, yet fit the car

creative slotting of the mount areas
[/b]


On the subject of the first item on your list:

17.1.4.D.5.d.1 sez...


Cars equipped with MacPherson strut suspension may
decamber wheels by the use of eccentric bushings at
control arm pivot points, by the use of eccentric bushings
at the strut-to-bearing-carrier joint, and/or by use of
slotted adjusting plates at the top mounting point. If
slotted plates are used, they shall be located on existing
chassis structure and may not serve as a reinforcement
for that structure. Material may be added or removed
from the top of the strut tower to facilitate installation
of adjuster plate.[/b]

(emphasis mine)

So, I think the eccentric control arm bushing is fine. The other two items, :018:

RSTPerformance
04-04-2006, 04:39 PM
nice responce Bill... I like your thinking :)

msogren
04-04-2006, 09:03 PM
Lets look at the facts;
How many ITB VWs are there??
How many blow axles every hour or so??
if all of the dubs had stock , long axles. They would bust a lot of axles. A2 are worse than A1 for some reason. Somewhere in the car, some correction has been made to keep axles in the car.
I actually have legal , stock off the shelf axles( autozone liftime ) in my current A1 Rocker. I have welded in lower bushings that seem to have solved that issue for me. The welded diff hurts them all by it self.
I had a Golf and a Rock and used the same axles for both, in the past.
MM

Bill Miller
04-04-2006, 09:41 PM
Lets look at the facts;
How many ITB VWs are there??
How many blow axles every hour or so??
if all of the dubs had stock , long axles. They would bust a lot of axles. A2 are worse than A1 for some reason. Somewhere in the car, some correction has been made to keep axles in the car.
I actually have legal , stock off the shelf axles( autozone liftime ) in my current A1 Rocker. I have welded in lower bushings that seem to have solved that issue for me. The welded diff hurts them all by it self.
I had a Golf and a Rock and used the same axles for both, in the past.
MM
[/b]


I'm not sure, but I think you just said it's ok to use alternate parts because the stock ones break.

JLawton
04-05-2006, 07:08 AM
Lets look at the facts;
How many ITB VWs are there??
How many blow axles every hour or so??
if all of the dubs had stock , long axles. They would bust a lot of axles. A2 are worse than A1 for some reason. Somewhere in the car, some correction has been made to keep axles in the car.
I actually have legal , stock off the shelf axles( autozone liftime ) in my current A1 Rocker. I have welded in lower bushings that seem to have solved that issue for me. The welded diff hurts them all by it self.
I had a Golf and a Rock and used the same axles for both, in the past.
MM
[/b]

Here we go again. The "it's OK to do because it makes the car more reliable" argument. :rolleyes: The ONLY legal way to fix the axle problem: Bring plenty of spares with you, get your camber from the strut, not the camber plates, rebuild/replace often and ...........bring spares!!

JamesB
04-05-2006, 11:33 AM
Spares spares spares. Thats really the only legal way to handle the proper ride height for suspension geomentry. shifting the motor or shortening the axles are blatently illegal. At least these axles are cheap as dirt now, so keeping a spare set isnt that hard.

RSTPerformance
04-05-2006, 01:15 PM
I think you could legaly "shift" the motor with stock mounts, at least you can on an Audi.

Where do you purchase ecentric control arm bushings...

Raymond

Bill Miller
04-05-2006, 02:43 PM
I think you could legaly "shift" the motor with stock mounts, at least you can on an Audi.

Where do you purchase ecentric control arm bushings...

Raymond
[/b]


You've probably got to have them fabricated. I've never heard of an off-the-shelf source for them. Maybe Bildon knows?

Spares w/o a doubt!! I used to carry two complete corners for the my ITB Rabbit. Had new axles, new hubs, fresh calipers w/ new pads, new rotors, control arms w/ new ball joints, everything. Also had individual spare parts (mostly for other VW racers :023: ). If something needed changing, the whole thing went on. Total of 11 bolts and a brake line, per side (2 strut bolts, 3 control arm bolts, and 6 axle bolts). Could change a side in ~ 10-15 minutes (10 for sure w/ air tools). The stuff that came off got rebuilt and put into the spares box for the next trip.

Ned Stevens
04-10-2006, 05:41 PM
Back to my original point. I have read with interest all of the responses, but one question still has not been answered. I can understand overworking the cv joints with extreme angles-I can understand the problem with the axles coming straight out from trans to the hub (problem of them being too long) but what if the axles are the same angle going up from the trans to the hub in lowered form as going down from the trans to the hub in stock form. I drive an '83 VW GTI everyday and the axles on that car are angled down to the hubs(approx. 3 degrees) So what is the difference - other than bump steer toeing out under compression as opposed to toeing in in stock height under compression? Thanks for reading my rambling, Al Stephenson ITB #14

joeg
04-11-2006, 09:08 AM
I think Bump steer is a function of where the rack and pinion is positioned. I doubt there is much adjustability there and the other way to cure it--tie rod ends--is also a legal dead end.

Knestis
04-11-2006, 01:33 PM
Common thinking is that, while a very low ride height might take the drive axle angles back to where they are not binding in plunge, the resulting negative angle of the lower control arm will put the roll center in a sub-optimal position.

That said, the BSI Golfs ran at CMP in 2004 with front ride heights that were lower than this approach dictates. With sufficiently stiff springs (or bars?) to limit front roll, who knows for SURE without actually testing a bunch of options?

That's the problem with "common thinking" and simply following the pack.

K

msogren
04-11-2006, 10:09 PM
The lower A arms pointing up give a very high roll center. According to all the experts and the engineering books.
But. The fast cars are under the flat arm height. Even if the A arms are set to point down alittle at rest, the arm moves as soon as you turn the car hard and the arm then points up anyway.
I was not clear if the car is a street car or race car
As for the street A 1 car; Lower the car until the arms are just above flat. set the camber and toe. you will need some real shox (Bilstein sport ? ) and springs( 250 to 350) to keep it from hitting bottom. use a strut brace. Every thing is a compromise the ride will get harsher . if it bottoms too much . or you live in the north, keep it up some. The strut bearing and fenders take a lot of abuse when done this way. Try the collasped rubber strut mounts with springs up to about 300#. over that spring rate, the strut bearing deflects more than the spring, and becomes the spring.
race springs are maybe 450 front /300 rear with a rear sway bar/open diff. (I use less)

You pick up a lot of driveability/turn in with some rear toe out(8-10 mm per side) and about 1* camber .
it allows a lot softer rear spring and wont spin as often.
5- 6mm is about zero scrub for 1degree camber.
WFM. MM

evanwebb
04-12-2006, 02:08 AM
Hey Mike (or anyone), how do you recommend adjusting camber and toe on the stub axles? I find the little blue plastic thingies to be less than satisfactory...




The lower A arms pointing up give a very high roll center. According to all the experts and the engineering books.
But. The fast cars are under the flat arm height. Even if the A arms are set to point down alittle at rest, the arm moves as soon as you turn the car hard and the arm then points up anyway.
I was not clear if the car is a street car or race car
As for the street A 1 car; Lower the car until the arms are just above flat. set the camber and toe. you will need some real shox (Bilstein sport ? ) and springs( 250 to 350) to keep it from hitting bottom. use a strut brace. Every thing is a compromise the ride will get harsher . if it bottoms too much . or you live in the north, keep it up some. The strut bearing and fenders take a lot of abuse when done this way. Try the collasped rubber strut mounts with springs up to about 300#. over that spring rate, the strut bearing deflects more than the spring, and becomes the spring.
race springs are maybe 450 front /300 rear with a rear sway bar/open diff. (I use less)

You pick up a lot of driveability/turn in with some rear toe out(8-10 mm per side) and about 1* camber .
it allows a lot softer rear spring and wont spin as often.
5- 6mm is about zero scrub for 1degree camber.
WFM. MM
[/b]

msogren
04-12-2006, 08:15 AM
I use steel washers. And a "Carquest" (for the VW) shim across the bottom bolts, plus a washer
The bottom front bolt gets about .060, the bottom rear gets about 020 shim The bolts get blue locktiite. This bolts them down crooked but has not come apart , ever.
This really transforms a pushing car. maybe a lttle nervous in the rain. but a drstic improvement.
I use .5in or more for a solo car and more for a roundy round car. The dynamic weight transfer is what gets this to work, plus, I hate a pushing car.
Welded diff can run a straighter rear, with more camber.IMHO. MM

itracer
04-12-2006, 08:46 AM
Try these. They are made for racing:

http://www.srsvw.com/parts/partdetail.asp?pid=93