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Thanks, that is exactly what I need. Wondering about getting some T1 bar or equivalent. Obviously will need better shocks with that.
What are peoples' experience with different manufacturers? I assume you can't buy true T1 bars on their own can you?
pretty sure you can - try gm parts house for lower prices
for just shocks (not coilovers) koni single adjustables (rebound) ($1100 to $1300) or KW double adjustable (compression and rebound) through strano parts ($1600 iirc)
if you have larger budget then you can go with top of the line penske 3 or 4 way adjustable with regressive blowoff cages
if you have a low budget then drm bilsteins
EDIT:
Pfadt chart with hotchkiss bars added in:
Last edited by el es tu; Aug 25, 2014 at 02:42 PM.
This is for track use for me, not AutoX. Also don't plan on using any more than a 275 front, either NT01 or BFG Rival . Rears will likely be 295 but could be 305 NT01
This is a cool chart, but I discovered the Pfadt bars are much softer than shown on the chart due to their aluminum arms. The bars themselves are steel, but the arms are aluminum. I happened to have one of the Pfadt low rate bars (35 mm) with 3 holes for adjustability as well as a T1 bar (38 mm) and Hotchkis bar (32 mm) so I just ran a test. My hunch was that the hotchkis bar at 32 mm would actually be stiffer than the Pfadt bar at 35 mm due to it's aluminum ends. I tested each bar including the 3 different settings on the Pfadt bar for torsional stiffness by jacking up the driver's side front tire with 600 lbs of force and measuring how far the passenger side rotor raised off the ground due to the sway bar. My results are as follows:
Starting point (distance from passneger side rotor to ground with car on lift) = 52.25"
Jack up driver's side tire with 600 lbs force (scale on a tranny jack):
Pfadt outer hole: 53.75"
Pfadt middle hole: 53.9"
Pfadt inner hole: 54.125"
Hotchkis bar: 54.25"
T1 bar: 54.75"
Sure enough, the Hotchkis bar is stiffer than the stiffest setting on the Pfadt bar. The chart shows the Hotchkis bar softer than the softest setting on the Pfadt bar because it doesn't account for the aluminum arms.
This is a cool chart, but I discovered the Pfadt bars are much softer than shown on the chart due to their aluminum arms. The bars themselves are steel, but the arms are aluminum. I happened to have one of the Pfadt low rate bars (35 mm) with 3 holes for adjustability as well as a T1 bar (38 mm) and Hotchkis bar (32 mm) so I just ran a test. My hunch was that the hotchkis bar at 32 mm would actually be stiffer than the Pfadt bar at 35 mm due to it's aluminum ends. I tested each bar including the 3 different settings on the Pfadt bar for torsional stiffness by jacking up the driver's side front tire with 600 lbs of force and measuring how far the passenger side rotor raised off the ground due to the sway bar. My results are as follows: Starting point (distance from passneger side rotor to ground with car on lift) = 52.25" Jack up driver's side tire with 600 lbs force (scale on a tranny jack): Pfadt outer hole: 53.75" Pfadt middle hole: 53.9" Pfadt inner hole: 54.125" Hotchkis bar: 54.25" T1 bar: 54.75" Sure enough, the Hotchkis bar is stiffer than the stiffest setting on the Pfadt bar. The chart shows the Hotchkis bar softer than the softest setting on the Pfadt bar because it doesn't account for the aluminum arms.
Any chance you can do a test with the Pfadt heavy rate bars compared to the T1. Front and rear?
Any chance you can do a test with the Pfadt heavy rate bars compared to the T1. Front and rear?
Sorry I don't have one. I run the T1 bar but my car had a hotchkis bar when I bought it. My friend let me try his old Pfadt bar last year so I just happened to have these handy.
So here is a question that shows my ignorance. Does the T1 race class allow camber changes and any size rim ? My thought is that if the rules don't allow these changes then body roll needs to be limited severely in the front at least to prevent camber gain which means a T1 bar (or LG as mentioned above) might be too stiff for a car with adequate camber.
Here is my situation, I have run stock bars and lots of camber with a fairly neutral car while using a square setup. This year for competition reasons, I went to a 275/295 setup and only stock camber.(neg 1.2 which dropped me a class in Time-attack competition) Big mistake, the car understeers like a pig: easy to drive but really slow. Question is, if I go back to sig camber (usually neg 2.5 up front and whatever I can get out back) and add in good aftermarket bars to prevent what I feel is too much body roll, would the T1 bar be too much?
pretty sure you can - try gm parts house for lower prices
for just shocks (not coilovers) koni single adjustables (rebound) ($1100 to $1300) or KW double adjustable (compression and rebound) through strano parts ($1600 iirc)
if you have larger budget then you can go with top of the line penske 3 or 4 way adjustable with regressive blowoff cages
if you have a low budget then drm bilsteins
EDIT:
Pfadt chart with hotchkiss bars added in:
Not so sure about the numbers on the Hotchkiss bars. Looking at their website, assuming they are actually the same bars for a C5 and C6, they imply that their C5 rear is significantly heavier duty than a stock C5 but virtually the same as a stock C6.
Any idea re the Strano bars?
My real concern with T1 bars is that they are better for cars that can generate a lot of grip with Hoosiers or similar tires.
the strano bars are 33 and 35 mm (with a hollow or solid option for the 35) for the fronts and 25.4 for the rear
my guess would be that the 33 would be somewhere around the stiffness of the Zr1 front bar which is also 33mm
and the hollow 35 would be somewhere around the pfadt Joc - the solid somewhere between that and the T1
the 25.4mm rear is the same diameter as the c6 z51 rear so Id guess its around that stiffness
that said the wall thickness, bends in the arms, and arm length all play into the actual rate so it would be impossible to know without testing or getting strano to provide some data
Not so sure about the numbers on the Hotchkiss bars. Looking at their website, assuming they are actually the same bars for a C5 and C6, they imply that their C5 rear is significantly heavier duty than a stock C5 but virtually the same as a stock C6.
Any idea re the Strano bars?
My real concern with T1 bars is that they are better for cars that can generate a lot of grip with Hoosiers or similar tires.
It was the Hotchkiss that I bought. While I don't have any scientific measurements, based on the size, weight and impact on the car's balance, I would say the comparison chart in the above thread is reasonably accurate.
Personally, if I was to buy another bar (front, rear, or both) I would reach out to Strano. The Hotchkiss bar doesn't fit in the front with stock endlinks and the supplied bushings were nothing special. Strano would point you in the right direction for your set up. I would probably stay away from T1 or T1 sized bars; way too much bar for street or light duty R comps. If you look at the chart a T1 front bar is 3.3x stiffer than your current bar. Without matching spring rate and shocks an overly heavy bar would not be fun on our bumpy cambered tracks.