best shocks for b-stock
#51
Hey guys,
I drilled an extra hole in both our stock and Mazdaspeed bars. 15 mins of labor and now they're adjustable. There's plenty of room on the flat spot. Not sure if our RB bar has room, I think it might. Just a thought. I'm gonna run calcs on them one of these days, and I'll post the numbers. I'm guessing between the three bars and the extra holes we'll have small enough steps to find the right setup.
Randy Noll
I drilled an extra hole in both our stock and Mazdaspeed bars. 15 mins of labor and now they're adjustable. There's plenty of room on the flat spot. Not sure if our RB bar has room, I think it might. Just a thought. I'm gonna run calcs on them one of these days, and I'll post the numbers. I'm guessing between the three bars and the extra holes we'll have small enough steps to find the right setup.
Randy Noll
#52
Originally Posted by Hassan
We have a RB front bar in our car. I have run ESP and SM cars before this. I have won a trophy at nationals in ESP and won the houston tour last year in SM. I think the bigger front bar works great on this car. It helps a lot through transitions and slaloms. The sweepers it does push but that can be dialed out with setup and a little different driving style. I only wish the car had a bit more torque. We are running an autox alignment, a front bar and 265 v700s on stock wheels.
#53
What is the best way to tune the car to have more oversteer with air pressures? Assuming the fronts are set at optium pressure, does it make sense to go higher with the rears, or maybe lower? I would think higher in the rear would make the car rotate easier as the contact patch is smaller, but it would also decrease traction out of the corners. Likewise, lower in the rear should let the tire deform and give up grip before the front. Any tips? I'd much rather control oversteer with the throttle than control understeer by reducing entry speed.
#54
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Either adding or reducing pressures relative to the optimal setting will decrease traction. I prefer adding pressure; reducing pressure can make that end of the car feel mushy.
Jason (ULLLOSE) and Ron and I were all running artificially high rear pressures at Atwater in order to loosen up our cars. But the preferred approach is always to fix the problem end of the car rather than reducing the non-problem end's grip.
Jason (ULLLOSE) and Ron and I were all running artificially high rear pressures at Atwater in order to loosen up our cars. But the preferred approach is always to fix the problem end of the car rather than reducing the non-problem end's grip.
#57
Using the formula on p.150 of Fred Puhn's book "How to Make Your Car Handle" and some rough measurements with my handy Stanley tape measure, I got the following:
Stock 1-1/16": 100%
Stock hole 2: 122%
Mazdaspeed 1-5/32": 140%
Mazdaspeed hole 2: 171%
Racing Beat 1-9/32": 211%
I only measured the stock bar and assumed the dimensions were the same for the others. The thicknesses are also from memory, so someone please correct me if I'm wrong. On a bar with longer arms, another hole might not have as much impact. But I measured center of bar to center of hole as 7-3/8". That's very short.
Even if I'm off (my 211% vs 231% for the RB bar stated above--which could also be in the different bushing material), it's not gonna change the relative values much. Also remember, if you drill an extra set of holes the bar is now 3-way adjustable--stiff, soft, and staggered. It helps to have adjustable endlinks for the last one.
Randy Noll
Stock 1-1/16": 100%
Stock hole 2: 122%
Mazdaspeed 1-5/32": 140%
Mazdaspeed hole 2: 171%
Racing Beat 1-9/32": 211%
I only measured the stock bar and assumed the dimensions were the same for the others. The thicknesses are also from memory, so someone please correct me if I'm wrong. On a bar with longer arms, another hole might not have as much impact. But I measured center of bar to center of hole as 7-3/8". That's very short.
Even if I'm off (my 211% vs 231% for the RB bar stated above--which could also be in the different bushing material), it's not gonna change the relative values much. Also remember, if you drill an extra set of holes the bar is now 3-way adjustable--stiff, soft, and staggered. It helps to have adjustable endlinks for the last one.
Randy Noll
#58
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well I was going by memory myself, these were quadruple checked, there may be some slight variance due to rounding off decimals, this is the info I have:
stock bar is 1.05" OD x 0.134" wall/0.79" ID (26.7mm x 3.4mm/20.2mm)
assuming same material coefficients and same geometry/dimensions
Mazdaspeed bar is 1.07"OD x 0.157" wall/0.76" ID (27.2mm x 4.0mm/19.2mm) + 18.2%
Racing Beat bar is 1.25" x 0.188" wall/0.88" ID (31.8mm x 4.8mm/22.2mm) + 123%
what is the new hole location measurement, I'm coming up with quite a long distance to get that percentage change
stock bar is 1.05" OD x 0.134" wall/0.79" ID (26.7mm x 3.4mm/20.2mm)
assuming same material coefficients and same geometry/dimensions
Mazdaspeed bar is 1.07"OD x 0.157" wall/0.76" ID (27.2mm x 4.0mm/19.2mm) + 18.2%
Racing Beat bar is 1.25" x 0.188" wall/0.88" ID (31.8mm x 4.8mm/22.2mm) + 123%
what is the new hole location measurement, I'm coming up with quite a long distance to get that percentage change
Last edited by TeamRX8; 10-18-2005 at 04:04 PM.
#59
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well I was going by memory myself, these were quadruple checked, there may be some slight variance due to rounding off decimals, this is the info I have:
stock bar is 1.05" OD x 0.134" wall/0.79" ID (26.7mm x 3.4mm/20.2mm)
assuming same material coefficients and same geometry/dimensions
Mazdaspeed bar is 1.07"OD x 0.157" wall/0.76" ID (27.2mm x 4.0mm/19.2mm) + 18.2%
Racing Beat bar is 1.25" x 0.188" wall/0.88" ID (31.8mm x 4.8mm/22.2mm) + 223%
what is the new hole location measurement, I'm coming up with quite a long distance to get that percentage change
stock bar is 1.05" OD x 0.134" wall/0.79" ID (26.7mm x 3.4mm/20.2mm)
assuming same material coefficients and same geometry/dimensions
Mazdaspeed bar is 1.07"OD x 0.157" wall/0.76" ID (27.2mm x 4.0mm/19.2mm) + 18.2%
Racing Beat bar is 1.25" x 0.188" wall/0.88" ID (31.8mm x 4.8mm/22.2mm) + 223%
what is the new hole location measurement, I'm coming up with quite a long distance to get that percentage change
#60
Originally Posted by Hassan
The biggest change I had to make in my driving style (as of now I dont have many events in the car) was not to trail brake.
One thing I wanted to ask was tire pressures? What are you guys running?
One thing I wanted to ask was tire pressures? What are you guys running?
We're running different tires than you, so pressure comparisons would be useless.
#61
Originally Posted by TeamRX8
well I was going by memory myself, these were quadruple checked, there may be some slight variance due to rounding off decimals, this is the info I have:
stock bar is 1.05" OD x 0.134" wall/0.79" ID (26.7mm x 3.4mm/20.2mm)
assuming same material coefficients and same geometry/dimensions
Mazdaspeed bar is 1.07"OD x 0.157" wall/0.76" ID (27.2mm x 4.0mm/19.2mm) + 18.2%
Racing Beat bar is 1.25" x 0.188" wall/0.88" ID (31.8mm x 4.8mm/22.2mm) + 223%
what is the new hole location measurement, I'm coming up with quite a long distance to get that percentage change
stock bar is 1.05" OD x 0.134" wall/0.79" ID (26.7mm x 3.4mm/20.2mm)
assuming same material coefficients and same geometry/dimensions
Mazdaspeed bar is 1.07"OD x 0.157" wall/0.76" ID (27.2mm x 4.0mm/19.2mm) + 18.2%
Racing Beat bar is 1.25" x 0.188" wall/0.88" ID (31.8mm x 4.8mm/22.2mm) + 223%
what is the new hole location measurement, I'm coming up with quite a long distance to get that percentage change
#62
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Originally Posted by rnoll98
I didn't take into account the different wall thicknesses. Just went by OD. So that's definitely a variable I'm missing. My stock hole is 7-3/8" from bar pivot center. The new hole is 6-3/4", a 5/8" difference or so. Like I said, they're all kinda rough measurements. I also measured the true arm length (including curves) to be 9-5/8" and 9" respectively. Looks like my formula is for a solid bar (these guys are heavy enough to be). Do you have a formula for a hollow bar?
same formula just calculate it for both the OD and ID (ID = OD - 2xwall), then subtract the ID number from the OD number
you have to use the straightline dimension, 7.375 is correct, that is the perpendicular torque arm length, the factory type bend will add a small amount of flexure, these calcs are simply rough estimates, you'd literally have to do finite element analysis to get accurate representations and even then there are variables that are hard to account for
the difference in hole position is strictly a proportional ratio, I come up with a 9.3% change (7.375/6.75) or approx. half that if you stagger
which adjustable endlinks are you using?
Last edited by TeamRX8; 05-05-2005 at 12:18 PM.
#63
Originally Posted by TeamRX8
the difference in hole position is strictly a proportional ratio, I come up with a 9.3% change (7.375/6.75) or approx. half that if you stagger
which adjustable endlinks are you using?
which adjustable endlinks are you using?
Don't have adjustable endlinks yet. I'll probably end up building some custom ones like I did for my SM2 car.
Randy
#67
Originally Posted by clyde
I didn't measure before taking the car to Koni, but they told me there was an 11mm drop. At my last local event I was gridded next to a stock shocked car (with street tires too) and the difference was striking.
Car 1 - base, sport, nav, prototype Konis
Car 2 - base, hitch from hitch-web
Car 3 - base, sport
Car 4 - GT plus ???
Front:
Car 1 9/16" lower than Car 4
Car 1 7/16" lower than Cars 2 & 3
Rear:
Car 1 9/16" lower than Cars 3 & 4
Car 1 5/16" lower than Car 2
#68
Originally Posted by TeamRX8
what formula are you using?
K=stiffness
D=diameter
A=effective arm length (center of bar to center of hole)
C=true arm length
B=length of center of bar
K=(500,000 x D^4)/((0.4244 x A^2) x B + (0.2264 x C^3))
#69
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Originally Posted by rnoll98
Just found an error in my numbers, I'll recalc today. I left out B. Here's the formula from the book.
K=stiffness
D=diameter
A=effective arm length (center of bar to center of hole)
C=true arm length
B=length of center of bar
K=(500,000 x D^4)/((0.4244 x A^2) x B + (0.2264 x C^3))
K=stiffness
D=diameter
A=effective arm length (center of bar to center of hole)
C=true arm length
B=length of center of bar
K=(500,000 x D^4)/((0.4244 x A^2) x B + (0.2264 x C^3))
yes, but the only thing you're changing when you move from one hole position to the other is the arm length, so the simple ratio I provided you earlier is good enough for government work.
You only use that formula if you are attempting to theoretically compare bars of alternate configurations
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