Buschur Racing dyno testing brake rotors?
Jul 10, 2006, 12:55 PM
#16
Warrtalon agreed, the point of the rotors are to improve the stopping power of the car. I didn't buy junk or go to a super lightweight set up (like the Wilwoods that we run from AMS on our black drag car-very good kit but not for road racing) just to gain some drag strip time. The drop in rotational inertia from the lighter rotor should also make the car stop faster as more of the clamp load is used to actually slow the car down and not so much of the energy used to slow down the inertia of the rotor.
The change in unsprung weight will let the suspension work better, the car stop faster and as we have now found out accelerate quicker.
The boost dropped overall in 3rd gear, I'd guess, from me going to WOT a little later than I did on the baseline run. I usually go to WOT when I am dynoing tests like this at 2,000 rpm on the dyno and the dyno starts recording at 3,000 rpm. In this particular case, as it was past time to go home for the day, I may not have stabbed the throttle until closer to 3,000 rpm.
The change in unsprung weight will let the suspension work better, the car stop faster and as we have now found out accelerate quicker.
The boost dropped overall in 3rd gear, I'd guess, from me going to WOT a little later than I did on the baseline run. I usually go to WOT when I am dynoing tests like this at 2,000 rpm on the dyno and the dyno starts recording at 3,000 rpm. In this particular case, as it was past time to go home for the day, I may not have stabbed the throttle until closer to 3,000 rpm.
Jul 10, 2006, 12:58 PM
#17
Ahhhh very cool.
Dave - I've been waiting for some hard evidence like this for a long time. Its very interesting to see the actual WHP gained, or freed I should say. Almost like adding some pullies! You gained HP throughout the entire range it appears... very nice. This mod would allow for better breaking (I would assume) as well as faster acceleration. The car wouldn't even need a retune to make the additional power..!
Dave - I've been waiting for some hard evidence like this for a long time. Its very interesting to see the actual WHP gained, or freed I should say. Almost like adding some pullies! You gained HP throughout the entire range it appears... very nice. This mod would allow for better breaking (I would assume) as well as faster acceleration. The car wouldn't even need a retune to make the additional power..!
Jul 10, 2006, 01:33 PM
#18
I've weighed my Baers on a postal scale when I first got them last year. The scale I was using said my stock front rotors were 23lbs and the Baer fronts were 16lbs. While this is off from what your stockers weighed, the difference in weight is what is important. I weighed them a few times because I could not believe the difference and everytime it was a 7lb difference. I'm a little fuzzy on the exact weights of the rear but I remember it was a 3-3.5lbs weight difference. Both front and rear netted a 21lb reduction in rotational mass. I've read that 1lb of rotational weight = 7lbs of static weight.
Jul 10, 2006, 01:35 PM
#19
I find it hard to believe that the Baers are that light, if they are actually that light then I may very well be changing my rotors again.
21 pounds sounds a lot better than 14.9 but it sounds too good to be true. I don't know where you would find that much additional weight without sacrificing something.....
21 pounds sounds a lot better than 14.9 but it sounds too good to be true. I don't know where you would find that much additional weight without sacrificing something.....
Jul 10, 2006, 01:38 PM
#20
Originally Posted by davidbuschur
I find it hard to believe that the Baers are that light, if they are actually that light then I may very well be changing my rotors again.
21 pounds sounds a lot better than 14.9 but it sounds too good to be true. I don't know where you would find that much additional weight without sacrificing something.....
21 pounds sounds a lot better than 14.9 but it sounds too good to be true. I don't know where you would find that much additional weight without sacrificing something.....
I can see Dave getting some Baers to add to this action now!!
I want to see what they really weigh now too....
Jul 10, 2006, 01:56 PM
#21
Originally Posted by davidbuschur
I find it hard to believe that the Baers are that light, if they are actually that light then I may very well be changing my rotors again.
21 pounds sounds a lot better than 14.9 but it sounds too good to be true. I don't know where you would find that much additional weight without sacrificing something.....
21 pounds sounds a lot better than 14.9 but it sounds too good to be true. I don't know where you would find that much additional weight without sacrificing something.....
They are not full floating. Maybe not having that additional hardware helps. I've had them on the car for over a year and they have been great with no problems what so ever.
Jul 10, 2006, 02:07 PM
#23
Drifto,
I'd actually be curious to see what the Baers weigh if you weigh them again. The 7 pound difference is just nuts. If they end up being that much lighter and you want to sell the spare set of front Baers you have I'd be interested in buying them.
zbomb,
Yes, it would apply to wheels/tires, rotors or any other part on the car that is turned.
I'd actually be curious to see what the Baers weigh if you weigh them again. The 7 pound difference is just nuts. If they end up being that much lighter and you want to sell the spare set of front Baers you have I'd be interested in buying them.
zbomb,
Yes, it would apply to wheels/tires, rotors or any other part on the car that is turned.
Jul 10, 2006, 02:09 PM
#24
Originally Posted by zbomb
would this apply to lighter wheels as well?
Last edited by Drifto; Jul 10, 2006 at 02:11 PM.
Jul 10, 2006, 02:12 PM
#25
This helps illustrate why the MR BBS rims are so valuable. They weigh 17.74lbs each while the stock Enkeis weigh 20.5 (VIII) and 20.17 (IX), respectively. That's a total of 11.04lbs and 9.72lbs of rotational mass saved. This is why I'm being picky on my purchase of 17X9 rims for racing with 275-width tires. I want a LIGHTER rim than my stock BBS's along with significantly lighter brakes for the reasons Dave has illustrated.
Jul 10, 2006, 02:14 PM
#26
Originally Posted by Warrtalon
This helps illustrate why the MR BBS rims are so valuable. They weigh 17.74lbs each while the stock Enkeis weigh 20.5 (VIII) and 20.17 (IX), respectively. That's a total of 11.04lbs and 9.72lbs of rotational mass saved. This is why I'm being picky on my purchase of 17X9 rims for racing with 275-width tires. I want a LIGHTER rim than my stock BBS's along with significantly lighter brakes for the reasons Dave has illustrated.
Jul 10, 2006, 02:21 PM
#28
I have SSR Competitions on my RS, 17x8.5's, I have in my notes that I saved 6.4#'s but I am pretty sure that was total that I saved including putting the BFG KD's on at the time with 255-40's on it. I think the wheel itself is 15.8 pounds each.
I'd be really interested to take some lightweight 15" wheels and Hoosier drag slicks and do the testing again.
I'd be really interested to take some lightweight 15" wheels and Hoosier drag slicks and do the testing again.
Jul 10, 2006, 02:23 PM
#29
Originally Posted by Warrtalon
This helps illustrate why the MR BBS rims are so valuable. They weigh 17.74lbs each while the stock Enkeis weigh 20.5 (VIII) and 20.17 (IX), respectively. That's a total of 11.04lbs and 9.72lbs of rotational mass saved. This is why I'm being picky on my purchase of 17X9 rims for racing with 275-width tires. I want a LIGHTER rim than my stock BBS's along with significantly lighter brakes for the reasons Dave has illustrated.
Jul 10, 2006, 02:23 PM
#30
I just need 17X9s that weigh less than 17lbs. I don't think 275s will fit on an 8.5-width rim too well...at least not well enough to fully utilize the whole contact patch. I'm not even sure 9" is enough to fully utilize 275s, but it's my plan for now.