which caliper do you recommend, i figure that one is superior to the other, one being steel vs aluminum. the steel one weighs considerably more ( few pounds more) at least...... If you were building a winning car today with an unlimited budget (choose steel or aluminum?) the aluminum calipers can cost up to 8 times more that the Sumitomos.
Would you go 50/50, steel in the front and aluminum in the back??
There are pros and cons to both. I will give you the facts, followed by my opinion, and you can decide for yourself.
Iron Calipers are heavier. They are just shy of 4lbs heavier per caliper. THis means you will be carryiing almost 16 lbs more in unsuspended weight. That being said, I dont think that the unsuspended fact is as important as the overall weight. What I mean is the weight disadvantage only becomes a disadvantage if you are currently fighting to find everylast pound to make the minimum weight.
The Iron Calipers do give a little better pedal feel/feedback. Any iron caliper will have less flex than an aluminum caliper in the price catagory. This definately helps with pedal modultion. Some may also argue that the lack of flex in the caliper would result in a quicker responce time. In theory I get it, but the actual measureable difference in reaction time, in my mind is about as equal as wearing stiffer sole shoe. So pedal feel is the determining factor in this arguement.
The biggest debate when it comes to Iron/Aluminum is the infamous dragging issue. The Aluminum Calipers do not deal with excessive heat as well as the Iron Calipers. When the Aluminum Calipers experience excessive heat they tend to "Drag". This is a very unsettling feeling to come into the pits, and the car is hard to push. The racer side of all of us says "This must be costing me time on track". From the testing we have done, the brakes only start to drag once they have had time to "Heat Soak". So on track, when you have air flowing over the calipers, the dragging is less present, if present at all.
When I say excessive heat, I mean some driver are more suseptible to excessive heat due to Braking habits/styles. If you are a heavy braker, or use a lot of trail braking, or use a lot of front brake bias, this can cause excessive heat, which will create brake drag.
My personal opinion is that I like the weight savings of the aluminum caliper. I feel that even if you were to experience brake drag, if you are over the minimum weight limit, the weight savings out weighs the drag.
I have also seen people use Iron on the front, and Aluminum on the rear. This may be a good option. The fronts generate more heat, so using the irons up front to help eliminate drag due to the excessive heat, and the aluminums on the rear to save about 8 lbs, is definately a good give and take scenario.
I would treat every driver different. If I could use all aluminum calipers, I would. If I experienced brake drag, I may opt for the Irons up front, as peace of mind.
At the end of the day, I dont think brake drag, or weight is what is going to win or lose a championship, but Peace of mind is always a factor of a championship effort.
As for the price difference, the Aluminums retail New for $1200. Irons New are $750. Just wanted to clearify that the cost is not 8 Times more.
thanks for the great explanation. its easier to understand why we have two types of calipers, it serves those who are overweight etc...
4 pounds is a lot per corner, could almost run dual aluminum calipers per corner in the front and be lighter than the one iron (has anybody that you know ever tried two calipers per upright??) our uprights have provisions for 2 calipers, that would be something if it worked and passed tech, cuz then you would be selling a lot of aluminum calipers, and since there are 2 the heat soak might be less, the drag might be twice as bad,, just kidding about the 2 calipers per corner :P
I am converting a FM into a CSR (OK no jokes, please!)...so I have rotors, steel calipers, 4 rebuilt Koni singles, springs, a spare 13a (not sealed) with 48 DCOE, all the suspension arms, nose frame, shear plates, a whole TON of stuff!!
Everything guaranteed to be "in new" condition. I usually sell "as new" for 50% of the cost of new, but I will sell the calipers of $150 ea, the rest of the stuff at 30% of new.
I am NOT selling the uprights as I am designing pushrod using these.
I am NOT selling the wheels as I will be using them
I am NOT selling rod ends; they are all used and I cannot guarantee them. Always better to put the car together with new rod ends...that is CHEAP insurance!
Anything you are interested in, just pm me, and I can take pictures and send to you. As well, if you get something and it is not what you thought it was, send'er back and I'll refund your money minus the shipping.
I really need to empty the shop of all this stuff, and the $$ will help me build the new car.
Season is beginning guys!! Here is a chance to get your spares at a true discount!
Now for the solicitous, self serving promotion. As I say, I am looking to build a conversion car from FM to CSR. The key word will be competitive car....so that means it will not be cheap. But with an Atlantic conversion costing in the $60 to $70's, this kit will probably run in the thirties, all in (with a competitive PP 13B} The objective is to use the main FM chassis, convert the car to run a more efficient push-rod suspension all round, and a new body and undertrays (full tunnel).
CFD work has been done and the initial numbers look at overall downforce in the two thousand pound region. In adddition, the CRB has reduced the restriction on 12a and 13b motors in CSR, so the horsepower of a fully done (and legal!!) engine should be around 280....Projected weight is 1200 pounds. So you have a car below the weight limit, 280 HP and 2000 pounds of downforce.
Now, if you have seen the really pretty body that Moses has sold, this car will be similar as we are "adapting" this bodywork. The big changes are at the front of the car (full under-wing) and the underside (full tunnels) and overall (lowered body height, full width wings). The car will be available with high and low downforce components.
Three cars are in process now, and we will be testing throughout 2011.
I really do not expect any customer cars to begin conversion until mid season at the earliest. However, interested parties are invited to pm me for more information.
--------------End of self-aggrandizing and sales promotion---------
But SERIOUSLY, we are building the cars, and are working with Moses to trial a migration path for open wheelers who love their Mazdas and who want to go a little faster.
Let me know about the spares, guys!
Owner - Browns Lane and Racelaminates.com