quote:

Originally posted by Bucky:

quote:

Originally posted by "The Bender":
FWIW the Big Bubbas are a low growth tire......and fast.

I believe he is running those

I tried a mickey 10.5 on a 15" on the dragster and expected my rpm to be much higher than it turned out being. That tire was shorter than my Hoosier, but the rpm didn't show it. I figured that 10.5 must have been growing a good amount? I have never seen anything indicating what growth on their tires is.

That's an old school high energy loss tire Bucky. M/T developed the 33 10.5 in the middle 2000's for ORSCA 10.5 heads up racing. If you look at any of the old ORSCA racing on YouTube, they raced that series on less than perfectly smooth surfaces in the south, small drags trip USA like Phenix City. High energy loss tires cope with bumpy less than perfectly prepped track surfaces same a no prep racing. The modern bubba tires are as a result of the advancements in diamond cut smooth track surfaces and better prep, low growth, low energy loss, low rolling resistance fast tire.

You can distinguish a high energy loss tire by its growth (deformation). The more it grows, the more deformed at all frequencies, the higher the energy loss. Lots of radial tire approach in terms of low rolling resistance in the big bubba tire. It's modern day technology, low growth, low energy losses at all frequencies.

quote:

Originally posted by Mike Rietow:
You can distinguish a high energy loss tire by its growth (deformation). The more it grows, the more deformed at all frequencies, the higher the energy loss. Lots of radial tire approach in terms of low rolling resistance in the big bubba tire. It's modern day technology, low growth, low energy losses at all frequencies.

Where does the energy that is lost go? Are we assuming it is heat loss? Seems like that would be an enormous amount of heat radiated and transferred. Any links to articles on this?

I learned about high energy loss drag slicks in high school auto mechanics, the teacher was a drag racer. Basically it used to be or the technology of the day was, the better the tire drag tire reformed itself for a flat contact patch every revolution, the better the traction, the higher the energy loss. If you ever see a Top Fuel or Fuel Coup tire at speed, that's a high energy loss tire.

Apparently there is new technology in drag tires which allows for less deformation but still allows for traction or low energy loss for drag racing slicks or radial tires. 10% growth at 200 plus MPH says there is new technology because that's an uncharacteristic percentage of growth at 200 plus mph for a drag slick. Usually you see twice that percentage at 200 plus mph.

I know the SS 275 radial tire we're running on our 66 Chevy II DXP Street car at Lights Out in a week and a half grows zero, and makes decent traction. We went teen sixty foot with 4 years ago at 3000 lbs with a 23 sbc. This is how you can easily distinguish a low energy loss tire.

I did a quick search low energy loss tires,this gives an idea, high and low energy loss pertains to all tires.

https://www.sciencelearn.org.n...1-rolling-resistance

I never ran that kind of power, but did try many brands and model converters. For some reason most of them don’t place efficiency or lock up high on the performance list. It was not till I let Coan build mine did I see 2% lockup and still be reliable and stupid consistent.
Good luck on your changes.

I used coan once for a new converter and it was such a nightmare I never went back

quote:

Originally posted by adv ET 266:
I never ran that kind of power, but did try many brands and model converters. For some reason most of them don’t place efficiency or lock up high on the performance list. It was not till I let Coan build mine did I see 2% lockup and still be reliable and stupid consistent.
Good luck on your changes.

Considering the variables tire growth,gearing, converter pressure, 1/8 or 1/4 mile, input shaft + stator tube design, a lot of it is pure luck. That's not to say Coan doesn't have a excellent product, but just fact. Now the closer every car comes to cookie cutter, the easier it gets. Meaning if one builder is building the majority of cars / dragsters, recommending the same tires, gears, stator tube + input shaft, trans line pressures, the easier it gets for the converter builder. An efficient converter that slips near zero for one racer is a slow converter for another racer. How much the converter slips isn't the only determining factor until the car in play ,is out of potential for rpm, gear or percentage of slip.

It's like the 30608 B&M converter back in the day, if you were paying attention you'd probably hear someone at your local track claiming it as miracle.

I should say a lot of it is pure luck over the counter based on a phone call. It's not a matter of what stator do I need when it comes to performance - et's, until all the variables have been discovered.

If you see a guy a tenth quicker than everyone else's same combo, off the trailer. It's either pure luck or all the variables have been discovered beforehand and applied into the converter/gearing according to approach based on principle performance fundamentals. That's the beauty of performance off the trailer, you burn less fuel in figuring it out.

quote:

Originally posted by Mike Rietow:
[QUOTE]Originally posted by adv ET 266:
QUOTE]


It's like the 20608 B&M converter back in the day, if you were paying attention you'd probably hear someone at your local track claiming it as miracle.

Fixed for you, again!

Yeah ya did Top.

Point being, with all the variables, it's pretty amazing how well these torque converter company's nail stall first go around. It's not often as some may think, they don't.