May 19, 2018, 07:30 AM
John DiBartolomeoSprags
An old story but still relevant today.
https://dragracingedge.com/fea...rag-or-not-to-sprag/May 19, 2018, 11:22 AM
markemarkInteresting article that still makes me undecided and unsure of what to use in my convertor replacement that I would like to make this year.
The 1991 ATI 8” convertor in my car has been freshened 3 times, stall changed one time and cut apart the last time to replace a cracked snout that drives the pump.
So I’m now undecided about if I should continue to use a sprag or if using a mechanical diode could be better.
ATI says they can duplicate what I now have as they have the information from my present convertor build and re-stall. No free re-stall.
FTI says they use mechanical diode, does not create any more heat than a sprag, offer a 1 yr warranty and free re-stall.
ATI and FTI are both 1000 + miles away.
ATD is 10 miles down the road from me. I have not called to ask about their convertors, but they list using Borg Warner sprags in their builds.
May 19, 2018, 04:12 PM
Mike BeckTo sprag or not too sprag, that is the question.....
After having issues twice with the sprag in my converter I had one built without a sprag, so far so good, as was to be expected, but also .1 and 1mph slower, which I was told was also to be expected. But I am fine with that, I am not a Class Racer.
I did have two converters made previously, one of each type, from two different companies. They were both too tight for the combination off the bottle, but on the bottle they were perfect. They were practically identical in performance to each other. They were within 100 rpm of each other off the line, and on the fall back at the shift. Same trap rpm.
So I was a little surprised at the performance difference between the two types now, but that's fine. I will get the sprag converter converted (pun intended) to a mechanical diode and see what it does, and have it as a spare.
May 19, 2018, 07:48 PM
racerdude2054regardless of what anyone says, if a convertor has a sprag in it, the sprag can break
May 19, 2018, 08:07 PM
EmanIf you race a car it can break.
Using a converter bracket racing what happens with or without a sprag if you're driving the stripe playing the throttle? What happens during that sudden decel/accel possibly a few times pretty quickly?
May 20, 2018, 12:05 AM
SC4400A mechanical diode is completely different than a roller sprag. I have one that is 23 years old. I have a friend who runs low 6.30's TS with a MD. I'm sure someone has broken one, but if you take one apart and look at how it's built, you'll become a believer. I'd like to see a picture of a broken one. And how you broke it.
RIP
May 20, 2018, 02:51 PM
nomadquote:
Originally posted by markemark:
Interesting article that still makes me undecided and unsure of what to use in my convertor replacement that I would like to make this year.
The 1991 ATI 8” convertor in my car has been freshened 3 times, stall changed one time and cut apart the last time to replace a cracked snout that drives the pump.
So I’m now undecided about if I should continue to use a sprag or if using a mechanical diode could be better.
ATI says they can duplicate what I now have as they have the information from my present convertor build and re-stall. No free re-stall.
FTI says they use mechanical diode, does not create any more heat than a sprag, offer a 1 yr warranty and free re-stall.
ATI and FTI are both 1000 + miles away.
ATD is 10 miles down the road from me. I have not called to ask about their convertors, but they list using Borg Warner sprags in their builds.
I like ATI and FTI. I use FTI because they are good and a couple hours down the road. I've had home delivery from them.
I would go see the guy close to you. Ask for the tour. If you like what you see, give your business to him. We break convertors and what's better going 10 miles away or shipping 1000K miles. Plus, he's a local business, pays local taxes, and employs some of your "neighbors".