What's a good driveshaft ratio at the 1/8th stripe for consistency? Luke says more than 10% is not good. I have a brand new FTI that reads 19% according to Racepak. The worn out Trans Specialties was only 14.

So if it is new you can get it restalled IF that is the "problem".
Not a lot be "worn out" in converters except bushings or torrintons.
Is the car faster or slower?
Is it the same?
Is it not repeating because of the converter, or is there something else in play?
Was the slip of the last converter with everything the same? Same fluid,tires, carb,etc.

He means in a quarter mile. I don't know of any normal bracket car, that runs well, anywhere near 10% in an 1/8th mile.

18 - 19% is pretty common. Mine is near 19% when I run 4.40s at 155 mph.

This message has been edited. Last edited by: Don Higgins Crew Chief Pro Software,

My bracket dragster with a FTI converter was about 22-24% slip in the 1/8th

My blown TD about that too in the 1/8th and anywhere from 7-4% in the 1/4 depending on conditions but I also have 3.70 gears so that helps keep it loose

Mine is 19% in the 1/8 and very consistent. I prefer my converter to be on the loose side for consistency and performance. Would like it tighter than that but I think it kills it too much. I think if your car is 10% in the 1/8 it would probably be a dog.

quote:

Originally posted by Curly1:
I think if your car is 10% in the 1/8 it would probably be a dog.

There's nothing probably about it, there's rpm's.

If you're crossing in high gear at 7000 rpm with the converter slipping 0%, you're going way quicker and faster than if you're crossing 7000 rpm in high gear with the converter slipping 19%. Same car, same 2 speed transmission.

In my experience, loose tends to be more consistent particularly with weather changes. Those numbers are not objectionable to me.

Any amount of converter efficiency at the stripe 1/8 or 1/4, is more consistent. It's not a subjective matter.

You want the driveshaft as close to 1 to 1 with the engine as you can get it, at the stripe 1/8 or 1/4.

For Super Pro bracket racing, it'll do everything better less slip at stripe. Slow down more precise / predictable ripping throttle.

Relatively speaking you want the converter inefficient early in the run and efficient late, for consistency.

Whoever Luke is , sounds like he's a tuner.

quote:

Originally posted by Mike Rietow:


Whoever Luke is , sounds like he's a tuner.

You're a special kind of stupid.

quote:

Originally posted by Roger McGinnis:

quote:

Originally posted by Mike Rietow:


Whoever Luke is , sounds like he's a tuner.

You're a special kind of stupid.

Why so triggered Roger? Are you confused?

These are basic automobile performance fundamentals.

Common sense mostly.

"Relatively speaking you want the converter inefficient early in the run and efficient late, for consistency"

Thank you all for the responses. My first thought was that I heard it wrong so I went back and listened again. Then I figured he must mean 1/4 mile but this is a video on the TIBR that's been up for a long time so I questioned my numbers because I've never compared mine to any others, until now. Thank you again for responding.

Mike, Luke Bogacki is a very accomplished, successful professional bracket/index racer that owns and operates This Is Bracket Racing. TIBR schools racers on all aspects of bracket racing at a cost of $99 per month but individual areas of instruction can be purchased too. I bought the tech bundle a month ago and that's where I watched the video on converters.

quote:

Originally posted by Ron Gusack:
Thank you all for the responses. My first thought was that I heard it wrong so I went back and listened again. Then I figured he must mean 1/4 mile but this is a video on the TIBR that's been up for a long time so I questioned my numbers because I've never compared mine to any others, until now. Thank you again for responding.

Mike, Luke Bogacki is a very accomplished, successful professional bracket/index racer that owns and operates This Is Bracket Racing. TIBR schools racers on all aspects of bracket racing at a cost of $99 per month but individual areas of instruction can be purchased too. I bought the tech bundle a month ago and that's where I watched the video on converters.

Ideally for any distance, relatively speaking you want the converter inefficient early in the run and efficient late.

I figured that's who you were speaking of but wasn't sure. The emphasis of the point I was making, is it sounds like he gets it.

There's parts available over the counter, to accomplish an efficient converter 1/8 mile. Luke is a tuner, if he has traveled this road.

I suspect he has.

Known dimensions in automobile performance are subjective, relative the user.

Although automobile performance fundamentals itself, are objective.

This message has been edited. Last edited by: Mike Rietow,

quote:

Originally posted by Mike Rietow:

quote:

Originally posted by Curly1:
I think if your car is 10% in the 1/8 it would probably be a dog.

There's nothing probably about it, there's rpm's.

If you're crossing in high gear at 7000 rpm with the converter slipping 0%, you're going way quicker and faster than if you're crossing 7000 rpm in high gear with the converter slipping 19%. Same car, same 2 speed transmission.

I will play. You tell me how you get a stall of say 6400 to get it in powerband and out of the hole and have 0% slip in the 1/8 mile?

quote:

Originally posted by Curly1:

quote:

Originally posted by Mike Rietow:

quote:

Originally posted by Curly1:
I think if your car is 10% in the 1/8 it would probably be a dog.

There's nothing probably about it, there's rpm's.

If you're crossing in high gear at 7000 rpm with the converter slipping 0%, you're going way quicker and faster than if you're crossing 7000 rpm in high gear with the converter slipping 19%. Same car, same 2 speed transmission.

I will play. You tell me how you get a stall of say 6400 to get it in powerband and out of the hole and have 0% slip in the 1/8 mile?

The performance fundamental for converter slip is common sense.

If the driveshaft is turning 7000 rpm's 1 to 1 with the crankshaft at the stripe, any given car in play is going way faster, than if the same driveshaft is turning 5600 rpm's at the stripe.

Common sense right?

The difference in the two scenario's is common sense as well, Power.

And a converter tight enough to get 0% in the 1/8 mile is going to be too tight to get good 60 foot and ET. Simple. Right? Wow.

quote:

Originally posted by Curly1:

quote:

Originally posted by Mike Rietow:

quote:

Originally posted by Curly1:
I think if your car is 10% in the 1/8 it would probably be a dog.

There's nothing probably about it, there's rpm's.

If you're crossing in high gear at 7000 rpm with the converter slipping 0%, you're going way quicker and faster than if you're crossing 7000 rpm in high gear with the converter slipping 19%. Same car, same 2 speed transmission.

I will play. You tell me how you get a stall of say 6400 to get it in powerband and out of the hole and have 0% slip in the 1/8 mile?

Recently I have learned a there is a lot about converters and about how to achieve stall and how to get the car accelerating. You can easily have a car that will stall two different converters the exact same RPM and will E.T. .05 different in the 1/8. There are so many variables to play with in a converter, that is why if you are working with a company they try to ask all of the basic questions about the setup, that way they can get you where you want to be and it should be close. The less info you give the more they have to guess. That's why I laugh sometimes when I see guys who buy converter from company "A" and its slower than they hoped so they go to company "B" to get one and its a little quicker, but had they gone back to company "A" with their results from the converter they got the first time, it can really tell the builder a lot more about what the combo may want.

quote:

Originally posted by Curly1:
And a converter tight enough to get 0% in the 1/8 mile is going to be too tight to get good 60 foot and ET. Simple. Right? Wow.

Wrong,

32" tire with enough power crosses at 8610 rpm's (before tire growth) 200 mph converter slipping 0% 4.10 gear.

You're clueless of basic performance fundamentals.

This message has been edited. Last edited by: Mike Rietow,

This is my 9" Cortina core converter pulling 3050 lbs with a bracket racing caliber sbc (7500rpm's) on a 275 dot radial.

Does the 60ft look slow? Converter slipping 6%

Even assuming your numbers are right 6% is 1/8 is still a long way from 0%. Sounds to me like a Nitrous or blown motor where you can run a tighter converter. Many blown motors are close to 0% at finish line in 1/4 mile.
I think the OP was asking about a 1/8 mile Bracket motor combo.
Anyway I am done with you and this thread. Have a nice day.

quote:

Originally posted by Curly1:
Even assuming your numbers are right 6% is 1/8 is still a long way from 0%. Sounds to me like a Nitrous or blown motor where you can run a tighter converter.

You started out talking 10%, I used 0% to indicate how wrong fundamentally your claims are.

The 8" opel core Transmission Specialties spragless converter I run in my Nova slips 7% dipping in the 5's N/A sbc at 3250 lbs. 1.27 60ft which is probably the quickest 60ft nationwide, for a car of its kind on a 10 x 28 bias tire n/a sbc.

You're clueless of basic automobile performance fundamentals.