Higher 2-step to leave softer??

[Gary Kubisch]

My ATI 9" converter seems a bit on the tight side.
Best results have come w/ the 2-step at 3800 and on the tach replay it on looks to flash to about 4400.
I tried to leavbe twice at 4200 and the car drives out pretty mellow.
I'm thinking I might be able to 60ft harder w/ a lower rpm on the 2-step??
Does this sound right?Seems backwards to me.

Car is 3370 w/ 505 Buick,T-400,4.10's and a 94''circ. slick

It's been 1.28 60ft. in good air but is more like 1.34-ish on average
Not that it's spining,It just seems lazy.

[Jeff Chandler]

Gary, one of those you have to try but I will tell you what I figured out. When Scott owned the car and was running Hot Street we were leaving pretty high, about 6500. Now the converter flashed about 68-6900. We would 60 in the lower 30's and every once in a while a high 20. We dropped the 2 step down to 5500 and the car went a 1.25 first pass and had a 1.23 best. All that changed was the 2 step setting.

[Gary Kubisch]

Thanks Jeff,
That's how I'm thinking,Might just have to play around to make it hook if it does get more aggressive.

[Hutch]

I have seem this many times, usually on 3 spd cars. I generally tell guys to leave at the lowest rpm possible tp keep the motor happy and keep trans temps down but everyone has their own opinion. I like numbers in the 3400-3800 range.

Hutch

[dizope]

I've heard the saying that what is gained in the 60 is doubled on top end (1/4) - is that true?

Jeff, what were your ET improvements in relation to the better 60's?

[Hutch]

I've heard the saying that what is gained in the 60 is doubled on top end (1/4) - is that true

NEVER.

.01 is .01

Hutch

[NOS-Nelson]

NEVER.

.01 is .01

Hutch

I have to respectfully disagree. I can tell you when our car loses a tenth in the 60ft. it loses 2 tenths in the quarter.

[Hutch]

I have to respectfully disagree. I can tell you when our car loses a tenth in the 60ft. it loses 2 tenths in the quarter.


Well then you had 2 problems not one. If you get your car to run like a bracket car and nothing changes other then it spins the tire a little or you staged differently effecting rollout you will only lose what you lose in 60.
I have a shoebox full of time slips that show exactly what I stated before and I either won or lost by .01, .02 etc. which all happened in 60 ft and was carried through every increment all the way down the track.

Hutch

[68Bird]

My old Hughes 9" converter always launched harder with the 2 step off and up on the converter all the way at 6000. That was with the old N/A motor. With this ProCharged motor and a 9.5" PTC converter it likes the 2 step at 5500 with a flash stall at about 6100. Any higher and the 60' falls off. PTC recommended I try 4800-5000 and said it may hit even harder..... have yet to try that to see if the 60' picks up any.

Seems some converters like to be 'shocked' by 500-1000 rpm and some don't.

Craig

[NOS-Nelson]

Well then you had 2 problems not one. If you get your car to run like a bracket car and nothing changes other then it spins the tire a little or you staged differently effecting rollout you will only lose what you lose in 60.
I have a shoebox full of time slips that show exactly what I stated before and I either won or lost by .01, .02 etc. which all happened in 60 ft and was carried through every increment all the way down the track.

Hutch

I need to find our timeslips from last year. We qualified #1 with a 8.19 and a 1.34 60ft. Nearest guy was in the low .30's so I backed the controller down 5% which gave me a 1.36 60 ft. and it ran 8.23. On a N/A car it might be a little different as they usually have a hard time pulling up top. Here's a simple example of a well tuned nitrous run.

5.50 1/8 = 8.46 1/4
5.40 1/8 = 8.30 1/4

.10 in the 1/8th nets a .15 gain in the quarter. I usually say that a .10 in the 60 ft. is 2-3 at the 1/4.

[nos396]

.10 in the 1/8th nets a .15 gain in the quarter. I usually say that a .10 in the 60 ft. is 2-3 at the 1/4.

He speaks the truth, in my experineces this has applied in everything from 9 second street cars cars down to 6 second pro street cars

[NOS-Nelson]

He speaks the truth, in my experineces this has applied in everything from 9 second street cars cars down to 6 second pro street cars

Greg I need to look at our Vegas slips from early this year in the Bu. Due to our gearing and tight converter we are gaining 37 mph out the back. We ran an 8.150 which should be a 5.30 1/8th but I think it was a high 5.30.

[Hutch]

I need to find our timeslips from last year. We qualified #1 with a 8.19 and a 1.34 60ft. Nearest guy was in the low .30's so I backed the controller down 5% which gave me a 1.36 60 ft. and it ran 8.23. On a N/A car it might be a little different as they usually have a hard time pulling up top. Here's a simple example of a well tuned nitrous run.

5.50 1/8 = 8.46 1/4
5.40 1/8 = 8.30 1/4

.10 in the 1/8th nets a .15 gain in the quarter. I usually say that a .10 in the 60 ft. is 2-3 at the 1/4.

Turned the controller 5% ? Are you saying you adjusted HP to change the 60 ft?

[NOS-Nelson]

Turned the controller 5% ? Are you saying you adjusted HP to change the 60 ft?

I just softened the initial hit on the progressive. I had the field covered so I didn't want to get greedy as it warmed up.

[Hutch]

I just softened the initial hit on the progressive. I had the field covered so I didn't want to get greedy as it warmed up.

Then you altered the HP and yes it will appear as though the 60ft losses looked worse or that they multiplied by the end.
What im saying is if the hp/torque stays the same and your car spins slightly in 60 or hooks better in 60 , whatever those gains/losses are will be almost exactly what the difference in the 60 was at the top.

Hutch

[milneratffe]

For 25 years,A tenth down low has been worth 2 up stairs-for us anyway.

[NOS-Nelson]

Then you altered the HP and yes it will appear as though the 60ft losses looked worse or that they multiplied by the end.
What im saying is if the hp/torque stays the same and your car spins slightly in 60 or hooks better in 60 , whatever those gains/losses are will be almost exactly what the difference in the 60 was at the top.

Hutch

Looks like we are thinking about different things. Now I understand your point.:cool:

[HotStreet3134]

Gary, one of those you have to try but I will tell you what I figured out. When Scott owned the car and was running Hot Street we were leaving pretty high, about 6500. Now the converter flashed about 68-6900. We would 60 in the lower 30's and every once in a while a high 20. We dropped the 2 step down to 5500 and the car went a 1.25 first pass and had a 1.23 best. All that changed was the 2 step setting.

Jeff, was that with Scott's setup or your's?

Thanks

[Jeff Chandler]

That was with Scott's.

[HotStreet3134]

Thanks Jeff. I'll be out testing in a week or two and will give the lower 2 step a try. I think I'm kicking a dead horse w/ the 360"/glide. Might be time to try the 3 speed, but I'm willing to give the glide hell. Last time out I was setting the 2 step about 200 rpm lower then the converter stall speed and was goig 1.30 to 1.32 ( stock suspension) and she was a little down on power. Hopefully with the right amount of HP now, we'll see some 1.2ish 60' times (and hopefully some 8 sec. et's).