t stop thoughts/debate

[THE LEGEND]

Shut down more with less time
or
Shut down less with more time.

Chip

[Bill Baer]

I would think it's a matter of preference, either will work but the less time on the stop the more MPH you'll carry at the stripe.

[JJ3159]

i like more shut down less time ,i try to find that spot that works for 9.90 and 10.90

[THE LEGEND]

I understand about the MPH thing. I'm looking for effeciency. I know when the blade are shut it affects air flow. If you change the rate or amount of air flow it's got to change the consistentcy/effeciency of the car so:
1) Do you have more air flow for a longer period
or

2) Less air flow for a shorter period

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[sc7667]

When starting out I was told and tried to set up the stop RPM so that you have a 2 to 2.5:1 ratio. even the stop manufacturers recommend this. I have had cars that it is 4000rpm and cars that that is closer to 5,000. I was told by Sherman Adcock once that you never want to go below 4000. I think it is because the convertor makes the car inconsistant.

Roy

[Bill Baer]

Originally Posted by sc7667

When starting out I was told and tried to set up the stop RPM so that you have a 2 to 2.5:1 ratio. even the stop manufacturers recommend this. I have had cars that it is 4000rpm and cars that that is closer to 5,000. I was told by Sherman Adcock once that you never want to go below 4000. I think it is because the convertor makes the car inconsistant.

Roy

I too have heard that and believe it's true.
Previously I tried to go back to near idle so my F.I. barrell valve would close but it wasn't consistent so some time ago I started to take it down to ~4500 and I found that to be much more consistent.
The type of stop you use can make a difference also, if you get too low rpm with a blade type of stop it possible to get a lean stumble when it opens because you won't get an accelerator pump shot. Which of course is not a problem with an in line type stop.

[sst7250]

Count me in the shut down more less time category. But I am on the stop a LONG time in S/ST..

[sc7667]

Originally Posted by Bill Baer

I too have heard that and believe it's true.
Previously I tried to go back to near idle so my F.I. barrell valve would close but it wasn't consistent so some time ago I started to take it down to ~4500 and I found that to be much more consistent.
The type of stop you use can make a difference also, if you get too low rpm with a blade type of stop it possible to get a lean stumble when it opens because you won't get an accelerator pump shot. Which of course is not a problem with an in line type stop.

I used to run F.I. and tried to stop it down to just above idle and it didnt work for me either i set the stop at 43-4500 and it seemed to repeat quit well.

[Barney B]

Originally Posted by sc7667

When starting out I was told and tried to set up the stop RPM so that you have a 2 to 2.5:1 ratio. even the stop manufacturers recommend this. I have had cars that it is 4000rpm and cars that that is closer to 5,000. I was told by Sherman Adcock once that you never want to go below 4000. I think it is because the convertor makes the car inconsistant.

Roy

Told by who?

[TS310C]

Originally Posted by sc7667

When starting out I was told and tried to set up the stop RPM so that you have a 2 to 2.5:1 ratio. even the stop manufacturers recommend this. I have had cars that it is 4000rpm and cars that that is closer to 5,000. I was told by Sherman Adcock once that you never want to go below 4000. I think it is because the convertor makes the car inconsistant.

Roy

I guarantee there are several (myself included) high HP guys that have to have the stop set below 4000 RPM. I would have 5 secs of stop in some situations at that high of an RPM.